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ruvnet--RuView/docs/adr/ADR-281-ble-cs-delay-doppler-pose-factorization.md
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Claude 42485495ed feat(ruview-unified): complete Gaussian update loop, separable delay-Doppler, property-tested boundary hardening
Third increment: closes the remaining implementable ADR-275 update-loop
steps, optimizes the delay-Doppler transform, and hardens every boundary
surface with property testing that found and fixed three real
input-controlled defects.

- ADR-275 update loop: GaussianMap::merge_overlapping (step 5 — mutual
  Mahalanobis + semantic-compatibility dedup catching drift the
  insert-time ±1-cell gate misses; orthogonal semantics stay separate)
  and lifetime-aware decay (step 7 — tau_eff = tau*(1+ln(1+lifetime/tau))
  so confirmed structures outlive transients at equal nominal tau).
- Separable delay-Doppler (ADR-281): O(B^2*S + S^2*B) instead of
  O(B^2*S^2), proven equivalent to the direct reference to <1e-10 and
  measured 8.3x faster (520us vs 4.34ms at 56x8). Direct form kept as
  the benchmark baseline + equivalence oracle.
- Security property tests (tests/security_boundaries.rs, 8 proptest
  properties over arbitrary values incl. NaN/inf via f64::from_bits).
  Found and fixed:
  * ble_cs_range unwrap infinite loop on non-finite phase (+inf) and
    ~1e299-iteration loop on finite-huge phase -> O(1) modular unwrap +
    plausibility bound (|phase| <= 1e6 rad);
  * subnormal Gaussian scale (5e-324) overflowing 1/sigma^2 to NaN
    density -> physical bounds (sigma in [1e-6, 1e4] m, occupancy in
    [0, 1e6] nepers/m).
  Properties proven: tensor/Gaussian/BoundedEvent constructors never
  panic; policy engine fail-closed for every (purpose,grants,zone);
  raw export structurally unreachable; coherent fusion rejects every
  non-finite/out-of-bounds sync state; occupancy reps never retain
  identity.
- New criterion benches for all increment-2/3 hot paths (to_canonical
  38us, ble_cs_range 481ns, AoI planner 647ns/200 regions, coherent
  fusion 1.5us/32 members, factorized pose 521ns, delay-Doppler
  separable vs direct).

Validation: ruview-unified 98 tests (87 lib + 3 acceptance + 8
security), 0 failed, clippy-clean; Python proof VERDICT PASS. Witness
bundle regeneration still blocked on the desktop/Tauri crate's GTK dev
headers (unavailable in this container) — pre-existing environment
limitation, flagged for the release owner.

Co-Authored-By: claude-flow <ruv@ruv.net>
Claude-Session: https://claude.ai/code/session_01Q1R5zhz6sSfXGRXpgBwpFX
2026-07-26 20:29:58 +00:00

5.3 KiB
Raw Blame History

ADR-281: New modality surfaces — BLE Channel Sounding, delay-Doppler-native tensors, P3162 import, and factorized pose

Field Value
Status Accepted — implemented (adapters.rs BLE CS + ranging evidence, tensor.rs::delay_doppler_map, frame.rs P3162 import profile, heads.rs factorized pose; 8 new test suites)
Date 2026-07-26
Parent ADR-273; extends ADR-274
Relates to ADR-279 (FieldAxis native axes), ADR-152 (geometry conditioning intake), ADR-021/263 (radar hardware)

0. PROOF discipline

Grades per ADR-273 §0. Bluetooth SIG cm-level claims vs the ~2050 cm practical review, OTFS ISAC field trials, IEEE P3162, PerceptAlign's >60 % cross-domain error reduction, and RePos's 1021 % MPJPE gains are EXTERNAL-UNVERIFIED design inputs. Our numbers below are MEASURED-CODE / MEASURED-SYNTHETIC.

1. BLE Channel Sounding (§2) — likely the fastest path to consumer-scale spatial anchoring

BleCsFrame carries per-frequency-step round-trip tone phases plus optional RTT. Two rules:

  • Phase-based ranging and RTT are separate evidence sources. ble_cs_range computes both — d_phase = |dθ/df|·c/4π from the unwrapped phase-vs-frequency slope, d_rtt = rtt·c/2 — and cross-validates instead of averaging. Agreement raises confidence; divergence beyond 0.5 m yields RangingAnomaly::Divergent (multipath bias, relay attack, timing fault, or calibration problem) with confidence capped ≤ 0.2. Measured: exact recovery at 1.5/5/12 m (< 1 µm error on clean synthetic phases, 40 steps × 1 MHz); a relay-style RTT inflation to ~51 m against a 5 m phase estimate is flagged, not blended (ble_cs_flags_relay_style_divergence_instead_of_averaging).
  • The tensor view (BleCsAdapter, nrf54-cs in the registry) never detrends phase — the ranging ramp is the measurement; the preserved ramp is asserted in test.

Single-source evidence (no RTT) is capped at confidence 0.5 — one mechanism alone is never high-trust ranging.

2. Delay-Doppler-native support (§3)

FieldAxis (ADR-279) makes delay/Doppler first-class native axes so OTFS-style captures are stored natively, and RfTensor::delay_doppler_map provides the standard transform for frequency-time tensors: IDFT over bins (→ delay) × DFT over snapshots (→ Doppler). Measured: a synthetic scatterer at (delay 7, Doppler 3) produces a unit peak with < 1e-9 leakage everywhere else. The transform is implemented separably (delay IDFT per snapshot, then Doppler DFT per delay row — O(B²S + S²B) vs the direct form's O(B²S²)), proven equivalent to the direct reference to < 1e-10 and measured 8.3× faster (520 µs vs 4.34 ms at 56×8 in the criterion bench). Rule: derived features may be small, but delay-Doppler maps are not collapsed into scalar motion energy before provenance and local storage.

3. IEEE P3162 synthetic-aperture import (§5)

SyntheticApertureSoundingDataset (frequency range, aperture poses, directional PDP, coordinate system, processing-manifest hash) is the validated import profile — the calibration bridge between measured environments, Sionna-class simulators, and learned RF scene models. Schema + validation only; parsers arrive with the first real dataset.

4. Factorized pose (RePos) + log-age gating

FactorizedPoseHead separates what generalizes from what conditions:

  • relative skeleton branch reads the environment-invariant content representation (cannot learn room-position shortcuts);
  • root localization branch reads the geometry-conditioned representation (sensor pose is signal there — the PerceptAlign lesson);
  • absolute = root + relative (PoseOutput::absolute_joints_m), with calibrated per-joint and root residual σ so every pose output carries uncertainty (ADR-273 item 8).

The leakage experiment (factorized_pose_resists_room_shortcut_leakage): training rooms where room position correlates with body scale (the trap real deployments set), held-out room breaking the correlation — factorized MPJPE 0.0003 m vs monolithic absolute-head 0.2534 m (845× worse), on a toy that isolates the mechanism. MEASURED-CODE for the mechanism; not a pose-accuracy claim.

Budget: the structured pose head is the largest adapter at 740 params vs the 40,856-param backbone (1.8 %) — documented ceiling for structured heads is < 2 % (scalar heads keep the 1 % gate), both asserted in every_head_fits_the_one_percent_budget_at_deployment_config.

Age gating now matches the age-aware-CSI recipe exactly: the freshness gate input is log(1 + sample_age_ms) (encoder::age_feature), giving millisecond and multi-second staleness comparable input scale; the finite-difference gradient check re-proves the backward pass through the changed input.

5. Consequences

  • Bluetooth/UWB anchors slot in as geometric evidence while WiFi carries ambient activity — the complement strategy, in code.
  • The Gaussian primitive gained the lifecycle fields the update-loop spec requires (first_seen_ns, doppler_variance, bounded source_receipts lineage merged on fusion) — static structure is distinguishable from transients by lifetime, and every primitive traces to source frames.
  • Roadmap, explicitly not done: real nRF54 CS capture path, OTFS waveform generation, P3162 file parsing, pose heads on real MM-Fi-style data.