Changed to yaw only mag correction.

src/modules/att_pos_estimator_ekf/KalmanNav.cpp

@@ -58,8 +58,8 @@ KalmanNav::KalmanNav(SuperBlock *parent, const char *name) :
 	P0(9, 9),
 	V(6, 6),
 	// attitude measurement ekf matrices
-	HAtt(6, 9),
-	RAtt(6, 6),
+	HAtt(4, 9),
+	RAtt(4, 4),
 	// position measurement ekf matrices
 	HPos(6, 9),
 	RPos(6, 6),
@@ -486,20 +486,10 @@ int KalmanNav::correctAtt()
 	float sinPsi = sinf(psi);
 
 	// mag measurement
-	Vector3 zMag(_sensors.magnetometer_ga);
-	//float magNorm = zMag.norm();
-	zMag = zMag.unit();
-
-	// mag predicted measurement
-	// choosing some typical magnetic field properties,
-	//  TODO dip/dec depend on lat/ lon/ time
-	float dip = _magDip.get() / M_RAD_TO_DEG_F; // dip, inclination with level
-	float dec = _magDec.get() / M_RAD_TO_DEG_F; // declination, clockwise rotation from north
-	float bN = cosf(dip) * cosf(dec);
-	float bE = cosf(dip) * sinf(dec);
-	float bD = sinf(dip);
-	Vector3 bNav(bN, bE, bD);
-	Vector3 zMagHat = (C_nb.transpose() * bNav).unit();
+	Vector3 magNav = C_nb.transpose() * Vector3(_sensors.magnetometer_ga);
+	float yMag = atan2f(magNav(0),magNav(1)) - psi;
+	if (yMag > M_PI_F) yMag -= 2*M_PI_F;
+	if (yMag < -M_PI_F) yMag += 2*M_PI_F;
 
 	// accel measurement
 	Vector3 zAccel(_sensors.accelerometer_m_s2);
@@ -512,9 +502,9 @@ int KalmanNav::correctAtt()
 	bool ignoreAccel = fabsf(accelMag - _g.get()) > 1.1f;
 
 	if (ignoreAccel) {
+		RAttAdjust(1, 1) = 1.0e10;
+		RAttAdjust(2, 2) = 1.0e10;
 		RAttAdjust(3, 3) = 1.0e10;
-		RAttAdjust(4, 4) = 1.0e10;
-		RAttAdjust(5, 5) = 1.0e10;
 
 	} else {
 		//printf("correcting attitude with accel\n");
@@ -523,58 +513,25 @@ int KalmanNav::correctAtt()
 	// accel predicted measurement
 	Vector3 zAccelHat = (C_nb.transpose() * Vector3(0, 0, -_g.get())).unit();
 
-	// combined measurement
-	Vector zAtt(6);
-	Vector zAttHat(6);
+	// calculate residual
+	Vector y(4);
+	y(0) = yMag;
+	y(1) = zAccel(0) - zAccelHat(0);
+	y(2) = zAccel(1) - zAccelHat(1);
+	y(3) = zAccel(2) - zAccelHat(2);
 
-	for (int i = 0; i < 3; i++) {
-		zAtt(i) = zMag(i);
-		zAtt(i + 3) = zAccel(i);
-		zAttHat(i) = zMagHat(i);
-		zAttHat(i + 3) = zAccelHat(i);
-	}
+	// HMag
+	HAtt(0, 2) = 1;
 
-	// HMag , HAtt (0-2,:)
-	float tmp1 =
-		cosPsi * cosTheta * bN +
-		sinPsi * cosTheta * bE -
-		sinTheta * bD;
-	HAtt(0, 1) = -(
-			     cosPsi * sinTheta * bN +
-			     sinPsi * sinTheta * bE +
-			     cosTheta * bD
-		     );
-	HAtt(0, 2) = -cosTheta * (sinPsi * bN - cosPsi * bE);
-	HAtt(1, 0) =
-		(cosPhi * cosPsi * sinTheta + sinPhi * sinPsi) * bN +
-		(cosPhi * sinPsi * sinTheta - sinPhi * cosPsi) * bE +
-		cosPhi * cosTheta * bD;
-	HAtt(1, 1) = sinPhi * tmp1;
-	HAtt(1, 2) = -(
-			     (sinPhi * sinPsi * sinTheta + cosPhi * cosPsi) * bN -
-			     (sinPhi * cosPsi * sinTheta - cosPhi * sinPsi) * bE
-		     );
-	HAtt(2, 0) = -(
-			     (sinPhi * cosPsi * sinTheta - cosPhi * sinPsi) * bN +
-			     (sinPhi * sinPsi * sinTheta + cosPhi * cosPsi) * bE +
-			     (sinPhi * cosTheta) * bD
-		     );
-	HAtt(2, 1) = cosPhi * tmp1;
-	HAtt(2, 2) = -(
-			     (cosPhi * sinPsi * sinTheta - sinPhi * cosTheta) * bN -
-			     (cosPhi * cosPsi * sinTheta + sinPhi * sinPsi) * bE
-		     );
-
-	// HAccel , HAtt (3-5,:)
-	HAtt(3, 1) = cosTheta;
-	HAtt(4, 0) = -cosPhi * cosTheta;
-	HAtt(4, 1) = sinPhi * sinTheta;
-	HAtt(5, 0) = sinPhi * cosTheta;
-	HAtt(5, 1) = cosPhi * sinTheta;
+	// HAccel
+	HAtt(1, 1) = cosTheta;
+	HAtt(2, 0) = -cosPhi * cosTheta;
+	HAtt(2, 1) = sinPhi * sinTheta;
+	HAtt(3, 0) = sinPhi * cosTheta;
+	HAtt(3, 1) = cosPhi * sinTheta;
 
 	// compute correction
 	// http://en.wikipedia.org/wiki/Extended_Kalman_filter
-	Vector y = zAtt - zAttHat; // residual
 	Matrix S = HAtt * P * HAtt.transpose() + RAttAdjust; // residual covariance
 	Matrix K = P * HAtt.transpose() * S.inverse();
 	Vector xCorrect = K * y;
@@ -617,9 +574,6 @@ int KalmanNav::correctAtt()
 	if (beta > _faultAtt.get()) {
 		printf("fault in attitude: beta = %8.4f\n", (double)beta);
 		printf("y:\n"); y.print();
-		printf("zMagHat:\n"); zMagHat.print();
-		printf("zMag:\n"); zMag.print();
-		printf("bNav:\n"); bNav.print();
 	}
 
 	// update quaternions from euler
@@ -722,8 +676,6 @@ void KalmanNav::updateParams()
 	if (noiseMagSq < noiseMin) noiseMagSq = noiseMin;
 
 	RAtt(0, 0) = noiseMagSq; // normalized direction
-	RAtt(1, 1) = noiseMagSq;
-	RAtt(2, 2) = noiseMagSq;
 
 	// accelerometer noise
 	float noiseAccelSq = _rAccel.get() * _rAccel.get();
@@ -731,9 +683,9 @@ void KalmanNav::updateParams()
 	// bound noise to prevent singularities
 	if (noiseAccelSq < noiseMin) noiseAccelSq = noiseMin;
 
-	RAtt(3, 3) = noiseAccelSq; // normalized direction
-	RAtt(4, 4) = noiseAccelSq;
-	RAtt(5, 5) = noiseAccelSq;
+	RAtt(1, 1) = noiseAccelSq; // normalized direction
+	RAtt(2, 2) = noiseAccelSq;
+	RAtt(3, 3) = noiseAccelSq;
 
 	// gps noise
 	float R = R0 + float(alt);