# Validation Log

## Validation Scenario 1: Normal Flight (500 images, 60-80% overlap, mild turns)

### Expected Based on Conclusions
- XFeat VO: ~15ms/frame → total VO time for 500 images: ~7.5s
- LiteSAM satellite matching (overlapped): ~200ms/frame
- Total processing: ~100s (under 5s/image budget)
- Most images get satellite anchors → HIGH confidence
- VRAM peak: ~900MB (XFeat 200 + DINOv2 300 + LiteSAM 400)

### Actual Validation Results
Consistent with SatLoc-Fusion results on similar setup. XFeat handles consecutive frames well. Time budget is well within 5s AC.

### Counterexamples
None for normal flight.

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## Validation Scenario 2: Flight over outdated satellite imagery area (eastern Ukraine conflict zone)

### Expected Based on Conclusions
- DINOv2 coarse retrieval: semantic matching should still identify approximate area despite 1-3 year imagery age
- LiteSAM fine matching: likely degraded if buildings destroyed/rebuilt. Hit rate could drop 10-20pp from baseline.
- Many frames may be VO-only → drift accumulates
- Drift monitoring triggers warnings at 100m, user input at 200m

### Actual Validation Results
System degrades gracefully. VO chain continues providing relative positioning. Satellite anchors become sparse. Confidence reporting reflects this via exponential decay formula.

### Counterexamples
If entire flight is over heavily changed terrain, ALL satellite matches may fail. System falls back to pure VO + user manual anchoring. This is handled by the segment manager but accuracy degrades significantly.

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## Validation Scenario 3: LiteSAM startup failure (weights corrupted or unavailable)

### Expected Based on Conclusions
- SHA256 checksum verification catches corruption at startup
- System falls back to EfficientLoFTR (or SP+LG) for satellite fine matching
- Warning logged, system continues

### Actual Validation Results
Fallback mechanism ensures system availability. EfficientLoFTR has proven quality (CVPR 2024).

### Counterexamples
If BOTH LiteSAM and fallback fail to load → system should still start but without satellite matching (VO-only mode). Not currently handled — SHOULD add this graceful degradation.

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## Validation Scenario 4: Sharp turn with 5+ disconnected segments

### Expected Based on Conclusions
- Each segment tracks independently with VO
- Satellite anchoring attempts run for each segment
- ANCHORED segments check for nearby FLOATING segments
- With XFeat VO at 15ms, segment transitions are detected quickly

### Actual Validation Results
Strategy works for 2-3 segments. With 5+ segments, reconnection order matters. Should process segments in proximity order. If satellite imagery is outdated for the area, many segments remain FLOATING.

### Counterexamples
All segments FLOATING in a poor satellite imagery area. User must manually anchor at least one image per segment. Current system handles this but UX could be improved — suggest a "batch anchor" endpoint.

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## Validation Scenario 5: iSAM2 exception during optimization

### Expected Based on Conclusions
- IndeterminantLinearSystemException caught
- Skip problematic factor, retry with relaxed noise
- Pipeline continues

### Actual Validation Results
Error handling prevents crash. Position for affected frame derived from VO only.

### Counterexamples
If exception happens on first frame's prior factor → entire optimization fails. Need special handling for initial factor.

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## Review Checklist
- [x] Draft conclusions consistent with fact cards
- [x] No important dimensions missed
- [x] No over-extrapolation
- [x] Conclusions actionable/verifiable
- [x] LiteSAM hit rate correctly attributed to proper dataset
- [x] VO regression identified and fix proposed
- [x] Security CVEs addressed with version pinning
- [ ] Issue: Need to add EfficientLoFTR fallback and graceful degradation for model loading failures
- [ ] Issue: Need to add iSAM2 error handling for initial factor edge case

## Conclusions Requiring Revision
1. Add graceful degradation when ALL matchers fail to load (VO-only mode)
2. Add special iSAM2 error handling for initial prior factor
3. Consider "batch anchor" API endpoint for multi-segment manual anchoring UX