void Spice::ComputeSolarLongitude(double et) {
NaifStatus::CheckErrors();
if (iString(Target()).UpCase() == "SKY") {
p_solarLongitude = -999.0;
return;
}
if (p_bodyRotation->IsCached()) return;
double tipm[3][3], npole[3];
char frameName[32];
SpiceInt frameCode;
SpiceBoolean found;
cidfrm_c (p_spkBodyCode, sizeof(frameName), &frameCode, frameName, &found);
if ( found ) {
pxform_c("J2000",frameName,et,tipm);
}
else {
tipbod_c("J2000",p_spkBodyCode,et,tipm);
}
for (int i=0; i<3; i++) {
npole[i] = tipm[2][i];
}
double state[6], lt;
spkez_c(p_spkBodyCode,et,"J2000","NONE",10,state,<);
double uavel[3];
ucrss_c(state,&state[3],uavel);
double x[3], y[3], z[3];
vequ_c(uavel,z);
ucrss_c(npole,z,x);
ucrss_c(z,x,y);
double trans[3][3];
for (int i=0; i<3; i++) {
trans[0][i] = x[i];
trans[1][i] = y[i];
trans[2][i] = z[i];
}
spkez_c(10,et,"J2000","LT+S",p_spkBodyCode,state,<);
double pos[3];
mxv_c(trans,state,pos);
double radius, ls, lat;
reclat_c(pos,&radius,&ls,&lat);
ls *= 180.0 / Isis::PI;
if (ls < 0.0) ls += 360.0;
else if (ls > 360.0) ls -= 360.0;
p_solarLongitude = ls;
NaifStatus::CheckErrors();
}
//function to find the body state vector at epoch
int body::locate_body(const double& epoch, double* state, const bool& need_deriv, missionoptions* options)
{
double DT, n, M, E, V[6];
switch (body_ephemeris_source)
{
case 1: //SPICE
double LT_dump;
spkez_c(spice_ID, epoch - (51544.5 * 86400.0), "J2000", "NONE", this->central_body_spice_ID, state, <_dump);
if (need_deriv)
{
double statepert[6];
spkez_c(spice_ID, epoch - (51544.5 * 86400.0) + 10.0, "J2000", "NONE", this->central_body_spice_ID, statepert, <_dump);
state[6] = (statepert[3] - state[3]) / (10.0);
state[7] = (statepert[4] - state[4]) / (10.0);
state[8] = (statepert[5] - state[5]) / (10.0);
}
break;
case 0: //static ephemeris
//TODO static ephemeris is not ready!
//note, always should give in Earth equatorial J2000 coordinates for internal processing
DT = ( epoch - this->reference_epoch );
if (this->SMA > 0.0)
n = sqrt(this->universe_mu / (this->SMA*this->SMA*this->SMA));
else
n = sqrt(this->universe_mu / (-this->SMA*this->SMA*this->SMA));
M = this->MA + n*DT;
M = fmod(M, 2 * EMTG::math::PI);
E = Kepler::KeplerLaguerreConway(this->ECC, M);
V[0] = this->SMA;
V[1] = this->ECC;
V[2] = this->INC;
V[3] = this->RAAN;
V[4] = this->AOP;
true_anomaly = 2.0*atan(sqrt((1.0 + this->ECC) / (1.0 - this->ECC))*tan(E / 2.0));
V[5] = true_anomaly;
COE2inertial(V, this->universe_mu, state);
if (need_deriv)
{
double r = sqrt(state[0]*state[0] + state[1]*state[1] + state[2]*state[2]);
double r3 = r*r*r;
state[6] = -universe_mu/r3 * state[0];
state[7] = -universe_mu/r3 * state[1];
state[8] = -universe_mu/r3 * state[2];
}
break;
default:
cout << "Invalid ephemeris source " << body_ephemeris_source << " for object " << name << endl;
cout << "Program halted. Press enter to quit." << endl;
#ifndef BACKGROUND_MODE
cin.ignore();
#endif
}
return 0;
}
//function to load new data into the body
void body::load_body_data(const int& ibody_code, const string& iname, const string& ishortname, const int& ispice_ID, const double& imininum_altitude, const double& imass, const double& iradius, const double& iepoch, vector<double>& ireference_angles, vector<double>& iclassical_orbit_elements, const double& iuniverse_mu, const int& icentral_body_SPICE_ID, const string& icentral_body_name, const double& icentral_body_radius, missionoptions* options)
{
//copy information from the inputs into the body
this->name = iname;
this->short_name = ishortname;
this->universe_mu = iuniverse_mu;
this->body_code = ibody_code;
this->central_body_spice_ID = icentral_body_SPICE_ID;
this->central_body_name = icentral_body_name;
this->central_body_radius = icentral_body_radius;
this->spice_ID = ispice_ID;
this->minimum_safe_flyby_altitude = imininum_altitude;
this->mass = imass;
this->radius = iradius;
this->reference_epoch = iepoch;
this->SMA = iclassical_orbit_elements[0];
this->ECC = iclassical_orbit_elements[1];
this->INC = iclassical_orbit_elements[2] * EMTG::math::PI / 180.0;
this->RAAN = iclassical_orbit_elements[3] * EMTG::math::PI / 180.0;
this->AOP = iclassical_orbit_elements[4] * EMTG::math::PI / 180.0;
this->MA = iclassical_orbit_elements[5] * EMTG::math::PI / 180.0;
//compute additional values
mu = options->G * mass;
if (ECC < 0.2)
r_SOI = SMA * pow(mu / universe_mu, 0.4);
else
r_SOI = SMA * (1 - ECC) * pow(mu / (3.0 * universe_mu), 0.333333333333333333333333);
//determine which ephemeris to draw from
if (options->ephemeris_source == 0)
{
body_ephemeris_source = 0; //use static ephemeris
ephemeris_start_date = -0;
ephemeris_end_date = 1e+10;
}
else if (options->ephemeris_source == 1)
{
//first, check to see if the body exists in the currently loaded SPICE kernels
double temp_state[6];
double LT_dump;
spkez_c (spice_ID, reference_epoch - (51544.5 * 86400.0), "J2000", "NONE", central_body_spice_ID, temp_state, <_dump);
if (failed_c())
reset_c();
if (fabs(temp_state[0]) > 1.0e-6 && fabs(temp_state[0]) < 1.0e+50)
{
body_ephemeris_source = 1; //body can be located using SPICE
}
else
{
cout << "Warning, body " << name << " does not have a SPICE ephemeris file." << endl;
body_ephemeris_source = 0; //use static ephemeris
ephemeris_start_date = 0;
ephemeris_end_date = 1e+10;
}
}
J2000_body_equatorial_frame.initialize(ireference_angles[0], ireference_angles[1], ireference_angles[2], ireference_angles[3], ireference_angles[4], ireference_angles[5]);
}
