52 lines
1.7 KiB
C++
Executable File
52 lines
1.7 KiB
C++
Executable File
#include "OrbitalElements.h"
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OrbitalElements::OrbitalElements(const Tle& tle) {
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/*
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* extract and format tle data
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*/
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mean_anomoly_ = tle.MeanAnomaly(false);
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ascending_node_ = tle.RightAscendingNode(false);
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argument_perigee_ = tle.ArgumentPerigee(false);
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eccentricity_ = tle.Eccentricity();
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inclination_ = tle.Inclination(false);
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mean_motion_ = tle.MeanMotion() * kTWOPI / kMINUTES_PER_DAY;
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bstar_ = tle.BStar();
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epoch_ = tle.Epoch();
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/*
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* recover original mean motion (xnodp) and semimajor axis (aodp)
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* from input elements
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*/
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const double a1 = pow(kXKE / MeanMotion(), kTWOTHIRD);
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const double cosio = cos(Inclination());
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const double theta2 = cosio * cosio;
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const double x3thm1 = 3.0 * theta2 - 1.0;
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const double eosq = Eccentricity() * Eccentricity();
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const double betao2 = 1.0 - eosq;
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const double betao = sqrt(betao2);
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const double temp = (1.5 * kCK2) * x3thm1 / (betao * betao2);
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const double del1 = temp / (a1 * a1);
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const double a0 = a1 * (1.0 - del1 * (1.0 / 3.0 + del1 * (1.0 + del1 * 134.0 / 81.0)));
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const double del0 = temp / (a0 * a0);
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recovered_mean_motion_ = MeanMotion() / (1.0 + del0);
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/*
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* alternative way to calculate
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* doesnt affect final results
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* recovered_semi_major_axis_ = pow(XKE / RecoveredMeanMotion(), TWOTHIRD);
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*/
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recovered_semi_major_axis_ = a0 / (1.0 - del0);
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/*
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* find perigee and period
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*/
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perigee_ = (RecoveredSemiMajorAxis() * (1.0 - Eccentricity()) - kAE) * kXKMPER;
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period_ = kTWOPI / RecoveredMeanMotion();
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}
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OrbitalElements::~OrbitalElements(void) {
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}
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