WindEstimator: add test case for airspeed fusion singularity

src/lib/wind_estimator/CMakeLists.txt

@@ -37,6 +37,8 @@ add_library(wind_estimator
 )
 add_dependencies(wind_estimator prebuild_targets)
 
+add_subdirectory(test)
+
 add_custom_target(wind_estimator_generate_airspeed_fusion
 	COMMAND ${PYTHON_EXECUTABLE} derivation.py
 	#DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/derivation.py

src/lib/wind_estimator/test/CMakeLists.txt

@@ -0,0 +1,36 @@
+############################################################################
+#
+#   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.
+#
+############################################################################
+
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/..)
+
+px4_add_unit_gtest(SRC test_airspeed_fusion.cpp)

src/lib/wind_estimator/test/test_airspeed_fusion.cpp

@@ -0,0 +1,86 @@
+/****************************************************************************
+ *
+ *   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.
+ *
+ ****************************************************************************/
+
+/**
+ * Run this test only using make tests TESTFILTER=unit-test_airspeed_fusion
+ */
+
+#include <gtest/gtest.h>
+#include <matrix/math.hpp>
+#include <mathlib/math/Functions.hpp>
+#include "../python/generated/fuse_airspeed.h"
+
+using namespace matrix;
+
+TEST(TestAirspeedFusion, SingularityHandling)
+{
+	// GIVEN: all inputs set to zero (singularity point)
+	const float true_airspeed = 0.f;
+	const Vector3f vel_i{0.f, 0.f, 0.f};
+	const Vector3f state{0.f, 0.f, 0.f};
+	const Matrix<float, 3, 3> P;
+	const float tas_var = 0.f;
+
+	matrix::Matrix<float, 1, 3> H;
+	matrix::Matrix<float, 3, 1> K;
+	float innov_var;
+	float innov;
+
+	// WHEN: no singularity handling is done
+	float epsilon = 0.f;
+	sym::FuseAirspeed(vel_i, state, P, true_airspeed, tas_var, epsilon,
+			  &H, &K, &innov_var, &innov);
+
+	// THEN: some of the returned values are not finite
+	EXPECT_TRUE(std::isnan(H(0, 0))) << H(0, 0);
+	EXPECT_TRUE(std::isnan(H(0, 1))) << H(0, 1);
+	EXPECT_FLOAT_EQ(H(0, 2), 0.f) << H(0, 2);
+	EXPECT_TRUE(std::isnan(K(0, 0))) << K(0, 0);
+	EXPECT_TRUE(std::isnan(K(1, 0))) << K(1, 0);
+	EXPECT_TRUE(std::isnan(K(2, 0))) << K(2, 0);
+	EXPECT_TRUE(std::isnan(innov_var));
+	EXPECT_FLOAT_EQ(innov, 0.f);
+
+	// BUT WHEN: singularity is avoided by addind a small constant
+	epsilon = FLT_EPSILON;
+	sym::FuseAirspeed(vel_i, state, P, true_airspeed, tas_var, epsilon,
+			  &H, &K, &innov_var, &innov);
+
+	// THEN: the returned values are finite and the Kalman gain is null
+	EXPECT_FLOAT_EQ(H(0, 0), 0.f) << H(0, 0);
+	EXPECT_FLOAT_EQ(H(0, 1), 0.f) << H(0, 1);
+	EXPECT_FLOAT_EQ(H(0, 2), std::sqrt(FLT_EPSILON)) << H(0, 2);
+	EXPECT_TRUE(isEqual(K, Vector3f()));
+	EXPECT_FLOAT_EQ(innov_var, tas_var);
+	EXPECT_FLOAT_EQ(innov, 0.f);
+}