EKF: Increase measurement error allowance for accelerometer clipping

EKF/common.h

@@ -172,7 +172,7 @@ struct extVisionSample {
 // bad accelerometer detection and mitigation
 #define BADACC_PROBATION	10E6	// Number of usec that accel data declared bad must continuously pass checks to be declared good
 #define BADACC_HGT_RESET	1E6	// Number of usec that accel data must continuously fail checks to trigger a height reset
-#define BADACC_BIAS_PNOISE_MULT 2.0f	// The delta velocity process noise is multiplied by this value when accel data is declared bad
+#define BADACC_BIAS_PNOISE	4.9f	// The delta velocity process noise is set to this when accel data is declared bad (m/s**2)
 
 struct parameters {
 	// measurement source control

EKF/covariance.cpp

@@ -235,8 +235,9 @@ void Ekf::predictCovariance()
 	daxVar = dayVar = dazVar = sq(dt * gyro_noise);
 	float accel_noise = math::constrain(_params.accel_noise, 0.0f, 1.0f);
 	if (_bad_vert_accel_detected) {
-		// increase accelerometer process noise if bad accel data is detected
-		accel_noise *= BADACC_BIAS_PNOISE_MULT;
+		// Increase accelerometer process noise if bad accel data is detected. Measurement errors due to
+		// vibration induced clipping commonly reach an equivalent 0.5g offset.
+		accel_noise = BADACC_BIAS_PNOISE;
 	}
 	dvxVar = dvyVar = dvzVar = sq(dt * accel_noise);