ekf: refactor fake position control logic

2026-10-22 14:33:34 +08:00 · 2022-01-25 15:07:48 +01:00
parent 42404ade77
commit 1502d77df2
6 changed files with 134 additions and 61 deletions
@@ -0,0 +1,125 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2022 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
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+ *
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+ *
+ ****************************************************************************/
+
+/**
+ * @file fake_pos_control.cpp
+ * Control functions for ekf fake position fusion
+ */
+
+#include "ekf.h"
+
+void Ekf::controlFakePosFusion()
+{
+	// If we aren't doing any aiding, fake position measurements at the last known position to constrain drift
+	// During intial tilt aligment, fake position is used to perform a "quasi-stationary" leveling of the EKF
+	const bool fake_pos_data_ready = isTimedOut(_time_last_fake_pos_fuse, (uint64_t)2e5); // Fuse fake position at a limited rate
+
+	if (fake_pos_data_ready) {
+		const bool continuing_conditions_passing = !isHorizontalAidingActive();
+		const bool starting_conditions_passing = continuing_conditions_passing;
+
+		if (_using_synthetic_position) {
+			if (continuing_conditions_passing) {
+				fuseFakePosition();
+
+				const bool is_fusion_failing = isTimedOut(_time_last_fake_pos_fuse, (uint64_t)4e5);
+
+				if (is_fusion_failing) {
+					resetFakePosFusion();
+				}
+
+			} else {
+				stopFakePosFusion();
+			}
+
+		} else {
+			if (starting_conditions_passing) {
+				startFakePosFusion();
+
+				if (_control_status.flags.tilt_align) {
+					// The fake position fusion is not started for initial alignement
+					_warning_events.flags.stopping_navigation = true;
+					ECL_WARN("stopping navigation");
+				}
+			}
+		}
+	}
+}
+
+void Ekf::startFakePosFusion()
+{
+	if (!_using_synthetic_position) {
+		_using_synthetic_position = true;
+		_fuse_hpos_as_odom = false; // TODO: needed?
+		resetFakePosFusion();
+	}
+}
+
+void Ekf::resetFakePosFusion()
+{
+	_last_known_posNE = _state.pos.xy();
+	resetHorizontalPosition();
+	resetVelocity();
+	_time_last_fake_pos_fuse = _time_last_imu;
+}
+
+void Ekf::stopFakePosFusion()
+{
+	_using_synthetic_position = false;
+}
+
+void Ekf::fuseFakePosition()
+{
+	Vector3f fake_pos_obs_var;
+
+	if (_control_status.flags.in_air && _control_status.flags.tilt_align) {
+		fake_pos_obs_var(0) = fake_pos_obs_var(1) = sq(fmaxf(_params.pos_noaid_noise, _params.gps_pos_noise));
+
+	} else if (_control_status.flags.vehicle_at_rest) {
+		// Accelerate tilt fine alignment by fusing more
+		// aggressively when the vehicle is at rest
+		fake_pos_obs_var(0) = fake_pos_obs_var(1) = sq(0.1f);
+
+	} else {
+		fake_pos_obs_var(0) = fake_pos_obs_var(1) = sq(0.5f);
+	}
+
+	_gps_pos_innov.xy() = Vector2f(_state.pos) - _last_known_posNE;
+
+	const Vector2f fake_pos_innov_gate(3.0f, 3.0f);
+
+	if (fuseHorizontalPosition(_gps_pos_innov, fake_pos_innov_gate, fake_pos_obs_var,
+	                           _gps_pos_innov_var, _gps_pos_test_ratio, true)) {
+		_time_last_fake_pos_fuse = _time_last_imu;
+	}
+}