fix(crsf): fall back to GPS altitude while no baro frame has been decoded - #31
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fix(crsf): fall back to GPS altitude while no baro frame has been decoded#31b14ckyy wants to merge 1 commit into
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…oded The CRSF decoder published the altitude event as a hard 0.0 whenever VARIO frames arrived without BARO_ALTITUDE (0x09): the vario sets the fresh-altitude flag on its own, and `baro_alt` is only ever filled by the 0x09 frame. INAV sends that frame only since 9.0 (with a detected baro), so on INAV 8.x the ALT widget sat at 0.0 live and every recording stored a real zero into baro_alt_m — which replay then rightly preferred over the good GPS altitude sitting in alt_m. Flat 3D tracks, issue #30. Confirmed on the reporter's INAV 8.0.1 + ELRS 3.5.x. The fallback keys on presence, not value: a `seen_baro` flag flips the moment a 0x09 frame is actually decoded. A genuine baro reading of 0.0 stays 0.0, and a link that does send the frame (Crossfire, mLRS, ELRS with INAV 9) never enters the fallback branch — behaviour there is bit-identical to before. Both CRSF altitudes share the arming-relative reference for INAV, so consumers see no semantic change either way. Fixes #30 Co-Authored-By: Claude Opus 4.8
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Fixes #30.
Root cause. The CRSF decoder published the altitude event as a hard 0.0 whenever VARIO frames
arrived without BARO_ALTITUDE (0x09) — vario alone triggers the event, and
baro_altis only filledby the 0x09 frame. INAV sends that frame only since 9.0 (commit
67fb0859, first shipped2026-01-17) and gates it on a detected baro; VARIO goes out far earlier (baro or fixed-wing + GPS).
Confirmed on the reporter's setup: INAV 8.0.1 + ELRS 3.5.x — the FC never emits the frame, the
link is innocent. So the ALT widget sat at 0.0 live, and every recording stored a genuine zero into
baro_alt_m, which replay then rightly preferred over the good GPS altitude inalt_m→ flat 3Dtracks.
Fix. A
seen_baroflag flips the moment a 0x09 frame is actually decoded — presence, notvalue. Until then the altitude event carries the GPS frame's altitude, which INAV fills
arming-relative (verified against a real INAV 9.1 recording: both CRSF altitudes share the same
reference), so the existing ground-anchor machinery applies unchanged. A genuine baro reading of 0.0
stays 0.0, and any link that does send 0x09 (Crossfire, mLRS, ELRS + INAV 9) never enters the
fallback branch — behaviour there is bit-identical to before.
Deliberately not done: rescuing existing recordings (their
baro_alt_mholds real stored zeros).No migration effort pre-release; the fix applies to new recordings.
Checks:
cargo check+cargo test --no-runclean. Frontend untouched.Verification plan: release build from this branch goes to the reporter; merge on their
confirmation that the ALT widget and new recordings show altitude on INAV 8.x.