AlphaFilter add constructor that takes alpha and use in EKF

AlphaFilter/AlphaFilter.hpp

@@ -45,9 +45,12 @@
 #include <float.h>
 
 template <typename T>
-class AlphaFilter {
+class AlphaFilter
+{
 public:
 	AlphaFilter() = default;
+	explicit AlphaFilter(float alpha) : _alpha(alpha) {}
+
 	~AlphaFilter() = default;
 
 	/**
@@ -58,7 +61,8 @@ class AlphaFilter {
 	 * @param sample_interval interval between two samples
 	 * @param time_constant filter time constant determining convergence
 	 */
-	void setParameters(float sample_interval, float time_constant) {
+	void setParameters(float sample_interval, float time_constant)
+	{
 		const float denominator = time_constant + sample_interval;
 
 		if (denominator > FLT_EPSILON) {
@@ -85,7 +89,11 @@ class AlphaFilter {
 	 *
 	 * @return retrieve the filtered result
 	 */
-	void update(const T &sample) { _filter_state = updateCalculation(sample); }
+	const T &update(const T &sample)
+	{
+		_filter_state = updateCalculation(sample);
+		return _filter_state;
+	}
 
 	const T &getState() const { return _filter_state; }
 

EKF/ekf.cpp

@@ -48,9 +48,6 @@ bool Ekf::init(uint64_t timestamp)
 {
 	bool ret = initialise_interface(timestamp);
 	reset();
-	_accel_lpf.setAlpha(.1f);
-	_gyro_lpf.setAlpha(.1f);
-	_mag_lpf.setAlpha(.1f);
 	return ret;
 }
 

EKF/ekf.h

@@ -468,11 +468,11 @@ class Ekf final : public EstimatorInterface
 	bool _is_first_imu_sample{true};
 	uint32_t _baro_counter{0};		///< number of baro samples read during initialisation
 	uint32_t _mag_counter{0};		///< number of magnetometer samples read during initialisation
-	AlphaFilter<Vector3f> _accel_lpf;	///< filtered accelerometer measurement used to align tilt (m/s/s)
-	AlphaFilter<Vector3f> _gyro_lpf;	///< filtered gyro measurement used for alignment excessive movement check (rad/sec)
+	AlphaFilter<Vector3f> _accel_lpf{0.1f};	///< filtered accelerometer measurement used to align tilt (m/s/s)
+	AlphaFilter<Vector3f> _gyro_lpf{0.1f};	///< filtered gyro measurement used for alignment excessive movement check (rad/sec)
 
 	// Variables used to perform in flight resets and switch between height sources
-	AlphaFilter<Vector3f> _mag_lpf;		///< filtered magnetometer measurement for instant reset (Gauss)
+	AlphaFilter<Vector3f> _mag_lpf{0.1f};	///< filtered magnetometer measurement for instant reset (Gauss)
 	float _hgt_sensor_offset{0.0f};		///< set as necessary if desired to maintain the same height after a height reset (m)
 	float _baro_hgt_offset{0.0f};		///< baro height reading at the local NED origin (m)