feat: drop implausible-speed (teleport) locations via heuristic filter#2266
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mvanhorn wants to merge 1 commit into
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feat: drop implausible-speed (teleport) locations via heuristic filter#2266mvanhorn wants to merge 1 commit into
mvanhorn wants to merge 1 commit into
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Add an opt-in implausible-speed filter in LocationProcessor.publishLocationMessage that drops a new fix when it implies travel faster than a configurable maximum ground speed relative to the last published location. Gated by a new config-import-only integer preference maxImplausibleSpeedKmh, defaulting to 0 (disabled) so existing behaviour is unchanged. The filter sits alongside the existing accuracy and network-vs-gps discard heuristics, skips USER and CIRCULAR triggered reports, never blocks the first fix, and guards against zero or negative time deltas. The pure decision lives in an isImplausibleSpeed helper with JVM unit tests. Refs owntracks#2034 Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_012ye471qeNk1R7b7aQsZF5s
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Summary
Adds an opt-in implausible-speed (teleport) filter to
LocationProcessor.publishLocationMessage. When a new fix would imply travel faster than a configurable maximum ground speed relative to the last published location, the fix is dropped before it is queued for sending or persisted as the current published location.The filter is gated by a new config-import-only integer preference
maxImplausibleSpeedKmh, defaulting to0, which disables the filter and preserves current behaviour. It sits alongside the existing accuracy and network-vs-gps discard heuristics and follows the sameResult.failureplus Timber logging pattern.Why this matters
Users on the OSS (F-Droid/AOSP) flavour report occasional random published locations several miles from the device's true position while the phone is stationary, drawing long straight-line artifacts on the recorder map (#2034, also referenced in #2053). These come from the network/cell-tower provider supplying low-quality fixes that the OSS build forwards without the aggregation Play Services would normally apply.
On 2026-04-30 maintainer @growse scoped the work into two tracked items: (1) Kalman filtering of non-Play-Services locations, and (2) a heuristic to figure out if something looks weirdly wrong and optionally filter it out. This change implements item 2 only. A teleport fix implies an impossible ground speed relative to the previous fix, so dropping fixes above a user-set km/h ceiling removes the artifacts without touching plausible movement.
Behaviour details:
maxImplausibleSpeedKmh = 0(the default) disables the filter.The pure decision lives in an
isImplausibleSpeed(distanceMeters, timeDeltaMillis, maxSpeedKmh)helper so it can be unit tested without Android dependencies.Testing
Added
LocationProcessorTestwith JVM-pure unit tests for the decision helper covering: disabled threshold, a plausible slow move, a teleport (about 15 miles in 5 seconds, implying roughly 17,000 km/h), a zero time delta, and a negative time delta.Gradle was not run locally because this machine has no Java runtime; CI will validate the build and tests.
Refs #2034