Phase 6: the fused tracker's uncertainty, recalibrated, is inconclusive at G7
C.6's second follow-on asks whether the tracker that passed G5 can say how sure it is. The fused tracker is the frozen IMM with T2's range fused in.
The owner chose two things:
- Calibrate the fused tracker's stated uncertainty, without training.
- The test: calibrated and sharper. Its 50% and 90% intervals for range, course and speed must cover within ±2 points of nominal, and be narrower than the reference IMM's after the same recalibration.
What was done
- Stated sds. Both trackers now write them, from their covariance by the delta method. They are badly miscalibrated as stated: typical errors are a fraction of the stated sd, with heavy tails.
- Recalibration, post hoc. One pair of multipliers per output, fitted on validation, scales the sd into 50% and 90% intervals. A two-fold check on validation passed, and decision 33 froze the multipliers before seed 215 was generated for scoring.
Result: inconclusive
| Coverage on seed 215 (G5 rows) | 50% | 90% |
|---|---|---|
| Range (log) | 48.3% [47.8, 48.8] | 89.8% |
| Course | 50.5% | 90.2% |
| Speed | 49.3% | 89.6% |
The fused tracker's intervals are narrower than the IMM's: 0.73 × for range, 0.95 × for course and 0.89 × for speed. Eight of the nine checks pass. Range at 50% falls just short: its interval straddles the 48% floor.
What the panel added
Five independent reviewers agreed the verdict is right, and reproduced it byte for byte. They also narrowed what can be claimed:
- The intervals are calibrated only on the pooled mix of rows. On quiet straight legs before any manoeuvre they are far too wide: range 50% covers 67%. After a manoeuvre they are too narrow: 38%. One multiplier cannot fix that shape.
- Course and speed intervals are often uninformative. 17% of course 90% intervals span the whole circle, and 27% of speed 90% intervals reach below zero.
- The shortfall looks systematic, not noise. The likely cause is that T2's training epoch, the fusion settings and the multipliers were all chosen on the same validation split.
- The rules were the agent's. The owner did not get to review them before the decision record.
What next
The rules allow one re-score on a larger fresh seed. It would probably land near 48.3% again, so a pass would mean the range coverage just reaches the floor, not that the tracker is well calibrated. The owner decides whether to run it.
Record: experiments/20261106-p6u-g7/; spec 018.