---
title: "T017: Cospas-Sarsat Meosar Space Segment Commissioning Standard C"
description: "Official Cospas-Sarsat T-series document T017"
sidebar:
  badge:
    text: "T"
    variant: "note"
# Extended Cospas-Sarsat metadata
documentId: "T017"
series: "T"
seriesName: "Technical"
documentType: "specification"
isLatest: true
documentDate: "October 2025"
originalTitle: "Cospas-Sarsat Meosar Space Segment"
---

> **📋 Document Information**
>
> **Series:** T-Series (Technical)
> **Date:** October 2025
> **Source:** [Cospas-Sarsat Official Documents](https://www.cospas-sarsat.int/en/documents-pro/system-documents)

---

# T017 - T017-OCT-23-2025.pdf

**Pages:** 36

---


COSPAS-SARSAT MEOSAR SPACE SEGMENT 
COMMISSIONING STANDARD 
C/S T.017 
Issue 2 


COSPAS-SARSAT MEOSAR SPACE SEGMENT 
COMMISSIONING STANDARD 
 
 
HISTORY 
 
Issue 
Revision 
Date 
Comments 


Approved by the Cospas-Sarsat Council (CSC-51) 


Approved by the Cospas-Sarsat Council (CSC-53) 


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


Approved by the Cospas-Sarsat Council (CSC-57) 


Approved by the Cospas-Sarsat Council (CSC-59) 


Approved by the Cospas-Sarsat Council (CSC-64) 


Approved by the Cospas-Sarsat Council (CSC-67) 


Approved by the Cospas-Sarsat Council (CSC-73) 


TABLE OF CONTENTS 
Page 
History..................................................................................................................................................... i 
Table of Contents ................................................................................................................................... ii 
List of Figures ....................................................................................................................................... iii 
List of Tables ........................................................................................................................................ iii 
 
1. 
Introduction ..........................................................................................................................1-1 
1.1 
Purpose .......................................................................................................................1-1 
1.2 
Scope ..........................................................................................................................1-1 
1.2.1 
IOT – Commissioning ...................................................................................1-1 
1.2.2 
Routine Monitoring........................................................................................1-1 
1.3 
Reference Documents.................................................................................................1-2 
1.4 
Common System Units ...............................................................................................1-2 
2. 
On-Orbit Space Segment Testing and Commissioning ........................................................2-1 
2.1 
Commissioning Authority Definition .........................................................................2-1 
2.2 
Initial On-Orbit Tests .................................................................................................2-1 
2.3 
Commissioning Procedure .........................................................................................2-2 
2.4 
Satellite System Data..................................................................................................2-4 
2.5 
Routine Monitoring ....................................................................................................2-4 
2.6 
Decommissioning Procedure ......................................................................................2-4 
2.7 
Space Segment Problem Reporting and Investigation Procedures.............................2-4 
3. 
MEOSAR Space Segment Testing .......................................................................................3-1 
3.1 
SAR Repeater Gain ....................................................................................................3-2 
3.1.1 
Objective ........................................................................................................3-2 
3.1.2 
Procedure .......................................................................................................3-2 
3.2 
Translation Frequency ................................................................................................3-4 
3.2.1 
Objective ........................................................................................................3-4 
3.2.2 
Procedure .......................................................................................................3-4 
3.3 
SARR G/T ..................................................................................................................3-4 
3.3.1 
Objective ........................................................................................................3-4 
3.3.2 
Procedure .......................................................................................................3-4 
3.4 
Axial Ratio (Optional) ................................................................................................3-5 
3.4.1 
Objective ........................................................................................................3-5 
3.4.2 
Procedure .......................................................................................................3-5 
3.5 
SARR Dynamic Range in AGC Mode .......................................................................3-6 
3.5.1 
Objective ........................................................................................................3-6 
3.5.2 
Procedure .......................................................................................................3-6 


3.6 
Channel Bandwidth and Amplitude Ripple ................................................................3-7 
3.6.1 
Objective ........................................................................................................3-7 
3.6.2 
Procedure .......................................................................................................3-7 
3.7 
Linearity/Third Order Intermodulation ......................................................................3-8 
3.7.1 
Objective ........................................................................................................3-8 
3.7.2 
Procedure .......................................................................................................3-8 
3.8 
SARR Downlink EIRP ...............................................................................................3-9 
3.8.1 
Objective ........................................................................................................3-9 
3.8.2 
Procedure .......................................................................................................3-9 
3.9 
Transponder Group Delay Variation as a Function of Frequency .............................3-9 
3.9.1 
Objective ........................................................................................................3-9 
3.9.2 
Procedure .....................................................................................................3-10 
3.10 Spurious Output Levels ............................................................................................3-11 
3.10.1 Objective ......................................................................................................3-11 
3.10.2 Procedure .....................................................................................................3-11 
3.11 Beacon Signal Processing ........................................................................................3-12 
3.11.1 Objective ......................................................................................................3-12 
3.11.2 Procedure .....................................................................................................3-12 
4. 
MEOSAR Space Segment Parameter Assesment Compliance Indicators  ..........................4-1 
5. 
MEOSAR Satellite Status Communication .........................................................................5-1 
5.1 
MEOSAR Satellite Status Communication ................................................................5-1 
5.1.1 
MEOSAR Satellite IOC Communication ......................................................5-1 
5.1.2 
MEOSAR Satellite FOC Communication .....................................................5-1 
5.1.3 
MEOSAR Satellite LOC Communication .....................................................5-1 
5.2 
MEOSAR Satellite Information .................................................................................5-2 
5.2.1 
Satellite Status and Mode Information ..........................................................5-2 
5.2.2 
Commissioning Test Results Summary .........................................................5-2 
5.3 
Example of SIT 605 Communication for MEOSAR Satellite Commissioning Status 5-

6. 
MEOSAR Satellite Commissioning Report .........................................................................6-1 
 
LIST OF FIGURES 
 
Figure 2.1: MEOSAR Payload Commissioning Procedure ................................................................2-3 
Figure 2.2: MEOSAR Problem Reporting and Investigation Procedures...........................................2-5 


LIST OF TABLES 
 
Table 2.1: MEOSAR Commissioning Authorities Definition ............................................................2-1 
Table 3.1: List of Post-Launch Tests ..................................................................................................3-1 
Table 4.1: MEOSAR Space Segment Assessment Indicators / Compliance Levels ..........................4-1 
Table 5.1: Satellite Status Information ...............................................................................................5-2 
Table 5.2: Commissioned Payload Modes ..........................................................................................5-2 
Table 5.3: Commissioning Test Results Summary .............................................................................5-3 
Table 5.4: Example of SIT 605 Message for Initial Status Communication of MEOSAR Satellite ..5-4 
 
 
LIST OF ANNEXES 
ANNEX A ATMOSPHERIC ATTENUATION COMPUTATION 


 
1-1 

1. 
INTRODUCTION 
1.1 
Purpose 
This document presents a proposal of recommended tests, technical measurement standards and high-
level procedures for implementing on-orbit testing and commissioning of MEOSAR space segment 
payloads. 
 
The commissioning authority (defined in section 2) will produce detailed test procedures and results. 
1.2 
Scope 
The following two phases of MEOSAR space segment on-orbit testing are addressed: initial on-orbit 
testing (IOT) (commissioning) and routine monitoring. The basic responsibilities, specific tests 
recommended to be performed, and suggested test methodologies are defined by this document. 
1.2.1 
IOT – Commissioning  
Initial on-orbit tests are performed in order to establish that a MEOSAR payload can be placed in 
service to support SAR operations. The initial tests focus on establishing that the MEOSAR payload 
will properly operate and, therefore, will be able to interface with the beacon and the ground segment. 
It must be noted that MEOSAR payloads are non-inverting frequency translator instruments (repeaters) 
and, therefore, no on-board processing/demodulation of the signal is employed.  
 
If results of the initial on-orbit tests confirm that values for assessment indicators are within accepted 
values, the payload can be formally commissioned. The payload can then be used operationally and 
data exchanged as described in document C/S A.001. 
 
A list of recommended tests and a description of each test is provided in section 3. The test descriptions 
provide sufficient detail to define the measurement method including high level procedures, but are 
not intended to be specific detailed test procedures. It is the responsibility of the commissioning 
authority to develop detailed test procedures that are traceable to the methods described in this 
document for each recommended test conducted. 
1.2.2 
Routine Monitoring 
After initiation of MEOSAR payload operations, the space segment operator will conduct routine 
monitoring of the on-orbit payload performance using telemetry and other means as deemed necessary. 
Routine monitoring may include recommended tests identified as routine monitoring tests in section 3, 
Table 3.1. The detailed test procedure will be developed by space segment operators and may differ 
from the test procedures shown in section 3.  
 


 
1-2 

MEOLUT and MCC operators can also detect significant changes (e.g., loss of channel, etc.). 
Abnormal conditions detected by MEOLUT and MCC operators are reported to the commissioning 
authority for further tests and corrective action as required. If deemed necessary, operational 
limitations may be placed on the use of the payload or it may be de-commissioned. The commissioning 
authority will advise the Cospas-Sarsat Programme of any detected abnormal conditions, and any 
required tests will be developed by the commissioning authority. 
1.3 
Reference Documents 
The following documents contain useful information to the understanding of this document. 
 
C/S A.001 
Cospas-Sarsat Data Distribution Plan 
C/S T.013 
Cospas-Sarsat GEOSAR Space Segment Commissioning Standard 
C/S T.016 
Description of the 406 MHz Payloads Used in the Cospas-Sarsat MEOSAR System 
C/S R.012 
Cospas-Sarsat 406 MHz MEOSAR Implementation Plan 
C/S R.018 
Cospas-Sarsat Demonstration and Evaluation Plan for the 406 MHz MEOSAR System 
ITU-R P.676-6 15 
Attenuation by atmospheric gases 
1.4 
Common System Units 
The System International (SI) units of measurement will be used for exchange of interoperability 
parameters and test results.  
 
Interpretation of technical terms in exchanged documentation will be in accordance with the latest 
edition of the "IEEE Standard Dictionary of Electrical and Electronic Terms". 
 
 
 
- END OF SECTION 1 - 
 
 
 


 
2-1 

2. 
ON-ORBIT SPACE SEGMENT TESTING AND COMMISSIONING 
2.1 
Commissioning Authority Definition 
Commissioning authorities are defined as follows: 
 
MEOSAR Constellation 
Space Segment Operator 
Commissioning Authority 
SAR/Galileo 
European Commission 
European Commission 
SAR/GPS 
USA 
Canada and USA 
SAR/Glonass 
Russia 
Russia 
DASS S band (Note 1) 
USA (USAF) 
USA 
SAR/BDS 
China (P. R. of) 
China (P. R. of) 
Table 2.1: MEOSAR Commissioning Authorities Definition 
 
Note 1: this constellation is not planned to be declared as operational, but its data may be used 
operationally. 
2.2 
Initial On-Orbit Tests 
The payload parameters are defined in the following sections. On-orbit testing will provide a set of 
baseline values for the defined parameters, to be compared with compliance indicator values defined 
in section 4, or optionally with pre-launch values obtained with on-ground testing. 
 
It is the responsibility of each commissioning authority to develop the detailed procedures unique to 
the satellite and test facility for conducting tests on their MEOSAR payload. Such detailed procedures 
should be traceable to the test objectives and high-level procedures described in this document. 
Alternate test methods and procedures can be considered but must be described in detail in the 
commissioning report. In addition, other Participants may perform tests on the MEOSAR payload. 
These tests by other Participants may conform to the test objectives and high-level procedures 
described herein, however, their detailed test procedures must be provided to the responsible space 
segment operator beforehand to ensure the safety of the MEOSAR spacecraft. Furthermore, all 
Participants conducting tests shall conduct appropriate co-ordination within the Cospas-Sarsat 
Programme to ensure that there is no negative impact on Cospas-Sarsat operations. 
 
The commissioning authority will analyse the initial on-orbit test data and prepare a post launch 
commissioning report as detailed in section 6.  


 
2-2 

2.3 
Commissioning Procedure 
Commissioning is a formal declaration by the commissioning authority that the on-orbit MEOSAR 
payload parameter assessment indicators meet the required compliance levels and that the equipment 
is operational as part of the MEOSAR system. Commissioning may be declared with operational 
limitations if some compliance levels are not met and limited operation is deemed feasible. In such a 
case the status of the MEOSAR payload shall be designated as being at “limited operational capability” 
(LOC). 
 
Performing the initial on-orbit tests and preparing a report may be time consuming. During this time 
valid operational data will normally be available from the satellite payload that is under test. In view 
of this, an initial operational capability (IOC) status may be declared for the payload before the 
commissioning report is completed. This may be done at the option of the commissioning authority 
after sufficient tests have been conducted to establish confidence that use of the MEOSAR payload 
will not cause unnecessary expenditure of SAR resources. 
 
Satellite payload IOC is declared with a SIT 605 message issued on behalf of the commissioning 
authority by the MCC associated with the commissioning authority. The information to be included in 
the SIT 605 IOC message is detailed in section 5. Once declared, IOC status shall remain in effect until 
commissioning is completed, which shall normally be no more than 90 days after IOC status was 
declared.  
 
Commissioning an on-orbit MEOSAR instrument consists of confirming the basic health and safety of 
the payload and the measurement and analysis of post launch test data to verify compliance or non-
compliance with the expected values of the parameter assessment indicators. 
 
Figure 2.1 shows the general commissioning procedure. Upon completion of all tests, the 
commissioning authority will evaluate the assessment indicators and prepare a commissioning report 
as shown in section 6. The commissioning report will designate the status of the MEOSAR instrument 
as being either at full operational capability (FOC) or limited operational capability (LOC).  
 
The commissioning authority submits the commissioning report for a review by the Joint Committee 
or other body as instructed by the Cospas-Sarsat Council. The experts will review the report and decide 
whether the report is complete and/or provide feedback to commissioning authority to update the 
report, as necessary. If the payload was deemed operational by the commissioning authority after the 
commissioning tests have been completed, the declaration of the operational status may be done by the 
commissioning authority before such a review. 
 
The commissioning test results as summarized in section 5 shall be distributed by the MCC associated 
with the commissioning authority to all MCCs in the Cospas-Sarsat System using a SIT 605 message 
issued on behalf of the commissioning authority. 
 
A copy of the finalized report is permanently retained by the Cospas-Sarsat Secretariat. The Secretariat 
will provide copies of the report to Cospas-Sarsat Participants upon request. 
 
 


 
2-3 

Figure 2.1: MEOSAR Payload Commissioning Procedure 
Note: some paths may be taken in parallel  
 
 
 
Space Segment Operator 
launches satellite 
Commissioning Authority 
conducts commissioning tests
Conducted tests indicate 
that using SAR payload 
adversely affects
 SAR operations?
Commissioning Authority and Space 
Segment Operator investigates 
situation and inform the 
Programme of the payload 
operational status, as applicable
All tests are completed. Commissioning 
Authority prepares the commissioning report
(normally occurs no later than 90 days since  
the IOC declaration)
NO
YES
Commissioning Authority submits the report 
to Secretariat for review by the experts (at 
Joint Committee or Experts Working Group)
Experts review the report  and 
provide feedback to 
Commissioning Authority as 
necessary
Commissioning Authority updates the report 
(if necessary) and provides a final copy to 
Secretariat for permanent retention
Commissioning Authority decides 
whether it is feasible to declare 
payload at Initial Operational 
Capability (IOC) after a sufficient 
amount of testing is completed 
IOC is declared?
SIT 605 with test results is 
distributed.
MEOLUT operators process and 
distribute distress alert signals from 
MEOSAR payload
YES
Payload fully satisfies 
commissioning requirements?
NO
Commissioning Authority declares 
payload at Full Operational 
Capability (FOC) 
YES
Payload satisfies 
 requirements for Limited 
Operational Capability
 (LOC)?
NO
Secretariat prepares updates to System 
documents
Commissioning Authority 
declares payload at LOC and 
indicates limitations or special 
MEOLUT processing 
requirements
YES
NO
Council adopts changes to 
System documents
SIT 605 has been distributed.
MEOLUT operators process and 
distribute distress alert signals 
from MEOSAR payload if not 
done before (after IOC)


 
2-4 

2.4 
Satellite System Data 
In order for the Cospas-Sarsat Programme to operate the MEOSAR payloads at an IOC, LOC or FOC 
status, the MEOSAR space segment operator shall provide the Programme with the satellite/payload 
information necessary for conducting daily operations. Examples of such data are Search and Rescue 
Repeater (SARR) payload status on/off, gain control mode (Automatic Gain Control (AGC) / Fixed 
Gain (FG)), selected band mode Normal/Narrow band, and nominal downlink frequency. Such data 
shall be contained in SIT 605 messages as per section 5 and in the payload commissioning report. The 
Programme and the Ground Segment Operators must be kept up to date of changes in such information 
and payload status. 
2.5 
Routine Monitoring 
The routine monitoring of the MEOSAR space segment is performed by: 
• 
space segment operators, monitoring satellite telemetry and conducting routine monitoring 
on orbit tests such as those listed in Table 3.1,  
• 
MEOLUT operators, monitoring satellite tracking performances and processing anomalies, 
• 
MCC operators, comparing alerts produced by MEOSAR systems with information 
obtained from other sources. 
Problems are to be reported to the commissioning authority, which will perform further tests in order 
to confirm health status of the payload. 
2.6 
Decommissioning Procedure 
De-commissioning is a formal declaration by the MEOSAR commissioning authority that a MEOSAR 
payload is no longer a part of the MEOSAR system. A MEOSAR instrument that cannot meet the 
performance requirements for reliable Cospas-Sarsat service will be decommissioned. 
 
An operational MEOSAR instrument may also be de-commissioned by the space segment operator 
due to general spacecraft health and safety issues. In this case, the spacecraft operator shall notify the 
commissioning authority that the SARR payload should be de-commissioned. The commissioning 
authority would be responsible for distributing this information via the MCC network, and providing 
a copy to the Secretariat for permanent retention. A de-commissioned payload can later be re-
commissioned, with or without limitations, based on an evaluation of current values of the assessment 
indicators and the need within the Cospas-Sarsat Programme. 
2.7 
Space Segment Problem Reporting and Investigation Procedures 
Any space segment, MEOLUT or MCC operator that detects anomalies of a MEOSAR payload during 
routine monitoring or system operation shall inform the relevant commissioning authority so that 
special tests can be conducted and possible corrective action (e.g., switch to backup payload, etc.) 
taken. MEOLUT and MCC operators will report problems to the responsible commissioning authority 


 
2-5 

through the associated MCC in accordance with procedures given in document C/S A.001, and space 
segment operators shall report anomalies to the commissioning authority via the most effective means 
available. The procedure to be followed is shown in Figure 2.2. 
 
 
Figure 2.2: MEOSAR Problem Reporting and Investigation Procedures  
 
Upon being made aware of a possible problem with the MEOSAR payload, the commissioning 
authority shall advise the space segment operator, and conduct an investigation to evaluate the status 
and performance of the instrument. Based on the results of the investigation, the commissioning 
authority shall take one of the courses of action described below: 
a) should the investigation identify a serious problem with the payload which renders it unusable 
for SAR purposes, the commissioning authority shall decommission the payload in accordance 
with section 2.6; and 


 
2-6 

b) should the investigation identify a problem which confirms degraded payload performance, but 
indicates that the instrument is still useful for SAR purposes, the commissioning authority shall 
distribute an update of the payload status via the MCC network (using SIT 605), with a copy 
also provided to the Secretariat and to the space segment operator. The update shall specifically 
identify: 
• 
the problem with the payload, 
• 
the impact on MEOLUT processing, 
• 
the impact on the quality of distress alerts produced, 
• 
any special MEOLUT processing required. 
Should the investigation not confirm the problem or conclude that there is a problem which does not 
impact on MEOSAR performance, the commissioning authority shall liaise with the organization 
which identified the problem to confirm that MEOSAR performance is not affected. A copy of the 
conclusions shall also be provided to the Secretariat for retention. There would be no requirement to 
advise other Cospas-Sarsat Participants of the results of the investigation in such a circumstance. 
 
 
 
- END OF SECTION 2 - 
 
 
 


 
3-1 

3. 
MEOSAR SPACE SEGMENT TESTING 
Table 3.1 identifies the set of post launch tests recommended to be completed by the space segment 
operator in order to establish initial commissioning of a MEOSAR payload. Each space segment 
operator is also encouraged to conduct other tests that may more fully characterise payload 
performance.  
 
Table 3.1 also lists recommended routine monitoring tests that should be periodically conducted by the 
space segment operator. The schedule of the routine monitoring tests shall be determined by the space 
segment operator. 
 
Table 3.1: List of Post-Launch Tests 
 
Parameter tested 
Recommended for 
commissioning  
(y/n) 
Recommended routine 
monitoring test  
(y/n) (note 1) 
3.1  
SAR Repeater Gain 
y 
n 
3.2  
Translation frequency 
y 
y 
3.3  
SARR G/T 
y 
y 
3.4  
Axial Ratio 
optional 
n 
3.5  
SARR Dynamic Range in AGC Mode 
y 
n 
3.6  
Channel Bandwidth and Amplitude Ripple 
y 
y (operational mode only) 
3.7  
Linearity/Third Order Intermodulation 
y 
n 
3.8  
SARR Downlink EIRP 
y 
y 
3.9 
Transponder Group Delay Variation as a 
Function of Frequency 
y 
n 
3.10 Spurious Output Levels 
y 
y 
3.11 Beacon Signal Processing 
y 
y 
Note: 1. The schedule of these tests shall be determined by the space segment operator. 
 
Consistent with section 2.2, it is the responsibility of each commissioning authority to develop the 
detailed procedures for conducting tests on their MEOSAR payload. Such detailed procedures should 
be traceable to the test objectives and high-level procedures described in this section below. Alternate 
methods can be used but must be described in detail in the commissioning report, including the test 
setup, with the test result documentation provided. An example of an alternate method would be if the 
commissioning authority elects to specify uplink transmit power into the antenna instead of EIRP. 
 


 
3-2 

3.1 
SAR Repeater Gain 
3.1.1 
Objective 
The objective of this test is to measure the SARR gain including ultra-high frequency (UHF) receiver 
antenna gain, SARR payload and L-band transmitting antenna gain.  
3.1.2 
Procedure 
The SARR gain is to be expressed in boresight conditions for the satellite-onboard receive and transmit 
antennas. 
 
The SARR can be stimulated, in any operational mode, with a continuous wave (CW) frequency (UHF) 
signal generated by a signal generator. Then the satellite gain can be calculated based upon: 
• 
uplink transmitted EIRP, 
• 
power received from the satellite downlink (measured on ground). 
The procedure steps are the following: 
a) compute EIRPDL (SARR EIRP) in the direction of the ground station as: 
 
𝐸𝐼𝑅𝑃𝐷𝐿|𝑑𝐵𝑚= 𝑃𝑆𝐴|𝑑𝐵𝑚−𝐺𝐷𝐿|𝑑𝐵−𝐺𝐹𝑆𝐿|𝑑𝐵−𝐺𝐴𝑇𝑀
𝐷𝐿|𝑑𝐵−𝐺𝑃𝑂𝐿
𝐷𝐿|𝑑𝐵 
 
where: 
• 
PSA is the measured power level at the ground station spectrum analyser (SA), 
• 
GDL is the gain in the direction of the satellite of the ground station receiver chain path (i.e., 
from the receiver antenna (including antenna gain) to the spectrum analyser (SA)) (the test 
setup must ensure the stability of this term during the test), 
• 
GFSL is the free space loss in dB: 
𝐺𝐹𝑆𝐿= 20 𝑙𝑜𝑔( 𝜆
4𝜋𝑅) 
where R is the downlink range and λ is the downlink wavelength, 
• 
𝐺𝐴𝑇𝑀
𝐷𝐿 is the atmospheric loss expressed as a negative gain for the downlink path, as defined 
in Annex B, 
• 
𝐺𝑃𝑂𝐿
𝐷𝐿|𝑑𝐵– downlink polarization losses1 expressed as a negative gain.  
Compute the satellite EIRP downlink in boresight conditions, if possible.2 
 
1 Note that if the UHF ground transmitting antenna and the L-band ground receiving antenna match satellite antennas 
polarization this parameter can be neglected. 
2 Satellite maximum EIRP (boresight) can be derived from the EIRP in the direction of the ground station calculated 
above and the knowledge of the space-to-ground antenna geometry to compensate for the variations in antenna gains. 


 
3-3 

b) compute EIRPUL (uplink EIRP) in the direction of the satellite as: 
𝐸𝐼𝑅𝑃𝑈𝐿|𝑑𝐵= 𝑃𝑃𝑀|𝑑𝐵+ 𝐺𝑈𝐿|𝑑𝐵 
where:  
• 
PPM is the uplink transmitter power, 
• 
GUL is the gain of the uplink transmitting chain path from the output of the transmitter to 
the output of the transmitting antenna (including coupler losses) in the direction of the 
satellite. This could be found from the radiation pattern of the uplink antenna, if known. 
c) compute the Input Power Flux Density Uplink (IPFDUL) at the satellite as: 
𝐼𝑃𝐹𝐷𝑈𝐿|𝑑𝐵𝑚/𝑚2 = 𝐸𝐼𝑅𝑃𝑈𝐿|𝑑𝐵𝑚−𝑆𝐹|𝑑𝐵/𝑚2 + 𝐺𝐴𝑇𝑀
𝑈𝐿|𝑑𝐵 
where: 
• 
EIRPUL is computed above, 
• 
SF is the signal spreading factor:  
𝑆𝐹= 10𝑙𝑜𝑔(

4𝜋𝑅2) 
• 
𝐺𝐴𝑇𝑀
𝑈𝐿 is the atmospheric loss expressed as a negative gain for the uplink path, as defined in 
Annex B, 
d) compute GS satellite repeater gain as: 
𝐺𝑆|𝑑𝐵= 𝐸𝐼𝑅𝑃𝐷𝐿|𝑑𝐵𝑚−𝑃𝑖𝑛|𝑑𝐵𝑚 
where: 
• 
Pin is the power into the satellite receiver antenna (in boresight conditions)3: 
𝑃𝑖𝑛= 𝐼𝑃𝐹𝐷𝑈𝐿|𝑑𝐵𝑚/𝑚2 + 𝐴𝑒+ 𝐺𝑃𝑂𝐿
𝑈𝐿|𝑑𝐵 
• 
EIRPDL|dBm is the satellite downlink EIRP (in boresight conditions4): 
𝐺𝑆|𝑑𝐵= 𝐸𝐼𝑅𝑃𝐷𝐿|𝑑𝐵𝑚−𝐼𝑃𝐹𝐷𝑈𝐿|𝑑𝐵𝑚/𝑚2 −𝐴𝑒−𝐺𝑃𝑂𝐿
𝑈𝑃|𝑑𝐵 
where: 
• 
Ae is effective aperture: 
𝐴𝑒= 𝑋𝑆𝐼+ 𝐺𝑟  
with: 
▪ 
XSI is the isotropic cross section at the uplink frequency: 
𝑋𝑆𝐼= 10 𝑙𝑜𝑔(𝜆2
4𝜋) 
where λ is the uplink wavelength (at satellite UHF antenna), 
 
3 If Pin is not available in boresight conditions, satellite-to-ground station geometry should be provided. 
4 If the downlink EIRP is not available in boresight conditions, satellite-to-ground station geometry should be 
provided. 


 
3-4 

▪ 
Gr is the gain of the satellite onboard receiver antenna in the direction of 
the uplink transmitter which can be determined from the radiation pattern 
of the antenna5, 
• 
dB
UL
POL
G
is uplink polarization losses expressed as a negative gain. 
3.2 
Translation Frequency 
3.2.1 
Objective 
The objective of this test is to measure the frequency translation between uplink and downlink 
frequencies implemented by the SARR payload. The values measured will be compared with the 
requirements reported in the payload description. 
3.2.2 
Procedure 
The measurement system transmits a CW test carrier signal to the satellite and then measures the return 
carrier to earth station. The frequency of the downlink carrier is measured by a SA. Translation 
frequency is the difference between uplink and downlink frequencies. According to satellite ephemeris, 
uplink and downlink frequencies have to be corrected for Doppler shift. 
3.3 
SARR G/T 
3.3.1 
Objective 
The objective of this test is to measure the 406 MHz SARR receiver antenna gain-to-noise temperature 
ratio (G/T). The measured value will be compared with the level specified in document C/S T.016. 
3.3.2 
Procedure 
The on-orbit G/T in dB/K can be derived by using the following equation: 
𝐺
𝑇= 𝐶
𝑁0
(𝑢𝑝) −𝐸𝐼𝑅𝑃(𝑢𝑝)|
𝑑𝐵𝑚
−𝐺𝐹𝑆𝐿|𝑑𝐵−𝐺𝐴𝑇𝑀
𝑈𝑃|𝑑𝐵−𝐺𝑃𝑂𝐿
𝑈𝑃|𝑑𝐵+ 𝑘 
where: 
• 
𝐶
𝑁0 (𝑢𝑝) is the carrier to noise density ratio in the SAR repeater (dBHz), 
• 
EIRP(up) is the known up-link EIRP (dBm), 
• 
GFSL is the uplink free space path loss (dB), 
• 
𝐺𝐴𝑇𝑀
𝑈𝑃|𝑑𝐵 is the uplink negative valued atmospheric gain, 
 
5 If the gain is not available in in the direction of the uplink transmitter, satellite-to-ground station geometry should be 
provided. 


 
3-5 

• 
𝐺𝑃𝑂𝐿
𝑈𝑃 is the polarisation mismatch negative valued gain between the uplink antenna and the 
satellite receive antenna (dB), 
• 
k is the Boltzmann's constant (-198.6 dBm/Hz-K). 
 
C/N0(up) is calculated from the overall C/N0(total) measured at the ground test facility by subtracting 
out the ground station receiver noise. The N0 (total) observed at the ground station consists of two 
parts: N0(total) = N0(up) + N0(gs) where N0(gs) is the ground station receiver noise. N0(gs) can be 
measured by pointing the ground station antenna away from the MEOSAR spacecraft but not in the 
beam width of stellar sources emitting high radio frequency energy levels. 
 
The general procedure is as follows: 
a) Uplink a known CW EIRP ( 40 dBm) in a non operational channel of the 406 MHz band. 
b) Monitor the received signal using a spectrum analyser. This can be done after demodulation 
and/or filtering to baseband. Adjust ground station antenna azimuth and elevation to maximise 
the received level. Set analyser resolution bandwidth such that C/N(total)  20 dB. Measure 
values of C/N0(total), C, and N0(total). The noise spectral density values can be measured 
directly using the spectrum analyser if it has an automatic noise density measuring feature. If 
not, the noise power, N(total) measured in the analyser resolution bandwidth can be converted 
to No(total) by applying the bandwidth correction plus any other correction factors specified 
for the analyser. 
c) Adjust the ground station antenna pointing such that it points away from the MEOSAR satellite 
under test by at least 15 but not in the field of view (FOV) of stellar sources emitting high 
radio frequency energy levels. Measure the clear sky ground station receiver noise, N0(gs). 
d) Compute N0(up) = N0(total) - N0(gs) and use the value to determine C/N0(up) (convert as 
needed between numerics and dB). 
e) Derive G/T with the equation above. 
3.4 
Axial Ratio (Optional) 
3.4.1 
Objective 
The objective of this test is to measure the axial ratio of the satellite L-band transmit antenna, by means 
of a rotatory linearly polarized L-band receiving antenna at the measurement station. 
3.4.2 
Procedure 
A CW carrier in the 406 MHz band of suitable EIRP is uplinked to the satellite and the satellite 
downlink EIRP is computed as described in section 3.1.2. Next, the receiving antenna is rotated through 
a predetermined angle (e.g., a 10° step) and the satellite EIRP is measured again. These measurement 
steps are repeated until the receiving antenna has been turned by 180° or preferably 360°.  
 


 
3-6 

The axial ratio is derived by reconstructing the EIRP ellipse and finding its major and minor axes (i.e., 
maximum and minimum EIRP) using interpolation or curve fitting between data points as required. 
The axial ratio is then determined as the difference (ratio) between the maximum and minimum 
computed EIRP. 
3.5 
SARR Dynamic Range in AGC Mode 
3.5.1 
Objective 
The objective of this test is to determine the SARR dynamic range in AGC mode. 
3.5.2 
Procedure 
The dynamic range is a measure of the transponder output power versus transponder input power. This 
procedure uses unmodulated carrier signals only. The uplink signal EIRP is varied in level over the 
dynamic range of the SAR receiver, from near input noise to the maximum signal into the transponder 
at the threshold of triggering the AGC function. The resulting downlink carrier level, Cd, is measured 
using a spectrum analyzer. In a plot of transponder output power versus input power, the dynamic 
range is the linear part of the curve before the AGC is triggered. 
 
The general procedure is as follows: 
a) Begin with no uplink. Monitor the downlink to ensure that no active beacons or interference 
signals are present.  
b) Establish a CW uplink signal at a frequency near mid-band and an EIRP of 5 Watts. Observe 
this signal on the downlink using the spectrum analyzer. Increase the uplink signal level to the 
point where the observed downlink signal, Cd, does not continue to increase, i.e., the AGC is 
operating at the upper limit of the dynamic range. Record the uplink EIRP, the value of the 
measured downlink signal and the SAR receiver N0 (measured a few kHz away from Cd using 
the spectrum analyzer). The downlink should be free of interference when making these 
measurements. 
c) Decrement the CW uplink signal in 1 dB steps; monitor the downlink to ensure that there is no 
interference present and record the measured values of Cd, N0 and the uplink EIRP. Continue 
to reduce the uplink signal by 1 dB and make the measurements until Cd approaches the 
receiver noise level. 
d) The range of uplink EIRP from where the AGC starts to operate down to where Cd approaches 
the receiver noise level is the SARR transponder dynamic range in AGC mode. This can be 
confirmed if required by calculating transponder input power and output power pairs based on 
transmitted EIRP and received Cd, plotting those power pairs in numeric form, and confirming 
a linear plot. This test should be done rapidly to minimize change in satellite-to-ground 
geometry. 


 
3-7 

3.6 
Channel Bandwidth and Amplitude Ripple 
3.6.1 
Objective 
The objective of this test is to measure the downlink channel bandwidth and amplitude ripple in the 
MEOSAR repeater channel. The test must be performed for each channel bandwidth mode of operation 
intended for service (narrowband/wideband, fixed gain mode and AGC mode). 
3.6.2 
Procedure 
This test can be conducted as a passive test without uplink signal (preferrable if possible) or as an 
active test with uplink CW signals. 
 
In the passive case, the level of 406 MHz beacon signals received at the spacecraft is sufficiently small 
such that under normal situations a band of white noise generated by the payload LNA is transmitted 
on the channel. The amplitude ripple of the channel can be estimated by observing this band of noise 
power using the ground test facility equipment. The observation should be done during a "quiet" period, 
i.e., no interference or the appearance of large test signals. 
 
The procedure steps are the following: 
a) With the spacecraft in the narrowband fixed gain mode if applicable, monitor the downlink 
signal in the ground station receiver IF ahead of any filtering that would corrupt the channel 
measurement. The analyser centre frequency, resolution bandwidth and span should be 
adjusted to appropriately display the channel data. 
b) Take a spectrum plot during a quiet period. 
c) Estimate the amplitude ripple from the plot. 
d) Use the spectrum analyser offset markers to identify the 3-dB bandwidth. Record the 
measurement for the test report. 
e) Repeat steps a through d for the other possible modes as applicable narrowband AGC, 
wideband fixed gain, wideband AGC. 
If finding a “quiet period” is problematic, as an alternative, an active uplink swept frequency test can 
be used. In this active case, repeatedly uplink to the payload a CW signal at constant EIRP (e.g., 37 dBm 
EIRP) and capture the resulting downlink baseband spectral plot noting the CW C/N0. Start the uplink 
CW near the lower end of the 406 MHz SAR band, and increment the frequency of each repeated CW 
signal toward the upper end of the 406 MHz SAR band. Merge the spectral plots resulting from each 
uplinked CW signal into a single spectral plot. From the merged spectral plot, estimate the amplitude 
ripple from the envelope of baseband CW magnitude, and determine the 3-dB channel bandwidth of 
the repeater. This test should be done rapidly to minimize change in satellite-to-ground geometry. 


 
3-8 

3.7 
Linearity/Third Order Intermodulation 
3.7.1 
Objective 
The objective of this test is to detect and measure intermodulation products that might be produced by 
two large in-band test signals in the 406 MHz SARR frequency band. 
3.7.2 
Procedure 
For testing in-band intermodulation products, two strong uplink carriers are simultaneously transmitted 
from the test ground station to the 406 MHz SARR receiver. All tests are performed with the receivers 
in the AGC mode, using a nominal channel frequency of 406.050 MHz. The in-band uplink frequencies 
are as follows: 
• 
fl = nominal channel frequency - 1 kHz,  
• 
f2 = nominal channel frequency + 1 kHz. 
 
When intermodulation products are generated, the third order intermodulation products are generally 
the strongest and occur at 2f1-f2 and 2f2-f1. If f1 equals nominal frequency minus 1 kHz and f2 equals 
nominal frequency plus 1 kHz, then the third order intermodulation products would be at the nominal 
frequency -3 kHz and at the nominal frequency +3 kHz. Therefore, for a receive system with a 70 MHz 
IF frequency the (IF) frequencies to search in order to detect any third order intermodulation products 
are as follows: 
 
 
Nominal Channel 
Lower intermodulation 
product 
Upper intermodulation 
product 
Channel 
Frequency (MHz) 
Frequency (MHz) 
Frequency (MHz) 
406.05 MHz 

69.997 
70.003 
 
The uplink EIRP for each test signal should be strong enough to produce intermodulation products in 
the satellite receiver, but not too strong to cause any damage to the satellite receive system. One way 
to do this is to transmit each test signal at an EIRP of 7dBW, and then increase the uplink EIRP until 
intermodulation products are seen on the downlink spectrum. Increments in the uplink EIRP can be 
made as long as the combined uplink signal power into the satellite receiver payload remains 6 dB 
below the receiver input power upper limit. 
 
In order to avoid intermodulation products from the test ground station test system itself, separate 
transmitter chains are used for the two uplink signals. 
 
As a consequence of running this test, harmonic products may also be detected in the 406 MHz SARR 
frequency band and reported. 
 


 
3-9 

3.8 
SARR Downlink EIRP 
3.8.1 
Objective 
The objective of this test is to compute SARR maximum/minimum downlink EIRP, and to compare 
results with payload description. 
3.8.2 
Procedure 
This test should be conducted as a passive test without uplink test signal, for each operational mode of 
the satellite payload. 
 
Choose a high elevation satellite pass (e.g., 60 degrees or more), and monitor the satellite downlink 
signal using a spectrum analyser. Set the resolution bandwidth (RBW) value of the analyser to the 
satellite payload downlink 3 dB bandwidth frequency range (fR) (e.g., 100 kHz) as per document 
C/S T.016. Consider (fC) the centre frequency of the satellite downlink band. Set the analyser frequency 
measurement span at least from fC - 1.5fR to fC + 1.5fR, such that the analyser will sweep completely 
across the downlink frequency range. 
 
From time of start of test to end of test, capture at least 50 spectral plot snapshots equally spaced in 
time. The test should last long enough to capture the minimum and maximum EIRP values over a pass.  
 
For each spectral plot snapshot: 
a) Measure the peak power (PSA) captured by the spectrum analyser which should occur 
approximately at the downlink centre frequency (possibly plus or minus small Doppler shift). 
b) Calculate the downlink EIRP using the equation provided in section 3.1.2 (a). 
c) If the radiation pattern of the satellite downlink antenna is known, adjust the calculated 
downlink EIRP to the value that would be transmitted if the satellite was passing directly over 
the test facility ground station. 
Plot all downlink EIRP values (indicating whether they have been adjusted as above or not) on a graph. 
Report the graph, and maximum and minimum EIRP values from the graph. Report the geometry of 
the pass (e.g., elevation angles at the beginning and end of the measurement period, and at maximum). 
 
Alternate procedures may be possible (such as to use fixed tune mode with zero span for the spectrum 
analyzer), and some experimentation with detailed procedures and analyser settings by the tester may 
be required. 
3.9 
Transponder Group Delay Variation as a Function of Frequency 
3.9.1 
Objective 
The objective of this test is to compute transponder group delay variation as a function of frequency. 


 
3-10 

3.9.2 
Procedure 
The forward group delay of SARR payload is measured using the modulation envelope delay model. 
The frequency modulated uplink signal is generated by a signal synthesizer. The earth station group 
delay is calibrated out at the time of the measurement by switching between satellite signal and signal 
loopback through the Test Loop Translation, that upconverts the signal from the 406-MHz band to L-
band (or S-band). Both over-the-satellite and loopback calibration measurement are performed with 
the same SA signal captured in IQ sampling mode. 
 
Measured modulation data points are converted to a delay given the range to the satellite at the time of 
each data minus the one-way trip delay to the satellite (i.e., where the satellite was for the 
corresponding signal when it arrived at the SA). 
 
Transponder delay is computed as follows: 
 
𝑅𝑜𝑢𝑛𝑑𝑇𝑟𝑖𝑝𝐷𝑒𝑙𝑎𝑦= 𝑅𝐵𝐸𝐴𝐶𝑂𝑁
𝑐
+ 𝑅𝑀𝐸𝑂𝐿𝑈𝑇
𝑐
+ 𝐼𝑜𝑛𝑜𝑠𝑝ℎ𝑒𝑟𝑒𝐶𝑜𝑟𝑟𝑈𝐻𝐹+ 
𝐼𝑜𝑛𝑜𝑠𝑝ℎ𝑒𝑟𝑒𝐶𝑜𝑟𝑟𝐿𝑆𝑏𝑎𝑛𝑑+ 2𝑇𝑟𝑜𝑝𝑜𝑠𝑝ℎ𝑒𝑟𝑒𝐶𝑜𝑟𝑟 
 
 
RoundTripDelayPhaseShift = 360RoundTripDelay * Fm 
 
 
𝑇𝑟𝑎𝑛𝑠𝑝𝑜𝑛𝑑𝑒𝑟𝑃ℎ𝑎𝑠𝑒𝑆ℎ𝑖𝑓𝑡𝑅𝑎𝑤= −(
𝑀𝑒𝑎𝑠𝑢𝑟𝑒𝑑𝑃ℎ𝑎𝑠𝑒𝑆ℎ𝑖𝑓𝑡−
𝐿𝑜𝑜𝑝𝑏𝑎𝑐𝑘𝑃ℎ𝑎𝑠𝑒𝑆ℎ𝑖𝑓𝑡−𝑅𝑜𝑢𝑛𝑑𝑡𝑟𝑖𝑝𝑑𝑒𝑙𝑎𝑦𝑃ℎ𝑎𝑠𝑒𝑠ℎ𝑖𝑓𝑡) 
 
(in the range 0-360 degrees) 
 
𝑇𝑟𝑎𝑛𝑠𝑝𝑜𝑛𝑑𝑒𝑟𝐷𝑒𝑙𝑎𝑦= 𝑇𝑟𝑎𝑛𝑠𝑝𝑜𝑛𝑑𝑒𝑟𝑃ℎ𝑎𝑠𝑒𝑆ℎ𝑖𝑓𝑡


𝐹𝑚+ 𝐷𝑒𝑙𝑎𝑦𝐶𝑜𝑟𝑟𝑒𝑐𝑡𝑖𝑜𝑛 
 
where: 
• 
RBEACON and RMEOLUT are satellite ranges w.r.t. the beacon and the MEOLUT, respectively, 
• 
Fm is modulation frequency, 
• 
MeasuredPhaseShift is the signal phase measured for the downlink signal, 
• 
LoopbackPhaseShift is the signal phase measured for the loopback path, 
• 
DelayCorrection is a correction due to the slight difference in path between the loopback 
and the RF signal paths, 
• 
𝐼𝑜𝑛𝑜𝑠𝑝ℎ𝑒𝑟𝑒𝐶𝑜𝑟𝑟𝑈𝐻𝐹and 𝐼𝑜𝑛𝑜𝑠𝑝ℎ𝑒𝑟𝑒𝐶𝑜𝑟𝑟𝐿𝑆𝑏𝑎𝑛𝑑are ionospheric delays correction 
that have to be computed and taken into account. The measurement of ionospheric delay 
requires a double frequency GNSS receiver tracking the satellite under test: the 
computation of ionospheric delay is as follows: 
)

,
(
tRaw
rPhaseShif
Transponde
MOD
t
rPhaseShif
Transponde
=


 
3-11 

𝐼𝑜𝑛𝑜𝑠𝑝ℎ𝑒𝑟𝑒𝐶𝑜𝑟𝑟(𝑓𝑡) = 𝑓1
2𝑓2
2(𝜌2 −𝜌1)
(𝑓1
2 −𝑓2
2)𝑓𝑡

where: 
• 
ρ1 and ρ2 are the ranging measurement provided by the receiver from frequency f1 and 
f2 respectively, 
• 
f1 and f2 are the two frequencies of the two ranging signals,  
• 
ft is the frequency for which the ionospheric correction is calculated. 
 
Measurement of the group delay variation as a function of frequency can be performed repeating the 
previous procedure at different uplink frequencies (within the 406-406.1 MHz UHF band) or 
comparing the 406.05 MHz group delay with the one at the other frequencies. 
 
The commissioning authority will provide data on measurement accuracy in the commissioning report. 
3.10 
Spurious Output Levels 
3.10.1 
Objective 
The objective of this test is to determine the frequency and level of any in band spurious signals within 
the SARR bandwidth. 
3.10.2 
Procedure 
This test must be performed for all operational modes of the satellite payload. 
 
This test is passive without an uplink signal. Spurious signals within the repeater bandwidth can be 
monitored in the baseband spectrum using a spectrum analyser. These measurements should be made 
as accurately as possible; therefore, they should be made with as small a resolution bandwidth as 
practical (e.g., 100 Hz). 
 
Care must be exercised in identifying spurious signals generated by on-board equipment. To that end, 
if possible, monitor the spectrum prior to turning on the SARR payload. The spurious signals 
originating on board will in general not vary much in frequency due to the slow motion of the 
MEOSAR satellite (e.g., ± 1300 Hz). However, terrestrially emitted spurious signals in the 406 MHz 
band may also appear and will need to be disregarded. 
 
It may be necessary to take several spectrum plots over a number of days to identify on-board spurious 
signals from terrestrial emitters. The test personnel can also ask for assistance from MEOLUT 
operators in identifying terrestrial emitters. The MEOSAR spacecraft can be used to identify these 
terrestrial spurious signals due to their Doppler shift at the MEOSAR spacecraft. 
 


 
3-12 

The frequency and magnitude of any in-band spurious signal can be read using the spectrum analyser. 
The magnitude of the onboard spurious signal can be referred back to the payload using a link budget 
calculation. 
 
Finally, a comparison between spectra received from the spacecraft with reference spectra from the 
ground receiving system should be used to discriminate between suspected spacecraft generated 
onboard spurious signals and locally generated signals by the test receiver system on the ground. The 
receiving system reference spectrum must be taken with the ground station antenna not pointing at any 
spacecraft. 
3.11 
Beacon Signal Processing 
3.11.1 
Objective 
The objective of this test is to demonstrate that 406 MHz beacon signals relayed through the MEOSAR 
satellite repeater can be properly incorporated into the processing of a MEOLUT with sufficient 
reliability for distribution within the Cospas-Sarsat network. This test is also useful for trend analysis 
overtime and does not have a pass/fail criterion. 
 
This test is intended to be performed using FGB signals. In addition, testing may also be performed 
using SGB signals. 
3.11.2 
Procedure 
Beacon simulator output signals at specific transmitter power levels, or EIRP levels if a directional 
antenna is used, will be transmitted to the MEOSAR satellite and relayed to a MEOLUT tracking the 
payload for reception and processing. The results are compiled based on the MEOLUT processing of 
a single channel corresponding to the payload under test.  
 
The following procedures should be used: 
• 
ensure that the beacon simulator to be used for the test is located within the satellite 
footprint of the satellite as it is being tracked by the MEOLUT used for the test. 
• 
for the first generation beacon case, select a frequency channel to avoid as much as possible 
interference with operational channels. 
• 
transmit a minimum of 100 bursts at each of four transmitter power levels into the antenna 
(nominally 39, 37, 32, and 27 dBm, with an accuracy of ± [1] dB). If a directional antenna 
is used, the transmit EIRP levels should be 39, 37, 32, and 27 dBm, with an accuracy of 
± [1] dB based on the antenna vendor radiation pattern specification. The bursts at each 
power level should be repeated at intervals of every 20 seconds and the bursts between 
power levels should be interleaved with a 5-second interval, from highest to lowest power 
level. This script will produce a total of 400 bursts. The antenna pattern (e.g., as published 
by the vendor, or measured in an anechoic chamber), the start and stop time of the test, and 
the transmitter location information shall be provided. For the purpose of trend analysis 


 
3-13 

each execution of this procedure should be done during the same portion of the satellite 
pass used in previous tests (to the best extent possible). 
• 
for each transmitted burst, collect the received burst at the MEOLUT from the satellite 
under test and capture the associated C/N0 value. 
For each transmitted power level (or EIRP level): 
• 
determine and plot in a histogram and/or a cumulative distribution of the received burst 
C/N0 values, 
• 
compile the lists of all messages produced and determine the number of valid messages 
(NVM) and, optionally, the number of complete messages (NCM), 
• 
determine the number of transmitted bursts (NTB) that should have been received. 
Compute the single satellite channel throughput (NVM)/NTB) and the average C/N0 for each transmit 
power level or EIRP and compare the results with typical values. 
 
Optionally, compute the single satellite channel throughput for complete messages (NCM/NTB) and 
the average C/N0 for each transmit power level or EIRP. 
 
If this test is with SGB signals, the test procedure should be the same using the same transmit power 
levels (or EIRP levels), but only valid messages should be considering, as the complete/incomplete 
message category do not apply for SGBs. 
 
 
 
- END OF SECTION 3 - 
 
 
 


 
4-1 

4. 
MEOSAR SPACE SEGMENT PARAMETER ASSESMENT COMPLIANCE 
INDICATORS  
Assessment Indicator 
Compliance Level Reference 
GPS  
(S-band / L-band) 
GALILEO 
GLONASS 
BDS 
Translation Frequency 
S-band: C/S T.016, Table 3.1 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
Translation Frequency stability  
(if available) 
S-band: C/S T.016 Table 3.1 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
G/T 
S-band: C/S T.016, Table 3.1 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
Axial Ratio (optional) 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
Amplitude Transfer Function in AGC 
mode 
S-band: C/S T.016, Table 3.1 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
1 dB bandwidth in Narrowband Mode 
(2) 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
1 dB bandwidth in Normal Band Mode 
S-band: C/S T.016, Table 3.1 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
Third Order Intermodulation Level 
S-band: C/S T.016, Table 3.2 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
EIRP 
S-band: C/S T.016, Table 3.2 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
Forward Group Delay Slope 
S-band: C/S T.016, Table 3.1 
L-band: TBD 
C/S T.016,  
Table 4.3(1) 
C/S T.016,  
Table 5.2 
C/S T.016,  
Table 6.2 
Repeater Transmit Emission Mask 
TBD 
TBD 
TBD 
TBD 
Beacon Signal 
Processing(3) 
Single channel valid 
message detection 
probability 
No compliance level reference applicable 
Average C/N0 
No compliance level reference applicable 
Table 4.1: MEOSAR Space Segment Assessment Indicators / Compliance Levels 
Notes: 
(1) Refer to the “Interoperability Requirement” column of C/S T.016, Table 4.3 
(2) S-band satellites do not have a narrow band mode; availability of L-band narrow mode 
TBD 
(3) See document C/S T.017, section 3.11 
TBD: To Be Defined 


 
4-2 

- END OF SECTION 4 - 
 
 


 
5-1 

5. 
MEOSAR SATELLITE STATUS COMMUNICATION 
5.1 
MEOSAR Satellite Status Communication 
Once the commissioning tests are conducted, the commissioning authority shall communicate the 
MEOSAR satellite operational status for it to be used for operation by the Ground Segment Operators 
as per Figure 2.1. After the communication of the satellite commissioning status defined in this section, 
changes in MEOSAR payload status shall be notified to all Ground Segment Operators as defined in 
document C/S A.001. 
5.1.1 
MEOSAR Satellite IOC Communication 
Should the results of the commissioning tests conducted by the commissioning authority confirm that 
the payload performance does not adversely affects the SAR operations, the commissioning authority 
may inform Ground Segment Operators that the payload could now be used for initial operation by 
declaring its IOC status. Table 5.3 should provide sufficient results to offer assurance that the payload 
could be used safely. 
 
To communicate the IOC status of the payload, the commissioning authority shall distribute the 
information identified in sections 5.2.1 and 5.2.2, as available, throughout the System using a SIT 605 
message. This will allow the early operational use of the satellite and will inform MEOLUT operators 
that their MEOLUT(s) can now process and distribute distress signal alerts relayed from the MEOSAR 
payload while the commissioning report is in preparation. Items not tested during the commissioning 
tests must be so noted as comments in the SIT 605 message. An example of a SIT 605 message 
declaring a MEOSAR satellite IOC status is provided at section 5.3. 
5.1.2 
MEOSAR Satellite FOC Communication 
Should the commissioning test results allow the commissioning authority to declare the FOC status of 
the MEOSAR satellite, the commissioning authority shall distribute the information contained in the 
commissioning report as identified in sections 5.2.1 and 5.2.2 throughout the C/S System using a 
SIT 605 message to allow the full operational use of the satellite by MEOLUT operators and MCCs. 
An example of a SIT 605 message declaring a MEOSAR satellite FOC status is provided at section 5.3. 
5.1.3 
MEOSAR Satellite LOC Communication 
Should the MEOSAR payload be declared with a LOC status (see section 2.3), the commissioning 
authority shall distribute the information contained in the commissioning report as identified in 
sections 5.2.1 and 5.2.2, including the limitations identified, throughout the System using a SIT 605 
message to allow the operational use of the satellite by MEOLUT operators and MCCs. An example 
of a SIT 605 message declaring a MEOSAR satellite LOC status is provided at section 5.3. 


 
5-2 

5.2 
MEOSAR Satellite Information 
5.2.1 
Satellite Status and Mode Information 
Table 5.1 provides the satellite status information to be provided throughout the System. 
 
Payload Status: 
IOC, FOC or LOC 
Initial operational configuration 
 
Channel Bandwidth: 
WB or NB (where applicable) 
Gain Mode: 
AGC or FGM (where applicable) 
Operational Limitations: 
 
Other Remarks: 
 
Commissioning Authority: 
Date: 
Table 5.1: Satellite Status Information 
 
Table 5.2 provides the information regarding the commissioned payload modes to be provided 
throughout the System (only applicable to satellite FOC or LOC status communication). 
 
Spacecraft ID: 
Date: 
Mode 
Commissioning Status (FOC, 
LOC, Not Operational) 
Comments (e.g., initial operation mode) 
NB/FGM 
 
 
NB/AGC  
 
 
WB/FGM 
 
 
WB/AGC 
 
 
Table 5.2: Commissioned Payload Modes 
5.2.2 
Commissioning Test Results Summary 
Table 5.3 provides the technical information to be provided to MEOLUT operators throughout the 
System. 
 


 
5-3 

Spacecraft ID: 
Date: 
Test 
Results 
Pass/fail 
Comments 
3.1 
SAR Repeater Gain 
 
 
 
3.2 
Translation frequency 
 
 
 
3.3 
SARR G/T 
 
 
 
3.4 
Axial ratio (optional) 
 
 
 
3.5 
SARR Dynamic Range in AGC Mode 
 
 
 
3.6 
Channel Bandwidth and Amplitude Ripple 
 
 
 
3.7 
Linearity/Third Order Intermodulation 
 
 
 
3.8 
SARR Downlink EIRP 
 
 
 
3.9 
Transponder Group Delay Variation as a 
Function of Frequency 
 
 
 
3.10 
Spurious Output Levels 
 
 
 
3.11 
Beacon Signal Processing 
 
n/a 
 
Table 5.3: Commissioning Test Results Summary 
5.3 
Example of SIT 605 Communication for MEOSAR Satellite Commissioning Status 
An example of SIT 605 message to be sent to inform MCCs of MEOSAR satellite IOC, FOC or LOC 
status is provided in Table 5.4. 
 
FROM FMCC 
TO ALL MCC 
SUBJ: COSPAS-SARSAT MEOSAR-EQUIPPED SATELLITE COMMISSIONING 
 
A.  OBJECTIVE: SATELLITE GALILEO 436 COMMISSIONING 
 
B.  COMMISSIONING AUTHORITY: EC/GSA 
 
C.  SATELLITE DETAILS:  
        - COSPAS/SARSAT SATELLITE ID: 436 
        - SATELLITE NAME: GSAT0219 
        - SATELLITE ORBIT: MEO 
        - LAUNCH DATE (DD/MM/YYYY): 25/07/2018 
 
D.  STATUS: PAYLOAD COMMISSIONED AT [IOC/FOC/LOC] STATUS 
 
E.  SINCE (DD/MM/YYYY): DD/MM/YYYY 
 
F.  CURRENT SAR PAYLOAD MODE: 
    
- SART STATUS: ON 


 
5-4 

- SARR BW: 90 KHZ 
- SARR MODE: AGC  
   
- OPERATIONAL LIMITATIONS (IF ANY OR NONE): NONE 
 
G. COMMISSIONED MODES [FOR FOC OR LOC COMMUNICATION, AS APPLICABLE] 
CONFIGURATION                            PASS/FAIL               STATUS                        COMMENTS 
NB/FGM                                             PASS                         OPERATIONAL 
NB/AGC                                              PASS                         OPERATIONAL           INITIAL OPERATION MODE 
WB/FGM                                            PASS                         OPERATIONAL 
WB/AGC                                             PASS                         OPERATIONAL 
 
H. REMARKS 
[E.G., LOC LIMITATIONS IF ANY] 
 
I. TEST RESULTS 
TEST                                                     RESULT                   PASS/FAIL      COMMENTS 
3.1 SARR GAIN                                   174.65 DB                 PASS 
--------------------------------------------------------------------------------------------------------------- 
3.2 TRANSLATION FREQUENCY     1138.049998 MHZ   PASS 
--------------------------------------------------------------------------------------------------------------- 
3.3 SARR G/T                                      -11.71 DB/K             PASS                 AT CENTER OF COVERAGE 
--------------------------------------------------------------------------------------------------------------- 
3.4 AXIAL RATIO (OPTIONAL)         0.71 DB                    PASS                  IOT TEST 
--------------------------------------------------------------------------------------------------------------- 
3.5 SARR DYNAMIC RANGE                                              PASS 
      IN AGC MODE 
--------------------------------------------------------------------------------------------------------------- 
3.6 CHANNEL BANDWIDTH                                              PASS 
      AND AMPLITUDE RIPPLE 
--------------------------------------------------------------------------------------------------------------- 
3.7 LINEARITY/THIRD ORDER        > 29.32 DBC            PASS 
INTERMODULATION 
--------------------------------------------------------------------------------------------------------------- 
3.8 SARR EIRP                                   19.5 DBW                  PASS                  AT CENTER OF COVERAGE 
--------------------------------------------------------------------------------------------------------------- 
3.9 TRANSPONDER GROUP DELAY     < 10 μs/4kHz      PASS 
      VARIATION AS A FUNCTION OF FREQUENCY 
--------------------------------------------------------------------------------------------------------------- 
3.10 SPURIOUS OUTPUT LEVEL          NONE                  PASS 
--------------------------------------------------------------------------------------------------------------- 
3.11 BEACON SIGNAL PROCESSING    >95%                  N/A              AT 37 DBM OF BEACON POWER 
 
J.  ADDITIONAL INFORMATION: 
   - AVAILABLE AT WWW.COSPAS-SARSAT.INT  
   - THIS SATELLITE SUPPORTS THE SAR/GALILEO RETURN LINK SERVICE 
   -  … 
    
Table 5.4: Example of SIT 605 Message for 
Initial Status Communication of MEOSAR Satellite 
 
 
- END OF SECTION 5 - 


 
6-1 

6. 
MEOSAR SATELLITE COMMISSIONING REPORT 
As mentioned in previous sections, upon completion of all tests, the commissioning authority will 
evaluate the assessment indicators and prepare a commissioning report. Such a report shall include the 
results of the tests along with a description of the test objectives and procedures for each test conducted 
sufficient to allow interpretation of the data. 
 
Although there is no required structure for a commissioning report, it is recommended that the report 
include: 
a) a description with schematic diagram of the test set-up equipment used including signal 
generators, uplink and/or beacon simulator transmitter antenna(s) (geographical position, gain 
and polarization), ground station receiving antenna (geographical position, G/T and 
polarization), signal analysers, and MEOLUT ID, as appropriate. 
b) a summary table that consolidates the results and indicates whether each particular result is 
consistent with the expectations of space segment provider. 
c) a detailed description of test results and conclusions made by the commissioning authority with 
charts, spectrograms, formulas etc, as necessary (it is expected that each test result 
interpretation will be described to such extent that its clearly understood how the conclusion 
was drawn by the commissioning authority). 
 
To support the use of the commissioned MEOSAR satellite by the System, the following information 
should be provided in the report: 
a) reference to a website providing orbital elements for the satellite, for use in case navigation 
data ephemerids are not available to MEOLUTs, 
b) confirmation of the availability of SIT217 messages to the Ground Segment. 
 
 
 
- END OF SECTION 6 - 
-


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ANNEX TO DOCUMENT C/S T.017 
 
COSPAS-SARSAT MEOSAR SPACE SEGMENT 
COMMISSIONING STANDARD 
 
 
 
 


 
A-1 

ANNEX A 
 
ATMOSPHERIC ATTENUATION COMPUTATION 
In this annex, an atmospheric attenuation algorithm is presented which comes from data presented in 
ITU-R P.676-11. 
 
The algorithm is considered valid for satellite elevation between 5° and 90°. 
 
The total zenith values in dB/km includes both dry air attenuation and water vapor attenuation which 
are as follows for standard atmosphere conditions: 
Standard atmospheric conditions for ground level (sea level) water vapor pressure are P0- 7.5 g/m3, 
for temperature T=300.4222 K, and total atmospheric pressure is 1013.25 hPa. 
 
From ITU-R P.676-11, Figure 5, the specific attenuation in dB/km is: 
• 
406 MHz: dry air =0.004, water vapor =0.000008, total Lzenith is 0.004008, 
• 
L band: dry air=0.006, water vapor = 0.000017, total Lzenith is 0.00617, 
• 
S band: dry air = 0.007, water vapor = 0.00005, total Lzenith is 0.00705. 
 
The inputs required for sea level heights and standard atmospheric conditions are: 
• 
The satellite w.r.t reference beacon elevation Er (measure in radians), 
• 
The satellite w.r.t. station elevation Ea (measured in radians), 
• 
Htropo is the height of the troposphere, which ITU assumes to be 10 km from sea level. 
 
The uplink and downlink atmospheric attenuation values are then: 
• 
GULATM=Lzenith* Htropo* cosecant(Er),  
• 
GDLATM=Lzenith* Htropo* cosecant(Ea). 
 
For non-standard atmospheric conditions or reference beacons or MEOLUT stations not located at sea 
level, need to compute T and water vapor pressure (from ITU-R P.835) as a function of heights of the 
reference beacon and MEOLUT station. 
 
 
 
- END OF ANNEX A - 
 
 
 
- END OF DOCUMENT - 
 


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
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