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Diffstat (limited to 'apps/examples/kalman_demo/KalmanNav.cpp')
| -rw-r--r-- | apps/examples/kalman_demo/KalmanNav.cpp | 769 |
1 files changed, 0 insertions, 769 deletions
diff --git a/apps/examples/kalman_demo/KalmanNav.cpp b/apps/examples/kalman_demo/KalmanNav.cpp deleted file mode 100644 index 6df454a55..000000000 --- a/apps/examples/kalman_demo/KalmanNav.cpp +++ /dev/null @@ -1,769 +0,0 @@ -/**************************************************************************** - * - * Copyright (C) 2012 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. - * - ****************************************************************************/ - -/** - * @file KalmanNav.cpp - * - * kalman filter navigation code - */ - -#include <poll.h> - -#include "KalmanNav.hpp" - -// constants -// Titterton pg. 52 -static const float omega = 7.2921150e-5f; // earth rotation rate, rad/s -static const float R0 = 6378137.0f; // earth radius, m -static const float g0 = 9.806f; // standard gravitational accel. m/s^2 -static const int8_t ret_ok = 0; // no error in function -static const int8_t ret_error = -1; // error occurred - -KalmanNav::KalmanNav(SuperBlock *parent, const char *name) : - SuperBlock(parent, name), - // ekf matrices - F(9, 9), - G(9, 6), - P(9, 9), - P0(9, 9), - V(6, 6), - // attitude measurement ekf matrices - HAtt(6, 9), - RAtt(6, 6), - // position measurement ekf matrices - HPos(6, 9), - RPos(6, 6), - // attitude representations - C_nb(), - q(), - // subscriptions - _sensors(&getSubscriptions(), ORB_ID(sensor_combined), 5), // limit to 200 Hz - _gps(&getSubscriptions(), ORB_ID(vehicle_gps_position), 100), // limit to 10 Hz - _param_update(&getSubscriptions(), ORB_ID(parameter_update), 1000), // limit to 1 Hz - // publications - _pos(&getPublications(), ORB_ID(vehicle_global_position)), - _att(&getPublications(), ORB_ID(vehicle_attitude)), - // timestamps - _pubTimeStamp(hrt_absolute_time()), - _predictTimeStamp(hrt_absolute_time()), - _attTimeStamp(hrt_absolute_time()), - _outTimeStamp(hrt_absolute_time()), - // frame count - _navFrames(0), - // miss counts - _miss(0), - // accelerations - fN(0), fE(0), fD(0), - // state - phi(0), theta(0), psi(0), - vN(0), vE(0), vD(0), - lat(0), lon(0), alt(0), - // parameters for ground station - _vGyro(this, "V_GYRO"), - _vAccel(this, "V_ACCEL"), - _rMag(this, "R_MAG"), - _rGpsVel(this, "R_GPS_VEL"), - _rGpsPos(this, "R_GPS_POS"), - _rGpsAlt(this, "R_GPS_ALT"), - _rPressAlt(this, "R_PRESS_ALT"), - _rAccel(this, "R_ACCEL"), - _magDip(this, "ENV_MAG_DIP"), - _magDec(this, "ENV_MAG_DEC"), - _g(this, "ENV_G"), - _faultPos(this, "FAULT_POS"), - _faultAtt(this, "FAULT_ATT"), - _attitudeInitialized(false), - _positionInitialized(false), - _attitudeInitCounter(0) -{ - using namespace math; - - // initial state covariance matrix - P0 = Matrix::identity(9) * 0.01f; - P = P0; - - // initial state - phi = 0.0f; - theta = 0.0f; - psi = 0.0f; - vN = 0.0f; - vE = 0.0f; - vD = 0.0f; - lat = 0.0f; - lon = 0.0f; - alt = 0.0f; - - // initialize quaternions - q = Quaternion(EulerAngles(phi, theta, psi)); - - // initialize dcm - C_nb = Dcm(q); - - // HPos is constant - HPos(0, 3) = 1.0f; - HPos(1, 4) = 1.0f; - HPos(2, 6) = 1.0e7f * M_RAD_TO_DEG_F; - HPos(3, 7) = 1.0e7f * M_RAD_TO_DEG_F; - HPos(4, 8) = 1.0f; - HPos(5, 8) = 1.0f; - - // initialize all parameters - updateParams(); -} - -void KalmanNav::update() -{ - using namespace math; - - struct pollfd fds[1]; - fds[0].fd = _sensors.getHandle(); - fds[0].events = POLLIN; - - // poll for new data - int ret = poll(fds, 1, 1000); - - if (ret < 0) { - // XXX this is seriously bad - should be an emergency - return; - - } else if (ret == 0) { // timeout - return; - } - - // get new timestamp - uint64_t newTimeStamp = hrt_absolute_time(); - - // check updated subscriptions - if (_param_update.updated()) updateParams(); - - bool gpsUpdate = _gps.updated(); - bool sensorsUpdate = _sensors.updated(); - - // get new information from subscriptions - // this clears update flag - updateSubscriptions(); - - // initialize attitude when sensors online - if (!_attitudeInitialized && sensorsUpdate && - _sensors.accelerometer_counter > 10 && - _sensors.gyro_counter > 10 && - _sensors.magnetometer_counter > 10) { - if (correctAtt() == ret_ok) _attitudeInitCounter++; - - if (_attitudeInitCounter > 100) { - printf("[kalman_demo] initialized EKF attitude\n"); - printf("phi: %8.4f, theta: %8.4f, psi: %8.4f\n", - double(phi), double(theta), double(psi)); - _attitudeInitialized = true; - } - } - - // initialize position when gps received - if (!_positionInitialized && - _attitudeInitialized && // wait for attitude first - gpsUpdate && - _gps.fix_type > 2 - //&& _gps.counter_pos_valid > 10 - ) { - vN = _gps.vel_n_m_s; - vE = _gps.vel_e_m_s; - vD = _gps.vel_d_m_s; - setLatDegE7(_gps.lat); - setLonDegE7(_gps.lon); - setAltE3(_gps.alt); - _positionInitialized = true; - printf("[kalman_demo] initialized EKF state with GPS\n"); - printf("vN: %8.4f, vE: %8.4f, vD: %8.4f, lat: %8.4f, lon: %8.4f, alt: %8.4f\n", - double(vN), double(vE), double(vD), - lat, lon, alt); - } - - // prediciton step - // using sensors timestamp so we can account for packet lag - float dt = (_sensors.timestamp - _predictTimeStamp) / 1.0e6f; - //printf("dt: %15.10f\n", double(dt)); - _predictTimeStamp = _sensors.timestamp; - - // don't predict if time greater than a second - if (dt < 1.0f) { - predictState(dt); - predictStateCovariance(dt); - // count fast frames - _navFrames += 1; - } - - // count times 100 Hz rate isn't met - if (dt > 0.01f) _miss++; - - // gps correction step - if (_positionInitialized && gpsUpdate) { - correctPos(); - } - - // attitude correction step - if (_attitudeInitialized // initialized - && sensorsUpdate // new data - && _sensors.timestamp - _attTimeStamp > 1e6 / 20 // 20 Hz - ) { - _attTimeStamp = _sensors.timestamp; - correctAtt(); - } - - // publication - if (newTimeStamp - _pubTimeStamp > 1e6 / 50) { // 50 Hz - _pubTimeStamp = newTimeStamp; - - updatePublications(); - } - - // output - if (newTimeStamp - _outTimeStamp > 10e6) { // 0.1 Hz - _outTimeStamp = newTimeStamp; - //printf("nav: %4d Hz, miss #: %4d\n", - // _navFrames / 10, _miss / 10); - _navFrames = 0; - _miss = 0; - } -} - -void KalmanNav::updatePublications() -{ - using namespace math; - - // position publication - _pos.timestamp = _pubTimeStamp; - _pos.time_gps_usec = _gps.timestamp_position; - _pos.valid = true; - _pos.lat = getLatDegE7(); - _pos.lon = getLonDegE7(); - _pos.alt = float(alt); - _pos.relative_alt = float(alt); // TODO, make relative - _pos.vx = vN; - _pos.vy = vE; - _pos.vz = vD; - _pos.hdg = psi; - - // attitude publication - _att.timestamp = _pubTimeStamp; - _att.roll = phi; - _att.pitch = theta; - _att.yaw = psi; - _att.rollspeed = _sensors.gyro_rad_s[0]; - _att.pitchspeed = _sensors.gyro_rad_s[1]; - _att.yawspeed = _sensors.gyro_rad_s[2]; - // TODO, add gyro offsets to filter - _att.rate_offsets[0] = 0.0f; - _att.rate_offsets[1] = 0.0f; - _att.rate_offsets[2] = 0.0f; - - for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) - _att.R[i][j] = C_nb(i, j); - - for (int i = 0; i < 4; i++) _att.q[i] = q(i); - - _att.R_valid = true; - _att.q_valid = true; - - // selectively update publications, - // do NOT call superblock do-all method - if (_positionInitialized) - _pos.update(); - - if (_attitudeInitialized) - _att.update(); -} - -int KalmanNav::predictState(float dt) -{ - using namespace math; - - // trig - float sinL = sinf(lat); - float cosL = cosf(lat); - float cosLSing = cosf(lat); - - // prevent singularity - if (fabsf(cosLSing) < 0.01f) { - if (cosLSing > 0) cosLSing = 0.01; - else cosLSing = -0.01; - } - - // attitude prediction - if (_attitudeInitialized) { - Vector3 w(_sensors.gyro_rad_s); - - // attitude - q = q + q.derivative(w) * dt; - - // renormalize quaternion if needed - if (fabsf(q.norm() - 1.0f) > 1e-4f) { - q = q.unit(); - } - - // C_nb update - C_nb = Dcm(q); - - // euler update - EulerAngles euler(C_nb); - phi = euler.getPhi(); - theta = euler.getTheta(); - psi = euler.getPsi(); - - // specific acceleration in nav frame - Vector3 accelB(_sensors.accelerometer_m_s2); - Vector3 accelN = C_nb * accelB; - fN = accelN(0); - fE = accelN(1); - fD = accelN(2); - } - - // position prediction - if (_positionInitialized) { - // neglects angular deflections in local gravity - // see Titerton pg. 70 - float R = R0 + float(alt); - float LDot = vN / R; - float lDot = vE / (cosLSing * R); - float rotRate = 2 * omega + lDot; - float vNDot = fN - vE * rotRate * sinL + - vD * LDot; - float vDDot = fD - vE * rotRate * cosL - - vN * LDot + _g.get(); - float vEDot = fE + vN * rotRate * sinL + - vDDot * rotRate * cosL; - - // rectangular integration - vN += vNDot * dt; - vE += vEDot * dt; - vD += vDDot * dt; - lat += double(LDot * dt); - lon += double(lDot * dt); - alt += double(-vD * dt); - } - - return ret_ok; -} - -int KalmanNav::predictStateCovariance(float dt) -{ - using namespace math; - - // trig - float sinL = sinf(lat); - float cosL = cosf(lat); - float cosLSq = cosL * cosL; - float tanL = tanf(lat); - - // prepare for matrix - float R = R0 + float(alt); - float RSq = R * R; - - // F Matrix - // Titterton pg. 291 - - F(0, 1) = -(omega * sinL + vE * tanL / R); - F(0, 2) = vN / R; - F(0, 4) = 1.0f / R; - F(0, 6) = -omega * sinL; - F(0, 8) = -vE / RSq; - - F(1, 0) = omega * sinL + vE * tanL / R; - F(1, 2) = omega * cosL + vE / R; - F(1, 3) = -1.0f / R; - F(1, 8) = vN / RSq; - - F(2, 0) = -vN / R; - F(2, 1) = -omega * cosL - vE / R; - F(2, 4) = -tanL / R; - F(2, 6) = -omega * cosL - vE / (R * cosLSq); - F(2, 8) = vE * tanL / RSq; - - F(3, 1) = -fD; - F(3, 2) = fE; - F(3, 3) = vD / R; - F(3, 4) = -2 * (omega * sinL + vE * tanL / R); - F(3, 5) = vN / R; - F(3, 6) = -vE * (2 * omega * cosL + vE / (R * cosLSq)); - F(3, 8) = (vE * vE * tanL - vN * vD) / RSq; - - F(4, 0) = fD; - F(4, 2) = -fN; - F(4, 3) = 2 * omega * sinL + vE * tanL / R; - F(4, 4) = (vN * tanL + vD) / R; - F(4, 5) = 2 * omega * cosL + vE / R; - F(4, 6) = 2 * omega * (vN * cosL - vD * sinL) + - vN * vE / (R * cosLSq); - F(4, 8) = -vE * (vN * tanL + vD) / RSq; - - F(5, 0) = -fE; - F(5, 1) = fN; - F(5, 3) = -2 * vN / R; - F(5, 4) = -2 * (omega * cosL + vE / R); - F(5, 6) = 2 * omega * vE * sinL; - F(5, 8) = (vN * vN + vE * vE) / RSq; - - F(6, 3) = 1 / R; - F(6, 8) = -vN / RSq; - - F(7, 4) = 1 / (R * cosL); - F(7, 6) = vE * tanL / (R * cosL); - F(7, 8) = -vE / (cosL * RSq); - - F(8, 5) = -1; - - // G Matrix - // Titterton pg. 291 - G(0, 0) = -C_nb(0, 0); - G(0, 1) = -C_nb(0, 1); - G(0, 2) = -C_nb(0, 2); - G(1, 0) = -C_nb(1, 0); - G(1, 1) = -C_nb(1, 1); - G(1, 2) = -C_nb(1, 2); - G(2, 0) = -C_nb(2, 0); - G(2, 1) = -C_nb(2, 1); - G(2, 2) = -C_nb(2, 2); - - G(3, 3) = C_nb(0, 0); - G(3, 4) = C_nb(0, 1); - G(3, 5) = C_nb(0, 2); - G(4, 3) = C_nb(1, 0); - G(4, 4) = C_nb(1, 1); - G(4, 5) = C_nb(1, 2); - G(5, 3) = C_nb(2, 0); - G(5, 4) = C_nb(2, 1); - G(5, 5) = C_nb(2, 2); - - // continuous predictioon equations - // for discrte time EKF - // http://en.wikipedia.org/wiki/Extended_Kalman_filter - P = P + (F * P + P * F.transpose() + G * V * G.transpose()) * dt; - - return ret_ok; -} - -int KalmanNav::correctAtt() -{ - using namespace math; - - // trig - float cosPhi = cosf(phi); - float cosTheta = cosf(theta); - float cosPsi = cosf(psi); - float sinPhi = sinf(phi); - float sinTheta = sinf(theta); - 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(); - - // accel measurement - Vector3 zAccel(_sensors.accelerometer_m_s2); - float accelMag = zAccel.norm(); - zAccel = zAccel.unit(); - - // ignore accel correction when accel mag not close to g - Matrix RAttAdjust = RAtt; - - bool ignoreAccel = fabsf(accelMag - _g.get()) > 1.1f; - - if (ignoreAccel) { - RAttAdjust(3, 3) = 1.0e10; - RAttAdjust(4, 4) = 1.0e10; - RAttAdjust(5, 5) = 1.0e10; - - } else { - //printf("correcting attitude with accel\n"); - } - - // accel predicted measurement - Vector3 zAccelHat = (C_nb.transpose() * Vector3(0, 0, -_g.get())).unit(); - - // combined measurement - Vector zAtt(6); - Vector zAttHat(6); - - 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,:) - 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; - - // 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; - - // check correciton is sane - for (size_t i = 0; i < xCorrect.getRows(); i++) { - float val = xCorrect(i); - - if (isnan(val) || isinf(val)) { - // abort correction and return - printf("[kalman_demo] numerical failure in att correction\n"); - // reset P matrix to P0 - P = P0; - return ret_error; - } - } - - // correct state - if (!ignoreAccel) { - phi += xCorrect(PHI); - theta += xCorrect(THETA); - } - - psi += xCorrect(PSI); - - // attitude also affects nav velocities - if (_positionInitialized) { - vN += xCorrect(VN); - vE += xCorrect(VE); - vD += xCorrect(VD); - } - - // update state covariance - // http://en.wikipedia.org/wiki/Extended_Kalman_filter - P = P - K * HAtt * P; - - // fault detection - float beta = y.dot(S.inverse() * y); - - 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 - // angle correction - q = Quaternion(EulerAngles(phi, theta, psi)); - - return ret_ok; -} - -int KalmanNav::correctPos() -{ - using namespace math; - - // residual - Vector y(6); - y(0) = _gps.vel_n_m_s - vN; - y(1) = _gps.vel_e_m_s - vE; - y(2) = double(_gps.lat) - lat * 1.0e7 * M_RAD_TO_DEG; - y(3) = double(_gps.lon) - lon * 1.0e7 * M_RAD_TO_DEG; - y(4) = double(_gps.alt) / 1.0e3 - alt; - y(5) = double(_sensors.baro_alt_meter) - alt; - - // compute correction - // http://en.wikipedia.org/wiki/Extended_Kalman_filter - Matrix S = HPos * P * HPos.transpose() + RPos; // residual covariance - Matrix K = P * HPos.transpose() * S.inverse(); - Vector xCorrect = K * y; - - // check correction is sane - for (size_t i = 0; i < xCorrect.getRows(); i++) { - float val = xCorrect(i); - - if (isnan(val) || isinf(val)) { - // abort correction and return - printf("[kalman_demo] numerical failure in gps correction\n"); - // fallback to GPS - vN = _gps.vel_n_m_s; - vE = _gps.vel_e_m_s; - vD = _gps.vel_d_m_s; - setLatDegE7(_gps.lat); - setLonDegE7(_gps.lon); - setAltE3(_gps.alt); - // reset P matrix to P0 - P = P0; - return ret_error; - } - } - - // correct state - vN += xCorrect(VN); - vE += xCorrect(VE); - vD += xCorrect(VD); - lat += double(xCorrect(LAT)); - lon += double(xCorrect(LON)); - alt += double(xCorrect(ALT)); - - // update state covariance - // http://en.wikipedia.org/wiki/Extended_Kalman_filter - P = P - K * HPos * P; - - // fault detetcion - float beta = y.dot(S.inverse() * y); - - if (beta > _faultPos.get()) { - printf("fault in gps: beta = %8.4f\n", (double)beta); - printf("Y/N: vN: %8.4f, vE: %8.4f, lat: %8.4f, lon: %8.4f, alt: %8.4f\n", - double(y(0) / sqrtf(RPos(0, 0))), - double(y(1) / sqrtf(RPos(1, 1))), - double(y(2) / sqrtf(RPos(2, 2))), - double(y(3) / sqrtf(RPos(3, 3))), - double(y(4) / sqrtf(RPos(4, 4))), - double(y(5) / sqrtf(RPos(5, 5)))); - } - - return ret_ok; -} - -void KalmanNav::updateParams() -{ - using namespace math; - using namespace control; - SuperBlock::updateParams(); - - // gyro noise - V(0, 0) = _vGyro.get(); // gyro x, rad/s - V(1, 1) = _vGyro.get(); // gyro y - V(2, 2) = _vGyro.get(); // gyro z - - // accel noise - V(3, 3) = _vAccel.get(); // accel x, m/s^2 - V(4, 4) = _vAccel.get(); // accel y - V(5, 5) = _vAccel.get(); // accel z - - // magnetometer noise - float noiseMin = 1e-6f; - float noiseMagSq = _rMag.get() * _rMag.get(); - - 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(); - - // bound noise to prevent singularities - if (noiseAccelSq < noiseMin) noiseAccelSq = noiseMin; - - RAtt(3, 3) = noiseAccelSq; // normalized direction - RAtt(4, 4) = noiseAccelSq; - RAtt(5, 5) = noiseAccelSq; - - // gps noise - float R = R0 + float(alt); - float cosLSing = cosf(lat); - - // prevent singularity - if (fabsf(cosLSing) < 0.01f) { - if (cosLSing > 0) cosLSing = 0.01; - else cosLSing = -0.01; - } - - float noiseVel = _rGpsVel.get(); - float noiseLatDegE7 = 1.0e7f * M_RAD_TO_DEG_F * _rGpsPos.get() / R; - float noiseLonDegE7 = noiseLatDegE7 / cosLSing; - float noiseGpsAlt = _rGpsAlt.get(); - float noisePressAlt = _rPressAlt.get(); - - // bound noise to prevent singularities - if (noiseVel < noiseMin) noiseVel = noiseMin; - - if (noiseLatDegE7 < noiseMin) noiseLatDegE7 = noiseMin; - - if (noiseLonDegE7 < noiseMin) noiseLonDegE7 = noiseMin; - - if (noiseGpsAlt < noiseMin) noiseGpsAlt = noiseMin; - - if (noisePressAlt < noiseMin) noisePressAlt = noiseMin; - - RPos(0, 0) = noiseVel * noiseVel; // vn - RPos(1, 1) = noiseVel * noiseVel; // ve - RPos(2, 2) = noiseLatDegE7 * noiseLatDegE7; // lat - RPos(3, 3) = noiseLonDegE7 * noiseLonDegE7; // lon - RPos(4, 4) = noiseGpsAlt * noiseGpsAlt; // h - RPos(5, 5) = noisePressAlt * noisePressAlt; // h - // XXX, note that RPos depends on lat, so updateParams should - // be called if lat changes significantly -} |