Developer Guide

This guide explains how to set up the environment, run tests, and use the KURE x Tech LSIS-AFS implementation for development and experimentation.

Setup

  1. Clone the repository.
  2. Install dependencies as described in the project's build instructions (language-specific).
  3. Run the test suite to verify your environment.

Example:

# example only - adapt to your tooling
git clone https://github.com/KURE-x-Tech/lunanet-lsis-afs.git
cd lunanet-lsis-afs
make test

Code structure

The codebase is organised roughly as follows (names may vary by language):

  • src/codes/ - Gold, Weil, Legendre, secondary, and tiered code generators.
  • src/encoding/ - BCH, LDPC, CRC, and interleaver implementations.
  • src/messages/ - Subframe builders and parsers, frame assembly/disassembly.
  • src/signal/ - Baseband IQ generation and signal file I/O.
  • src/decoder/ - Frame synchronisation, symbol extraction, decoding pipeline.
  • tests/ - Unit and integration tests per gateway.

Refer to docs/gateways.md to see which modules correspond to each competition gateway.

Common workflows

Generate spreading codes and validate

  • Use the code generation CLI or library entrypoint to generate codes for a chosen PRN.
  • Run the provided tests or comparison script to check against Annex 3 reference codes.

Build a navigation frame

  • Call the SB1-SB4 builders with test data (ephemeris, clock, network access).
  • Assemble them into a 12-second frame using the frame builder.
  • Optionally export the frame as a symbol sequence for analysis.

Generate IQ samples

  • Choose PRN, frame content, and sample rate.
  • Use the baseband generator to create IQ samples representing AFS-I/AFS-Q.
  • Save samples as binary/CSV for downstream use.

Decode and parse a signal

  • Load IQ samples using the signal I/O utilities.
  • Run frame synchronisation to locate frame boundaries.
  • Decode SB1-SB4, verify CRCs, and parse navigation fields.

Performance and validation

The project includes tests and benchmarks aligned with the published requirements:

  • Code generation within 1 s per PRN.
  • Frame encoding within 100 ms per frame.
  • Frame decoding within 1 s per 12-second frame.
  • BER ~= 1e-5 at SNR 0 dB for the target scenarios.

See docs/compliance.md for details and how to run these checks.