Detailed Description

PreintegratedCombinedMeasurements integrates the IMU measurements (rotation rates and accelerations) and the corresponding covariance matrix.

The measurements are then used to build the CombinedImuFactor. Integration is done incrementally (ideally, one integrates the measurement as soon as it is received from the IMU) so as to avoid costly integration at time of factor construction.

Inheritance diagram for gtsam::PreintegratedCombinedMeasurements:

Public Member Functions
Constructors
	PreintegratedCombinedMeasurements ()
	Default constructor only for serialization and wrappers.
	PreintegratedCombinedMeasurements (const boost::shared_ptr< Params > &p, const imuBias::ConstantBias &biasHat=imuBias::ConstantBias())
	Default constructor, initializes the class with no measurements.
	PreintegratedCombinedMeasurements (const PreintegrationType &base, const Eigen::Matrix< double, 15, 15 > &preintMeasCov)
	Construct preintegrated directly from members: base class and preintMeasCov.
	~PreintegratedCombinedMeasurements () override
	Virtual destructor.
Basic utilities
void	resetIntegration () override
	Re-initialize PreintegratedCombinedMeasurements.
Params &	p () const
	const reference to params, shadows definition in base class
Access instance variables
Return pre-integrated measurement covariance
Matrix	preintMeasCov () const
Testable
print
void	print (const std::string &s="Preintegrated Measurements:") const override
bool	equals (const PreintegratedCombinedMeasurements &expected, double tol=1e-9) const
	equals
Main functionality
void	integrateMeasurement (const Vector3 &measuredAcc, const Vector3 &measuredOmega, const double dt) override
	Add a single IMU measurement to the preintegration.
Public Member Functions inherited from gtsam::ManifoldPreintegration
	ManifoldPreintegration (const boost::shared_ptr< Params > &p, const imuBias::ConstantBias &biasHat=imuBias::ConstantBias())
	Constructor, initializes the variables in the base class.
NavState	deltaXij () const override
Rot3	deltaRij () const override
Vector3	deltaPij () const override
Vector3	deltaVij () const override
Matrix3	delRdelBiasOmega () const
Matrix3	delPdelBiasAcc () const
Matrix3	delPdelBiasOmega () const
Matrix3	delVdelBiasAcc () const
Matrix3	delVdelBiasOmega () const
bool	equals (const ManifoldPreintegration &other, double tol) const
void	update (const Vector3 &measuredAcc, const Vector3 &measuredOmega, const double dt, Matrix9 A, Matrix93 B, Matrix93 *C) override
	Update preintegrated measurements and get derivatives It takes measured quantities in the j frame Modifies preintegrated quantities in place after correcting for bias and possibly sensor pose NOTE(frank): implementation is different in two versions.
Vector9	biasCorrectedDelta (const imuBias::ConstantBias &bias_i, OptionalJacobian< 9, 6 > H=boost::none) const override
	Given the estimate of the bias, return a NavState tangent vector summarizing the preintegrated IMU measurements so far NOTE(frank): implementation is different in two versions.
virtual boost::shared_ptr< ManifoldPreintegration >	clone () const
	Dummy clone for MATLAB.
Public Member Functions inherited from gtsam::PreintegrationBase
	PreintegrationBase (const boost::shared_ptr< Params > &p, const imuBias::ConstantBias &biasHat=imuBias::ConstantBias())
	Constructor, initializes the variables in the base class.
void	resetIntegrationAndSetBias (const Bias &biasHat)
bool	matchesParamsWith (const PreintegrationBase &other) const
	check parameters equality: checks whether shared pointer points to same Params object.
const boost::shared_ptr< Params > &	params () const
	shared pointer to params
Params &	p () const
	const reference to params
const imuBias::ConstantBias &	biasHat () const
double	deltaTij () const
Vector6	biasHatVector () const
std::pair< Vector3, Vector3 >	correctMeasurementsBySensorPose (const Vector3 &unbiasedAcc, const Vector3 &unbiasedOmega, OptionalJacobian< 3, 3 > correctedAcc_H_unbiasedAcc=boost::none, OptionalJacobian< 3, 3 > correctedAcc_H_unbiasedOmega=boost::none, OptionalJacobian< 3, 3 > correctedOmega_H_unbiasedOmega=boost::none) const
	Subtract estimate and correct for sensor pose Compute the derivatives due to non-identity body_P_sensor (rotation and centrifugal acc) Ignore D_correctedOmega_measuredAcc as it is trivially zero.
NavState	predict (const NavState &state_i, const imuBias::ConstantBias &bias_i, OptionalJacobian< 9, 9 > H1=boost::none, OptionalJacobian< 9, 6 > H2=boost::none) const
	Predict state at time j.
Vector9	computeError (const NavState &state_i, const NavState &state_j, const imuBias::ConstantBias &bias_i, OptionalJacobian< 9, 9 > H1, OptionalJacobian< 9, 9 > H2, OptionalJacobian< 9, 6 > H3) const
	Calculate error given navStates.
Vector9	computeErrorAndJacobians (const Pose3 &pose_i, const Vector3 &vel_i, const Pose3 &pose_j, const Vector3 &vel_j, const imuBias::ConstantBias &bias_i, OptionalJacobian< 9, 6 > H1=boost::none, OptionalJacobian< 9, 3 > H2=boost::none, OptionalJacobian< 9, 6 > H3=boost::none, OptionalJacobian< 9, 3 > H4=boost::none, OptionalJacobian< 9, 6 > H5=boost::none) const
	Compute errors w.r.t.

Public Types
typedef PreintegrationCombinedParams	Params
Public Types inherited from gtsam::PreintegrationBase
typedef imuBias::ConstantBias	Bias
typedef PreintegrationParams	Params

Protected Attributes
Eigen::Matrix< double, 15, 15 >	preintMeasCov_
Protected Attributes inherited from gtsam::ManifoldPreintegration
NavState	deltaXij_
	Pre-integrated navigation state, from frame i to frame j Note: relative position does not take into account velocity at time i, see deltap+, in [2] Note: velocity is now also in frame i, as opposed to deltaVij in [2].
Matrix3	delRdelBiasOmega_
	Jacobian of preintegrated rotation w.r.t. angular rate bias.
Matrix3	delPdelBiasAcc_
	Jacobian of preintegrated position w.r.t. acceleration bias.
Matrix3	delPdelBiasOmega_
	Jacobian of preintegrated position w.r.t. angular rate bias.
Matrix3	delVdelBiasAcc_
	Jacobian of preintegrated velocity w.r.t. acceleration bias.
Matrix3	delVdelBiasOmega_
	Jacobian of preintegrated velocity w.r.t. angular rate bias.
Protected Attributes inherited from gtsam::PreintegrationBase
boost::shared_ptr< Params >	p_
Bias	biasHat_
	Acceleration and gyro bias used for preintegration.
double	deltaTij_
	Time interval from i to j.

Friends
class	CombinedImuFactor
class	boost::serialization::access
	Serialization function.

Additional Inherited Members
Protected Member Functions inherited from gtsam::ManifoldPreintegration
	ManifoldPreintegration ()
	Default constructor for serialization.
Protected Member Functions inherited from gtsam::PreintegrationBase
	PreintegrationBase ()
	Default constructor for serialization.
virtual	~PreintegrationBase ()
	Virtual destructor for serialization.

Constructor & Destructor Documentation

◆ PreintegratedCombinedMeasurements() [1/2]

gtsam::PreintegratedCombinedMeasurements::PreintegratedCombinedMeasurements	(	const boost::shared_ptr< Params > &	p,
		const imuBias::ConstantBias &	biasHat = imuBias::ConstantBias() )

inline

Default constructor, initializes the class with no measurements.

Parameters

p	Parameters, typically fixed in a single application
biasHat	Current estimate of acceleration and rotation rate biases

◆ PreintegratedCombinedMeasurements() [2/2]

gtsam::PreintegratedCombinedMeasurements::PreintegratedCombinedMeasurements	(	const PreintegrationType &	base,
		const Eigen::Matrix< double, 15, 15 > &	preintMeasCov )

inline

Construct preintegrated directly from members: base class and preintMeasCov.

Parameters

Base	PreintegrationType instance
preintMeasCov	Covariance matrix used in noise model.

Member Function Documentation

◆ integrateMeasurement()

void gtsam::PreintegratedCombinedMeasurements::integrateMeasurement	(	const Vector3 &	measuredAcc,
		const Vector3 &	measuredOmega,
		const double	dt )

overridevirtual

Add a single IMU measurement to the preintegration.

Both accelerometer and gyroscope measurements are taken to be in the sensor frame and conversion to the body frame is handled by body_P_sensor in PreintegrationParams.

Parameters

measuredAcc	Measured acceleration (as given by the sensor)
measuredOmega	Measured angular velocity (as given by the sensor)
dt	Time interval between two consecutive IMU measurements

Reimplemented from gtsam::PreintegrationBase.