id: apollo_ranging_demod
label: Apollo Ranging Demodulator
category: '[Apollo USB]'
flags: [python]

parameters:
- id: chip_rate
  label: Chip Rate (Hz)
  dtype: int
  default: '993963'
- id: sample_rate
  label: Sample Rate (Hz)
  dtype: real
  default: '5120000'
- id: correlation_length
  label: Correlation Length (samples)
  dtype: int
  default: '100000'
- id: two_way
  label: Two-Way Ranging
  dtype: bool
  default: 'True'
  options: ['True', 'False']
  option_labels: ['Two-way (ground-SC-ground)', 'One-way']

inputs:
- label: in
  domain: stream
  dtype: float

outputs:
- label: range
  domain: message

templates:
  imports: from apollo.ranging_demod import ranging_demod
  make: >-
    apollo.ranging_demod.ranging_demod(
        chip_rate=${chip_rate},
        sample_rate=${sample_rate},
        correlation_length=${correlation_length},
        two_way=${two_way})

documentation: |-
  Apollo Ranging Demodulator

  Correlates received signal against known PRN ranging code to measure
  spacecraft range. Accumulates samples in batches, performs FFT-based
  cross-correlation, and emits range measurement PDUs.

  Message output (range):
    delay_chips: Measured delay in chip periods
    range_m: Computed range in meters
    correlation_peak: Peak correlation value
    peak_to_avg_ratio: Peak-to-average ratio (signal quality)
    timestamp: Measurement timestamp

  Parameters:
    chip_rate: Expected PRN chip rate (default 993,963 Hz)
    sample_rate: Input sample rate (default 5.12 MHz)
    correlation_length: Samples per correlation batch (default 100,000)
    two_way: If True, divide range by 2 for round-trip measurement

file_format: 1