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>
Ole-Morten Duesund
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