339 lines
10 KiB
C++
339 lines
10 KiB
C++
//
|
|
// Author: Joshua Cohen
|
|
// Copyright 2016
|
|
//
|
|
|
|
#include <cstdio>
|
|
#include <cstdlib>
|
|
#include <fstream>
|
|
#include <string>
|
|
#include "Constants.h"
|
|
#include "Orbit.h"
|
|
|
|
using std::getline;
|
|
using std::ifstream;
|
|
using std::ofstream;
|
|
using std::showpos;
|
|
using std::string;
|
|
|
|
// Default constructor
|
|
Orbit::Orbit() {
|
|
position = NULL;
|
|
velocity = NULL;
|
|
UTCtime = NULL;
|
|
nVectors = 0;
|
|
basis = 0;
|
|
}
|
|
|
|
Orbit::Orbit(const Orbit &orb) {
|
|
nVectors = orb.nVectors;
|
|
basis = orb.basis;
|
|
position = new double[3*nVectors];
|
|
velocity = new double[3*nVectors];
|
|
UTCtime = new double[nVectors];
|
|
for (int i=0; i<nVectors; i++) {
|
|
UTCtime[i] = orb.UTCtime[i];
|
|
position[(3*i)] = orb.position[(3*i)];
|
|
position[(3*i)+1] = orb.position[(3*i)+1];
|
|
position[(3*i)+2] = orb.position[(3*i)+2];
|
|
velocity[(3*i)] = orb.velocity[(3*i)];
|
|
velocity[(3*i)+1] = orb.velocity[(3*i)+1];
|
|
velocity[(3*i)+2] = orb.velocity[(3*i)+2];
|
|
}
|
|
}
|
|
|
|
Orbit::~Orbit() {
|
|
if (position) delete[] position;
|
|
if (velocity) delete[] velocity;
|
|
if (UTCtime) delete[] UTCtime;
|
|
}
|
|
|
|
// Unfortunately due to the way the algorithm works it will set up an Orbit and resize the internal
|
|
// vectors later
|
|
void Orbit::setOrbit(int nvec, int bs) {
|
|
if (position) delete[] position;
|
|
if (velocity) delete[] velocity;
|
|
if (UTCtime) delete[] UTCtime;
|
|
position = new double[3*nvec];
|
|
velocity = new double[3*nvec];
|
|
UTCtime = new double[nvec];
|
|
nVectors = nvec;
|
|
basis = bs;
|
|
}
|
|
|
|
// Can set the Orbit by reading in a CSV HDR file (size=(nVec x 7))
|
|
void Orbit::setOrbit(const char *filename, int bs) {
|
|
string line;
|
|
double pos[3], vel[3];
|
|
double t;
|
|
int count = 0;
|
|
|
|
nVectors = 0;
|
|
basis = bs;
|
|
ifstream fs(filename);
|
|
if (!fs.is_open()) {
|
|
printf("Error in Orbit::Orbit - Unable to open HDR file: %s\n", filename);
|
|
exit(1);
|
|
}
|
|
|
|
// Rapid iterator to count number of lines safely
|
|
while (getline(fs,line)) ++nVectors;
|
|
if (position) delete[] position;
|
|
if (velocity) delete[] velocity;
|
|
if (UTCtime) delete[] UTCtime;
|
|
position = new double[3*nVectors];
|
|
velocity = new double[3*nVectors];
|
|
UTCtime = new double[nVectors];
|
|
|
|
// Reset filestream before reading lines
|
|
fs.clear();
|
|
fs.seekg(0);
|
|
|
|
// Take advantage of filestream overridden >>/<< operators
|
|
while (fs >> t >> pos[0] >> pos[1] >> pos[2] >> vel[0] >> vel[1] >> vel[2]) {
|
|
setStateVector(count,t,pos,vel);
|
|
count++;
|
|
}
|
|
fs.close();
|
|
printf("Read in %d State Vectors from %s\n", nVectors, filename);
|
|
}
|
|
|
|
void Orbit::getPositionVelocity(double tintp, double pos[3], double vel[3]) {
|
|
if (basis == WGS84_ORBIT) interpolateWGS84Orbit(tintp, pos, vel);
|
|
else interpolateSCHOrbit(tintp, pos, vel);
|
|
}
|
|
|
|
void Orbit::setStateVector(int idx, double t, double pos[3], double vel[3]) {
|
|
if ((idx >= nVectors) || (idx < 0)) {
|
|
printf("Error in Orbit::setStateVector - Trying to set state vector %d out of %d\n", idx, nVectors);
|
|
exit(1);
|
|
}
|
|
UTCtime[idx] = t;
|
|
for (int i=0; i<3; i++) {
|
|
position[(3*idx)+i] = pos[i];
|
|
velocity[(3*idx)+i] = vel[i];
|
|
}
|
|
}
|
|
|
|
void Orbit::getStateVector(int idx, double &t, double pos[3], double vel[3]) {
|
|
if ((idx >= nVectors) || (idx < 0)) {
|
|
printf("Error in Orbit::getStateVector - Trying to get state vector %d out of %d\n", idx, nVectors);
|
|
exit(1);
|
|
}
|
|
t = UTCtime[idx];
|
|
for (int i=0; i<3; i++) {
|
|
pos[i] = position[(3*idx)+i];
|
|
vel[i] = velocity[(3*idx)+i];
|
|
}
|
|
}
|
|
|
|
// Common interface for orbit interpolation (avoid setting function pointers in main controller
|
|
int Orbit::interpolateOrbit(double tintp, double opos[3], double ovel[3], int method) {
|
|
int ret;
|
|
|
|
if (method == HERMITE_METHOD) ret = interpolateWGS84Orbit(tintp,opos,ovel);
|
|
else if (method == SCH_METHOD) ret = interpolateSCHOrbit(tintp,opos,ovel);
|
|
else if (method == LEGENDRE_METHOD) ret = interpolateLegendreOrbit(tintp,opos,ovel);
|
|
else {
|
|
printf("Error in Orbit::interpolateOrbit - Invalid orbit interpolation method.\n");
|
|
exit(1);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
int Orbit::interpolateSCHOrbit(double tintp, double opos[3], double ovel[3]) {
|
|
double pos[2][3], vel[2][3];
|
|
double t[2];
|
|
double frac,num,den;
|
|
|
|
if (nVectors < 2) {
|
|
printf("Error in Orbit::interpolateSCHOrbit - Need at least 2 state vectors for SCH orbit interpolation.\n");
|
|
exit(1);
|
|
}
|
|
if ((tintp < UTCtime[0]) || (tintp > UTCtime[nVectors-1])) {
|
|
printf("Error in Orbit::interpolateSCHOrbit - Requested epoch outside orbit state vector span.\n");
|
|
exit(1);
|
|
}
|
|
for (int i=0; i<3; i++) {
|
|
opos[i] = 0.0;
|
|
ovel[i] = 0.0;
|
|
}
|
|
for (int i=0; i<nVectors; i++) {
|
|
frac = 1.0;
|
|
getStateVector(i,t[0],pos[0],vel[0]);
|
|
for (int j=0; j<nVectors; j++) {
|
|
if (i==j) continue;
|
|
getStateVector(j,t[1],pos[1],vel[1]);
|
|
num = t[1] - tintp;
|
|
den = t[1] - t[0];
|
|
frac = frac * (num / den);
|
|
}
|
|
for (int k=0; k<3; k++) {
|
|
opos[k] = frac * pos[0][k];
|
|
ovel[k] = frac * vel[0][k];
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int Orbit::interpolateWGS84Orbit(double tintp, double opos[3], double ovel[3]) {
|
|
double pos[4][3], vel[4][3];
|
|
double t[4];
|
|
int ii;
|
|
|
|
if (nVectors < 4) return 1;
|
|
for (int i=0; i<nVectors; i++) {
|
|
ii = i;
|
|
if (UTCtime[i] >= tintp) break;
|
|
}
|
|
ii = ii - 2;
|
|
if (ii < 0) ii = 0;
|
|
if (ii > (nVectors - 4)) ii = (nVectors - 4);
|
|
|
|
for (int j=0; j<4; j++) getStateVector((ii+j),t[j],pos[j],vel[j]);
|
|
orbitHermite(pos,vel,t,tintp,opos,ovel);
|
|
|
|
if ((tintp < UTCtime[0]) || (tintp > UTCtime[(nVectors-1)])) return 1;
|
|
else return 0;
|
|
}
|
|
|
|
int Orbit::interpolateLegendreOrbit(double tintp, double opos[3], double ovel[3]) {
|
|
double pos[9][3], vel[9][3];
|
|
double t[9];
|
|
double noemer[] = {40320.0, -5040.0, 1440.0, -720.0, 576.0, -720.0, 1440.0, -5040.0, 40320.0};
|
|
double trel, coeff, teller;
|
|
int ii;
|
|
|
|
for (int i=0; i<3; i++) {
|
|
opos[i] = 0.0;
|
|
ovel[i] = 0.0;
|
|
}
|
|
if (nVectors < 9) return 1;
|
|
for (int i=0; i<nVectors; i++) {
|
|
ii = i;
|
|
if (UTCtime[i] >= tintp) break;
|
|
}
|
|
ii = ii - 5;
|
|
if (ii < 0) ii = 0;
|
|
if (ii > (nVectors - 9)) ii = (nVectors - 9);
|
|
|
|
for (int j=0; j<9; j++) getStateVector((ii+j),t[j],pos[j],vel[j]);
|
|
|
|
trel = (8.0 * (tintp - t[0])) / (t[8] - t[0]);
|
|
teller = 1.0;
|
|
for (int j=0; j<9; j++) teller = teller * (trel - j);
|
|
|
|
if (teller == 0.0) {
|
|
int i = int(trel);
|
|
for (int j=0; j<3; j++) {
|
|
opos[j] = pos[i][j];
|
|
ovel[j] = vel[i][j];
|
|
}
|
|
} else {
|
|
for (int i=0; i<9; i++) {
|
|
coeff = (teller / noemer[i]) / (trel - i);
|
|
for (int j=0; j<3; j++) {
|
|
opos[j] = opos[j] + (coeff * pos[i][j]);
|
|
ovel[j] = ovel[j] + (coeff * vel[i][j]);
|
|
}
|
|
}
|
|
}
|
|
if ((tintp < UTCtime[0]) || (tintp > UTCtime[(nVectors-1)])) return 1;
|
|
else return 0;
|
|
}
|
|
|
|
int Orbit::computeAcceleration(double tintp, double acc[3]) {
|
|
double xbef[3], vbef[3], xaft[3], vaft[3];
|
|
double temp;
|
|
int stat;
|
|
|
|
for (int i=0; i<3; i++) acc[i] = 0.0;
|
|
temp = tintp - 0.01;
|
|
stat = interpolateWGS84Orbit(temp, xbef, vbef);
|
|
if (stat != 0) return 1;
|
|
temp = tintp + 0.01;
|
|
stat = interpolateWGS84Orbit(temp, xaft, vaft);
|
|
if (stat != 0) return 1;
|
|
for (int i=0; i<3; i++) acc[i] = (vaft[i] - vbef[i]) / 0.02;
|
|
return 0;
|
|
}
|
|
|
|
void Orbit::orbitHermite(double x[4][3], double v[4][3], double t[4], double time, double xx[3], double vv[3]) {
|
|
double h[4], hdot[4], f0[4], f1[4], g0[4], g1[4];
|
|
double sum, product;
|
|
|
|
for (int i=0; i<4; i++) {
|
|
h[i] = 0.;
|
|
hdot[i] = 0.;
|
|
f0[i] = 0.;
|
|
f1[i] = 0.;
|
|
g0[i] = 0.;
|
|
g1[i] = 0.;
|
|
}
|
|
for (int i=0; i<4; i++) {
|
|
f1[i] = time - t[i];
|
|
sum = 0.0;
|
|
for (int j=0; j<4; j++) {
|
|
if (i != j) sum = sum + (1.0 / (t[i] - t[j]));
|
|
}
|
|
f0[i] = 1.0 - (2. * (time - t[i]) * sum);
|
|
}
|
|
for (int i=0; i<4; i++) {
|
|
product = 1.0;
|
|
for (int k=0; k<4; k++) {
|
|
if (k != i) product = product * ((time - t[k]) / (t[i] - t[k]));
|
|
}
|
|
h[i] = product;
|
|
sum = 0.0;
|
|
for (int j=0; j<4; j++) {
|
|
product = 1.0;
|
|
for (int k=0; k<4; k++) {
|
|
if ((k != i) && (k != j)) product = product * ((time - t[k]) / (t[i] - t[k]));
|
|
}
|
|
if (j != i) sum = sum + ((1.0 / (t[i] - t[j])) * product);
|
|
}
|
|
hdot[i] = sum;
|
|
}
|
|
for (int i=0; i<4; i++) {
|
|
g1[i] = h[i] + (2.0 * (time - t[i]) * hdot[i]);
|
|
sum = 0.0;
|
|
for (int j=0; j<4; j++) {
|
|
if (i != j) sum = sum + (1.0 / (t[i] - t[j]));
|
|
}
|
|
g0[i] = 2.0 * ((f0[i] * hdot[i]) - (h[i] * sum));
|
|
}
|
|
for (int k=0; k<3; k++) {
|
|
sum = 0.0;
|
|
for (int i=0; i<4; i++) sum = sum + (((x[i][k] * f0[i]) + (v[i][k] * f1[i])) * h[i] * h[i]);
|
|
xx[k] = sum;
|
|
sum = 0.0;
|
|
for (int i=0; i<4; i++) sum = sum + (((x[i][k] * g0[i]) + (v[i][k] * g1[i])) * h[i]);
|
|
vv[k] = sum;
|
|
}
|
|
}
|
|
|
|
void Orbit::dumpToHDR(const char* filename) {
|
|
ofstream fs(filename);
|
|
if (!fs.is_open()) {
|
|
printf("Error in Orbit::dumpToHDR - Unable to open HDR file: %s\n", filename);
|
|
exit(1);
|
|
}
|
|
printf("Writing %d vectors to %s\n", nVectors, filename);
|
|
fs << showpos;
|
|
fs.precision(16);
|
|
for (int i=0; i<nVectors; i++) {
|
|
fs << UTCtime[i] << "\t" << position[(3*i)] << "\t" << position[(3*i)+1] << "\t" << position[(3*i)+2]
|
|
<< "\t" << velocity[(3*i)] << "\t" << velocity[(3*i)+1] << "\t" << velocity[(3*i)+2] << "\n";
|
|
}
|
|
fs.close();
|
|
}
|
|
|
|
void Orbit::printOrbit() {
|
|
for (int i=0; i<nVectors; i++) {
|
|
printf("UTC = %lf\n", UTCtime[i]);
|
|
printf("Position = [ %lf, %lf, %lf ]\n", position[(3*i)], position[(3*i)+1], position[(3*i)+2]);
|
|
printf("Velocity = [ %lf, %lf, %lf ]\n\n", velocity[(3*i)], velocity[(3*i)+1], velocity[(3*i)+2]);
|
|
}
|
|
}
|
|
|