ekf2: do not fuse ZVU if other velocity source is active #20611
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dagar
reviewed
Nov 15, 2022
| @@ -45,15 +45,16 @@ void Ekf::controlZeroVelocityUpdate() | |||
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| if (zero_velocity_update_data_ready) { | |||
| const bool continuing_conditions_passing = _control_status.flags.vehicle_at_rest | |||
| && _control_status_prev.flags.vehicle_at_rest; | |||
| && _control_status_prev.flags.vehicle_at_rest | |||
| && !isVerticalVelocityAidingActive(); // otherwise the filter is "too rigid" to follow a position drift | |||
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How about just skipping vz fuse below if vertical velocity aiding active? ~ line 65
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The only sources of velocity are VIO and GNSS and when active they're fusing a 3D vector so isVerticalVelocityAidingActive is the same as "is velocity aiding active" (maybe I should make a function that makes this obvious). I think that the same logic should apply on the horizontal axes, this is why I implemented it that way
dagar
approved these changes
Nov 15, 2022
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Describe problem solved by this pull request
Some people are still seeing annoying "height estimate not stable" messages primarily because the GNSS altitude drifted by a couple of meters after initializing the EKF origin. The problem is that with Zero Velocity Updates in addition to GNSS velocity fusion, the variance of the velocity estimate becomes really small and makes the position estimate too rigid and it can take several tens of seconds to move by a couple of meters.
Describe your solution
_NED_origin_initialisedthat relates to GNSS directly)Test data / coverage
Unit tests, SITL