---
title: "R021: Cospas-Sarsat Meosar System Demonstration And Evaluation Phase I Report C"
description: "Official Cospas-Sarsat R-series document R021"
sidebar:
  badge:
    text: "R"
    variant: "note"
# Extended Cospas-Sarsat metadata
documentId: "R021"
series: "R"
seriesName: "Reports"
documentType: "report"
isLatest: true
issue: 2
revision: 1
documentDate: "December 2015"
originalTitle: "Cospas-Sarsat Meosar System"
---

> **📋 Document Information**
>
> **Series:** R-Series (Reports)
> **Version:** Issue 2 - Revision 1
> **Date:** December 2015
> **Source:** [Cospas-Sarsat Official Documents](https://www.cospas-sarsat.int/en/documents-pro/system-documents)

---

COSPAS-SARSAT MEOSAR SYSTEM
DEMONSTRATION AND EVALUATION
PHASE I REPORT
C/S R.021
Issue 1


COSPAS-SARSAT MEOSAR SYSTEM
DEMONSTRATION AND EVALUATION
PHASE I REPORT
HISTORY
Issue
Revision
Date
Comments


Approved by the Cospas-Sarsat Council (CSC-55)


TABLE OF CONTENTS
Page
History..................................................................................................................................................... i
Table of Contents ................................................................................................................................... ii
List of Figures ....................................................................................................................................... iv
List of Tables ........................................................................................................................................ iv
Document Summary .............................................................................................................................. v
1.
BACKGROUND ................................................................................................................1-6
1.1
MEOSAR System Description ...................................................................................1-6
1.2
The Cospas-Sarsat MEOSAR Demonstration and Evaluation Plan ...........................1-6
1.3
The Phase I of the Cospas-Sarsat MEOSAR D&E ....................................................1-7
1.3.1
Objective of the D&E Phase I ........................................................................1-7
1.3.2
Report of the D&E Phase I ............................................................................1-7
2.
CONDUCT OF PHASE I AND MEOSAR SYSTEM CONFIGURATION .................2-1
2.1
Tests Conducted During the Phase I ..........................................................................2-1
2.2
Participants in the D&E Phase I .................................................................................2-3
2.3
Configuration of the D&E Phase I .............................................................................2-5
2.3.1
Experimental Space Segment ........................................................................2-5
2.3.2
Experimental Ground Segment ......................................................................2-5
2.3.3
Beacon Simulators and Test Beacons ............................................................2-6
2.4
Test Coordination .......................................................................................................2-7
2.5
Operational Issues Encountered during the Phase I Testing ......................................2-7
2.6
Data Collection ...........................................................................................................2-8
3.
RESULTS OF THE TECHNICAL TESTS AND DISCUSSION ..................................3-1
3.1
Test T-1 (Processing Threshold and System Margin) ................................................3-1
3.1.1
Analysis .........................................................................................................3-1
3.1.2
Interpretation ..................................................................................................3-1
3.2
Test T-2 (Impact of Interference) ...............................................................................3-4
3.2.1
Analysis .........................................................................................................3-4
3.2.2
Interpretation ..................................................................................................3-4
3.3
Test T-3 (Valid/Complete Message Acquisition).....................................................3-10
3.3.1
Analysis .......................................................................................................3-10
3.3.2
Interpretation ................................................................................................3-10


3.4
Test T-4 (Independent 2D Location Capability) ......................................................3-14
3.4.1
Analysis .......................................................................................................3-14
3.4.2
Interpretation ................................................................................................3-14
3.5
Test T-5 (Independent 2D Location Capability for Operational Beacons) ..............3-20
3.5.1
Analysis .......................................................................................................3-20
3.5.2
Interpretation ................................................................................................3-21
3.6
Test T-6 (MEOSAR System Capacity) ....................................................................3-29
3.6.1
Analysis .......................................................................................................3-29
3.6.2
Interpretation ................................................................................................3-30
3.7
Test T-7 (Networked MEOLUT Advantage) ...........................................................3-33
3.8
Test T-8 (Combined MEO/GEO Operation Performance (Optional)) .....................3-33
4.
CONCLUSIONS AND RECOMMENDATIONS ...........................................................4-1
4.1
Conclusion ..................................................................................................................4-1
4.1.1
Test T-1 (Processing Threshold and System Margin) ...................................4-1
4.1.2
Test T-2 (Impact of Interference) ..................................................................4-1
4.1.3
Test T-3 (MEOLUT Valid/Complete Message Acquisition) ........................4-1
4.1.4
Test T-4 (Independent Location Capability)..................................................4-2
4.1.5
Test T-5 (Independent 2D Location Capability for Operational Beacons) ....4-3
4.1.6
Test T-6 (MEOSAR System Capacity) .........................................................4-5
4.1.7
Test T-7 (Networked MEOLUT Advantage) ................................................4-5
4.1.8
Test T-8 (Combined MEO/GEO Operation Performance (Optional)) ..........4-5
4.2
Recommendations for the Conduct of Subsequent D&E Phases ...............................4-5
4.2.1
Test T-1 (Processing Threshold and System Margin) ...................................4-5
4.2.2
Test T-2 (Impact of Interference) ..................................................................4-6
4.2.3
Test T-3 (MEOLUT Valid/Complete Message Acquisition) ........................4-6
4.2.4
Test T-4 (Independent Location Capability)..................................................4-6
4.2.5
Test T-5 (Independent 2D Location Capability for Operational Beacons) ....4-6
4.2.6
Test T-6 (MEOSAR System Capacity) .........................................................4-6
4.2.7
Test T-7 (Networked MEOLUT Advantage) ................................................4-6
4.2.8
Test T-8 (Combined MEO/GEO Operation Performance (Optional)) ..........4-7
4.3
Recommendations for the Implementation of the MEOSAR System ........................4-7
LIST OF ANNEXES
ANNEX A
DETAILED LOG OF PHASE I TESTS


LIST OF FIGURES
Figure 1: The MEOSAR System Concept ..........................................................................................1-6
Figure 2: Phase I Test Planning (as Run) ............................................................................................2-3
Figure 3: MEOLUTs Involved in Phase I Testing with 3,000 km Radius Circles .............................2-6
Figure 4: Beacon Simulators Used in the MEOSAR D&E Phase I ....................................................2-7
Figure 5: Spectrum Graphic Sample of T-1 Run 2 .............................................................................3-5
Figure 6: Test T-4 Activations in Red, Some Other Transmission Overlapping Boxed in Green .....3-6
Figure 7: Interference for Test T-5 as Seen by Galileo .......................................................................3-7
Figure 8: Average Throughput for Each Antenna for Test T-5 Observed by the Ottawa MEOLUT .3-8
Figure 9: Test T-6 Beacon Bursts and Overlapping Interference Seen by DASS Satellites. ..............3-9
Figure 10: Location of the 33 Operational Beacons Deployed for Test T-5 ....................................3-21
LIST OF TABLES
Table 1: List of Technical Tests, Test Coordinators and Test Reports ...............................................2-2
Table 2: Participation in MEOSAR D&E Phase I Tests .....................................................................2-4
Table 3: List of Experimental MEOSAR Satellites Used During the MEOSAR D&E Phase I .........2-5
Table 4: MEOLUTs Participating in MEOSAR D&E Phase I Tests..................................................2-6


DOCUMENT SUMMARY
This document provides the report of Phase I of the Cospas-Sarsat MEOSAR Demonstration and
Evaluation (D&E), tests which were conducted from February 2013 to March 2014.
Section 1 provides background on the MEOSAR system and reference material.
Section 2 reviews the planning and conduct of the tests, noting the list of participants, MEOSAR space
and ground assets configuration used during the tests and information of interest on the coordination
of the tests.
Section 3 details, for each D&E test the key results and interpretations as provided by each test
participant that contributed to this Report (Canada, France, Russia, Turkey and USA). The underlying
sub-sections were provided under the responsibility of these administrations and, therefore, were not
reviewed nor commonly agreed by the Correspondence Working Group on the Phase I Report.
Section 4 provides, for each test, the conclusions and recommendations agreed by the Correspondence
Working Group on the Phase I Report, as well as general recommendation regarding the
implementation of the MEOSAR system.

1-6

1.
BACKGROUND
1.1
MEOSAR System Description
Figure 1 provides a graphical summary of the MEOSAR concept. This picture shows the relay of
beacon signals, via multiple satellites, to the MEOLUT. Beacon data is processed by the MEOLUT
that derive the beacon locations, and passed onto the MCC, which in turn notifies the RCC.
Figure 1: The MEOSAR System Concept
1.2
The Cospas-Sarsat MEOSAR Demonstration and Evaluation Plan
The Cospas-Sarsat Council has directed that a demonstration and evaluation (D&E) be performed to
confirm the expected capabilities and benefits of a satellite system in medium-altitude Earth orbit
(MEO) that uses onboard repeater instruments to relay distress alert signals emanating from 406 MHz
distress radiobeacons. The CSC further directed that the D&E should establish the technical and
operational performance characteristics of the MEOSAR system.
The framework for the D&E of the MEOSAR system is provided in document C/S R.018 “Cospas-
Sarsat Demonstration and Evaluation Plan for the 406 MHz MEOSAR System”. In particular,
documents provide guidelines for:

1-7


conducting the D&E of the MEOSAR system in a standard manner among the participants,

collecting a set of results from individual participants, using compatible formats, that can be
consolidated into a final report for review by Cospas-Sarsat participants and other interested
parties,

analysing and translating the results into a set of recommendations for a decision by the
Cospas-Sarsat Council to enter the Initial Operational Capability Phase.
Additional resources regarding the MEOSAR system (e.g, space segment information) are available in
document C/S R.012 “Cospas-Sarsat 406 MHz MEOSAR Implementation Plan”.
CSC-49 agreed to divide the MEOSAR D&E Phase into three phases:

Phase I, during which the participants perform only technical tests,

Phase II, during which the participants perform technical and operational tests,

Phase III, during which the participants replicate the tests of the Phases I and II, when satellites
with L-band downlinks are widely available.
1.3
The Phase I of the Cospas-Sarsat MEOSAR D&E
1.3.1
Objective of the D&E Phase I
In MEOSAR D&E Phase I, participants performed only technical tests (see the detailed definition in
document C/S R.018) to characterise the technical performance of the MEOSAR system. Due to the
limited space segment available, some tests had to be coordinated and the processing be tuned
accordingly, in particular for location accuracy tests.
1.3.2
Report of the D&E Phase I
The D&E Phase I report was produced by a Correspondence Working Group with the support of the
Secretariat, based on:

the reports on the conduct of the tests provided by the test coordinators (see Table 1),

contributions from the test participants, which provided their interpretation of the test results
(see section 3),

agreement among the participants on common conclusions and recommendation for the D&E
Phase I (see section 4).
- END OF SECTION 1 -

2-1

2.
CONDUCT OF PHASE I AND MEOSAR SYSTEM CONFIGURATION
2.1
Tests Conducted During the Phase I
Table 1 provides the list of technical tests planned for the Phase I, their completeness status, the
participants undertaking the role of test coordinator and the reference to the test reports written by the
test coordinators. The detailed conduct of each test can be found in the test coordinator’s reports.
Planning of the D&E Phase I.
The initial planning of the MEOSAR D&E tests, as proposed at Annex L of document C/S R.018,
showed an estimated Phase I duration of 20 weeks assuming a beginning in January 2013, leading to
completion in May 2013. Due to unexpected delays in the January 2013 commencement, and to the
unavailability of some participants during the EWG-1/2013 meeting, this planning was re-evaluated at
the end of February 2013 and the end of Phase I was delayed until the end of June 2013.
However the test campaign did not progress as anticipated and several additional delays were
encountered during the tests performed by the participants.
At the JC-27 Meeting in June 2013, the D&E participants agreed upon the tests to be conducted during
the summer 2013 period, which included the second run of tests T-1 (Processing Threshold and System
Margin) and T-4 (Independent 2D Location Capability).
At the TG-1/2013 Meeting in September 2013, the D&E participants agreed upon the tests remaining
for the conclusion of the Phase I with a test T-5 conducted in November 2013 and a test T-6 conducted
in December 2013 and beginning of March 2014.
The test participants also agreed to not conduct the runs of test T-7 (Networked MEOLUT Advantage)
because the network configuration was not available and optional test T-8 (Combined MEO/GEO
Operation Performance), due to the time constraints. Consequently, the technical tests of the MEOSAR
D&E Phase I can be considered as completed (see Annex A that provides the detailed log of the Phase I
tests as conducted).
As agreed by the Council (see section 5.2.14 of the CSC-51 report), Phase I will be concluded once
the Phase I report is reviewed by the Joint Committee at its JC-28 session in June 2014. The production
of the Phase I report, for which a draft version was anticipated to be provided at the TG-2/2014
Meeting, was delayed due to the late provision of the Test Coordinators’ reports.
Table 1 and Figure 2 provide the schedule of the tests conducted during the Phase I testing as run.

2-2

Test
Definition
Run
Status
Test
Coordinator
Test Report Reference
T-1
Processing Threshold and System
Margin

Completed in February - March 2013
USA
Dated 28 February 2014

Completed in July – August 2013
T-2
Impact of Interference
Records available only for tests T-1
Run 2, T-4 Run 2, T-5 and T-6 Run 2
Canada
No report available
T-3
Valid/Complete Message Acquisition


France
SAR-RE-DEMEO-783-CNES Iss 1 Rev 3,
dated 14 May 2013

Replaced by a test run at lower
transmission rate conducted in April

T-4
Independent 2D Location Capability

Completed in April 2013
USA
Dated 28 February 2014

Completed in June – August 2013
T-5
Independent 2D Location Capability
for Operational Beacons
-
Completed in November 2013
Turkey
T-5 Run1 Beacon Deployment Report -
consolidated v2 - 26.02.2014
T-5 Run1 Test Coordinator Report v1 - 6.05.2014
T-6
MEOSAR System Capacity

Completed in May 2013
France
SAR-RE-DEMEO-788-CNES Iss 1 Rev 1,
dated 23 April 2014

Completed in December 2013 and

T-7
Networked MEOLUT Advantage

Cancelled (network not ready)
Canada
Not applicable

Cancelled (network not ready)
T-8
Combined
MEO/GEO
Operation
Performance
-
Cancelled (optional test)
Turkey
Not applicable
Table 1: List of Technical Tests, Test Coordinators and Test Reports

2-3

Figure 2: Phase I Test Planning (as Run)
2.2
Participants in the D&E Phase I
Table 2 provides the participants in each run of test, which provided at least raw data as per Table J.1
of document C/S R.018 or a test report. Some participants did not provide test results and/or test report.
Table 2 also provides the test during which spectrum of the 406 MHz band was recorded. For test T-5,
the participation in test T-5 is identified either in supplying test beacons or in involving MEOLUTs.

2-4

Test
Definition
Run
T-2: Impact of
Interference
(by Canada)
Australia
Brazil
Canada
France
Russia
Turkey
UK
USA
Hawaii
Maryland
T-1
Processing Threshold and System
Margin

X
(1- channel)
X
X
(1-channel)
X
X
X
X
X
X

X
X
X
X
Under
repair
Under
upgrade
X
X
X
T-3
Valid/Complete Message
Acquisition

X
(1-channel)
X
X
(2-channel)
X
X
X
X
X
X
Modified
script
Under Upgrade
X
Under
Upgrade
X
X
X
X
T-4
Independent 2D Location
Capability

Under Upgrade
Under
Upgrade
X
X
(2-channel)
X
X

X
X
X
Under
upgrade
X
X
T-5
Independent 2D
Location
Capability for
Operational
Beacons
Test
beacon

X
X
X
X
X
X
X
MEOLUT
X
X
X
X
X
X
T-6
MEOSAR System Capacity

X
X
X
X
X
X
(2 channels)
X
X

X (Toulouse run
only)
X
X
X
X
X
Table 2: Participation in MEOSAR D&E Phase I Tests

2-5

2.3
Configuration of the D&E Phase I
2.3.1
Experimental Space Segment
Table 3 provides the list of experimental MEOSAR satellites available for testing during MEOSAR
D&E Phase I.
MEOSAR
Constellation
Satellite
(C/S ID)
Satellite availability status for Phase I or launch date
DASS (GPS-II)

Available

Available

Available

Available

Available

Available

Available

Available

Available

Available

Available subsequent to launch on 4 October 2012

Available subsequent to launch d on 15 May 2013
Galileo

Available for testing from March 2013

Available for testing from March 2013
Glonass

Available with limitations (no ephemeris data available)
Table 3: List of Experimental MEOSAR Satellites Used
During the MEOSAR D&E Phase I
2.3.2
Experimental Ground Segment
The ground segment equipment in place for the Phase I of the MEOSAR D&E consisted of
experimental MEOLUTs located in Brazil, Canada, France, Russia, Turkey, the UK and the USA.
Table 4 provides the MEOLUTs available for testing, their number of antennas, their software
configuration and their availability (note that some participants may have experienced unexpected
down periods for some channels, thus limiting their participation in particular tests, see the Test
Coordinators reports for more detail).

2-6

Country/
Organisation
Location
Number of
Antennas
Configuration
Available for
D&E testing since
Brazil
Brasilia

HGT MEOLUT 600
LP v 1.6 / SP v 1.4 / FP v 1.4

Canada
Ottawa

HGT MEOLUT 600
LP v1.5 / SP v1.3 / FP v1.3

France
Toulouse

HGT MEOLUT 600
LP v1.6 / SP v1.4 / FP v1.4

Russia
Moscow

Not provided

Turkey
Ankara

HGT MEOLUT600
LP v1.6 / SP v1.4 / FP v1.4


UK
Kinloss

HGT MEOLUT 600 (S-band only)
LP v1.7 / SP v1.5 / FP v1.5

USA
Hawaii

Not provided

Maryland

Not provided

Table 4: MEOLUTs Participating in MEOSAR D&E Phase I Tests
Figure 3: MEOLUTs Involved in Phase I Testing with 3,000 km Radius Circles
2.3.3
Beacon Simulators and Test Beacons
Three beacon simulators were used during the Phase I testing, located in Hawaii and Maryland, USA
and Toulouse, France. After each test, the beacon log files were provided by each administration
providing beacon simulators.

2-7

Figure 4: Beacon Simulators Used in the MEOSAR D&E Phase I
(MEOSAR Visibility Circles at Five Degree Elevation)
2.4
Test Coordination
A smooth progression of the D&E planning and tests has been observed thanks to the active
participation of the Test Coordinators and Test Participants.  No formal D&E test had to be postponed
or re-scheduled due to a coordination issue.
However, a dry-run test encountered some difficulty because of the work simultaneously being
performed by the Galileo Programme. In addition to this particular case, other tests had been planned
by Test Participants at times similar to those of SAR/Galileo commissioning tests, requiring an active
coordination between France and EC/ESA in order to avoid the simultaneous transmission of beacon
signals.
2.5
Operational Issues Encountered during the Phase I Testing
The Cospas-Sarsat operational community was informed of upcoming D&E tests by a SIT605 message
prior to each test. So far, no major operational issue was encountered during the MESOAR D&E tests,
and at no time did it become necessary to terminate beacon simulator transmissions.
In order to prevent any issues related to the unexpected behaviour of the SARP-3 processors aboard
Sarsat 11, Sarsat 12 and Sarsat 13, as detailed in Attachment 2 of document JC-26/Inf.14, each beacon
test script was verified and cleared in coordination with France.  Nonetheless, during the T-3 test run

2-8

using the Hawaii beacon simulator, the memory of two SARP-3 instruments recorded a limited number
of erroneous messages sent by the simulator, and some LEOLUTs produced a few erroneous location
solutions. These solutions were filtered out by the MCCs as the messages were invalid and clearly
related to the on-going tests.
Further investigation confirmed that erroneous messages were recorded in the SARP-3 memory and
that LEOLUT processing should not have produced any location solution given that each erroneous
message was unique in the SARP-3 memory.  The number of erroneous messages recorded remains
acceptable in comparison to the size of the SARP-3 memory and no specific mitigation action had to
be undertaken for the particular test T-3. However, additional investigations were conducted and,
taking the most cautious approach, this matter will be carefully monitored during upcoming future tests
to prevent any filling of the SARP-3 memory with erroneous messages. As an additional risk mitigation
measure, not beacon message transmissions were conducted during test T-6 (System Capacity), for
which the number of transmitted bursts is larger than for the other technical tests.
2.6
Data Collection
During the tests, the participants collected the following data:

beacon log data to collect the beacon IDs transmitted (if applicable),

MEOLUT raw data as per csv format defined in Table J.1 of document C/S R.018,

MEOLUT location data as per csv format defined in Table J.2 of document C/S R.018,

MEOLUT pass schedule data as per csv format defined in Table J.3 of document C/S R.018.
All the data provided by the test participants were saved on the MEOSAR D&E FTP server.
- END OF SECTION 2 -

3-1

3.
RESULTS OF THE TECHNICAL TESTS AND DISCUSSION
The following sections provide, for each test:

references to the test participant’s reports presenting the results of the MEOSAR D&E tests
conducted during the Phase I testing,

a summary of the interpretation of the test analyses, as provided by each administration.
3.1
Test T-1 (Processing Threshold and System Margin)
3.1.1
Analysis
The following test reports were provided by the participants:
Administration
Test report reference
France
“C/S D&E T-1 Test Report Processing Threshold And System Margin”
SAR-RE-DEMEO-762-CNES, v1.3
Russia
Test report available on FTP server
Turkey
TRMEO T-1 Report, dated 10 April 2013
USA
USA Hawaii MEOLUT Report Revision 1.0, dated 15 April 2013
Technical Test T1 Run 1 - USA Maryland Test Report, dated 21 May 2013
Technical Test T1 Run 02 - USA Maryland Test Report, dated 12 September 2013
3.1.2
Interpretation
3.1.2.1 Canada
Data was collected for the first run of test T-1 for the Maryland simulator run only and from one of the
original antennas used during the MEOSAR Proof of Concept. Average C/No calculated at the ground
station was 33.7 dB.Hz. The lowest signal power level received by the old antenna was a 29 dBm burst.
For the second Maryland run, a new four-antenna set was available. The average C/No increased to
35.7 dB.Hz (calculated over all signals received) and all four antennas received signals as lows as
2 dBm.
The results showed that the new antennas performed much better than the older ones. However, for the
second run, while detection rates did reach the 70% threshold for all antennas individually for power
levels above 35 dBm, below this power level, detection rates varied greatly, and these rates were much
less than the 70% threshold. Overall detection rate was much lower than 70% for each antenna.
However, all antennas did detect signals as low as 22 dBm.  This fact was a positive outcome
considering the interference present in the entire band, as noted in test T-2 spectrum graphic
collections. Interference impacts the automatic gain control of the repeaters and therefore can impair

3-2

the detection of weaker signals. As well, weaker signals fade out often for certain passes due to the
elevation angle of the beacon simulator from the repeaters view point, which would be one more reason
for the variability and reduction of the detection threshold for signals below 35 dBm.
Canada cannot provide further interpretations at this time, but would consider analysing its data in the
future to help with comparisons with and insights when comparing with the results of Phase II testing.
3.1.2.2 France
Best results were obtained during run 2 with the Maryland transmission. At 37 dBm of transmitted
power, up to 71% of single satellite channels have a valid message throughput higher than 70% (target
value).
It was noted that the results in term of message throughput are significantly dependent on the elevation
angle between the beacon and the satellite due to the beacon antenna pattern.
An issue was observed with the French MEOLUT regarding confirmed messages detection, whose
throughput is too low compared to valid message throughput. Further work is required to investigate
and resolve the issue.
Also to be investigated, low performances with the Toulouse transmission were observed, for which
only 25% of single satellite channels have a valid message throughput higher than 70%.
3.1.2.3 Russia
In rare occasions, the throughput for beacons emitting at 37 dBm was higher than 80%, with lower
throughput values for 35 dBm and further down to 22 dBm. The possible reasons for this behaviour
were investigated and it was found out that the receiver message integration capability was left
unchanged after test T-3 and was operating in such a way that the period deviation of the emitting
beacon was restrained to 50±0.1 seconds to discard other beacon messages emitting at the same
frequency. Unfortunately, the period of the messages in was 48 seconds and that hindered the receiver
from getting bursts integrated. It was believed that this might led to the poor results, especially in the
lower power range.
The results obtained at MEOLUT for run 1 have shown that the throughput performance might have
been better. Considering the burst integration issue at Russian MEOLUT, a retest may be required to
correctly and comprehensively assess the throughput performance.
Unfortunately, the Moscow MEOLUT was unable to participate in run 2 of test T-1 due to an antenna
damage.
3.1.2.4 Turkey
For the Toulouse transmission of 13-14 March 2013, the 2-channel Ankara MEOLUT had a maximum
valid (resp. complete) system message throughput of 60% (resp. 55%), not reaching the 70% threshold
aimed by test T-1 in the transmitted 22 dBm - 37 dBm power range. It took the addition of the GEO
channel for the 3-channel Ankara MEOLUT (2 MEOSAR + 1 GEOSAR channels) to reach a valid

3-3

(resp. complete) system message throughput of 70% at 31 dBm (resp. 35 dBm) with corresponding
average C/No values of 37 dB-Hz (resp. 39 dB-Hz).
For the Maryland transmission of 20-21 February 2013, even the GEO-complemented 3-channel
Ankara MEOLUT had a maximum valid (resp. complete) message throughput of 57% (resp. 49%),
and for the Hawaii transmission of 7-8 March 2013, a maximum valid (resp. complete) message
throughput of 46% (resp. 38%), not reaching the 70% threshold aimed by T-1 in the transmitted
22 dBm - 37 dBm power range.
The results seemed to indicate that the processing threshold would be improved (i.e., get lower) and
consequently the system margin would increase by the addition of more MEOSAR channels as well
as the proximity of the transmission source (i.e., the beacon simulator). Clearly, a 2-channel MEOLUT
was not adequate to have a system throughput above the targeted 70% threshold.
3.1.2.5 USA-Hawaii
Following the analysis of data collected during the test T-1, run 1 the following key observations were
noticed:

Erroneous messages were received by different LEOLUTs tracking SARP-3-equipped
satellites at various geographical locations during the testing period, and this behaviour was
investigated further both by the USA and France,

Single channel throughput statistics for satellites being tracked in the northwest quadrant were
lower by around 10%,

Antenna \#2 had significantly lower overall detections than others,

Antenna \#6 got no detections at all,

The two agreed upon methodologies for obtaining the average C/No values appeared to
generate very similar numbers.
As a conclusion to this run, the data was too inconsistent to obtain a reliable estimate of system margin,
either for the single satellite or the multiple antenna scenarios.  In particular, the required detection
threshold of 70% detection rate was generally not achieved for the single channel case.
Following the analysis of data collected during the test T-1, run 2 the following key observations were
noticed:

The rerun of technical test T-1 provided one of the first opportunities at the Hawaii MEOLUT
to successfully compare the performance of DASS satellites to Galileo satellites, which proved
to be a very productive exercise as the detection rates or the Galileo satellites were notably
better,

Overall the Hawaii MEOLUT results for run 2 showed a marked improvement in comparison
to run 1 (even when removing antennas \#2 and \#6 from the run 1 analysis),

As seen before for the Hawaii MEOLUT, detection statistics for satellites being tracked in the
northwest quadrant were lower by around 10% (although not as pronounced with the Galileo
data collected).
Compared to run1, there was considerable improvement in performance, both in consistency and in
general.  However, there was still not enough consistency to arrive at any single value for system
margin either from throughput of single satellite/antenna pairings or multiple antenna cases.

3-4

3.1.2.6 USA-Maryland
Single channel results demonstrate variability caused by the effect the beacon antenna pattern, ground
blockage, and differences in the amount of earth noise in the uplink, have on the results. As the
elevation angle to the satellite exceeds 50 degrees, the transmitted EIRP of the beacon decreases and
the probability of reception, therefore, decreases. Similarly, when the footprint of the satellite receive
antenna is over different geographical areas, the earth noise increases and the C/No of the received
beacon messages decreases and the probability of reception, therefore, decreases. More examples of
these effects were contained in document EWG-1/2008/3/9.
The multi antenna results showed that, for four antennas, the message throughput ranges from 97% to
88% for values of beacon output power down to 32 dBm. It is useful to note that the throughput is 96%
at the minimum allowed beacon output power of 35 dBm as specified in document C/S T.001 (see the
table below).
Power
(dBm)
Number of
Transmitted
Bursts
Detection rate of
Valid Message
received
Detection rate of
Valid Complete
received


0.98
0.97


0.98
0.97


0.96
0.96


0.91
0.90


0.91
0.90


0.89
0.88
3.2
Test T-2 (Impact of Interference)
3.2.1
Analysis
The following test reports were provided by the participants:
Administration
Test report reference
Canada
Documents EWG-1/2014/2/2 and TG-1/2013/Inf. 15
3.2.2
Interpretation
3.2.2.1 Canada
All spectrum graphics recorded during the MEOSAR D&E tests are available on the FTP D&E server.
Spectrum graphics can be viewed either using the GIMP tool provided to all participants for download
within the T-2 test folder, or by using any common picture viewer. A very small sample of certain time
periods to enforce an observation and help with the interpretation of the results is provided below, but
to fully appreciate and explore the spectrum graphics it is strongly recommended to view the sample
here in their native image file using GIMP.

3-5

Spectrums recorded during test T-1
Data was collected for test T-1 for the first run from one of the original antennas from the MEOSAR
Proof of Concept. For the second run, all four antennas were available. The results showed that the
new antennas performed better than the older ones. However, while detection rates did reach the
70% throughput threshold for all antennas individually for power levels above 35 dBm, below that,
detection rates varied greatly, dropping below threshold quickly.
Looking at the spectrum graphics produced for test T-1 (see Figure 5), immediate and directly
overlapping interference was not present as often enough, so as to attribute the low detection rate to
interference alone. Looking at the RF levels received, in many instances the ground station LUT
processors should have been able to decode the beacon simulator signals, but no burst was detected,
and hence no beacon message was decoded. Clearly, there were occasions were the actual signal was
received at the ground station and downconverted properly to the LUT signal processors, but for
whatever reason, the signal was not decoded. This lead to the observation that the signal processors
are burdened with dealing with the interference and the multitude of signals that could be considered
as possible beacon bursts.  This observation was important to note, as anything from more reference
beacons to more interference or increased number of users just above or below the distress band would
negatively impact detection rates, with the current processing techniques used and capabilities of,
heritage/conventional processors.
Figure 5: Spectrum Graphic Sample of T-1 Run 2
(as presented in document TG-1/2013/Inf.15)
Spectrums recorded during test T-3
Data was collected for test T-3 for the first run from two of the original antennas used during the
MEOSAR Proof of Concept. For the second run only one LUT channel was available and, as such,

3-6

only spectrum graphics for test T-2 was collected. As such, Canada can only comment that detection
rate issues would have been impacted by the interference present at the times of the tests.
Spectrums recorded during test T-4
Data was collected from all beacon simulators active in test T-4, from all four MEOLUT antennas.
Canada did not have time to analyse the complete data sets. From partial analysis of its data, Canada
noticed interference and fade outs (possible scintillation events) when comparing to the spectrum
graphics of test T-2 that would have impacted some of the test burst transmissions, and which could
explain various missed bursts seen by other  LUTs as well.
Clearly, as seen in Figure 6, there were occasions were the actual signal was received at the ground
station and downconverted properly to the LUT signal processors, but for whatever reason, the signal
was not decoded, just as in test T-1. This lead to the observation that the signal processors are burdened
with dealing with the interference and the multitude of signals that could be considered possible beacon
bursts.
Figure 6: Test T-4 Activations in Red, Some Other Transmission Overlapping Boxed in Green
Spectrums recorded during test T-5
As seen in Figure 7 (this figure was presented and detailed in document EWG-1/2014/2/2), channels
used by test beacons operating from 406.037 to 406.040 MHz were in the clear for most of the time
for all three test dates, although some interference were observed around 406.045 MHz. Beacons in
the 406.020 to 406.030 MHz channels suffered from interferers most of the time, especially around
406.024 MHz. This would mean that detection rates of the 406.028 MHz beacons would present lower
detection or throughput rates than those in the 406.037 and 406.040 MHz channels.

3-7

Figure 7: Interference for Test T-5 as Seen by Galileo
Note the interferers throughout the band
Ottawa’s LUT detection rates from test T-5 are provided in Figure 8 as a point of comparison. Antenna
15 had an intermittently active signal processing card, and thus had lower detection rates at certain
times. Note that it was not an antenna or RF path activity issue, just a hardware problem that would
not have been seen and easily determined without the help of the spectrum graphics.

3-8

Figure 8: Average Throughput for Each Antenna for Test T-5
Observed by the Ottawa MEOLUT.
At this stage, the results do not provide clear guidance for the specifications and parameters regarding
the exact coverage areas in which the locations can meet the accuracy requirements within 5 km, 95%
of the time, as proposed currently in documents C/S R.012 and C/S R.018.
Country
Beacon ID
Antenna 14
Antenna 15
Antenna 16
Antenna 17
1 In 4 Antennas 4 In 4 Antennas Average Antenna
Australia
BEFC0 00000 000E3
0.0
0.0
0.2
0.4
0.6
0.0
0.2
Austratlia Average
0.0
0.0
0.2
0.4
0.6
0.0
0.2
279C6 32662 FFBFF
33.2
56.0
38.8
49.1
87.2
4.7
44.3
279C6 360D0 FFBFF
37.0
2.3
24.7
28.9
64.9
0.5
23.3
279C6 7A164 FFBFF
76.6
32.5
51.8
70.1
91.9
12.3
57.7
279C7 4DCFE FFBFF
0.0
0.0
0.0
0.1
0.0
0.0
0.02
279C7 53BAE FFBFF
69.8
62.8
51.8
51.8
92.2
12.6
59.0
279C7 53CA0 FFBFF
45.8
63.2
52.3
57.8
89.2
11.7
54.8
Canada Average
Within Canada
56.4
53.6
48.7
57.2
90.1
10.3
54.0
1C7C0 84B5A FFBFF
21.6
30.9
16.7
21.4
65.8
0.0
22.7
1C7C0 84B5C FFBFF
40.9
4.9
26.2
28.1
70.7
0.0
25.0
9C7E4 3316C 0028C
2.6
7.4
1.5
9.9
19.6
0.0
5.3
9C7E4 333E4 0028C
7.9
2.4
0.6
2.9
12.9
0.0
3.5
9C7E4 C37BA 73590
0.2
0.2
0.1
0.1
0.3
0.0
0.1
9C7E4 C37BA 735D0
7.9
9.7
2.6
7.6
24.9
0.0
6.9
9C7FE 28D29 90CA0
8.9
15.8
4.7
27.5
48.8
0.0
14.2
9C7FE 28D41 52900
3.7
0.2
0.0
0.8
4.2
0.0
1.2
France Average
11.7
9.0
6.5
12.3
30.9
0.0
9.9
21FD0 F9502 FFBFF
5.8
3.7
2.1
4.4
13.8
0.0
4.0
21FD0 F9514 FFBFF
27.4
20.5
24.1
12.7
64.8
0.1
21.2
21FD0 F9520 FFBFF
27.4
3.2
10.6
24.7
56.4
0.0
16.5
21FD0 F9532 FFBFF
9.9
3.9
2.8
7.5
22.0
0.0
6.0
21FD0 F953A FFBFF
11.3
7.1
7.5
3.2
27.2
0.0
7.3
Turkey Average
16.4
7.7
9.4
10.5
36.8
0.0
11.0
1D1C0 007D2 FFBFF
18.5
16.0
8.2
8.4
44.7
0.0
12.8
1D1C0 007D4 FFBFF
32.6
25.8
16.4
15.6
66.7
0.0
22.6
1D1C0 007D6 FFBFF
26.5
21.2
13.9
11.3
57.9
0.0
18.2
1D1D6 10002 FFBFF
28.4
2.6
17.7
18.5
49.8
0.1
16.8
1D1D6 28018 FFBFF
42.7
29.8
21.6
23.8
78.2
0.6
29.5
1D1E0 6C6BF 81FE0
51.0
8.3
35.3
37.6
81.5
0.1
33.1
1D1E1 21ABF 81FE0
34.3
5.9
18.9
26.2
63.1
0.1
21.3
1D1E4 F1BBF 81FE0
47.6
3.7
25.6
33.9
76.1
0.1
27.7
UK Average
35.2
14.2
19.7
21.9
64.8
0.1
22.7
2DDC6 7A0B4 FFBFF
64.0
46.8
49.2
35.3
87.7
5.7
48.8
2DDC6 7A0C4 FFBFF
29.7
32.2
26.3
30.4
73.6
0.5
29.7
2DDC7 52E20 FFBFF
69.3
41.7
50.9
57.3
89.8
9.8
54.8
2DDC7 52E2A FFBFF
2.7
10.2
14.1
21.6
44.9
0.0
12.1
ADDE4 11528 00330
14.5
10.9
9.4
7.4
21.1
1.0
10.6
USA Average
36.0
28.4
30.0
30.4
63.4
3.4
31.2
USA
Canada
France
Turkey
UK

3-9

Spectrums recorded during test T-6
Canada collected data from the run 2 of test T-6 with the Toulouse beacon simulator in December 2013
(see Figure 9). From its analysis the detection rates did not significantly drop with the increase of the
number of transmitted bursts.  The 406.070 MHz interferer directly overlapped one to three frequency
channels (runs) in which the test T-6 Run 2 tests were executed for the Toulouse beacon.  The interferer
was present more than half the time of the test beacon simulator sequence.
Figure 9: Test T-6 Beacon Bursts and Overlapping Interference Seen by DASS Satellites.
Note fading of bursts in purple box.
As well, the 406.060 MHz interferer was also present in many portions of the test run. This would
mean that a reduction anywhere from 10% to 30% in the number of received bursts would be expected,
due the interference seen during the runs of test T-6. Despite the interference, overall the detection
rates and location accuracies were slightly better than those seen in test T-5.

3-10

Overall summary of test T-2
From the analysis and interpretation provided above for the technical tests, it was noted that persistent
interference was seen by all MEOSAR satellites around 406.070 MHz, as well as intermittent
interference around 406.060 MHz, when in view of north and eastern quadrature of the globe.  This
interference was not typically seen in the upper half of the 406 MHz band when satellites do not see
Western Africa and Eurasia. Similar interference and noise behaviour was observed in all spectrum
graphics for all tests.
Canada underlines the importance of spectrum monitoring and recommends to continue monitoring
the 406 MHz band spectrum and analysing the detection rate per channel, or probability of detection
per channel, for all technical tests. This parameter had been assumed to be very high (i.e., 85%), but
was not met yet by the Ottawa ground station. Current tests showed average detection rate to be no
better than 70% per single satellite channel in distances less than 1,000 km away from the MEOLUT,
and to be around 40% for beacons up to 5,000 km away. This would mean that a 6-channel MEOLUT
would be needed to achieve single burst locations better than 95% of the time for distances up to 5,000
km away from the beacon.
3.3
Test T-3 (Valid/Complete Message Acquisition)
3.3.1
Analysis
The following test reports were provided by the participants:
Administration
Test report reference
France
“C/S
D&E
T-3
Test
Report
MEOLUT
Valid/Complete
Message
Acquisition”
SAR-RE-DEMEO-750-CNES v1.1
Russia
Test report is available on FTP D&E server
Turkey
TRMEO T-3 Report v3 – dated 2 June 2013
USA
Technical Test T-3 Run1 – USA Hawaii MEOLUT Report, Revision 1.0 dated 3 April 2013
Technical Test T3 Run1 - USA Maryland Test Report, dated 15 April 2013
Technical Test T3 ReRun - USA Maryland Test Report, dated 31 May 2013
3.3.2
Interpretation
3.3.2.1 Canada
Data was collected for test T-3 for the first run from two of the original antennas from the MEOSAR
Proof of Concept. For the second run only one MEOLUT channel was available and the signal
processing at the MEOLUT was intermittent due to a hardware issue. As such, only spectrum graphics
for test T-2 were collected. As such Canada can only comment that detection rates could have been
impacted by the interference present at the times of the tests, which would have increased the time to
obtain a valid message.

3-11

3.3.2.2 France
At 37 dBm, for the Toulouse transmission with the modified script (i.e., at a lower beacon transmission
rate), the probability to obtain a valid message after one transmitted burst with the French MEOLUT
was 90% and reached 100% after seven transmitted bursts, and the transfer time was about 10 s.
When the distance of the beacon increased to 6,000 km, the probability to receive a valid message after
seven transmitted bursts decreased to 90% or 80%.
France noted that the Ankara and French MEOLUTs demonstrated improved results with this run of
test T-3 using a modified script, thus showing some limitations on the receiving capacity. This
observation remained to be further investigated.
3.3.2.3 Russia
No consistent results were obtained due to MEOLUT inability to properly integrate beacon bursts
emitted as per T-3 script. However, in order to prepare for run 1 of test T-3, the receiver firmware was
upgraded to retain signal integration capability and ensure compliance with test scenario that required
receiver to process 50 beacons transmitting at the same frequency with a one second transmission rate.
In the view of the above there might have been occasions when beacon message from various beacons
were mixed in one integration sequence. This occurrences being unlikely have not been investigated,
however a certain “cushion” was foreseen to eliminate the probability of taking them into account
while processing the results.
Generally, the results have shown the deterioration of the valid/complete message detection
performance as the emissions locations moved from Toulouse towards Maryland and further to Hawaii,
with the decrease of C/No ratio accordingly. Nonetheless, taking into account the aggressive scenarios
of the tests the results proved the capability of the Russian MEOLUT to process the beacon messages
relayed through MEOSAR satellites with certain level of quality that may be sufficient to meet
expected performance requirements.
3.3.2.4 Turkey
For the run using the Toulouse beacon simulator with the modified script (at a lower beacon
transmission rate), the valid message average detection probability of the Ankara MEOLUT increased
from 88% (resp. 86%) for 1 burst to 99% (resp. 98%) for 7 bursts for a beacon transmission power of
37 dBm (resp. 33 dBm). The Ankara MEOLUT complete message average detection probability
increased from 87% (resp. 84%) for 1 burst to 99% (resp. 97%) for 7 bursts for a beacon transmission
power of 37 dBm (resp. 33 dBm). Valid (resp. complete) message transfer times of 8 seconds (resp.
10 seconds) were obtained at 37 dBm, and valid (resp. complete) message transfer times of 13 seconds
(resp. 18 seconds) were obtained at 33 dBm.
For the run using the Maryland beacon simulator with the modified script, the valid message average
detection probability of the Ankara MEOLUT increased from 68% (resp. 51%) for 1 burst to 99%
(resp. 78%) for 7 bursts for a beacon transmission power of 37 dBm (resp. 33 dBm). The complete
message average detection probability of the Ankara MEOLUT increased from 63% (resp. 40%) for
1 burst to 98% (resp. 78%) for 7 bursts for a beacon transmission power of 37 dBm (resp. 33 dBm).
Valid (resp. complete) message transfer times of 22 seconds (resp. 26 seconds) were obtained at

3-12

37 dBm, and valid (resp. complete) message transfer times of 77 seconds (resp. 92 seconds) were
obtained at 33 dBm.
The results seemed to indicate that average detection probabilities improved, as expected, with the
number of transmitted bursts as well as with the beacon transmission power. Similarly, message
transfer times improved (i.e., got shorter) with the beacon transmission power. On the other hand, for
the test run using the Toulouse beacon simulator with the modified script, 1-burst detection
probabilities well exceeded 70% for both 37 dBm and 33 dBm, in contrast with the lower system
throughputs obtained in test T-1 at the highest beacon transmission power of 37 dBm – a point that
needs to be further investigated.
3.3.2.5 USA-Hawaii
Following the analysis of data collected during the test T-3, run 1 the following key observations:

Antennas \#2 and \#6 had significantly lower performance (for detection rate, in particular),

Degradation in the performance to the north and northwest of the MEOLUT was noted and
was more pronounced at the lower transmit power (33 dBm vs. 37 dBm)

In comparing the performance of the Hawaii MEOLUT between the first and the additional
modified run, the detection percentage on 3 of the 4 good antennas showed improvement, but
overall the differences were not significant.
Due to unexplained inconsistencies in the data, there was no definitive conclusion with regard to the
test objectives as a result of the testing.  However, it is clear that MEOSAR in general is a very good
system for beacon message detection (both valid and complete), with minimal delays in transfer times
as well.
3.3.2.6 USA-Maryland
Results for 37 dBm are somewhat limited by satellite visibility at the time of the test but are still
excellent.

3-13

Single Burst Valid Message Probability (37 dBm) and
Number of Satellites for the Maryland MEOLUT with the Maryland Simulator
Seven Burst Valid Message Probability (37 dBm) and
Number of Satellites for the Maryland MEOLUT with the Maryland Simulator
Gaps in performance can also be caused by ground based interference degrading satellite performance.

3-14

3.4
Test T-4 (Independent 2D Location Capability)
3.4.1
Analysis
The following test reports were provided by the participants:
Administration
Test report reference
France
“C/S D&E T4 Test Report: Independent 2D Location Capability”
SAR-RE-DEMEO-765-CNES 0100 v2.0
Turkey
TRMEO T-4 Report, dated 29 April 2013
USA
Technical Test T-4 Run1 - USA Hawaii MEOLUT Report, Revision 1.0 dated 24 May 2013
Technical Test T4 - USA Maryland Test Report, dated 31 May 2013
3.4.2
Interpretation
3.4.2.1 Canada
From partial analysis of its data, Canada noticed interference and fade outs (possible scintillation
events), when comparing to the spectrum graphics of test T-2, that would have impacted some of the
beacon bursts transmitted  and which could explain various missed bursts seen by other participants’
MEOLUTs.  Some interference was noted as well on the upper transmission channel from the Toulouse
beacon simulator. Canada could not provide further conclusions at this time, but would consider
analysing this data in the future to help with comparisons with, and insights for, the results of Phase II
testing.
3.4.2.2 France
Run 2 performances improved with respect to run 1 results, thanks to the script modification (i.e., lower
beacon transmission rate), the pass schedule optimization and the technical issue of antenna \#3 fixed.
For the run 2, the computed independent location probability was respectively 82 % for the Toulouse
transmission and 64% for the Maryland transmission (both after 4 bursts), which seemed to be
encouraging, even if the results cannot be directly compared to the requirement of 95% after
12 transmitted bursts.
The probability to obtain an independent location accuracy better than 5 km was respectively 72% for
the Toulouse transmission and 56% for the Maryland transmission. The location error was reduced if
only locations derived from four-satellite measurements were considered.
The probability to obtain single burst independent location accuracy better than 5 km did not meet the
requirement of 95%. A complementary analysis showed that this could be due to inaccurate TOA
calibration of the French MEOLUT. However, the location accuracy of the standalone MEOLUT could
be improved by increasing the number of antennas in order to obtain locations with four or more
tracked satellites.

3-15

The time to obtain the first independent location within 5 km from the actual beacon position was of
about two minutes (in the range from 100s to 150s).
3.4.2.3 Turkey
Whereas the 2-channel Ankara MEOLUT generated a number of locations for the run 2 with the
Toulouse beacon simulator, some of them relatively accurate, we consider that a 2-channel MEOLUT
was not really suitable to be involved in location-related tests such as test T-4.
3.4.2.4 USA-Hawaii
Following the analysis of data collected during the test T-4, run 2 the following key observations were
noticed:

An aspect of performance not directly captured in the required results for test T-4 was location
probability.  The following table indicates the percentage of the time that the MEOLUT
computed a single burst location relative to when the mutual visibility of three or more satellites
presented the opportunity to compute one, and while much better at higher power, the overall
numbers are somewhat low.
Transmitted
Power (dBm)
Single Burst
Locations Received
Single Burst
Locations Expected
Percentage


71.5%


29.3%
Both Powers


49.9%
Single Burst Location Probability

The data in the three main result tables required for test T-4 did not appear to have a definitive
pattern which may have been a product of the limited data set, specifically due to the low
number of beacon IDs per slot (which also appeared to skew results for the 95th percentile),

The expected pattern of improvement as more bursts are used to compute a location was
successfully demonstrated,

Recording the number of mutually visible satellites and channels provided useful additional
information in the result tables.
As a conclusion, the percentage of locations generated was low, and location accuracy suffered as well
due to many of available locations having poor geometries.  The space segment of 11 satellites used
by the Hawaii MEOLUT during this testing did however provide a limited capability, and matters were
compounded by issues with data collection for the Maryland and Toulouse beacon simulator runs.
The Hawaii MEOLUT had very limited participation in test T-4, run 2.  The Hawaii reference beacon
(simulator) did not successfully run due to an unexpected issue with the newest script that had been
agreed at JC-27.  Due to the lack of mutual visibility between the space segment, the Hawaii MEOLUT
and the Maryland and Toulouse simulators, the number of locations generated was very limited and no
data analysis was possible.

3-16

3.4.2.5 USA-Maryland
The following three charts plot the probability of calculating a location:

The first chart shows how the average probability of location increases as the number of bursts
(NB) increases.

The second chart shows more detail about how the probability of single burst location varies
across time slots and how it may be affected by the number of satellites that were being tracked.
The probability of single burst location varies quite a bit and there is not as strong a correlation
with the number of satellites being tracked as expected.

The third chart shows more detail about how the probability of multi-burst locations (for cases
of NB = 6 and 7) varies across time slots and how it may be affected by the number of satellites
that were being tracked. The probability of multi-burst locations (for cases of NB = 6 and 7) is
more consistent and the correlation with the number of satellites being tracked is more evident.

3-17

The following three charts plot the accuracy of the locations calculated:

The first chart shows how the average location errors decrease as the number of bursts (NB)
increases. For values of NB greater than 2 the average location error is less than 5 km for the
case of nominal beacon power.

The second chart shows more detail about how the accuracy of single burst location varies
across time slots and how it may be affected by the DOP of the satellites that were being

3-18

tracked. The accuracy of single burst location varies quite a bit and the expectation that as DOP
increases, the location accuracy decreases is not consistent.

The third chart shows more detail about how the accuracy of multi-burst locations (for cases
of NB = 6 and 7) varies across time slots and how it may be affected by the number of satellites
that were being tracked. The probability of multi-burst locations (for cases of NB = 6 and 7) is
more consistent and the correlation with the DOP of satellites being tracked is more evident.

3-19

3-20

3.5
Test T-5 (Independent 2D Location Capability for Operational Beacons)
3.5.1
Analysis
The following test reports were provided by the participants:
Administration
Test report reference
Australia
Beacon deployment report (see annex of the Beacon Deployment Report, Rev. 1, dated 26
February 2014, consolidated by the test coordinator)
Canada
Beacon deployment report (see annex of the Beacon Deployment Report, Rev. 1, dated 26
February 2014, consolidated by the test coordinator)
France
“Operational Beacons Deployment For D&E Test T-5 France Participation”
SAR-RE-DEMEO-833-CN v1.0
“D&E T-5 Test Report: Independent 2d Location Capability For Operational Beacons”
SAR-RE-DEMEO-811-CN v1.0
Turkey
T-5 Run1 Turkey Beacon Deployment Report - 24.02.2014
T-5 Run1 TRMEO Report v1 - 23.02.2014
UK
Beacon deployment report (see annex of the Beacon Deployment Report, Rev. 1, dated 26
February 2014, consolidated by the test coordinator)
USA
Participant Report T5 Run01-Maryland, dated 27 February 2014
US Beacon Deployment Report
Figure 10 below provides the locations of the test beacons used for test T-5. More details on the beacon
models, beacon features and their 24-hour activation periods are available in the Beacon Deployment
Report (Rev. 1, dated 26 February 2014) consolidated by the test coordinator from test participants’
reports.

3-21

Figure 10: Location of the 33 Operational Beacons Deployed for Test T-5
3.5.2
Interpretation
3.5.2.1 Canada
The frequency channels of test beacons activated in the range 406.037 to 406.040 MHz, were clear of
interference for most of the time for all three days of testing, except for some interference around
406.045 MHz. Beacons in the 406.020 to 406.030 MHz frequency channels had interferers most of the
time especially around 406.024 MHz. This would mean that detection rates of the 406.028 MHz
beacons would present lower detection or throughput rates than those in the range 406.037 and
406.040 MHz. Detection rates for beacons within 800 km of the Ottawa station was about 54%, and
just under 40% for activations within 5,000 km.
Overall detection rate for each antenna of the Ottawa ground station for T-5 tests.
Comparing the spectrum graphics with the MEOLUT results from Ottawa, which showed average
detection rates to be no better than 60% per single channel in distances less than 1,000 km away from
the MEOLUT; and to be around 0.25 or 25% for beacons up to 5,000 km away, interference is clearly
impacting the detection rates. With this lower rate, it would mean a ten-channel MEOLUT or a network
of ten antennas would be needed to achieve single burst locations better than 95% of the time within
Avg Ottawa LUT
Within 800 km
59.0
51.2
49.1
57.2
90.1
10.2
54.1
3000- 5000 km
34.7
15.6
22.7
23.7
59.0
0.9
24.2
5000- 8000 km
24.5
14.8
14.5
15.5
52.8
0.1
17.3
8000- 12500 km
12.5
10.1
9.5
16.8
41.4
0.0
12.2
Beyond 12500 km
4.3
1.3
0.7
2.3
8.0
0.0
2.2
Average
Within 5000km
46.8
33.4
35.9
40.4
74.5
5.6
39.1
Beyond 5000km
15.4
9.8
9.3
12.5
37.4
0.0
11.7

3-22

an equivalent coverage area with radius or distance up to 5,000 km, or about 15% of the earth’s surface.
For around 1,000 km (about 1% earth’s surface), a five-channel MEOLUT would give single burst
locations better than 95% of the time. At this stage, however, the results did not provide clear guidance
for the specifications and parameters regarding the exact coverage areas in which the locations could
meet the accuracy requirements of 5 km, 95% of the time, as proposed currently in documents
C/S R.012 and C/S R.018.
Regarding location accuracy, analysis of the Canadian data showed that for unique single burst
locations, where location solutions converged within 2,000 iterations, the error was better than 5 km
more than 75% of the time. Solutions that needed more than 2,000 iterations to converge, or solutions
using multiple bursts, from multiple antennas, showed a greater variance in errors. In any case, the
errors were not less than 5 km, at least or better than, 95% of the time.  One reason for this is the
interference which impacts the C/No of the beacon bursts seen at the satellite. At this stage, the results
did not provide clear enough guidance for specifications and parameters regarding the location
accuracy and coverage areas in which the locations can meet the requirements within 5 km, 95% of the
time as proposed currently.  More beacons need to be activated in ranges between 1,000 to 3,000 km
range.
All in all though, considering the in-band interference, MEOSAR has good detection capability and
the results are promising regarding the location accuracy, but further testing is needed with more
antennas “seeing” the satellites so more statistically meaningful results regarding the error and
coverage areas requirements can be deduced.
3.5.2.2 France
The methodology to be followed for the post-processing of test T-5 should be reviewed for future runs.
In fact, the use of a fix window for the locations computation was not fully adapted to the current
processing of the French MEOLUT and could affect the interpretation of the results.
The French MEOLUT was configured in automatic antenna tracking mode and collected data with
only three channels most of the time due to a hardware failure on antenna \#4. As a consequence,
location probability and accuracy were strongly impacted by this failure.  On top of that, the number
of locations was too low for some beacons, thus preventing the generation of reliable statistics. The
single channel throughput did not exceed 70% even for beacons near the MEOLUT.
Beyond a certain distance between the beacons and the MEOLUT (~ 13,000 km) the detection
probability is sensibly degraded. The probability to obtain a location with an error lower than 5 km is
higher for multi-burst locations than for single burst locations. The overall accuracy results showed
that about 70% of the locations errors are below 5 km. The 95th percentile of the location error is above
22 km for the Toulouse1 France beacon and equals to 15 km for the Maine-United States beacon signals
(single and multi-burst locations included).
Independent location probability with an error less than 5 km after seven transmitted bursts seems to
be non-compliant with the requirement of 95% after 12 transmitted bursts.
Better results are expected for future runs of test T-5 with a MEOLUT nominal configuration (i,e.,
with four channels available) and with the development of the MEOSAR constellations.

3-23

3.5.2.3 Turkey
Prior to test T-5, the Ankara MEOLUT was upgraded from two channels to six channels.
Regarding the detection of activated beacons, 30 out of the 33 beacons deployed were detected by the
Ankara MEOLUT during testT-5, the remaining three beacons either having transmission issues or
being located too far away from the MEOLUT. Five of the 30 beacons detected were located more
than 10,000 km away from the TRMEO, thus confirming the detection benefit of the MEOSAR system,
even with a limited MEOSAR space segment.
Regarding the System Throughput (i.e. probability of burst detection with at least one satellite), on
average around 60% of the transmitted bursts were detected, increasing to 75% for beacons in the
immediate vicinity of the MEOLUT, thus confirming the “low detection rate” issue observed during
earlier tests. Concerning the detection of bursts by multiple channels, only 7.6% of the transmitted
bursts were detected over three days through at least four satellites, and 24.3% through at least three
satellites, which can be attributed to the aforementioned “low detection rate” issue.
Regarding the location probability (i.e., the ratio of the number of n-burst locations to the expected
number of n-burst locations during at least four-satellite covisibility periods), no correlation was
observed between location probability and the distance between the beacons and the MEOLUT.
Location accuracy was, as expected, better within the geographic region of the MEOLUT (a circle
centered at the MEOLUT with a radius of 3,500 km), with a 50th percentile of 2 km and a 75th percentile
of 5 km. However, at its 95th percentile, the location accuracy went up to the 10-30 km range and
sometimes beyond that range. In addition, the following observations were made:

No significant improvement was noticed due to the integraton of up to 7 bursts. In general,
single-burst locations were almost as accurate as multi-burst locations.

The number of satellites used in the calculation of a location seemed to be the most significant
factor determining location accuracy.
Consequently, Turkey anticipated the definition of “nominal locations” as those locations calculated
with four or more satellites, and “marginal locations” as those locations calculated with three or fewer
satellites, possibly with the use, as well, of the DOP value in those definitions, pointing out the potential
necessity for MEOLUT networking in the real world.
If the current “low detection rate” issue was not significantly improved by the future L-band satellites,
four-channel MEOLUTs might have difficulties in systematically generating locations derived from
four satellites.
Turkey recommended that the following parameters be noted and taken into account in the ongoing
work on MEOLUT Specifications and Design Guidelines:

Burst detection rates (MEOLUT System Throughput),

Impact on location accuracy of the number of satellites used to calculate a location,

Concept of “nominal” and “marginal” locations.

3-24

3.5.2.4 USA-Hawaii
Following the analysis of data collected during the test T-5, the following key observations were
noticed

Two beacons supplied by France provided the closest activations to the Hawaii MEOLUT
during test T-5 test, but both were still quite far away (about 4,440 km).  There was significantly
less data received from Papeete1 (75 single burst locations) compared to Papeete2 (538 single
burst locations).  This large gap from both systems implied either a problem with the Papeete1
beacon, or a very significant difference in the environment in which it was deployed. For those
locations generated, the accuracy was reasonably good, in particular with the limited
constellation of 12 DASS satellites applied, coming in at 70.7% of single burst location
produced within 5 km, and 100% within 5 km at seven received bursts.

While most other statistics were significantly impacted by distance, the range of the MEOSAR
system was soundly demonstrated by a number of cases.

A fair amount of correlation between DOP and location accuracy can be seen, and although
there are areas that do not coincide, DOP values appear to provide useful information and a
good basis for a potential quality factor for MEOSAR data.
As a conclusion, it is emphasized that this test was performed with the limited space segment of
12 DASS S-Band satellites.  In addition, all of the beacon activations were a significant distance from
the Hawaii MEOLUT. Overall the location accuracy could be better, but under these less than ideal
circumstances, many good locations were still generated.
3.5.2.5 USA-Maryland
The performance measured during this test was affected by several factors:
1. the distance between the MEOLUT and the beacon,
2. the amount of mutual visibility of the satellites to the beacon and the MEOLUT, and
3. the resulting satellite geometries, or DOP, used to create the single burst solutions.
As mentioned previously, the Maryland MEOLUT used its automatically generated pass schedule each
day, which included the 12 DASS S-Band satellites only being tracked by four antennas. Therefore,
there was no attempt to optimize the pass schedule for any particular beacon location.
However, the number of available satellites was limited to half the number that will be available in the
operational system, which yielded values of DOP that are worse than what would be achievable with
a full satellite constellation, and, therefore, limited the performance of the system.
In order to illustrate these effects, graphs are presented that show the single burst location accuracy
along with the DOP of the satellites used to generate the location as a function of time. On the same
graph the number of satellites with mutual visibility to both the beacon and the MEOLUT is shown.
These graphs were produced for four beacons on Day 3 of testing that were located within 3,000 miles
of the MEOLUT. It can be seen that location accuracy improves as the DOP value is reduced. It can
also be seen that there are significant portions of the 24-hour period that contained fewer than three
satellites with mutual visibility between the beacon and the MEOLUT. Since it takes three or more

3-25

satellites to produce a single burst location, the amount of available data was limited by satellite
visibility.
Of course, this situation will greatly improve as more satellites are added to the MEOSAR
constellation, but the current situation must be taken into account when interpreting the current results.
Admin
Beacon-id (15 Hex)
Beacon
Type
Freq
(MHz)
GPS
Location
Alt
(m)
Approx distance
(km) from
MEOLUT
Received
raw
packets
Location
results
Canada
279C753BAEFFBFF
EPIRB
406.037
Yes
Leland, Frontenac, Ont., Canada




USA
2DDC752E20FFBFF
EPIRB
406.037
Yes
Maine, United States




USA
ADDE41152800330
EPIRB
406.028
Yes
San Juan, Puerto Rico
6.1



USA
2DDC67A0B4FFBFF
PLB
406.028
Yes
Honduras





3-26

3-27

Method 1 Results
The goal for this method was to see how well the MEOLUT could locate the beacon after 1,2,3,…,7
transmitted bursts. Every merged location reported as “7 burst” location was produced by combining
as many single burst locations that occurred within a 7 transmitted burst window.
The following graph includes all beacons for which the Maryland MEOLUT received data. It,
therefore, includes data from beacons that are as far as 8,600 km away from the MEOLUT.
Nevertheless, there is performance improvement as more opportunity, i.e., larger window size, is made
available.

3-28

The counts are given below:
1 Burst
2 Bursts
3 Bursts
4 Bursts
5 Bursts
6 Bursts
7 Bursts
Error 1 km


Error 5 km


Error 10 km


Total


Method 2 Results
The goal for this method was to determine how the merged locations improve as more single burst
locations are used to produce them. In this method, merged locations were reported using the actual
number of single burst locations used to produce the merged locations, not the number of transmitted
bursts.
The following graph includes all beacons for which the Maryland MEOLUT received data. It,
therefore, includes data from beacons that are as far as 8,600 km away from the MEOLUT.
Nevertheless, there is significant improvement as more data is used to produce the merged location.
The slight dip from 6 to 7 bursts is attributed to the relatively small amount of data available for the
7 burst results.

3-29

The following lists the number of data points for each burst count.
1 Burst
2 Bursts
3 Bursts
4 Bursts
5 Bursts
6 Bursts
7 Bursts
Error 1 km


Error 5 km


Error 10 km


Total


3.6
Test T-6 (MEOSAR System Capacity)
3.6.1
Analysis
The following test reports were provided by the participants:
Administration
Test report reference
France
“C/S D&E T6 Test Report MEOSAR System Capacity”
SAR-RE-DEMEO-788-CNES v1.0
Russia
Test report is available on FTP server
Turkey
TRMEO T-6 Report, dated 30 September 2013
USA
Technical Test T-6 Run2 – USA Hawaii MEOLUT Report, Revision 1.0, dated 11 April 2014
Technical Test T-6 Run1 - USA Hawaii MEOLUT Report, Revision 1.0, dated 18 July 2013
Technical Test T6 Run 01 - USA Maryland Test Report, dated 6 September 2013
Technical Test T6 Run 02 - USA Maryland Test Report, dated 21 August 2014

3-30

3.6.2
Interpretation
3.6.2.1 Canada
The 406.070 MHz interferer directly overlapped one to three frequency channels in which the run 2 of
test T-6 was executed for the Toulouse beacon.  The interferer was present more than half the time of
the test beacon simulator sequence. As well, the 406.060 MHz interferer was also present in many
portions of the test run. This would mean that a reduction anywhere from 10% to 30% in the number
of received bursts would be expected due the interference seen during the T-6 tests. Despite the
interference, overall the detection rates were better, and location accuracies were slightly better, than
those seen in test T-5.
T-6 detection rate or throughput for Toulouse beacon simulator.
Note that the throughput here was about twice the rate than the average throughput
for the T-5 tests from equivalent distances.
While the overall system detection capability results were very good, the location accuracy was not as
good as initially hypothesised would be achieved with a four-antenna system. One reason for this was
the interference which impacted the C/No level of bursts signals as received by the satellite, which
negatively affected frequency and time of arrival estimation accuracy, and thus, the location accuracy.
Based on the current detection rates seen, by increasing the number of antennas, the time to locate and
the location accuracy would improve.
From the analysis, the results did not provide clear guidance on the system capacity threshold or limit.
Canada would recommend that, in Phase II testing, the number of transmitted bursts (NB) be increased
and two more NB levels of 150 and 200 be added, if the beacon simulators could handle this level of
transmissions for the testing duration.  As well, analysis might need to be done in smaller time period
ranges or “chunks”, so one could better compare results when specific interferers were not present, or
when beacon view elevation angles were approximately in the same range. All in all, considering the
in-band interference, the MEOSAR system still has very good capacity and the results from Phase I
were promising.
3.6.2.2 France
The system capacity in test T-6 was evaluated in the range of 25 to 100 simultaneous active beacons
and assessed for two system parameters:

throughput performance (detection probability and time to first Valid/Complete Messages),

location performance.
For both parameters, no drop-off value was observed and the system capacity could not be assessed by
any participants.
Antenna

Antenna

Antenna

Antenna

1 In 4
Antenna
Average
4 In 4
Antennas
Antenna

Antenna

Antenna

Antenna

1 In 4
Antenna
Average
4 In 4
Antennas

46.1
43.0
72.2
46.9
91.3
52.0
10.0
41.4
40.5
69.5
45.0
90.2
49.1
7.0

42.9
34.4
60.9
44.7
83.1
45.7
6.5
39.6
32.4
58.4
43.1
81.9
43.4
4.9

35.7
34.9
56.9
53.9
86.2
45.4
6.5
32.9
32.8
54.7
51.8
85.1
43.1
4.9

29.1
31.6
52.6
58.4
81.8
42.9
6.1
26.7
29.8
50.6
56.4
80.8
40.9
4.7
NB
Valid Messages Detection Probability(%)
Complete Messages Detection Probability(%)

3-31

The computation of the multi-burst locations was specific to each MEOLUT due to the diversity in
manufacturer, software and parameter settings. Participants were then invited to provide as much
information as possible about MEOLUTs features and parameters setting in order to consolidate the
analysis of multi-burst location performances.
In order to quantify the system capacity, France suggested conducting future runs of test T-6 with a
larger range of simultaneous active beacons (from 50 to 200 beacons for example).
3.6.2.3 Russia
No observations were available from Run 1 of test T-6 and only data pertaining to a first portion of run
2 of test T-6 was analysed. Note also that only the system capacity using the MEOLUT throughput
performance was assessed as the Russian MEOLUT featured only one antenna. Results from two slots
were slightly inferior to others.
MEOSAR detection probability requirement is defined in document C/S R.012, Annex E, as the
probability of detecting the transmission of a 406 MHz beacon and recovering at the MEOLUT a valid
beacon message, within ten minutes from the first beacon message transmission shall be a minimum
of 99%.
After 350 s, which is a little less than six minutes, the probabilities of producing first complete and
valid message when 100 beacons were transmitting were slightly lower than 80% and slightly above
90% if two specific slots were discarded from consideration. Assuming that the requirement did not
take into account the number of channels of the MEOLUT, a multichannel MEOLUT would
doubtlessly demonstrate better probabilities, drawing nearer to 100%.
T-6 run 1 results had shown almost the same probabilities with Toulouse transmission approaching
100% and Maryland transmission being around 80%.
It was, therefore, assumed that the system capacity based on the MEOLUT throughput performance
was 100 beacons or higher.
3.6.2.4 Turkey
Valid/complete message detection probabilities and times to first valid/complete messages would
normally be expected to worsen as the number of simultaneously active beacons (NB = 25, 50, 75,
100) increased. This was not always observed in the results as the second-best performance for the
Toulouse transmission, run 1 was obtained for NB=100 and the best performance for the Maryland
transmission, run 1 was obtained for NB=50.
Valid/complete message detection probabilities around 80% to 90% for the Toulouse transmission
were achieved regardless of the number of simultaneously active beacons (NB = 25, 50, 75, 100)
whereas the performance was down to around 40% for the Maryland Tx - a direct impact of the large
distance between the MEOLUT and the Maryland beacon simulator. No significant drop in
valid/complete message detection probabilities was observed when NB increased from 25 to 100.
After 100 seconds, almost a 100% message detection rate was achieved to obtain a valid/complete
message in the case of the Toulouse transmission regardless of the number of simultaneously active

3-32

beacons (NB = 25, 50, 75, 100). This performance was around 70% in the case of the Maryland
transmission after 350 seconds - again, a direct impact of the large distance between the MEOLUT and
the Maryland beacon simulator.
As it could be expected, a reliable determination of system capacity in terms of location capability (i.e.,
the NB value which met the 95% probability of a multi-burst location error lower than 5 km) was not
possible with the results obtained by a two-channel MEOLUT (in other words, a 2-channel MEOLUT
was not really suitable to be involved in location-related tests ).
Note that the Ankara MEOLUT did not participate in run 2 of test T-6.
3.6.2.5 USA-Hawaii
Following the analysis of data collected during the test T-6, run 1 the following key observations were
noticed:

Overall, the detection percentages were low, and the expected behaviour was not demonstrated,

For the Maryland transmission, the results remained low even when taking actual mutual
visibility into account, but for Toulouse the detection rates within mutually visible time periods
were high albeit this was a limited time frame.
As a conclusion, the results did not provide the desired outcome.  Specifically, a degradation in
performance as the number of beacons increases would be expected, and was not observed.  While this
is could be interpreted as a positive result indicating a high system capacity, the distance between the
Hawaii MEOLUT and both simulators, did not produce enough data to drive the test.
Data from test T-6, run 2 with the Toulouse beacon simulator was collected and minimally analysed,
but no results were uploaded to the MEOSAR D&E FTP server. The reference beacon collocated with
the MEOLUT in Hawaii could not provide transmissions at the short intervals required for this test due
to its inherent design.  As the purpose of test T-6 was to determine the system capacity of the MEOSAR
system, the more test data that was processed through the MEOLUT the more likely it would be that
the capacity where performance falls off can be determined.  The distances between the Hawaii
MEOLUT and both the Maryland and Toulouse beacon simulators severely limited the usefulness of
T-6 results, and with no co-located simulator, no consistent or identifiable pattern from the results
could be achieved.
3.6.2.6 USA-Maryland
The probability of obtaining a Valid or Complete message from a single beacon burst ranged from
95% to 64% for NB equal 25 to 100, respectively. The range of probabilities change from 96% to 75%
if we compensated for the collisions of beacon bursts resulting from the design of the test script. As
expected, the improvement was greater as NB increased.
The probability of obtaining a Valid or Complete message rapidly increased as more beacon bursts
were used until it reached nearly 100% within 350 seconds, or seven transmitted bursts, for all values
of NB.

3-33

The probability of obtaining a location was affected by the number of satellites being tracked by the
MEOLUT. Of course, this was a function of the number of antennas tracking satellites with mutual
visibility to the beacon.
The probability of obtaining a location from a single beacon burst when four satellites were in clear
view of the beacon ranged from 62% to 39% for NB equal 25 to 100, respectively. The average
probability for time slots when fewer satellites were in clear view was significantly smaller,
demonstrating the significant effect that the number of satellites within view has on location
probability.
The probability of obtaining a multi-burst location when four satellites were in clear view of the beacon
ranged from 1% to 93% for NB equal 25 to 100, respectively. Once again, there was degradation, that
was more pronounced as NB increases, when fewer satellites were used.
Location accuracy was clearly affected by the DOP used to calculate the location. It was also clear that
the typical DOP values used to generate this data was not the same as the typical DOP for a full
constellation of 24 GPS satellites. However, the data showed that, when we approached that value,
location performance improved significantly. Therefore, an overall average for location accuracy did
not provide enough insight into the underlying conditions affecting location accuracy to be useful by
itself.
In an attempt to normalize DOP so that a comparison can be made as NB increases, the location
accuracy for the time slot that had the lowest average DOP for each NB was considered. The
probability that the single burst location error was less than 5 km range from 67% to 56% as NB
increased. The probability that the multi-burst location error was less than 5 km ranged from 92% to
65% as NB increases.
To determine system capacity, a required level of performance needed to be determined for each
parameter. However, at this time the partial satellite constellation available added some uncertainty as
to how to use the data measured during this test. The good news was that this test would be run again
during Phase 2 and those results would add clarity to the determination of system capacity.
3.7
Test T-7 (Networked MEOLUT Advantage)
The D&E participants decided to not conduct test T-7 because the network configuration was not
available.
3.8
Test T-8 (Combined MEO/GEO Operation Performance (Optional))
The D&E participants decided to not conduct test T-8 (optional test) due to time constraints.
- END OF SECTION 3 -

4-1

4.
CONCLUSIONS AND RECOMMENDATIONS
This section provides the conclusions commonly agreed by participants in the MEOSAR D&E tests
and their recommendations for future conduct of the tests in the MEOSAR D&E Phase II.
4.1
Conclusion
4.1.1
Test T-1 (Processing Threshold and System Margin)
The test participants agreed on the following conclusions regarding test T-1.

System margin for single-burst throughput using single-channel results
The detection percentage produced from the single-channel testing varied enough and did not
consistently surpass the 70% threshold defined in document C/S R.018, and therefore it was not
possible to arrive at a system margin for single-burst throughput using single-channel results.

System margin for single-burst throughput using multi-antenna results
Results were improved using multi antennas and a margin above the 70% threshold was achieved when
at least four antennas were used. However, it was the view of the participants that the 70% threshold
value was not the right number to use for the multi-antenna results.
Reference Participants’ reports for description of underlying causes of the variability of the results.
4.1.2
Test T-2 (Impact of Interference)
The test participants agreed on the following conclusions regarding test T-2.
From Canada’s analysis, in its T-2 report, it was noted that persistent interference is seen by all
MEOAR satellites around 406.070 MHz, as well as intermittent interference around 406.060 MHz,
when in view of north and eastern quadrature of the globe.  This interference is not typically seen in
the upper half of the 406 MHz band when satellites do not see Western Africa and Eurasia. Similar
interference and noise behaviour was observed in all spectrum graphics for all tests. Locations of these
interferes are provided in the T-2 report.
These interferers directly impact the transmissions of the beacon simulators used for all such tests, and
indirectly on all tests due to the effect of the interference energy on the AGCs of the satellite repeaters;
and other interferers directly impacted T-5. This is one reason for the difficulty in determining and
reaching capacity and system thresholds, and for the negative impact on the detection rates seen in
tests T-1, T-3 and T-6 of Phase I.
4.1.3
Test T-3 (MEOLUT Valid/Complete Message Acquisition)
Two runs of test T-3 were conducted. While not all MEOLUTs participated in a second run referred
as a modified test, whose script was characterized by a lower transmission rate, compared to run 1.

4-2

Most of the participating MEOLUT got improved results with the second run using the modified test
script.
For nominal power of 37 dBm, the results of the test T-3 has shown that the probability of detection of
a valid message is about 90% after 1 burst and higher than 99% after 7 bursts, which is compatible
with expectation for minimum performance at full operational capability (FOC) contained in Annex E
of document C/S R.012 (99% after 10 minutes) for many MEOLUTs.
The expected performances were not reached for some MEOLUTs, and while all causes could not be
explained, many might be explained by:

limited co-visibility conditions (in term of number of channels) with the beacon simulators,

the test script restricted beacon transmission to 7 consecutive bursts per beacon ID (350 sec vs.
600 sec, which is equivalent to the 10 minutes allowed for 99 % probability of detection as per
the MIP),

limited functionality and/or limited participation of some MEOLUTs to some test runs,

interference
The main conclusions drawn from the test were the following:
 the results are compatible with the expectation for minimum performance at full operational
capability (FOC) contained in Annex E of document C/S R.012 (MIP).
 the results have shown the deterioration of the valid/complete message production performance
as the distance between MEOLUT and the beacon simulator increases.
 the average detection probabilities improved with an increase of the number of transmitted bursts
as well as with an increase of the beacon transmission power.
 the transfer time measured for valid messages was around 5 to 10 seconds. Message transfer
times improved (i.e, got shorter) with the beacon transmission power.
 the difference between the first run and the modified script may be explained by some limitations
in the processing capacity of the participating MEOLUTs. It was decided to use the modified
test script for the subsequent runs of tests T-3 and T-4, which was agreed by Participants and
included in document C/S R.018 Issue 2 –Revision 1 at CSC-51.
It is expected that the results will improve as the MEOSAR L-band space segment is expanded in the
future.
4.1.4
Test T-4 (Independent Location Capability)
The initial run of test T-4 highlighted issues that necessitated a revision of the test script and a second
run of the test. Run 2 of test T-4 was conducted with a modified transmission script as agreed during
JC-27 in order to reduce the beacon transmission rate (one beacon every two seconds with only one
frequency, instead of one beacon every 0.5 second alternating between two frequencies). The results
summarized here, therefore, result from the analysis of run 2 of test T-4 only.
Independent Location Probability
The probability that a MEOLUT provides an independent 2D location with a location error less than
X km (X = 1, 5 or 10 km) did not reach desired values. Performance for X = 5 km varied but was
always less than 95% but improved as the number of transmitted bursts used was increased.

4-3

Independent Location Accuracy
The 50th percentile, the 75th percentile, and the 95th percentile of the location error of 2D locations did
not reach desired values. Performance for 95th percentile varied but was always greater than 5 km but
improved as the number of transmitted bursts used was increased
Time to First Independent Location
The time elapsed between the first burst transmitted and the first 2D independent location with an error
less than X km (X = 1, 5 or 10 km) was not more than 2 to 3 minutes.
Conclusions
While the results were not as good as expected, the tests results showed that:

The probability of calculating a location was affected by:
o the single channel throughput,
o the number of satellites being tracked with mutual visibility to the beacon,
o the amount of time, or number of beacon bursts transmitted.

The accuracy of calculated locations were impacted by many reasons including:
o the number of satellites used to derive the location (locations derived with additional
satellites were statistically more accurate),
o the geometry of the satellites tracked by MEOLUT antennas (characterized by DOP
for example),
o the signal to noise ratio (C/No) of each channel,
o the accuracy and the calibration of TOA/FOA measurements produced by the
MEOLUTs.
It is expected that the results will improve in the future as:

the probability of location and the location accuracy of the standalone MEOLUT will increase
as the number of available antennas-satellite pairing increases, thus allowing the MEOLUT to
obtain locations with more tracked satellites.

the availability of more satellites on orbit will allow for the typical DOP to be improved which
will increase location accuracy.
4.1.5
Test T-5 (Independent 2D Location Capability for Operational Beacons)
Detection benefit of the MEOSAR system
The tests carried out over 3 days with 33 operational beacons deployed worldwide soundly
demonstrated the vast geographic range of individual MEOLUTs and confirmed the detection benefit
of the MEOSAR system, even with a limited MEOSAR space segment that consisted, at the time of
the tests, of 12 DASS, 2 Galileo and 1 Glonass satellites. Some participants only tracked the DASS
satellites whereas other participants tracked all available satellites.

4-4

Detection rates
The detection probability was gradually degraded as the distance between the beacons and the
MEOLUTs increased. These results, which were corroborated by the detection rates observed during
earlier tests, led the participants to the conclusion that an increase in the number of available satellites
the number of antennas per MEOLUT and an improvement of the single channel detection rate
hopefully brought by the advent of operational L-band satellites would be needed to improve
performance on system detection and meet the expectation on location probability and accuracy.
Independent Location Probability
The location probability did not meet the expectation for minimum performance of 98% at full
operational capability (FOC) contained in Annex E of document C/S R.012. However, some accurate
locations were generated for beacons at extreme distances (e.g., greater than 7,000 km) from the
MEOLUT, which is indicative of the range of MEOSAR.
Independent Location Accuracy
The location accuracy did not meet the expectation for minimum performance of 5 km accuracy, 95%
of the time at full operational capability (FOC) contained in Annex E of document C/S R.012.
However, the location accuracy was, as expected, better within the geographic region of the MEOLUTs
(a circle centered at the MEOLUT with a radius of some 3,000 km), location error was frequenctly
below 5 km wihin that geographic region. Composite locations calculated by the integration of up to
7 bursts offered a higher probability to obtain a location accuracy better than 5 km.
T-5 processing methodology
Run 1 of the T-5 tests has been an opportunity to identify certain missing aspects of the original T-5
processing methodology, and to amend the “windowing methodology” and include MEOLUT System
Throughput and n-Burst Independent Location Probability into the list of data to be analyzed and
reported by Participants.
Conclusion
The test results showed that:

the MEOSAR system’s capability to detect beacons is very good, sometimes beyond
expectations,

the location accuracy was not as good during this first run of test T-5 as initially hypothesized,

the results did not provide clear guidance for the specifications and parameters regarding the
exact coverage areas in which the calculated locations could meet the accuracy minimum
performance expectation at full operational capability (FOC) contained in Annex E of
document C/S R.012 (MIP) (5 km, 95% of the time),

one reason for the limitation in the location accuracy performance was the negative impact of
interference on the channel detection rates,

increasing the number of MEOLUT antenna-satellites pairings would improve the location
probability and accuracy, as well as the time to locate,

all in all, MEOSAR has very good detection capability and the location results were promising.

4-5

4.1.6
Test T-6 (MEOSAR System Capacity)
The system capacity in test T-6 (standalone MEOLUT configuration) was evaluated in the range of 25
to 100 simultaneous active beacons and assessed for two system parameters:

throughput performance (detection probability and time to first Valid/Complete Messages),

location performance.
The test did not lead to clear conclusion regarding throughput and location performances and it was
agreed to increase the number of transmitted beacon to try reaching a clear decrease of performance.
The expected outcome in term of location probability and accuracy were not always observed by the
participants even for NB = [25,50,75,100] simultaneous beacons.
Participants at EGW-1/2014 agreed to modify the definition of test T-6 for future runs, which was
subsequently approved in document C/S R.018 Issue 2 – Revision 2 at CSC-53.
The modifications to the test T-6 definition were:

an increase of the number of NB transmitted beacons from NB = [25,50,75,100] to NB =
[25,50,75,100,150,200],

modification of the analysis methodology to introduce the computation of the probability to
produce single burst locations.
The computation of the composite locations is specific to each MEOLUT (manufacturer, software and
parameters setting). Therefore, participants are invited to provide as much information as possible
about MEOLUTs features and parameter settings to assist the analyses.
4.1.7
Test T-7 (Networked MEOLUT Advantage)
No conclusions were drawn on test T-7 as this test was not conducted during the MEOSAR D&E
Phase I.
4.1.8
Test T-8 (Combined MEO/GEO Operation Performance (Optional))
No conclusions were drawn on test T-8 as this optional test was not conducted during the MEOSAR
D&E Phase I.
4.2
Recommendations for the Conduct of Subsequent D&E Phases
4.2.1
Test T-1 (Processing Threshold and System Margin)
It is recommended in the analysis of future runs of test T-1 to:

attempt to correlate lower performance cases with occurrence of channel interferers,

attempt to determine a more suitable threshold value for the assessment of the system margin
for single-burst throughput using multi-antenna results.

4-6

4.2.2
Test T-2 (Impact of Interference)
It is recommended to continue to monitor the 406 MHz spectrum and prepare spectrum plots so that
the single-channel throughput can be analysed for any technical tests, to allow the evaluation of the
negative impact interference has on the MEOSAR, and by extension the entire Cospas-Sarsat System.
4.2.3
Test T-3 (MEOLUT Valid/Complete Message Acquisition)
It is recommended that the test be modified to be able to compare the test results with the expectation
for minimum performance at full operational capability (FOC) contained in Annex E of document
C/S R.012 (i.e., 99% probability of valid beacon message detection within ten minutes). Specifically,
beacon transmission could be extended to 13 transmitted bursts (i.e., ten minute beacon transmission)
or the test analysis could aggregate results from multiple beacon IDs to generate the desired results
without changing the test script. The final methodology shall be proposed by the Test Coordinator and
agreed with other participants.
4.2.4
Test T-4 (Independent Location Capability)
It is recommended that further analyses be conducted to evaluate the relationship between location
accuracy and various parameters (e.g., DOP, number of satellites used in location determination, C/No
measurements, etc.).
In order to achieve expected results when T-4 is run as part of Phase II, more satellites than were
available during this Phase I test runs are needed. It is desirable to have as many L-band satellites as
possible.
4.2.5
Test T-5 (Independent 2D Location Capability for Operational Beacons)
It is recommended to continue monitoring the 406 MHz spectrum and it is suggested that participants
optionally analyze the detection rates per channel and per satellite type (L-band vs. S-band).
4.2.6
Test T-6 (MEOSAR System Capacity)
Modifications to the test T-6 definition regarding the number of simultaneous active beacons and the
analysis methodology were agreed at EWG-1/2014 and it is recommended that test participants
conduct future runs of test T-6 accordingly.
Participants are invited:

to provide as much information as possible about MEOLUTs features and parameter settings
to assist the analyses,

to provide details about the methodology applied to compute statistics regarding detection and
location performances and in particular about the mutual visibility conditions of the test periods
selected for the test.
4.2.7
Test T-7 (Networked MEOLUT Advantage)
No recommendations were provided on test T-7 as this test was not conducted during the MEOSAR
D&E Phase I.

4-7

4.2.8
Test T-8 (Combined MEO/GEO Operation Performance (Optional))
No recommendations were provided on test T-8 as this test was not conducted during the MEOSAR
D&E Phase I.
4.3
Recommendations for the Implementation of the MEOSAR System
It has been noted over many MEOSAR-related meetings and tests to date that TOA and FOA
measurement accuracies were amongst crucial factors affecting location accuracy. It is therefore
recommended that Participants revisit and fine tune their MEOLUT TOA/FOA measurements
techniques in order to improve location accuracy
It is recommended that further analyses be conducted to evaluate the relationship between location
accuracy and various parameters (e.g., DOP, number of satellites used in location determination, C/No
measurements, etc.) to provide useful information and a basis for a potential Quality Factor for
MEOSAR data.
- END OF SECTION 4 -

A-1

ANNEX A
DETAILED LOG OF PHASE I TESTS
Week
Nb
Date Start
Test
Test
Run
Time 1st Tx
(yyyy-mm-dd UTC)
Time last Tx
(yyyy-mm-dd UTC)
Beacon
location
Comments

2014-03-05
T-6

2014-03-05 14:45:00
2014-03-07 23:58:00
Maryland

2014-02-05
T-6

2014-02-05 16:05:00
2014-02-07 19:13:00
Maryland
CANCELLED due to weather conditions

2014-01-03
T-6

2014-01-03 18:00:00
2014-01-03 18:41:00
Maryland
Dry run (one sequence)

2013-12-16
T-6

2013-12-16 17:53:00
2013-12-18 22:45:00
Maryland
Retest - DISREGARD due to simulator issue

2013-12-11
T-6

2013-12-11 21:40
2013-12-13 16:00:00
Toulouse

2013-12-09
T-6

2013-12-09
2013-12-11
Maryland
CANCELLED due to weather conditions


2013-11-
14/19/21
T-5

2013-11-14
14:00:00
2013-11-19
14:00:00
2013-11-21 14:00:00
2013-11-15
14:00:00
2013-11-20
14:00:00
2013-11-22 14:00:00
Many
locations
Beacons of various types but in any case test coded and homer device
deactivated

2013-08-29
T-4

2013-08-29 14:00:00
2013-08-30 14:00:00
Toulouse
Retest of the test conducted on 2013-07-25

2013-08-13
T-1

2013-08-13 17:00:00
2013-08-14 17:00:00
Hawaii
With the script agreed at JC-27, except used country code 367 instead of
338.
Transmissions were on whole second intervals (3 & 4 seconds apart)

2013-08-01
T-1

2013-08-01 14:00:00
2013-08-02 14:00:00
Maryland
With the script agreed at JC-27

2013-07-31
T-1

2013-07-31 14:00:00
2013-08-01 14:00:00
Toulouse
With the script agreed at JC-27

2013-07-25
T-4

2013-07-25 14:00:00
2013-07-26 14:00:00
Toulouse
With the script agreed at JC-27

2013-07-24
T-4

2013-07-24 14:00:00
2013-07-25 14:00:00
Hawaii
TRANSMISSION CANCELED due to a simulator issue.

2013-07-23
T-4

2013-07-23 14:00:00
2013-07-24 14:00:00
Maryland
With the script agreed at JC-27

2013-05-23
T-6

2013-05-23 14:00:00
2013-05-24 14:00:00
Maryland
The 24 minute script will run once each hour

2013-05-16
T-6

2013-05-16 12:00:00
2013-05-16 14:00:00
Toulouse
Transmission slot calculated to maximize the satellite visibility for all
the MEOLUTs (except Hawaii). Beginning of each sequence: 12:00,
12:30, 13:00 and 13:30

2013-05-14
T-6
Dry run
2013-05-14 13:00:00
2013-05-14 14:30:00
Toulouse
Each transmission slot with NB=25,50,75,100 beacons

2013-04-25
T3
modified
-
2013-04-25 14:00:00
2013-04-26 14:00:00
Maryland
T-3 at a lower beacon transmission rate (24 beacons in 48 seconds)

2013-04-23
T3
modified
-
2013-04-23 13:00:00
2013-04-24 13:00:00
Toulouse
T-3 at a lower beacon transmission rate (50 beacons in 48 seconds)

2013-04-04
T-4

2013-04-04 13:00:00
2013-04-05 13:00:00
Hawaii

2013-04-02
T-4

2013-04-02 13:00:00
2013-04-03 13:00:00
Toulouse
Transmission stop between April 2, 21:00 UTC and April 3,
07:00 UTC. Transmission extended until April 4, 01:00 UTC

2013-04-01
T-4
Dry
Run
2013-04-01 16:00:00
2013-04-01 18:00:00
Hawaii
Dry run

2013-03-28
T-4
Dry
Run
2013-03-28 15:00:00
2013-03-28 17:00:00
Toulouse
Dry run

2013-03-25
T-4

2013-03-25 14:00:00
2013-03-26 14:00:00
Maryland

2013-03-20
T-4
Dry run
2013-03-20 14:00:00
2013-03-20 20:00:00
Maryland
Dry run

2013-03-13
T-1

2013-03-13 13:00:00
2013-03-14 13:00:00
Maryland
Toulouse

A-2

2013-03-07
T-1

2013-03-07 13:00:00
2013-03-08 13:00:00
Hawaii

2013-03-06
T-1
Dry run
2013-03-06 18:00:00
2013-03-06 19:00:00
Hawaii
1 hour dry run

2013-02-25
T-1
Dry run
2013-02-25 11:00:00
2013-02-25 13:00:00
Toulouse

2013-02-20
T-1

2013-02-20 14:00:00
2013-02-21 14:00:00
Maryland

2013-02-14
T-3

2013-02-14 14:00:00
2013-02-15 14:00:00
Maryland

2013-02-13
T-3

2013-02-13 13:00:00
2013-02-14 13:00:00
Hawaii
24 beacons transmitted per power level (instead of 100)

2013-02-08
T-3
Dry run
2013-02-08 16:00:00
2013-02-08 18:00:00
Hawaii
Subset of test T-3 (24 beacons transmitted per power level, instead of
100). Beacon log file available on the D&E server.

2013-02-05
T-3

2013-02-05 13:00:00
2013-02-06 13:00:00
Toulouse
NOTICE: the test started on 2013-02-05 at 14:00:00 and  ended on
2013-02-06 at 14:00:00.
No beacon messages transmitted between 15:00:00 and 15:15:00 on
2013-02-05

2013-01-29
T-3
Dry run
2013-01-29 21:30:00
2013-01-30 21:30:00
Maryland
Subset of test T-3

2013-01-10
T-3
Dry run  2013-01-10 08:30:00
2013-01-11 08:30:00
Toulouse
Beacon log file available on the D&E server

2012-12-20
T-3
Dry run
07:30:00
10:11:00
Toulouse
Subset of test T-3

2012-12-06
T-3
Dry run
09:00:00
10:11:40
Toulouse
Subset of test T-3. Back-up window 12:55:00 – 14:16:40
- END OF ANNEX A -
- END OF DOCUMENT -

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Telephone: +1 514 500 7999  /  Fax: +1 514 500 7996
Email: mail@cospas-sarsat.int
Website: www.cospas-sarsat.int