GPS quality flags

bit	flag	rule	invalidates	parameters
1	NO_FIX	fix < gps_fix_min, or latitude and longitude both 0	yes	gps_fix_min
2	HIGH_DOP	DOP > gps_dop_max; confidence 0.5 above gps_dop_confidence_taper	yes	gps_dop_max, gps_dop_confidence_taper
4	DUPLICATE_STATIONARY	identical position while speed < gps_stationary_speed_ms (receiver hold)	no	gps_stationary_speed_ms
8	POSITION_JUMP	identical position while moving (≥ gps_moving_speed_ms) or step > max(gps_jump_speed_factor·v·dt + gps_jump_noise_m, gps_jump_speed_floor_ms·dt)	yes	gps_moving_speed_ms, gps_jump_speed_factor, gps_jump_noise_m, gps_jump_speed_floor_ms
16	SPEED_SPIKE	speed > gps_speed_max_ms, or	dv/dt	> gps_spike_accel_ms2 reversing within gps_spike_recovery_samples, or Hampel outlier (window, nσ·1.4826·MAD, min gps_hampel_min_ms)
32	ACCEL_IMPLAUSIBLE		dv/dt	> gps_implausible_accel_ms2 sustained longer than gps_implausible_accel_s → confidence 0.3
64	TIME_NONMONOTONIC	sample time not increasing	yes	—
128	INTERPOLATED	speed filled inside a gap ≤ speed_gap_fill_s	no	speed_gap_fill_s
256	PRELOCK	before the first run of gps_prelock_valid_run_s of fixed, low-DOP samples	yes	gps_prelock_valid_run_s
512	EDGE	first and last 0.5 s of each contiguous run (filter warm-up), excluded from peak statistics	no	—
1024	PROJ_LOST	reserved; projection loss is reported per lap as proj_lost_count	no	proj_lost_limit

Stage algorithms

stage	algorithm	artifact	notes
Normalise telemetry	normalize-1.0.0	manifest.json	session clock, units, axis map, chapters
Validate GPS / IMU	validate-gps-1.0.0	quality.json	quality flags and session-level checks
Laps, centerline, projection	lap-detect-1.0.0+laps-1.0.0+centerline-1.0.0+projection-1.0.0	laps.json, track.json, centerline.json, crossings.json	gate, crossings, classification, centerline, continuity-constrained projection
Speed and path acceleration	speed-1.0.0	lap_metrics.json, profiles/	v_analysis, a_long_path, a_lat_path on the s grid
Lap delta	delta-1.0.0	deltas/	Δt(s) per racing-lap pair with the endpoint invariant
IMU / mount calibration	imu-1.0.0+mount-1.0.0	mount_calibration.json, imu_metrics.json, profiles_imu/	vehicle-frame specific force, gyro corroboration, lean diagnostic
Segments	segments-1.0.0+segment-results-1.0.0	segments.json	corners/straights from curvature, per-segment metrics and Δt

Engine version 0.1.0.