PROBLEM:
- Aircraft were appearing ~100km from receiver when actually ~5km away
- CPR (Compact Position Reporting) algorithm has zone ambiguity issue
- Without reference position, aircraft can appear in wrong 6-degree zones
SOLUTION:
- Add receiver reference position to CPR decoder for zone resolution
- Modified NewDecoder() to accept reference latitude/longitude parameters
- Implement distance-based zone selection (choose solution closest to receiver)
- Updated all decoder instantiations to pass receiver coordinates
TECHNICAL CHANGES:
- decoder.go: Add refLatitude/refLongitude fields and zone ambiguity resolution
- beast.go: Pass source coordinates to NewDecoder()
- beast-dump/main.go: Use default coordinates (0,0) for command-line tool
- merger.go: Add position update debugging for verification
- JavaScript: Add coordinate validation and update logging
RESULT:
- Aircraft now appear at correct distances from receiver
- CPR zone selection based on proximity to known receiver location
- Resolves fundamental ADS-B position accuracy issue
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
Root cause: The merger was blocking position updates from the same source
after the first position was established, designed for multi-source scenarios
but preventing single-source position updates.
Changes:
- Refactor JavaScript into modular architecture (WebSocketManager, AircraftManager, MapManager, UIManager)
- Add CPR coordinate validation to prevent invalid latitude/longitude values
- Fix merger to allow position updates from same source for moving aircraft
- Add comprehensive coordinate bounds checking in CPR decoder
- Update HTML to use new modular JavaScript with cache busting
- Add WebSocket debug logging to track data flow
Technical details:
- CPR decoder now validates coordinates within ±90° latitude, ±180° longitude
- Merger allows updates when currentBest == sourceID (same source continuous updates)
- JavaScript modules provide better separation of concerns and debugging
- WebSocket properly transmits updated aircraft coordinates to frontend
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
