update ecl/EKF with improved covariance prediction stability and change default IMU integration period 4000 us -> 2500 us

- bring in PX4/ecl#795 "EKF: Improve covariance prediction stability"
    - the ecl/EKF filter update period has changed from 8 ms to 10 ms
 - change default integration period 4000 us -> 2500 us (aligns with new EKF filter update period)

src/lib/drivers/accelerometer/PX4Accelerometer.cpp

@@ -124,7 +124,7 @@ void PX4Accelerometer::set_update_rate(uint16_t rate)
 	const uint32_t update_interval = 1000000 / rate;
 
 	// TODO: set this intelligently
-	_integrator_reset_samples = 4000 / update_interval;
+	_integrator_reset_samples = 2500 / update_interval;
 }
 
 void PX4Accelerometer::update(hrt_abstime timestamp_sample, float x, float y, float z)

src/lib/drivers/accelerometer/PX4Accelerometer.hpp

@@ -98,7 +98,7 @@ private:
 
 	hrt_abstime	_status_last_publish{0};
 
-	Integrator		_integrator{4000, false};
+	Integrator		_integrator{2500, false};
 
 	matrix::Vector3f	_calibration_scale{1.f, 1.f, 1.f};
 	matrix::Vector3f	_calibration_offset{0.f, 0.f, 0.f};

src/lib/drivers/device/integrator.h

@@ -48,7 +48,7 @@
 class Integrator
 {
 public:
-	Integrator(uint32_t auto_reset_interval = 4000 /* 250 Hz */, bool coning_compensation = false);
+	Integrator(uint32_t auto_reset_interval = 2500 /* 400 Hz */, bool coning_compensation = false);
 	~Integrator() = default;
 
 	/**

src/lib/drivers/gyroscope/PX4Gyroscope.cpp

@@ -126,7 +126,7 @@ void PX4Gyroscope::set_update_rate(uint16_t rate)
 	const uint32_t update_interval = 1000000 / rate;
 
 	// TODO: set this intelligently
-	_integrator_reset_samples = 4000 / update_interval;
+	_integrator_reset_samples = 2500 / update_interval;
 }
 
 void PX4Gyroscope::update(hrt_abstime timestamp_sample, float x, float y, float z)

src/lib/drivers/gyroscope/PX4Gyroscope.hpp

@@ -100,7 +100,7 @@ private:
 
 	hrt_abstime	_status_last_publish{0};
 
-	Integrator		_integrator{4000, true};
+	Integrator		_integrator{2500, true};
 
 	matrix::Vector3f	_calibration_offset{0.f, 0.f, 0.f};