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flightgear/src/FDM/JSBSim/models/flight_control/FGMagnetometer.cpp
2009-09-09 08:56:31 +02:00

254 lines
8.4 KiB
C++
Executable file

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Module: FGMagnetometer.cpp
Author: Matthew Chave
Date started: August 2009
------------- Copyright (C) 2009 -------------
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
details.
You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA.
Further information about the GNU Lesser General Public License can also be found on
the world wide web at http://www.gnu.org.
FUNCTIONAL DESCRIPTION
--------------------------------------------------------------------------------
HISTORY
--------------------------------------------------------------------------------
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
COMMENTS, REFERENCES, and NOTES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGMagnetometer.h"
#include "simgear/magvar/coremag.hxx"
#include <ctime>
namespace JSBSim {
static const char *IdSrc = "$Id$";
static const char *IdHdr = ID_MAGNETOMETER;
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS IMPLEMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
FGMagnetometer::FGMagnetometer(FGFCS* fcs, Element* element) : FGSensor(fcs, element),\
counter(0),
INERTIAL_UPDATE_RATE(1000)
{
Propagate = fcs->GetExec()->GetPropagate();
MassBalance = fcs->GetExec()->GetMassBalance();
Inertial = fcs->GetExec()->GetInertial();
Element* location_element = element->FindElement("location");
if (location_element) vLocation = location_element->FindElementTripletConvertTo("IN");
else {cerr << "No location given for magnetometer. " << endl; exit(-1);}
vRadius = MassBalance->StructuralToBody(vLocation);
Element* orient_element = element->FindElement("orientation");
if (orient_element) vOrient = orient_element->FindElementTripletConvertTo("RAD");
else {cerr << "No orientation given for magnetometer. " << endl;}
Element* axis_element = element->FindElement("axis");
if (axis_element) {
string sAxis = element->FindElementValue("axis");
if (sAxis == "X" || sAxis == "x") {
axis = 1;
} else if (sAxis == "Y" || sAxis == "y") {
axis = 2;
} else if (sAxis == "Z" || sAxis == "z") {
axis = 3;
} else {
cerr << " Incorrect/no axis specified for magnetometer; assuming X axis" << endl;
axis = 1;
}
}
CalculateTransformMatrix();
//assuming date wont significantly change over a flight to affect mag field
//would be better to get the date from the sim if its simulated...
time_t rawtime;
time( &rawtime );
tm * ptm = gmtime ( &rawtime );
int year = ptm->tm_year;
if(year>100)
{
year-= 100;
}
//the months here are zero based TODO find out if the function expects 1s based
date = (yymmdd_to_julian_days(ptm->tm_year,ptm->tm_mon,ptm->tm_mday));//Julian 1950-2049 yy,mm,dd
updateInertialMag();
Debug(0);
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FGMagnetometer::~FGMagnetometer()
{
Debug(1);
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGMagnetometer::updateInertialMag(void)
{
counter++;
if(counter > INERTIAL_UPDATE_RATE)//dont need to update every iteration
{
counter = 0;
usedLat = (Propagate->GetGeodLatitudeRad());//radians, N and E lat and long are positive, S and W negative
usedLon = (Propagate->GetLongitude());//radians
usedAlt = (Propagate->GetGeodeticAltitude()*fttom*0.001);//km
//this should be done whenever the position changes significantly (in nTesla)
double magvar = calc_magvar( usedLat,
usedLon,
usedAlt,
date,
field );
}
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
bool FGMagnetometer::Run(void )
{
// There is no input assumed. This is a dedicated acceleration sensor.
vRadius = MassBalance->StructuralToBody(vLocation);
updateInertialMag();
//Inertial magnetic field rotated to the body frame
vMag = Propagate->GetTl2b() * FGColumnVector3(field[3], field[4], field[5]);
//allow for sensor orientation
vMag = mT * vMag;
Input = vMag(axis);
Output = Input; // perfect magnetometer
// Degrade signal as specified
if (fail_stuck) {
Output = PreviousOutput;
return true;
}
if (lag != 0.0) Lag(); // models magnetometer lag
if (noise_variance != 0.0) Noise(); // models noise
if (drift_rate != 0.0) Drift(); // models drift over time
if (bias != 0.0) Bias(); // models a finite bias
if (gain != 0.0) Gain(); // models a gain
if (fail_low) Output = -HUGE_VAL;
if (fail_high) Output = HUGE_VAL;
if (bits != 0) Quantize(); // models quantization degradation
// if (delay != 0.0) Delay(); // models system signal transport latencies
Clip(); // Is it right to clip an magnetometer?
return true;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGMagnetometer::CalculateTransformMatrix(void)
{
double cp,sp,cr,sr,cy,sy;
cp=cos(vOrient(ePitch)); sp=sin(vOrient(ePitch));
cr=cos(vOrient(eRoll)); sr=sin(vOrient(eRoll));
cy=cos(vOrient(eYaw)); sy=sin(vOrient(eYaw));
mT(1,1) = cp*cy;
mT(1,2) = cp*sy;
mT(1,3) = -sp;
mT(2,1) = sr*sp*cy - cr*sy;
mT(2,2) = sr*sp*sy + cr*cy;
mT(2,3) = sr*cp;
mT(3,1) = cr*sp*cy + sr*sy;
mT(3,2) = cr*sp*sy - sr*cy;
mT(3,3) = cr*cp;
// This transform is different than for FGForce, where we want a native nozzle
// force in body frame. Here we calculate the body frame accel and want it in
// the transformed magnetometer frame. So, the next line is commented out.
// mT = mT.Inverse();
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// The bitmasked value choices are as follows:
// unset: In this case (the default) JSBSim would only print
// out the normally expected messages, essentially echoing
// the config files as they are read. If the environment
// variable is not set, debug_lvl is set to 1 internally
// 0: This requests JSBSim not to output any messages
// whatsoever.
// 1: This value explicity requests the normal JSBSim
// startup messages
// 2: This value asks for a message to be printed out when
// a class is instantiated
// 4: When this value is set, a message is displayed when a
// FGModel object executes its Run() method
// 8: When this value is set, various runtime state variables
// are printed out periodically
// 16: When set various parameters are sanity checked and
// a message is printed out when they go out of bounds
void FGMagnetometer::Debug(int from)
{
string ax[4] = {"none", "X", "Y", "Z"};
if (debug_lvl <= 0) return;
if (debug_lvl & 1) { // Standard console startup message output
if (from == 0) { // Constructor
cout << " Axis: " << ax[axis] << endl;
}
}
if (debug_lvl & 2 ) { // Instantiation/Destruction notification
if (from == 0) cout << "Instantiated: FGMagnetometer" << endl;
if (from == 1) cout << "Destroyed: FGMagnetometer" << endl;
}
if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
}
if (debug_lvl & 8 ) { // Runtime state variables
}
if (debug_lvl & 16) { // Sanity checking
}
if (debug_lvl & 64) {
if (from == 0) { // Constructor
cout << IdSrc << endl;
cout << IdHdr << endl;
}
}
}
}