feat(ekf2): remove zero innovation heading update

This is no longer necessary with the heading observability check

src/modules/ekf2/CMakeLists.txt

@@ -132,7 +132,6 @@ list(APPEND EKF_SRCS
 	EKF/aid_sources/fake_pos_control.cpp
 	EKF/aid_sources/ZeroGyroUpdate.cpp
 	EKF/aid_sources/ZeroVelocityUpdate.cpp
-	EKF/aid_sources/zero_innovation_heading_update.cpp
 )
 
 if(CONFIG_EKF2_AIRSPEED)

src/modules/ekf2/EKF/CMakeLists.txt

@@ -53,7 +53,6 @@ list(APPEND EKF_SRCS
 	aid_sources/fake_pos_control.cpp
 	aid_sources/ZeroGyroUpdate.cpp
 	aid_sources/ZeroVelocityUpdate.cpp
-	aid_sources/zero_innovation_heading_update.cpp
 )
 
 if(CONFIG_EKF2_AIRSPEED)

src/modules/ekf2/EKF/aid_sources/zero_innovation_heading_update.cpp

@@ -1,69 +0,0 @@
-/****************************************************************************
- *
- *   Copyright (c) 2022 PX4 Development Team. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- * 3. Neither the name PX4 nor the names of its contributors may be
- *    used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- ****************************************************************************/
-
-/**
- * @file zero_innovation_heading_update.cpp
- * Control function for ekf heading update when at rest or no other heading source available
- */
-
-#include "ekf.h"
-
-void Ekf::controlZeroInnovationHeadingUpdate()
-{
-	const bool yaw_aiding = _control_status.flags.mag_hdg || _control_status.flags.mag_3D
-				|| _control_status.flags.ev_yaw || _control_status.flags.gnss_yaw;
-
-	// fuse zero innovation at a limited rate if the yaw variance is too large
-	if (!yaw_aiding
-	    && isTimedOut(_time_last_heading_fuse, (uint64_t)200'000)) {
-
-		// Use an observation variance larger than usual but small enough
-		// to constrain the yaw variance just below the threshold
-		const float obs_var = _control_status.flags.tilt_align ? 0.25f : 0.001f;
-
-		estimator_aid_source1d_s aid_src_status{};
-		aid_src_status.observation = getEulerYaw(_state.quat_nominal);
-		aid_src_status.observation_variance = obs_var;
-		aid_src_status.innovation = 0.f;
-
-		VectorState H_YAW;
-
-		computeYawInnovVarAndH(obs_var, aid_src_status.innovation_variance, H_YAW);
-
-		if (!_control_status.flags.tilt_align
-		    || (aid_src_status.innovation_variance - obs_var) > sq(_params.ekf2_head_noise)) {
-			// The yaw variance is too large, fuse fake measurement
-			fuseYaw(aid_src_status, H_YAW);
-		}
-	}
-}

src/modules/ekf2/EKF/control.cpp

@@ -154,8 +154,6 @@ void Ekf::controlFusionModes(const imuSample &imu_delayed)
 	updateTerrainValidity();
 #endif // CONFIG_EKF2_TERRAIN
 
-	controlZeroInnovationHeadingUpdate();
-
 	_zero_velocity_update.update(*this, imu_delayed);
 
 	if (_params.ekf2_imu_ctrl & static_cast<int32_t>(ImuCtrl::GyroBias)) {

src/modules/ekf2/EKF/ekf.h

@@ -951,8 +951,6 @@ private:
 	void resetHeightToLastKnown();
 	void stopFakeHgtFusion();
 
-	void controlZeroInnovationHeadingUpdate();
-
 #if defined(CONFIG_EKF2_AUXVEL)
 	// control fusion of auxiliary velocity observations
 	void controlAuxVelFusion(const imuSample &imu_sample);