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/***********************************************/
/**
* @file simulateStarCameraSentinel1.cpp
*
* @brief simulate star camera data for Sentinel 1A.
*
* @author Norbert Zehentner
* @date 2016-03-23
*/
/***********************************************/
// Latex documentation
#define DOCSTRING docstring
static const char *docstring = R"(
This program simulates \file{star camera}{instrument} measurements at each satellite's position for the Sentinel 1A satellite.
The \configFile{inputfileOrbit}{instrument} must contain positions and velocities (see \program{OrbitAddVelocityAndAcceleration}).
The resulting rotation matrices rotate from satellite frame to inertial frame.
)";
/***********************************************/
#include "programs/program.h"
#include "files/fileInstrument.h"
#ifndef GROOPS_DISABLE_ERFA
#include <erfa.h>
#endif
/***** CLASS ***********************************/
/** @brief simulate star camera data for Sentinel 1A.
* @ingroup programsGroup */
class SimulateStarCameraSentinel1
{
public:
void run(Config &config, Parallel::CommunicatorPtr comm);
};
GROOPS_REGISTER_PROGRAM(SimulateStarCameraSentinel1, PARALLEL, "simulate star camera data for Sentinel 1", Simulation, Instrument)
/***********************************************/
void SimulateStarCameraSentinel1::run(Config &config, Parallel::CommunicatorPtr comm)
{
try
{
FileName orbitName, starCameraName;
readConfig(config, "outputfileStarCamera", starCameraName, Config::MUSTSET, "", "");
readConfig(config, "inputfileOrbit", orbitName, Config::MUSTSET, "", "position and velocity defines the orientation of the satellite at each epoch");
if(isCreateSchema(config)) return;
// StarCamera-Daten erzeugen
// -----------------------
logStatus<<"read orbit and generate star camera data"<<Log::endl;
Ellipsoid ellipsoid(DEFAULT_GRS80_a, DEFAULT_GRS80_f);
InstrumentFile orbitFile(orbitName);
std::vector<Arc> arcList(orbitFile.arcCount());
Parallel::forEach(arcList, [&](UInt arcNo)
{
OrbitArc orbit = orbitFile.readArc(arcNo);
StarCameraArc arc;
for(UInt i=0; i<orbit.size(); i++)
{
// get rotation form inertial to TOD frame
Double rc2i[3][3];
#ifdef GROOPS_DISABLE_ERFA
throw(Exception("compiled without ERFA library"));
#else
const Time timeTT = timeGPS2TT(orbit.at(i).time);
Double X=0, Y=0, S=0;
eraXys00b(2400000.5+timeTT.mjdInt(), timeTT.mjdMod(), &X, &Y, &S);
eraC2ixys(X, Y, S, rc2i);
#endif
Matrix R(3,3);
R(0,0) = rc2i[0][0]; R(0,1) = rc2i[1][0]; R(0,2) = rc2i[2][0];
R(1,0) = rc2i[0][1]; R(1,1) = rc2i[1][1]; R(1,2) = rc2i[2][1];
R(2,0) = rc2i[0][2]; R(2,1) = rc2i[1][2]; R(2,2) = rc2i[2][2];
Rotary3d rot(R);
Vector3d pos = orbit.at(i).position;
Vector3d vel = orbit.at(i).velocity;
const Double omega = 0.729211585e-4;
vel.x() += omega*pos.y(); // Correct velocity for earth rotation
vel.y() += -omega*pos.x();
// correct position
// compute subsatellite point
Angle L, B;
Double h;
ellipsoid(pos, L, B, h); // FIXME rot.rotate(pos)???
Vector3d posGround = ellipsoid(L, B, 0);
Vector3d x = normalize(vel);
Rotary3d rotC2ZD = Rotary3d(x, crossProduct(x, pos-posGround)) * rot;
// part 2: rotation from zero-Doppler reference frame to sentinel 1 reference frame (body)
ellipsoid(rot.rotate(pos), L, B, h); // compute height
const Double rThetaRef = 0.513999; // rad
const Double rAlphaRoll = 9.878564e-7; // rad/meter
const Double rHref = 711700;
const Rotary3d rot2 = rotaryX(Angle(rThetaRef - rAlphaRoll*(h-rHref)));
StarCameraEpoch epoch;
epoch.time = orbit.at(i).time;
epoch.rotary = rotC2ZD*rot2;
arc.push_back(epoch);
}
return arc;
}, comm); // forEach
// write
// -----
if(Parallel::isMaster(comm))
{
logStatus<<"write star camera data to file <"<<starCameraName<<">"<<Log::endl;
InstrumentFile::write(starCameraName, arcList);
}
}
catch(std::exception &e)
{
GROOPS_RETHROW(e)
}
}
/***********************************************/
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