KURE x Tech is building a software reference implementation of the LunaNet Signal-In-Space - Augmented Forward Signal (LSIS-AFS) specification for NASA's LunaNet programme. The focus is pure software digital signal processing: spreading codes, message encoding/decoding, frame structure, and baseband IQ sample generation - not RF hardware.

This implementation is being developed as part of the LSIS-AFS Reference Implementation Competition running March-August 2026, which uses a gateway-based approach and scores teams on correctness, performance, completeness, code quality, and innovation.

At a high level, the project aims to provide:

• Spreading code generators (Gold, Weil, Legendre; primary, secondary, tertiary) for PRN 1-210, validated against Annex 3 reference codes.
• Forward error correction and integrity: BCH(51,8), rate 1/2 LDPC encoders/decoders for SB2-SB4, and CRC-24 generation/validation.
• Navigation message framing: 12-second frames with sync pattern, Subframes 1-4, and correct bit/symbol allocations per LSIS-AFS Volume A.
• Baseband signal generation: dual-channel BPSK AFS-I/AFS-Q at 1.023 Mchips and 5.115 Mchips, producing IQ sample files at configurable sample rates.
• Decoding and parsing: frame synchronization, FEC decoding, CRC checking, and extraction of clock, ephemeris, and network access data.
• Validation utilities: test vectors, BER vs SNR checks, and LSIS requirement compliance reports.

See the Gateway Roadmap for how these capabilities are broken down and validated over Gateways 0-8.

This repository is meant for:

• Competition judges who need to verify gateway completion, LSIS compliance, and performance against the published requirements and deliverables.
• Contributors implementing or extending the LSIS-AFS reference stack in any programming language with a focus on reproducible, test-driven DSP.
• Researchers and students looking for a worked example of a GNSS-style lunar navigation signal implementation aligned with the official LunaNet interoperability specification.

For technical background on LunaNet and LSIS-AFS, see the official specification and competition documents in docs/spec/.

The documentation is organised into the following sections:

• Project Overview & Requirements - docs/overview.md
  Short summary of the LSIS-AFS reference implementation scope and the functional/non-functional requirements.

• Gateway Roadmap - docs/gateways.md
  One section per gateway (0-8), with goals, deliverables, validation criteria, and links to the relevant modules and tests.

• Developer Guide - docs/developer-guide.md
  How to set up the environment, run tests, generate frames and IQ samples, and execute end-to-end encode -> decode workflows.

• Compliance & Testing - docs/compliance.md
  Mapping between LSIS-AFS "shall" requirements, competition success criteria, and the concrete tests/artefacts in this repo.

• Concept Guides - docs/concepts/
  Narrative tutorials such as The Anatomy of a Space Mission: From Orbit to Earth, providing context on space, ground, and user segments.

If you are a judge, start with:

1. docs/overview.md - project scope and requirements.
2. docs/gateways.md - gateway completion status and deliverables.
3. docs/compliance.md - LSIS requirement coverage and validation strategy.

If you are a developer:

1. Read docs/developer-guide.md to set up the environment and run the tests.
2. Implement or inspect modules gateway-by-gateway as described in docs/gateways.md.
3. Consult docs/concepts/anatomy-of-a-space-mission.md for background on space mission architecture and LunaNet context as needed.