AVECT Train Speed Monitor

AVECT 1.1.0 completely refreshes the core vehicle-state engine. Speed, position, rail segment, and grade now run consistently through one event-driven chain. - Velocity: trustworthy GNSS remains the absolute speed reference. IMU use is bounded to observable launch detection and short bridging between GNSS updates. Delayed GNSS is reconciled at measurement time, with explicit handling for outliers, outages, stop recovery, and uncertainty. Stale low-quality fixes can no longer establish a cold-start speed by themselves. - Position: accepted velocity is integrated downstream and corrected by GNSS position. Distance and position uncertainty are tracked, with no feedback from position or station context into speed. - Rail segments: when AVECT is opened mid-journey, one clear valid GNSS fix on an unambiguous single-line alignment can show a direction-free “Station A—Station B” segment without prior station history or a confirmed previous station. Direction can be established later from course or additional observations; parallel tracks, junctions, close alignments, and tied candidates remain withheld. - Altitude and vertical speed: GNSS provides a slowly corrected altitude datum while fine pressure-height changes remain responsive. Vertical speed in m/min and ft/min makes indoor and elevator movement observable. When aircraft cabin pressure causes a large disagreement, pressure altitude is rejected and GNSS altitude takes priority. - Grade: changes in barometric altitude are checked against GNSS altitude, then estimated robustly over distance. A grade-only shield excludes cabin-pressure changes correlated with acceleration and braking, and a clear GNSS/barometer trend disagreement withholds the value. Grade never feeds back into speed or position. - Logging and Guide: each recording now saves speed, position, sensor, and estimator-state data in one CSV file. GUIDE now documents segment Quick Look, the estimator chain, communications, and privacy. - Subscription: entitlement is checked before network-backed product metadata at launch, so active subscribers enter the app without passing through the purchase screen. Product-loading retry and safer measurement/CSV finalisation during access transitions are also included.