# Validation Log

## Validation Scenario
Using the provided sample data: 60 consecutive images from a flight starting at (48.275292, 37.385220) heading generally south-southwest. Camera: 26MP at 400m altitude.

## Expected Behavior Based on Conclusions

### Normal consecutive frames (AD000001-AD000032)
- VO successfully matches consecutive frames (60-73% overlap)
- Satellite matching every 5-10 frames provides absolute correction
- Position error stays within 20-50m corridor around ground truth
- Heading estimated from homography, corrected by satellite matching

### Apparent maneuver zone (AD000033-AD000048)
- The coordinates show the UAV making a complex turn around images 33-48
- Some consecutive pairs may have low overlap → VO quality drops
- Satellite matching becomes the primary position source
- New segments may be created if VO fails completely
- Position confidence drops in this zone

### Return to straight flight (AD000049-AD000060)
- VO re-establishes strong consecutive matching
- Satellite matching re-anchors position
- Accuracy returns to normal levels

## Actual Validation (Calculated)

Distances between consecutive samples in the data:
- AD000001→002: ~180m (larger than stated 100m — likely exaggeration in problem description)
- AD000002→003: ~115m
- Typical gap: 80-180m
- At 376m footprint width and 250m height, even 180m gap gives 52-73% overlap → sufficient for VO

At the turn zone (images 33-48):
- AD000041→042: ~230m with direction change → overlap may drop to 30-40%
- AD000042→043: ~230m with direction change → overlap may drop significantly
- AD000045→046: ~160m with direction change → may be <20% overlap
- These transitions are where VO may fail → satellite matching needed

## Counterexamples

1. **Homogeneous terrain**: If a section of the flight is over large uniform agricultural fields with no distinguishing features, both VO and satellite matching may fail. Mitigation: use higher zoom satellite tiles, rely on VO with lower confidence.

2. **Conflict-damaged area**: If satellite imagery shows pre-war structures that no longer exist, satellite matching will produce incorrect position estimates. Mitigation: confidence scoring will flag inconsistent matches.

3. **FullHD resolution flight**: At GSD 20cm/pixel instead of 6cm, matching quality degrades ~3x. The 50m target may still be achievable but 20m will be very difficult.

## Review Checklist
- [x] Draft conclusions consistent with fact cards
- [x] No important dimensions missed
- [x] No over-extrapolation
- [x] Issue found: The problem states "within 100 meters of each other" but actual data shows 80-230m. Pipeline must handle larger baselines.
- [x] Issue found: Tile download strategy needs to handle unknown route direction — progressive expansion needed.

## Conclusions Requiring Revision
- Photo spacing is 80-230m not strictly 100m — increases the range of overlap variations. Still functional but wider variance than assumed.
- Route direction is unknown at start — satellite tile pre-loading must use expanding radius strategy, not directional pre-loading.
