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/*
* =====================================================================================
*
* Filename: body.cpp
*
* Description: Method definitions for body class.
*
* Version: 1.0
* Created: 03/17/2017 08:07:35 PM
* Revision: none
* Compiler: gcc
*
* Author: Martin Miller (MHM), miller7@illinois.edu
* Organization: Aerospace Robotics and Controls Lab (ARC)
*
* =====================================================================================
*/
#include "body.h"
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: update
* Description: Increments the state by dx after a Kalman update.
*--------------------------------------------------------------------------------------
*/
void
Body::update ( const Matrix<double,9,1> &dx )
{
X += dx;
return ;
} /* ----- end of method Body::update ----- */
void
Body::vel ( const Matrix<double,3,1> &v )
{
X.segment(3,3) = v;
return ;
} /* ----- end of method Body::vel ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: S
* Description: Returns the matrix S=HPH.T+R. HPH.T is trivial, so Body::H() is
* not called explicitly.
*--------------------------------------------------------------------------------------
*/
Matrix<double,1,1>
Body::S ( const Matrix<double,9,9> &P )
{
Matrix<double,1,1> S;
S << P(2,2);
return S+R();
} /* ----- end of method Body::S ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: enu
* Description: Stores the position input as ENU. Internally stored as NED.
*--------------------------------------------------------------------------------------
*/
void
Body::enu ( const UTM &utm )
{
utm_c = utm.zone_c;
utm_i = utm.zone_i;
X[0] = utm.northing;
X[1] = utm.easting;
X[2] = -utm.up;
return ;
} /* ----- end of method Body::enu ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: R
* Description: Returns R matrix of measurement noise for height measurement.
*--------------------------------------------------------------------------------------
*/
Matrix<double,1,1>
Body::R()
{
Matrix<double,1,1> R;
R << 1e-3;
return R;
}
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: Q
* Description: Returns Q matrix of process noise for the body.
*--------------------------------------------------------------------------------------
*/
Matrix<double,9,9>
Body::Q (double dt)
{
Matrix<double,9,9> Q;
Q = Matrix<double,9,9>::Zero();
Q.block<3,3>(0,0) = 0.25*dt*dt*dt*dt*Matrix<double,3,3>::Identity();
Q.block<3,3>(3,0) = 0.5*dt*dt*dt*Matrix<double,3,3>::Identity();
Q.block<3,3>(0,3) = 0.5*dt*dt*dt*Matrix<double,3,3>::Identity();
Q.block<3,3>(3,3) = dt*dt*Matrix<double,3,3>::Identity();
Q *= 800e-5;
Q.block<3,3>(6,6) = dt*dt*5e-6*Matrix<double,3,3>::Identity();
return Q;
} /* ----- end of method Body::q ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: H
* Description: Returns the Jacobian of the measurement model, H.
*--------------------------------------------------------------------------------------
*/
Matrix<double,1,9>
Body::H ( )
{
Matrix<double,1,9> H;
H = Matrix<double,1,9>::Zero();
H[0,2] = 1;
return H ;
} /* ----- end of method Body::H ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: h
* Description: Returns the predicted measurement vector, h.
*--------------------------------------------------------------------------------------
*/
Matrix<double,1,1>
Body::h ( )
{
Matrix<double,1,1> h;
h[0] = X[2];
return h;
} /* ----- end of method Body::h_hat ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: F
* Description: Returns the Jacobian of the motion model of the body.
*--------------------------------------------------------------------------------------
*/
Matrix<double,9,9>
Body::F ( const Vector3d &ang, const Quaterniond &q, double dt )
{
Matrix<double,9,9> F = Matrix<double,9,9>::Zero();
Matrix<double,3,3> Rbw(q.toRotationMatrix());
Matrix<double,3,3> W;
W = skewSymmetric(ang);
F.block<3,3>(0,3) = Rbw;
F.block<3,3>(3,3) = -W;
F.block<3,3>(3,6) = -Matrix<double,3,3>::Identity();
F *= dt;
F += Matrix<double,9,9>::Identity();
return F;
} /* ----- end of method Body::F ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: motionModel
* Description: Propagates the motion model of the body into vector X.
*--------------------------------------------------------------------------------------
*/
void
Body::motionModel ( const Vector3d &acc, const Vector3d &ang, const Quaterniond &q, const double dt)
{
Vector3d bias(X.segment(6,3));
Vector3d gravity_world(0.,0.,9.80655);
Matrix<double,6,3> A;
Matrix<double,6,1> b;
A = Matrix<double,6,3>::Zero();
b = Matrix<double,6,1>::Zero();
Matrix<double,3,3> Rbw(q.toRotationMatrix());
A.block<3,3>(0,0) = Rbw;
Matrix<double,3,3> W;
W = skewSymmetric(ang);
A.block<3,3>(3,0) = -W;
b.segment(3,3) = acc-bias+Rbw.transpose()*gravity_world;
X.segment(0,6) += (A*X.segment(3,3)+b)*dt;
return ;
} /* ----- end of method Body::motionModel ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: skewSymmetric
* Description: Create the skew symmetric matrix y from the vector x.
*--------------------------------------------------------------------------------------
*/
Matrix<double,3,3>
Body::skewSymmetric ( const Vector3d &x )
{
Matrix<double,3,3> y;
y << 0.,-x[2], x[1], x[2],0.,-x[0],-x[1],x[0],0.;
return y;
} /* ----- end of method Body::skewSymmetric ----- */
void
Body::unicsv ( )
{
printf("%d,%c,%f,%f,%f,%f,%f,%f,%f,%f,%f\n", utm_i, utm_c,
X[0], X[1], -X[2],
X[3], X[4], X[5],
X[6], X[7], X[8]);
return ;
} /* ----- end of method Body::unicsv ----- */
void
Body::accelerometer_bias ( const Vector3d &b )
{
X.segment(6,3) = b;
return ;
} /* ----- end of method State::accelerometer_bias ----- */
/*
*--------------------------------------------------------------------------------------
* Class: Body
* Method: Body :: ned
* Description: Returns the body position in NED coordinates.
*--------------------------------------------------------------------------------------
*/
Vector3d
Body::ned ( )
{
return X.segment(0,3) ;
} /* ----- end of method Body::ned ----- */
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