split ImuFactor in .h and .cpp

release/4.3a0
Luca 2014-12-02 14:59:21 -05:00
parent b6c375db0d
commit b818a548c5
2 changed files with 570 additions and 473 deletions

View File

@ -0,0 +1,438 @@
/* ----------------------------------------------------------------------------
* GTSAM Copyright 2010, Georgia Tech Research Corporation,
* Atlanta, Georgia 30332-0415
* All Rights Reserved
* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
* See LICENSE for the license information
* -------------------------------------------------------------------------- */
/**
* @file ImuFactor.h
* @author Luca Carlone
* @author Stephen Williams
* @author Richard Roberts
* @author Vadim Indelman
* @author David Jensen
* @author Frank Dellaert
**/
#include <gtsam/navigation/ImuFactor.h>
/* External or standard includes */
#include <ostream>
namespace gtsam {
//------------------------------------------------------------------------------
// Inner class PreintegratedMeasurements
//------------------------------------------------------------------------------
ImuFactor::PreintegratedMeasurements::PreintegratedMeasurements(
const imuBias::ConstantBias& bias, const Matrix3& measuredAccCovariance,
const Matrix3& measuredOmegaCovariance, const Matrix3& integrationErrorCovariance,
const bool use2ndOrderIntegration) :
biasHat_(bias), deltaPij_(Vector3::Zero()), deltaVij_(Vector3::Zero()),
// TODO: add this deltaRij_(Rot3()),
deltaTij_(0.0),
delPdelBiasAcc_(Z_3x3), delPdelBiasOmega_(Z_3x3),
delVdelBiasAcc_(Z_3x3), delVdelBiasOmega_(Z_3x3),
delRdelBiasOmega_(Z_3x3), use2ndOrderIntegration_(use2ndOrderIntegration)
{
measurementCovariance_.setZero();
measurementCovariance_.block<3,3>(0,0) = integrationErrorCovariance;
measurementCovariance_.block<3,3>(3,3) = measuredAccCovariance;
measurementCovariance_.block<3,3>(6,6) = measuredOmegaCovariance;
PreintMeasCov_.setZero(9,9);
}
//------------------------------------------------------------------------------
void ImuFactor::PreintegratedMeasurements::print(const std::string& s) const {
std::cout << s << std::endl;
biasHat_.print(" biasHat");
std::cout << " deltaTij " << deltaTij_ << std::endl;
std::cout << " deltaPij [ " << deltaPij_.transpose() << " ]" << std::endl;
std::cout << " deltaVij [ " << deltaVij_.transpose() << " ]" << std::endl;
deltaRij_.print(" deltaRij ");
std::cout << " measurementCovariance = \n [ " << measurementCovariance_ << " ]" << std::endl;
std::cout << " PreintMeasCov = \n [ " << PreintMeasCov_ << " ]" << std::endl;
}
//------------------------------------------------------------------------------
bool ImuFactor::PreintegratedMeasurements::equals(const PreintegratedMeasurements& expected, double tol) const {
return biasHat_.equals(expected.biasHat_, tol)
&& equal_with_abs_tol(measurementCovariance_, expected.measurementCovariance_, tol)
&& equal_with_abs_tol(deltaPij_, expected.deltaPij_, tol)
&& equal_with_abs_tol(deltaVij_, expected.deltaVij_, tol)
&& deltaRij_.equals(expected.deltaRij_, tol)
&& std::fabs(deltaTij_ - expected.deltaTij_) < tol
&& equal_with_abs_tol(delPdelBiasAcc_, expected.delPdelBiasAcc_, tol)
&& equal_with_abs_tol(delPdelBiasOmega_, expected.delPdelBiasOmega_, tol)
&& equal_with_abs_tol(delVdelBiasAcc_, expected.delVdelBiasAcc_, tol)
&& equal_with_abs_tol(delVdelBiasOmega_, expected.delVdelBiasOmega_, tol)
&& equal_with_abs_tol(delRdelBiasOmega_, expected.delRdelBiasOmega_, tol);
}
//------------------------------------------------------------------------------
void ImuFactor::PreintegratedMeasurements::resetIntegration(){
deltaPij_ = Vector3::Zero();
deltaVij_ = Vector3::Zero();
deltaRij_ = Rot3();
deltaTij_ = 0.0;
delPdelBiasAcc_ = Z_3x3;
delPdelBiasOmega_ = Z_3x3;
delVdelBiasAcc_ = Z_3x3;
delVdelBiasOmega_ = Z_3x3;
delRdelBiasOmega_ = Z_3x3;
PreintMeasCov_.setZero(9,9);
}
//------------------------------------------------------------------------------
void ImuFactor::PreintegratedMeasurements::integrateMeasurement(
const Vector3& measuredAcc, const Vector3& measuredOmega, double deltaT,
boost::optional<const Pose3&> body_P_sensor) {
// NOTE: order is important here because each update uses old values (i.e., we have to update
// jacobians and covariances before updating preintegrated measurements).
// First we compensate the measurements for the bias
Vector3 correctedAcc = biasHat_.correctAccelerometer(measuredAcc);
Vector3 correctedOmega = biasHat_.correctGyroscope(measuredOmega);
// Then compensate for sensor-body displacement: we express the quantities (originally in the IMU frame) into the body frame
if(body_P_sensor){
Matrix3 body_R_sensor = body_P_sensor->rotation().matrix();
correctedOmega = body_R_sensor * correctedOmega; // rotation rate vector in the body frame
Matrix3 body_omega_body__cross = skewSymmetric(correctedOmega);
correctedAcc = body_R_sensor * correctedAcc - body_omega_body__cross * body_omega_body__cross * body_P_sensor->translation().vector();
// linear acceleration vector in the body frame
}
const Vector3 theta_incr = correctedOmega * deltaT; // rotation vector describing rotation increment computed from the current rotation rate measurement
const Rot3 Rincr = Rot3::Expmap(theta_incr); // rotation increment computed from the current rotation rate measurement
const Matrix3 Jr_theta_incr = Rot3::rightJacobianExpMapSO3(theta_incr); // Right jacobian computed at theta_incr
// Update Jacobians
/* ----------------------------------------------------------------------------------------------------------------------- */
if(!use2ndOrderIntegration_){
delPdelBiasAcc_ += delVdelBiasAcc_ * deltaT;
delPdelBiasOmega_ += delVdelBiasOmega_ * deltaT;
}else{
delPdelBiasAcc_ += delVdelBiasAcc_ * deltaT - 0.5 * deltaRij_.matrix() * deltaT*deltaT;
delPdelBiasOmega_ += delVdelBiasOmega_ * deltaT - 0.5 * deltaRij_.matrix()
* skewSymmetric(biasHat_.correctAccelerometer(measuredAcc)) * deltaT*deltaT * delRdelBiasOmega_;
}
delVdelBiasAcc_ += -deltaRij_.matrix() * deltaT;
delVdelBiasOmega_ += -deltaRij_.matrix() * skewSymmetric(correctedAcc) * deltaT * delRdelBiasOmega_;
delRdelBiasOmega_ = Rincr.inverse().matrix() * delRdelBiasOmega_ - Jr_theta_incr * deltaT;
// Update preintegrated measurements covariance
// as in [2] we consider a first order propagation that can be seen as a prediction phase in an EKF framework
/* ----------------------------------------------------------------------------------------------------------------------- */
const Vector3 theta_i = Rot3::Logmap(deltaRij_); // parametrization of so(3)
const Matrix3 Jr_theta_i = Rot3::rightJacobianExpMapSO3(theta_i);
Rot3 Rot_j = deltaRij_ * Rincr;
const Vector3 theta_j = Rot3::Logmap(Rot_j); // parametrization of so(3)
const Matrix3 Jrinv_theta_j = Rot3::rightJacobianExpMapSO3inverse(theta_j);
Matrix H_pos_pos = I_3x3;
Matrix H_pos_vel = I_3x3 * deltaT;
Matrix H_pos_angles = Z_3x3;
Matrix H_vel_pos = Z_3x3;
Matrix H_vel_vel = I_3x3;
Matrix H_vel_angles = - deltaRij_.matrix() * skewSymmetric(correctedAcc) * Jr_theta_i * deltaT;
// analytic expression corresponding to the following numerical derivative
// Matrix H_vel_angles = numericalDerivative11<Vector3, Vector3>(boost::bind(&PreIntegrateIMUObservations_delta_vel, correctedOmega, correctedAcc, deltaT, _1, deltaVij), theta_i);
Matrix H_angles_pos = Z_3x3;
Matrix H_angles_vel = Z_3x3;
Matrix H_angles_angles = Jrinv_theta_j * Rincr.inverse().matrix() * Jr_theta_i;
// analytic expression corresponding to the following numerical derivative
// Matrix H_angles_angles = numericalDerivative11<Vector3, Vector3>(boost::bind(&PreIntegrateIMUObservations_delta_angles, correctedOmega, deltaT, _1), thetaij);
// overall Jacobian wrt preintegrated measurements (df/dx)
Matrix F(9,9);
F << H_pos_pos, H_pos_vel, H_pos_angles,
H_vel_pos, H_vel_vel, H_vel_angles,
H_angles_pos, H_angles_vel, H_angles_angles;
// first order uncertainty propagation:
// the deltaT allows to pass from continuous time noise to discrete time noise
// measurementCovariance_discrete = measurementCovariance_contTime * (1/deltaT)
// Gt * Qt * G =(approx)= measurementCovariance_discrete * deltaT^2 = measurementCovariance_contTime * deltaT
PreintMeasCov_ = F * PreintMeasCov_ * F.transpose() + measurementCovariance_ * deltaT ;
// Extended version, without approximation: Gt * Qt * G =(approx)= measurementCovariance_contTime * deltaT
// This in only kept for documentation.
//
// Matrix G(9,9);
// G << I_3x3 * deltaT, Z_3x3, Z_3x3,
// Z_3x3, deltaRij.matrix() * deltaT, Z_3x3,
// Z_3x3, Z_3x3, Jrinv_theta_j * Jr_theta_incr * deltaT;
//
// PreintMeasCov = F * PreintMeasCov * F.transpose() + G * (1/deltaT) * measurementCovariance * G.transpose();
// Update preintegrated measurements (this has to be done after the update of covariances and jacobians!)
/* ----------------------------------------------------------------------------------------------------------------------- */
if(!use2ndOrderIntegration_){
deltaPij_ += deltaVij_ * deltaT;
}else{
deltaPij_ += deltaVij_ * deltaT + 0.5 * deltaRij_.matrix() * biasHat_.correctAccelerometer(measuredAcc) * deltaT*deltaT;
}
deltaVij_ += deltaRij_.matrix() * correctedAcc * deltaT;
deltaRij_ = deltaRij_ * Rincr;
deltaTij_ += deltaT;
}
//------------------------------------------------------------------------------
// ImuFactor methods
//------------------------------------------------------------------------------
ImuFactor::ImuFactor() :
preintegratedMeasurements_(imuBias::ConstantBias(), Z_3x3, Z_3x3, Z_3x3), use2ndOrderCoriolis_(false){}
//------------------------------------------------------------------------------
ImuFactor::ImuFactor(
Key pose_i, Key vel_i, Key pose_j, Key vel_j, Key bias,
const PreintegratedMeasurements& preintegratedMeasurements,
const Vector3& gravity, const Vector3& omegaCoriolis,
boost::optional<const Pose3&> body_P_sensor,
const bool use2ndOrderCoriolis) :
Base(noiseModel::Gaussian::Covariance(preintegratedMeasurements.PreintMeasCov_), pose_i, vel_i, pose_j, vel_j, bias),
preintegratedMeasurements_(preintegratedMeasurements),
gravity_(gravity),
omegaCoriolis_(omegaCoriolis),
body_P_sensor_(body_P_sensor),
use2ndOrderCoriolis_(use2ndOrderCoriolis){
}
//------------------------------------------------------------------------------
gtsam::NonlinearFactor::shared_ptr ImuFactor::clone() const {
return boost::static_pointer_cast<gtsam::NonlinearFactor>(
gtsam::NonlinearFactor::shared_ptr(new This(*this)));
}
//------------------------------------------------------------------------------
void ImuFactor::print(const std::string& s, const KeyFormatter& keyFormatter) const {
std::cout << s << "ImuFactor("
<< keyFormatter(this->key1()) << ","
<< keyFormatter(this->key2()) << ","
<< keyFormatter(this->key3()) << ","
<< keyFormatter(this->key4()) << ","
<< keyFormatter(this->key5()) << ")\n";
preintegratedMeasurements_.print(" preintegrated measurements:");
std::cout << " gravity: [ " << gravity_.transpose() << " ]" << std::endl;
std::cout << " omegaCoriolis: [ " << omegaCoriolis_.transpose() << " ]" << std::endl;
this->noiseModel_->print(" noise model: ");
if(this->body_P_sensor_)
this->body_P_sensor_->print(" sensor pose in body frame: ");
}
//------------------------------------------------------------------------------
bool ImuFactor::equals(const NonlinearFactor& expected, double tol) const {
const This *e = dynamic_cast<const This*> (&expected);
return e != NULL && Base::equals(*e, tol)
&& preintegratedMeasurements_.equals(e->preintegratedMeasurements_, tol)
&& equal_with_abs_tol(gravity_, e->gravity_, tol)
&& equal_with_abs_tol(omegaCoriolis_, e->omegaCoriolis_, tol)
&& ((!body_P_sensor_ && !e->body_P_sensor_) || (body_P_sensor_ && e->body_P_sensor_ && body_P_sensor_->equals(*e->body_P_sensor_)));
}
//------------------------------------------------------------------------------
Vector ImuFactor::evaluateError(const Pose3& pose_i, const Vector3& vel_i, const Pose3& pose_j, const Vector3& vel_j,
const imuBias::ConstantBias& bias,
boost::optional<Matrix&> H1, boost::optional<Matrix&> H2,
boost::optional<Matrix&> H3, boost::optional<Matrix&> H4,
boost::optional<Matrix&> H5) const
{
const double& deltaTij = preintegratedMeasurements_.deltaTij_;
const Vector3 biasAccIncr = bias.accelerometer() - preintegratedMeasurements_.biasHat_.accelerometer();
const Vector3 biasOmegaIncr = bias.gyroscope() - preintegratedMeasurements_.biasHat_.gyroscope();
// we give some shorter name to rotations and translations
const Rot3 Rot_i = pose_i.rotation();
const Rot3 Rot_j = pose_j.rotation();
const Vector3 pos_i = pose_i.translation().vector();
const Vector3 pos_j = pose_j.translation().vector();
// We compute factor's Jacobians
/* ---------------------------------------------------------------------------------------------------- */
const Rot3 deltaRij_biascorrected = preintegratedMeasurements_.deltaRij_.retract(preintegratedMeasurements_.delRdelBiasOmega_ * biasOmegaIncr, Rot3::EXPMAP);
// deltaRij_biascorrected is expmap(deltaRij) * expmap(delRdelBiasOmega * biasOmegaIncr)
Vector3 theta_biascorrected = Rot3::Logmap(deltaRij_biascorrected);
Vector3 theta_biascorrected_corioliscorrected = theta_biascorrected -
Rot_i.inverse().matrix() * omegaCoriolis_ * deltaTij; // Coriolis term
const Rot3 deltaRij_biascorrected_corioliscorrected =
Rot3::Expmap( theta_biascorrected_corioliscorrected );
const Rot3 fRhat = deltaRij_biascorrected_corioliscorrected.between(Rot_i.between(Rot_j));
const Matrix3 Jr_theta_bcc = Rot3::rightJacobianExpMapSO3(theta_biascorrected_corioliscorrected);
const Matrix3 Jtheta = -Jr_theta_bcc * skewSymmetric(Rot_i.inverse().matrix() * omegaCoriolis_ * deltaTij);
const Matrix3 Jrinv_fRhat = Rot3::rightJacobianExpMapSO3inverse(Rot3::Logmap(fRhat));
if(H1) {
H1->resize(9,6);
Matrix3 dfPdPi;
Matrix3 dfVdPi;
if(use2ndOrderCoriolis_){
dfPdPi = - Rot_i.matrix() + 0.5 * skewSymmetric(omegaCoriolis_) * skewSymmetric(omegaCoriolis_) * Rot_i.matrix() * deltaTij*deltaTij;
dfVdPi = skewSymmetric(omegaCoriolis_) * skewSymmetric(omegaCoriolis_) * Rot_i.matrix() * deltaTij;
}
else{
dfPdPi = - Rot_i.matrix();
dfVdPi = Z_3x3;
}
(*H1) <<
// dfP/dRi
Rot_i.matrix() * skewSymmetric(preintegratedMeasurements_.deltaPij_
+ preintegratedMeasurements_.delPdelBiasOmega_ * biasOmegaIncr + preintegratedMeasurements_.delPdelBiasAcc_ * biasAccIncr),
// dfP/dPi
dfPdPi,
// dfV/dRi
Rot_i.matrix() * skewSymmetric(preintegratedMeasurements_.deltaVij_
+ preintegratedMeasurements_.delVdelBiasOmega_ * biasOmegaIncr + preintegratedMeasurements_.delVdelBiasAcc_ * biasAccIncr),
// dfV/dPi
dfVdPi,
// dfR/dRi
Jrinv_fRhat * (- Rot_j.between(Rot_i).matrix() - fRhat.inverse().matrix() * Jtheta),
// dfR/dPi
Z_3x3;
}
if(H2) {
H2->resize(9,3);
(*H2) <<
// dfP/dVi
- I_3x3 * deltaTij
+ skewSymmetric(omegaCoriolis_) * deltaTij * deltaTij, // Coriolis term - we got rid of the 2 wrt ins paper
// dfV/dVi
- I_3x3
+ 2 * skewSymmetric(omegaCoriolis_) * deltaTij, // Coriolis term
// dfR/dVi
Z_3x3;
}
if(H3) {
H3->resize(9,6);
(*H3) <<
// dfP/dPosej
Z_3x3, Rot_j.matrix(),
// dfV/dPosej
Matrix::Zero(3,6),
// dfR/dPosej
Jrinv_fRhat * ( I_3x3 ), Z_3x3;
}
if(H4) {
H4->resize(9,3);
(*H4) <<
// dfP/dVj
Z_3x3,
// dfV/dVj
I_3x3,
// dfR/dVj
Z_3x3;
}
if(H5) {
const Matrix3 Jrinv_theta_bc = Rot3::rightJacobianExpMapSO3inverse(theta_biascorrected);
const Matrix3 Jr_JbiasOmegaIncr = Rot3::rightJacobianExpMapSO3(preintegratedMeasurements_.delRdelBiasOmega_ * biasOmegaIncr);
const Matrix3 JbiasOmega = Jr_theta_bcc * Jrinv_theta_bc * Jr_JbiasOmegaIncr * preintegratedMeasurements_.delRdelBiasOmega_;
H5->resize(9,6);
(*H5) <<
// dfP/dBias
- Rot_i.matrix() * preintegratedMeasurements_.delPdelBiasAcc_,
- Rot_i.matrix() * preintegratedMeasurements_.delPdelBiasOmega_,
// dfV/dBias
- Rot_i.matrix() * preintegratedMeasurements_.delVdelBiasAcc_,
- Rot_i.matrix() * preintegratedMeasurements_.delVdelBiasOmega_,
// dfR/dBias
Matrix::Zero(3,3),
Jrinv_fRhat * ( - fRhat.inverse().matrix() * JbiasOmega);
}
// Evaluate residual error, according to [3]
/* ---------------------------------------------------------------------------------------------------- */
const Vector3 fp =
pos_j - pos_i
- Rot_i.matrix() * (preintegratedMeasurements_.deltaPij_
+ preintegratedMeasurements_.delPdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements_.delPdelBiasOmega_ * biasOmegaIncr)
- vel_i * deltaTij
+ skewSymmetric(omegaCoriolis_) * vel_i * deltaTij*deltaTij // Coriolis term - we got rid of the 2 wrt ins paper
- 0.5 * gravity_ * deltaTij*deltaTij;
const Vector3 fv =
vel_j - vel_i - Rot_i.matrix() * (preintegratedMeasurements_.deltaVij_
+ preintegratedMeasurements_.delVdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements_.delVdelBiasOmega_ * biasOmegaIncr)
+ 2 * skewSymmetric(omegaCoriolis_) * vel_i * deltaTij // Coriolis term
- gravity_ * deltaTij;
const Vector3 fR = Rot3::Logmap(fRhat);
Vector r(9); r << fp, fv, fR;
return r;
}
//------------------------------------------------------------------------------
PoseVelocity ImuFactor::Predict(const Pose3& pose_i, const Vector3& vel_i,
const imuBias::ConstantBias& bias, const PreintegratedMeasurements preintegratedMeasurements,
const Vector3& gravity, const Vector3& omegaCoriolis, boost::optional<const Pose3&> body_P_sensore,
const bool use2ndOrderCoriolis)
{
const double& deltaTij = preintegratedMeasurements.deltaTij_;
const Vector3 biasAccIncr = bias.accelerometer() - preintegratedMeasurements.biasHat_.accelerometer();
const Vector3 biasOmegaIncr = bias.gyroscope() - preintegratedMeasurements.biasHat_.gyroscope();
const Rot3 Rot_i = pose_i.rotation();
const Vector3 pos_i = pose_i.translation().vector();
// Predict state at time j
/* ---------------------------------------------------------------------------------------------------- */
Vector3 pos_j = pos_i + Rot_i.matrix() * (preintegratedMeasurements.deltaPij_
+ preintegratedMeasurements.delPdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements.delPdelBiasOmega_ * biasOmegaIncr)
+ vel_i * deltaTij
- skewSymmetric(omegaCoriolis) * vel_i * deltaTij*deltaTij // Coriolis term - we got rid of the 2 wrt ins paper
+ 0.5 * gravity * deltaTij*deltaTij;
Vector3 vel_j = Vector3(vel_i + Rot_i.matrix() * (preintegratedMeasurements.deltaVij_
+ preintegratedMeasurements.delVdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements.delVdelBiasOmega_ * biasOmegaIncr)
- 2 * skewSymmetric(omegaCoriolis) * vel_i * deltaTij // Coriolis term
+ gravity * deltaTij);
if(use2ndOrderCoriolis){
pos_j += - 0.5 * skewSymmetric(omegaCoriolis) * skewSymmetric(omegaCoriolis) * pos_i * deltaTij*deltaTij; // 2nd order coriolis term for position
vel_j += - skewSymmetric(omegaCoriolis) * skewSymmetric(omegaCoriolis) * pos_i * deltaTij; // 2nd order term for velocity
}
const Rot3 deltaRij_biascorrected = preintegratedMeasurements.deltaRij_.retract(preintegratedMeasurements.delRdelBiasOmega_ * biasOmegaIncr, Rot3::EXPMAP);
// deltaRij_biascorrected is expmap(deltaRij) * expmap(delRdelBiasOmega * biasOmegaIncr)
Vector3 theta_biascorrected = Rot3::Logmap(deltaRij_biascorrected);
Vector3 theta_biascorrected_corioliscorrected = theta_biascorrected -
Rot_i.inverse().matrix() * omegaCoriolis * deltaTij; // Coriolis term
const Rot3 deltaRij_biascorrected_corioliscorrected =
Rot3::Expmap( theta_biascorrected_corioliscorrected );
const Rot3 Rot_j = Rot_i.compose( deltaRij_biascorrected_corioliscorrected );
Pose3 pose_j = Pose3( Rot_j, Point3(pos_j) );
return PoseVelocity(pose_j, vel_j);
}
} /// namespace gtsam

View File

@ -28,21 +28,7 @@
#include <gtsam/geometry/Pose3.h> #include <gtsam/geometry/Pose3.h>
#include <gtsam/base/debug.h> #include <gtsam/base/debug.h>
/* External or standard includes */
#include <ostream>
namespace gtsam { namespace gtsam {
/**
* Struct to hold return variables by the Predict Function
*/
struct PoseVelocity {
Pose3 pose;
Vector3 velocity;
PoseVelocity(const Pose3& _pose, const Vector3& _velocity) :
pose(_pose), velocity(_velocity) {
}
};
/** /**
* *
@ -60,19 +46,34 @@ struct PoseVelocity {
* [3] L. Carlone, S. Williams, R. Roberts, "Preintegrated IMU factor: Computation of the Jacobian Matrices", Tech. Report, 2013. * [3] L. Carlone, S. Williams, R. Roberts, "Preintegrated IMU factor: Computation of the Jacobian Matrices", Tech. Report, 2013.
*/ */
/**
* Struct to hold return variables by the Predict Function
*/
struct PoseVelocity {
Pose3 pose;
Vector3 velocity;
PoseVelocity(const Pose3& _pose, const Vector3& _velocity) :
pose(_pose), velocity(_velocity) {
}
};
class ImuFactor: public NoiseModelFactor5<Pose3,Vector3,Pose3,Vector3,imuBias::ConstantBias> { class ImuFactor: public NoiseModelFactor5<Pose3,Vector3,Pose3,Vector3,imuBias::ConstantBias> {
public: public:
/** Struct to store results of preintegrating IMU measurements. Can be build /**
* incrementally so as to avoid costly integration at time of factor construction. */ * PreintegratedMeasurements accumulates (integrates) the IMU measurements
* (rotation rates and accelerations) and the corresponding covariance matrix.
/** CombinedPreintegratedMeasurements accumulates (integrates) the IMU measurements (rotation rates and accelerations) * The measurements are then used to build the Preintegrated IMU factor (ImuFactor class).
* and the corresponding covariance matrix. The measurements are then used to build the Preintegrated IMU factor*/ * Can be built incrementally so as to avoid costly integration at time of
* factor construction.
*/
class PreintegratedMeasurements { class PreintegratedMeasurements {
friend class ImuFactor; friend class ImuFactor;
protected: protected:
imuBias::ConstantBias biasHat_; ///< Acceleration and angular rate bias values used during preintegration imuBias::ConstantBias biasHat_; ///< Acceleration and angular rate bias values used during preintegration
Eigen::Matrix<double,9,9> measurementCovariance_; ///< (continuous-time uncertainty) Covariance of the vector [integrationError measuredAcc measuredOmega] in R^(9X9) Eigen::Matrix<double,9,9> measurementCovariance_; ///< (continuous-time uncertainty) "Covariance" of the vector [integrationError measuredAcc measuredOmega] in R^(9X9)
Vector3 deltaPij_; ///< Preintegrated relative position (does not take into account velocity at time i, see deltap+, in [2]) (in frame i) Vector3 deltaPij_; ///< Preintegrated relative position (does not take into account velocity at time i, see deltap+, in [2]) (in frame i)
Vector3 deltaVij_; ///< Preintegrated relative velocity (in global frame) Vector3 deltaVij_; ///< Preintegrated relative velocity (in global frame)
@ -84,64 +85,33 @@ struct PoseVelocity {
Matrix3 delVdelBiasAcc_; ///< Jacobian of preintegrated velocity w.r.t. acceleration bias Matrix3 delVdelBiasAcc_; ///< Jacobian of preintegrated velocity w.r.t. acceleration bias
Matrix3 delVdelBiasOmega_; ///< Jacobian of preintegrated velocity w.r.t. angular rate bias Matrix3 delVdelBiasOmega_; ///< Jacobian of preintegrated velocity w.r.t. angular rate bias
Matrix3 delRdelBiasOmega_; ///< Jacobian of preintegrated rotation w.r.t. angular rate bias Matrix3 delRdelBiasOmega_; ///< Jacobian of preintegrated rotation w.r.t. angular rate bias
Eigen::Matrix<double,9,9> PreintMeasCov_; ///< Covariance matrix of the preintegrated measurements (first-order propagation from *measurementCovariance*) Eigen::Matrix<double,9,9> PreintMeasCov_; ///< Covariance matrix of the preintegrated measurements (first-order propagation from *measurementCovariance*)
bool use2ndOrderIntegration_; ///< Controls the order of integration bool use2ndOrderIntegration_; ///< Controls the order of integration
public: public:
/** Default constructor, initialize with no IMU measurements */
PreintegratedMeasurements(
const imuBias::ConstantBias& bias, ///< Current estimate of acceleration and rotation rate biases
const Matrix3& measuredAccCovariance, ///< Covariance matrix of measuredAcc
const Matrix3& measuredOmegaCovariance, ///< Covariance matrix of measured Angular Rate
const Matrix3& integrationErrorCovariance, ///< Covariance matrix of integration errors
const bool use2ndOrderIntegration = false ///< Controls the order of integration
) : biasHat_(bias), deltaPij_(Vector3::Zero()), deltaVij_(Vector3::Zero()), deltaTij_(0.0),
delPdelBiasAcc_(Z_3x3), delPdelBiasOmega_(Z_3x3),
delVdelBiasAcc_(Z_3x3), delVdelBiasOmega_(Z_3x3),
delRdelBiasOmega_(Z_3x3), use2ndOrderIntegration_(use2ndOrderIntegration)
{
measurementCovariance_ << integrationErrorCovariance , Z_3x3, Z_3x3,
Z_3x3, measuredAccCovariance, Z_3x3,
Z_3x3, Z_3x3, measuredOmegaCovariance;
PreintMeasCov_.setZero(9,9);
}
// TODO: in what context is this constructor used and why do you init to zero? /**
PreintegratedMeasurements() : * Default constructor, initialize the class with no measurements
biasHat_(imuBias::ConstantBias()), deltaPij_(Vector3::Zero()), deltaVij_(Vector3::Zero()), deltaTij_(0.0), * @param bias Current estimate of acceleration and rotation rate biases
delPdelBiasAcc_(Z_3x3), delPdelBiasOmega_(Z_3x3), * @param measuredAccCovariance Covariance matrix of measuredAcc
delVdelBiasAcc_(Z_3x3), delVdelBiasOmega_(Z_3x3), * @param measuredOmegaCovariance Covariance matrix of measured Angular Rate
delRdelBiasOmega_(Z_3x3), use2ndOrderIntegration_(false) * @param integrationErrorCovariance Covariance matrix of integration errors (velocity -> position)
{ * @param use2ndOrderIntegration Controls the order of integration
measurementCovariance_.setZero(9,9); * (if false: p(t+1) = p(t) + v(t) deltaT ; if true: p(t+1) = p(t) + v(t) deltaT + 0.5 * acc(t) deltaT^2)
PreintMeasCov_.setZero(9,9); */
} PreintegratedMeasurements(const imuBias::ConstantBias& bias,
const Matrix3& measuredAccCovariance, const Matrix3& measuredOmegaCovariance,
const Matrix3& integrationErrorCovariance, const bool use2ndOrderIntegration = false);
/** print */ /// print
void print(const std::string& s = "Preintegrated Measurements:") const { void print(const std::string& s = "Preintegrated Measurements:") const;
std::cout << s << std::endl;
biasHat_.print(" biasHat");
std::cout << " deltaTij " << deltaTij_ << std::endl;
std::cout << " deltaPij [ " << deltaPij_.transpose() << " ]" << std::endl;
std::cout << " deltaVij [ " << deltaVij_.transpose() << " ]" << std::endl;
deltaRij_.print(" deltaRij ");
std::cout << " measurementCovariance [ " << measurementCovariance_ << " ]" << std::endl;
std::cout << " PreintMeasCov [ " << PreintMeasCov_ << " ]" << std::endl;
}
/** equals */ /// equals
bool equals(const PreintegratedMeasurements& expected, double tol=1e-9) const { bool equals(const PreintegratedMeasurements& expected, double tol=1e-9) const;
return biasHat_.equals(expected.biasHat_, tol)
&& equal_with_abs_tol(measurementCovariance_, expected.measurementCovariance_, tol) /// methods to access class variables
&& equal_with_abs_tol(deltaPij_, expected.deltaPij_, tol)
&& equal_with_abs_tol(deltaVij_, expected.deltaVij_, tol)
&& deltaRij_.equals(expected.deltaRij_, tol)
&& std::fabs(deltaTij_ - expected.deltaTij_) < tol
&& equal_with_abs_tol(delPdelBiasAcc_, expected.delPdelBiasAcc_, tol)
&& equal_with_abs_tol(delPdelBiasOmega_, expected.delPdelBiasOmega_, tol)
&& equal_with_abs_tol(delVdelBiasAcc_, expected.delVdelBiasAcc_, tol)
&& equal_with_abs_tol(delVdelBiasOmega_, expected.delVdelBiasOmega_, tol)
&& equal_with_abs_tol(delRdelBiasOmega_, expected.delRdelBiasOmega_, tol);
}
Matrix measurementCovariance() const {return measurementCovariance_;} Matrix measurementCovariance() const {return measurementCovariance_;}
Matrix deltaRij() const {return deltaRij_.matrix();} Matrix deltaRij() const {return deltaRij_.matrix();}
double deltaTij() const{return deltaTij_;} double deltaTij() const{return deltaTij_;}
@ -155,121 +125,20 @@ struct PoseVelocity {
Matrix delRdelBiasOmega() const{ return delRdelBiasOmega_;} Matrix delRdelBiasOmega() const{ return delRdelBiasOmega_;}
Matrix preintMeasCov() const { return PreintMeasCov_;} Matrix preintMeasCov() const { return PreintMeasCov_;}
/// Re-initialize PreintegratedMeasurements
void resetIntegration();
void resetIntegration(){ /**
deltaPij_ = Vector3::Zero(); * Add a single IMU measurement to the preintegration.
deltaVij_ = Vector3::Zero(); * @param measuredAcc Measured acceleration (in body frame)
deltaRij_ = Rot3(); * @param measuredOmega Measured angular velocity
deltaTij_ = 0.0; * @param deltaT Time interval between two consecutive IMU measurements
delPdelBiasAcc_ = Z_3x3; * @param body_P_sensor Optional sensor frame (pose of the IMU in the body frame)
delPdelBiasOmega_ = Z_3x3; */
delVdelBiasAcc_ = Z_3x3; void integrateMeasurement(const Vector3& measuredAcc, const Vector3& measuredOmega, double deltaT,
delVdelBiasOmega_ = Z_3x3; boost::optional<const Pose3&> body_P_sensor = boost::none);
delRdelBiasOmega_ = Z_3x3;
PreintMeasCov_ = Matrix::Zero(9,9);
}
/** Add a single IMU measurement to the preintegration. */
void integrateMeasurement(
const Vector3& measuredAcc, ///< Measured linear acceleration (in body frame)
const Vector3& measuredOmega, ///< Measured angular velocity (in body frame)
double deltaT, ///< Time step
boost::optional<const Pose3&> body_P_sensor = boost::none ///< Sensor frame
) {
// NOTE: order is important here because each update uses old values.
// First we compensate the measurements for the bias
Vector3 correctedAcc = biasHat_.correctAccelerometer(measuredAcc);
Vector3 correctedOmega = biasHat_.correctGyroscope(measuredOmega);
// Then compensate for sensor-body displacement: we express the quantities (originally in the IMU frame) into the body frame
if(body_P_sensor){
Matrix3 body_R_sensor = body_P_sensor->rotation().matrix();
correctedOmega = body_R_sensor * correctedOmega; // rotation rate vector in the body frame
Matrix3 body_omega_body__cross = skewSymmetric(correctedOmega);
correctedAcc = body_R_sensor * correctedAcc - body_omega_body__cross * body_omega_body__cross * body_P_sensor->translation().vector();
// linear acceleration vector in the body frame
}
const Vector3 theta_incr = correctedOmega * deltaT; // rotation vector describing rotation increment computed from the current rotation rate measurement
const Rot3 Rincr = Rot3::Expmap(theta_incr); // rotation increment computed from the current rotation rate measurement
const Matrix3 Jr_theta_incr = Rot3::rightJacobianExpMapSO3(theta_incr); // Right jacobian computed at theta_incr
// Update Jacobians
/* ----------------------------------------------------------------------------------------------------------------------- */
if(!use2ndOrderIntegration_){
delPdelBiasAcc_ += delVdelBiasAcc_ * deltaT;
delPdelBiasOmega_ += delVdelBiasOmega_ * deltaT;
}else{
delPdelBiasAcc_ += delVdelBiasAcc_ * deltaT - 0.5 * deltaRij_.matrix() * deltaT*deltaT;
delPdelBiasOmega_ += delVdelBiasOmega_ * deltaT - 0.5 * deltaRij_.matrix()
* skewSymmetric(biasHat_.correctAccelerometer(measuredAcc)) * deltaT*deltaT * delRdelBiasOmega_;
}
delVdelBiasAcc_ += -deltaRij_.matrix() * deltaT;
delVdelBiasOmega_ += -deltaRij_.matrix() * skewSymmetric(correctedAcc) * deltaT * delRdelBiasOmega_;
delRdelBiasOmega_ = Rincr.inverse().matrix() * delRdelBiasOmega_ - Jr_theta_incr * deltaT;
// Update preintegrated measurements covariance
/* ----------------------------------------------------------------------------------------------------------------------- */
const Vector3 theta_i = Rot3::Logmap(deltaRij_); // parametrization of so(3)
const Matrix3 Jr_theta_i = Rot3::rightJacobianExpMapSO3(theta_i);
Rot3 Rot_j = deltaRij_ * Rincr;
const Vector3 theta_j = Rot3::Logmap(Rot_j); // parametrization of so(3)
const Matrix3 Jrinv_theta_j = Rot3::rightJacobianExpMapSO3inverse(theta_j);
// Update preintegrated measurements covariance: as in [2] we consider a first order propagation that
// can be seen as a prediction phase in an EKF framework
Matrix H_pos_pos = I_3x3;
Matrix H_pos_vel = I_3x3 * deltaT;
Matrix H_pos_angles = Z_3x3;
Matrix H_vel_pos = Z_3x3;
Matrix H_vel_vel = I_3x3;
Matrix H_vel_angles = - deltaRij_.matrix() * skewSymmetric(correctedAcc) * Jr_theta_i * deltaT;
// analytic expression corresponding to the following numerical derivative
// Matrix H_vel_angles = numericalDerivative11<Vector3, Vector3>(boost::bind(&PreIntegrateIMUObservations_delta_vel, correctedOmega, correctedAcc, deltaT, _1, deltaVij), theta_i);
Matrix H_angles_pos = Z_3x3;
Matrix H_angles_vel = Z_3x3;
Matrix H_angles_angles = Jrinv_theta_j * Rincr.inverse().matrix() * Jr_theta_i;
// analytic expression corresponding to the following numerical derivative
// Matrix H_angles_angles = numericalDerivative11<Vector3, Vector3>(boost::bind(&PreIntegrateIMUObservations_delta_angles, correctedOmega, deltaT, _1), thetaij);
// overall Jacobian wrt preintegrated measurements (df/dx)
Matrix F(9,9);
F << H_pos_pos, H_pos_vel, H_pos_angles,
H_vel_pos, H_vel_vel, H_vel_angles,
H_angles_pos, H_angles_vel, H_angles_angles;
// first order uncertainty propagation:
// the deltaT allows to pass from continuous time noise to discrete time noise
// measurementCovariance_discrete = measurementCovariance_contTime * (1/deltaT)
// Gt * Qt * G =(approx)= measurementCovariance_discrete * deltaT^2 = measurementCovariance_contTime * deltaT
PreintMeasCov_ = F * PreintMeasCov_ * F.transpose() + measurementCovariance_ * deltaT ;
// Extended version, without approximation: Gt * Qt * G =(approx)= measurementCovariance_contTime * deltaT
//
// Matrix G(9,9);
// G << I_3x3 * deltaT, Z_3x3, Z_3x3,
// Z_3x3, deltaRij.matrix() * deltaT, Z_3x3,
// Z_3x3, Z_3x3, Jrinv_theta_j * Jr_theta_incr * deltaT;
//
// PreintMeasCov = F * PreintMeasCov * F.transpose() + G * (1/deltaT) * measurementCovariance * G.transpose();
// Update preintegrated measurements
/* ----------------------------------------------------------------------------------------------------------------------- */
if(!use2ndOrderIntegration_){
deltaPij_ += deltaVij_ * deltaT;
}else{
deltaPij_ += deltaVij_ * deltaT + 0.5 * deltaRij_.matrix() * biasHat_.correctAccelerometer(measuredAcc) * deltaT*deltaT;
}
deltaVij_ += deltaRij_.matrix() * correctedAcc * deltaT;
deltaRij_ = deltaRij_ * Rincr;
deltaTij_ += deltaT;
}
// TODO: move to testImuFactor
/* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */ /* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
// This function is only used for test purposes (compare numerical derivatives wrt analytic ones) // This function is only used for test purposes (compare numerical derivatives wrt analytic ones)
static inline Vector PreIntegrateIMUObservations_delta_vel(const Vector& msr_gyro_t, const Vector& msr_acc_t, const double msr_dt, static inline Vector PreIntegrateIMUObservations_delta_vel(const Vector& msr_gyro_t, const Vector& msr_acc_t, const double msr_dt,
@ -340,63 +209,38 @@ struct PoseVelocity {
#endif #endif
/** Default constructor - only use for serialization */ /** Default constructor - only use for serialization */
ImuFactor() : preintegratedMeasurements_(imuBias::ConstantBias(), Z_3x3, Z_3x3, Z_3x3), use2ndOrderCoriolis_(false){} ImuFactor();
/** Constructor */ /**
ImuFactor( * Constructor
Key pose_i, ///< previous pose key * @param pose_i Previous pose key
Key vel_i, ///< previous velocity key * @param vel_i Previous velocity key
Key pose_j, ///< current pose key * @param pose_j Current pose key
Key vel_j, ///< current velocity key * @param vel_j Current velocity key
Key bias, ///< previous bias key * @param bias Previous bias key
const PreintegratedMeasurements& preintegratedMeasurements, ///< preintegrated IMU measurements * @param preintegratedMeasurements Preintegrated IMU measurements
const Vector3& gravity, ///< gravity vector * @param gravity Gravity vector expressed in the global frame
const Vector3& omegaCoriolis, ///< rotation rate of the inertial frame * @param omegaCoriolis Rotation rate of the global frame w.r.t. an inertial frame
boost::optional<const Pose3&> body_P_sensor = boost::none, ///< The Pose of the sensor frame in the body frame * @param body_P_sensor Optional pose of the sensor frame in the body frame
const bool use2ndOrderCoriolis = false ///< When true, the second-order term is used in the calculation of the Coriolis Effect * @param use2ndOrderCoriolis When true, the second-order term is used in the calculation of the Coriolis Effect
) : */
Base(noiseModel::Gaussian::Covariance(preintegratedMeasurements.PreintMeasCov_), pose_i, vel_i, pose_j, vel_j, bias), ImuFactor(Key pose_i, Key vel_i, Key pose_j, Key vel_j, Key bias,
preintegratedMeasurements_(preintegratedMeasurements), const PreintegratedMeasurements& preintegratedMeasurements,
gravity_(gravity), const Vector3& gravity, const Vector3& omegaCoriolis,
omegaCoriolis_(omegaCoriolis), boost::optional<const Pose3&> body_P_sensor = boost::none, const bool use2ndOrderCoriolis = false);
body_P_sensor_(body_P_sensor),
use2ndOrderCoriolis_(use2ndOrderCoriolis){
}
virtual ~ImuFactor() {} virtual ~ImuFactor() {}
/// @return a deep copy of this factor /// @return a deep copy of this factor
virtual gtsam::NonlinearFactor::shared_ptr clone() const { virtual gtsam::NonlinearFactor::shared_ptr clone() const;
return boost::static_pointer_cast<gtsam::NonlinearFactor>(
gtsam::NonlinearFactor::shared_ptr(new This(*this))); }
/** implement functions needed for Testable */ /** implement functions needed for Testable */
/** print */ /// print
virtual void print(const std::string& s, const KeyFormatter& keyFormatter = DefaultKeyFormatter) const { virtual void print(const std::string& s, const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
std::cout << s << "ImuFactor("
<< keyFormatter(this->key1()) << ","
<< keyFormatter(this->key2()) << ","
<< keyFormatter(this->key3()) << ","
<< keyFormatter(this->key4()) << ","
<< keyFormatter(this->key5()) << ")\n";
preintegratedMeasurements_.print(" preintegrated measurements:");
std::cout << " gravity: [ " << gravity_.transpose() << " ]" << std::endl;
std::cout << " omegaCoriolis: [ " << omegaCoriolis_.transpose() << " ]" << std::endl;
this->noiseModel_->print(" noise model: ");
if(this->body_P_sensor_)
this->body_P_sensor_->print(" sensor pose in body frame: ");
}
/** equals */ /// equals
virtual bool equals(const NonlinearFactor& expected, double tol=1e-9) const { virtual bool equals(const NonlinearFactor& expected, double tol=1e-9) const;
const This *e = dynamic_cast<const This*> (&expected);
return e != NULL && Base::equals(*e, tol)
&& preintegratedMeasurements_.equals(e->preintegratedMeasurements_, tol)
&& equal_with_abs_tol(gravity_, e->gravity_, tol)
&& equal_with_abs_tol(omegaCoriolis_, e->omegaCoriolis_, tol)
&& ((!body_P_sensor_ && !e->body_P_sensor_) || (body_P_sensor_ && e->body_P_sensor_ && body_P_sensor_->equals(*e->body_P_sensor_)));
}
/** Access the preintegrated measurements. */ /** Access the preintegrated measurements. */
const PreintegratedMeasurements& preintegratedMeasurements() const { const PreintegratedMeasurements& preintegratedMeasurements() const {
@ -408,205 +252,20 @@ struct PoseVelocity {
/** implement functions needed to derive from Factor */ /** implement functions needed to derive from Factor */
/** vector of errors */ /// vector of errors
Vector evaluateError(const Pose3& pose_i, const Vector3& vel_i, const Pose3& pose_j, const Vector3& vel_j, Vector evaluateError(const Pose3& pose_i, const Vector3& vel_i, const Pose3& pose_j, const Vector3& vel_j,
const imuBias::ConstantBias& bias, const imuBias::ConstantBias& bias,
boost::optional<Matrix&> H1 = boost::none, boost::optional<Matrix&> H1 = boost::none,
boost::optional<Matrix&> H2 = boost::none, boost::optional<Matrix&> H2 = boost::none,
boost::optional<Matrix&> H3 = boost::none, boost::optional<Matrix&> H3 = boost::none,
boost::optional<Matrix&> H4 = boost::none, boost::optional<Matrix&> H4 = boost::none,
boost::optional<Matrix&> H5 = boost::none) const boost::optional<Matrix&> H5 = boost::none) const;
{
const double& deltaTij = preintegratedMeasurements_.deltaTij_; // predicted states from IMU
const Vector3 biasAccIncr = bias.accelerometer() - preintegratedMeasurements_.biasHat_.accelerometer();
const Vector3 biasOmegaIncr = bias.gyroscope() - preintegratedMeasurements_.biasHat_.gyroscope();
// we give some shorter name to rotations and translations
const Rot3 Rot_i = pose_i.rotation();
const Rot3 Rot_j = pose_j.rotation();
const Vector3 pos_i = pose_i.translation().vector();
const Vector3 pos_j = pose_j.translation().vector();
// We compute factor's Jacobians
/* ---------------------------------------------------------------------------------------------------- */
const Rot3 deltaRij_biascorrected = preintegratedMeasurements_.deltaRij_.retract(preintegratedMeasurements_.delRdelBiasOmega_ * biasOmegaIncr, Rot3::EXPMAP);
// deltaRij_biascorrected is expmap(deltaRij) * expmap(delRdelBiasOmega * biasOmegaIncr)
Vector3 theta_biascorrected = Rot3::Logmap(deltaRij_biascorrected);
Vector3 theta_biascorrected_corioliscorrected = theta_biascorrected -
Rot_i.inverse().matrix() * omegaCoriolis_ * deltaTij; // Coriolis term
const Rot3 deltaRij_biascorrected_corioliscorrected =
Rot3::Expmap( theta_biascorrected_corioliscorrected );
const Rot3 fRhat = deltaRij_biascorrected_corioliscorrected.between(Rot_i.between(Rot_j));
const Matrix3 Jr_theta_bcc = Rot3::rightJacobianExpMapSO3(theta_biascorrected_corioliscorrected);
const Matrix3 Jtheta = -Jr_theta_bcc * skewSymmetric(Rot_i.inverse().matrix() * omegaCoriolis_ * deltaTij);
const Matrix3 Jrinv_fRhat = Rot3::rightJacobianExpMapSO3inverse(Rot3::Logmap(fRhat));
if(H1) {
H1->resize(9,6);
Matrix3 dfPdPi;
Matrix3 dfVdPi;
if(use2ndOrderCoriolis_){
dfPdPi = - Rot_i.matrix() + 0.5 * skewSymmetric(omegaCoriolis_) * skewSymmetric(omegaCoriolis_) * Rot_i.matrix() * deltaTij*deltaTij;
dfVdPi = skewSymmetric(omegaCoriolis_) * skewSymmetric(omegaCoriolis_) * Rot_i.matrix() * deltaTij;
}
else{
dfPdPi = - Rot_i.matrix();
dfVdPi = Z_3x3;
}
(*H1) <<
// dfP/dRi
Rot_i.matrix() * skewSymmetric(preintegratedMeasurements_.deltaPij_
+ preintegratedMeasurements_.delPdelBiasOmega_ * biasOmegaIncr + preintegratedMeasurements_.delPdelBiasAcc_ * biasAccIncr),
// dfP/dPi
dfPdPi,
// dfV/dRi
Rot_i.matrix() * skewSymmetric(preintegratedMeasurements_.deltaVij_
+ preintegratedMeasurements_.delVdelBiasOmega_ * biasOmegaIncr + preintegratedMeasurements_.delVdelBiasAcc_ * biasAccIncr),
// dfV/dPi
dfVdPi,
// dfR/dRi
Jrinv_fRhat * (- Rot_j.between(Rot_i).matrix() - fRhat.inverse().matrix() * Jtheta),
// dfR/dPi
Z_3x3;
}
if(H2) {
H2->resize(9,3);
(*H2) <<
// dfP/dVi
- I_3x3 * deltaTij
+ skewSymmetric(omegaCoriolis_) * deltaTij * deltaTij, // Coriolis term - we got rid of the 2 wrt ins paper
// dfV/dVi
- I_3x3
+ 2 * skewSymmetric(omegaCoriolis_) * deltaTij, // Coriolis term
// dfR/dVi
Z_3x3;
}
if(H3) {
H3->resize(9,6);
(*H3) <<
// dfP/dPosej
Z_3x3, Rot_j.matrix(),
// dfV/dPosej
Matrix::Zero(3,6),
// dfR/dPosej
Jrinv_fRhat * ( I_3x3 ), Z_3x3;
}
if(H4) {
H4->resize(9,3);
(*H4) <<
// dfP/dVj
Z_3x3,
// dfV/dVj
I_3x3,
// dfR/dVj
Z_3x3;
}
if(H5) {
const Matrix3 Jrinv_theta_bc = Rot3::rightJacobianExpMapSO3inverse(theta_biascorrected);
const Matrix3 Jr_JbiasOmegaIncr = Rot3::rightJacobianExpMapSO3(preintegratedMeasurements_.delRdelBiasOmega_ * biasOmegaIncr);
const Matrix3 JbiasOmega = Jr_theta_bcc * Jrinv_theta_bc * Jr_JbiasOmegaIncr * preintegratedMeasurements_.delRdelBiasOmega_;
H5->resize(9,6);
(*H5) <<
// dfP/dBias
- Rot_i.matrix() * preintegratedMeasurements_.delPdelBiasAcc_,
- Rot_i.matrix() * preintegratedMeasurements_.delPdelBiasOmega_,
// dfV/dBias
- Rot_i.matrix() * preintegratedMeasurements_.delVdelBiasAcc_,
- Rot_i.matrix() * preintegratedMeasurements_.delVdelBiasOmega_,
// dfR/dBias
Matrix::Zero(3,3),
Jrinv_fRhat * ( - fRhat.inverse().matrix() * JbiasOmega);
}
// Evaluate residual error, according to [3]
/* ---------------------------------------------------------------------------------------------------- */
const Vector3 fp =
pos_j - pos_i
- Rot_i.matrix() * (preintegratedMeasurements_.deltaPij_
+ preintegratedMeasurements_.delPdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements_.delPdelBiasOmega_ * biasOmegaIncr)
- vel_i * deltaTij
+ skewSymmetric(omegaCoriolis_) * vel_i * deltaTij*deltaTij // Coriolis term - we got rid of the 2 wrt ins paper
- 0.5 * gravity_ * deltaTij*deltaTij;
const Vector3 fv =
vel_j - vel_i - Rot_i.matrix() * (preintegratedMeasurements_.deltaVij_
+ preintegratedMeasurements_.delVdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements_.delVdelBiasOmega_ * biasOmegaIncr)
+ 2 * skewSymmetric(omegaCoriolis_) * vel_i * deltaTij // Coriolis term
- gravity_ * deltaTij;
const Vector3 fR = Rot3::Logmap(fRhat);
Vector r(9); r << fp, fv, fR;
return r;
}
/** predicted states from IMU */
static PoseVelocity Predict(const Pose3& pose_i, const Vector3& vel_i, static PoseVelocity Predict(const Pose3& pose_i, const Vector3& vel_i,
const imuBias::ConstantBias& bias, const PreintegratedMeasurements preintegratedMeasurements, const imuBias::ConstantBias& bias, const PreintegratedMeasurements preintegratedMeasurements,
const Vector3& gravity, const Vector3& omegaCoriolis, boost::optional<const Pose3&> body_P_sensor = boost::none, const Vector3& gravity, const Vector3& omegaCoriolis, boost::optional<const Pose3&> body_P_sensor = boost::none,
const bool use2ndOrderCoriolis = false) const bool use2ndOrderCoriolis = false);
{
const double& deltaTij = preintegratedMeasurements.deltaTij_;
const Vector3 biasAccIncr = bias.accelerometer() - preintegratedMeasurements.biasHat_.accelerometer();
const Vector3 biasOmegaIncr = bias.gyroscope() - preintegratedMeasurements.biasHat_.gyroscope();
const Rot3 Rot_i = pose_i.rotation();
const Vector3 pos_i = pose_i.translation().vector();
// Predict state at time j
/* ---------------------------------------------------------------------------------------------------- */
Vector3 pos_j = pos_i + Rot_i.matrix() * (preintegratedMeasurements.deltaPij_
+ preintegratedMeasurements.delPdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements.delPdelBiasOmega_ * biasOmegaIncr)
+ vel_i * deltaTij
- skewSymmetric(omegaCoriolis) * vel_i * deltaTij*deltaTij // Coriolis term - we got rid of the 2 wrt ins paper
+ 0.5 * gravity * deltaTij*deltaTij;
Vector3 vel_j = Vector3(vel_i + Rot_i.matrix() * (preintegratedMeasurements.deltaVij_
+ preintegratedMeasurements.delVdelBiasAcc_ * biasAccIncr
+ preintegratedMeasurements.delVdelBiasOmega_ * biasOmegaIncr)
- 2 * skewSymmetric(omegaCoriolis) * vel_i * deltaTij // Coriolis term
+ gravity * deltaTij);
if(use2ndOrderCoriolis){
pos_j += - 0.5 * skewSymmetric(omegaCoriolis) * skewSymmetric(omegaCoriolis) * pos_i * deltaTij*deltaTij; // 2nd order coriolis term for position
vel_j += - skewSymmetric(omegaCoriolis) * skewSymmetric(omegaCoriolis) * pos_i * deltaTij; // 2nd order term for velocity
}
const Rot3 deltaRij_biascorrected = preintegratedMeasurements.deltaRij_.retract(preintegratedMeasurements.delRdelBiasOmega_ * biasOmegaIncr, Rot3::EXPMAP);
// deltaRij_biascorrected is expmap(deltaRij) * expmap(delRdelBiasOmega * biasOmegaIncr)
Vector3 theta_biascorrected = Rot3::Logmap(deltaRij_biascorrected);
Vector3 theta_biascorrected_corioliscorrected = theta_biascorrected -
Rot_i.inverse().matrix() * omegaCoriolis * deltaTij; // Coriolis term
const Rot3 deltaRij_biascorrected_corioliscorrected =
Rot3::Expmap( theta_biascorrected_corioliscorrected );
const Rot3 Rot_j = Rot_i.compose( deltaRij_biascorrected_corioliscorrected );
Pose3 pose_j = Pose3( Rot_j, Point3(pos_j) );
return PoseVelocity(pose_j, vel_j);
}
private: private:
@ -621,7 +280,7 @@ struct PoseVelocity {
ar & BOOST_SERIALIZATION_NVP(omegaCoriolis_); ar & BOOST_SERIALIZATION_NVP(omegaCoriolis_);
ar & BOOST_SERIALIZATION_NVP(body_P_sensor_); ar & BOOST_SERIALIZATION_NVP(body_P_sensor_);
} }
}; // \class ImuFactor }; // class ImuFactor
typedef ImuFactor::PreintegratedMeasurements ImuFactorPreintegratedMeasurements; typedef ImuFactor::PreintegratedMeasurements ImuFactorPreintegratedMeasurements;