Changes to FindPositionSDP4()
Daniel Warner
parent
4bfa3405f9
commit
0970a0f44a
67
SGDP4.cpp
67
SGDP4.cpp
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@ -135,7 +135,7 @@ void SGDP4::Initialize(const double& theta2, const double& betao2, const double&
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double qoms24 = constants_.QOMS2T;
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if (Perigee() < 156.0) {
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s4 = Perigee() - 78.0;
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if (Perigee() <= 98.0) {
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if (Perigee() < 98.0) {
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s4 = 20.0;
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}
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qoms24 = pow((120.0 - s4) * constants_.AE / constants_.XKMPER, 4.0);
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@ -256,12 +256,12 @@ void SGDP4::FindPositionSDP4(Eci& eci, double tsince) {
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/*
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* the final values
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*/
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double e;
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double e = Eccentricity();
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double a;
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double omega;
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double xl;
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double xnode;
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double xincl;
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double xincl = Inclination();
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/*
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* update for secular gravity and atmospheric drag
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@ -270,33 +270,58 @@ void SGDP4::FindPositionSDP4(Eci& eci, double tsince) {
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double omgadf = ArgumentPerigee() + i_omgdot_ * tsince;
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const double xnoddf = AscendingNode() + i_xnodot_ * tsince;
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omega = omgadf;
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const double tsq = tsince * tsince;
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xnode = xnoddf + i_xnodcf_ * tsq;
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double tempa = 1.0 - i_c1_ * tsince;
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double tempe = BStar() * i_c4_ * tsince;
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double templ = i_t2cof_ * tsq;
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double em = Eccentricity();
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double xinc = Inclination();
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double xn = RecoveredMeanMotion();
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DeepSecular(tsince, xmdf, omgadf, xnode, em, xinc, xn);
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/* t, xll, omgasm, xnodes, em, xinc, xn */
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DeepSecular(tsince, xmdf, omega, xnode, e, xincl, xn);
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a = pow(constants_.XKE / xn, constants_.TWOTHRD) * pow(tempa, 2.0);
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e = em - tempe;
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double xmam = xmdf + RecoveredMeanMotion() * templ;
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DeepPeriodics(tsince, e, xinc, omgadf, xnode, xmam);
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if (xinc < 0.0) {
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xinc = -xinc;
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xnode += Globals::PI();
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omgadf -= Globals::PI();
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if (xn <= 0.0) {
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throw new SatelliteException("Error: 2 (xn <= 0.0)");
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}
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xl = xmam + omgadf + xnode;
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xincl = xinc;
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omega = omgadf;
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a = pow(constants_.XKE / xn, constants_.TWOTHRD) * pow(tempa, 2.0);
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e -= tempe;
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/*
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* fix tolerance for error recognition
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*/
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if (e >= 1.0 || e < -0.001) {
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throw new SatelliteException("Error: 1 (e >= 1.0 || e < -0.001)");
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}
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/*
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* fix tolerance to avoid a divide by zero
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*/
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if (e < 1.0e-6)
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e = 1.0e-6;
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xmdf += RecoveredMeanMotion() * templ;
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double xlm = xmdf + omega + xnode;
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xnode = fmod(xnode, Globals::TWOPI());
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omega = fmod(omega, Globals::TWOPI());
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xlm = fmod(xlm, Globals::TWOPI());
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double xmam = fmod(xlm - omega - xnode, Globals::TWOPI());
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DeepPeriodics(tsince, e, xincl, omega, xnode, xmam);
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if (xincl < 0.0) {
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xincl = -xincl;
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xnode += Globals::PI();
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omega -= Globals::PI();
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}
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xl = xmam + omega + xnode;
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if (e < 0.0 || e > 1.0) {
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throw new SatelliteException("Error: 3 (e < 0.0 || e > 1.0)");
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}
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/*
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* re-compute the perturbed values
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@ -599,7 +624,7 @@ void SGDP4::DeepSpaceInitialize(const double& eosq, const double& sinio, const d
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*/
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const double d_day_ = Epoch().FromJan1_12h_1900();
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const double xnodce = 4.5236020 - 9.2422029e-4 * d_day_;
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const double xnodce = fmod(4.5236020 - 9.2422029e-4 * d_day_, Globals::TWOPI());
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const double stem = sin(xnodce);
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const double ctem = cos(xnodce);
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const double zcosil = 0.91375164 - 0.03568096 * ctem;
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@ -1007,7 +1032,7 @@ void SGDP4::DeepPeriodics(const double& t, double& em,
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void SGDP4::DeepSecular(const double& t, double& xll, double& omgasm,
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double& xnodes, double& em, double& xinc, double& xn) {
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static const double THDT = 4.3752691E-3;
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static const double THDT = 4.37526908801129966e-3;
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static const double STEP2 = 259200.0;
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static const double STEP = 720.0;
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20
SGDP4.h
20
SGDP4.h
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@ -45,20 +45,20 @@ private:
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*/
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double i_cosio_;
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double i_sinio_;
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double i_x3thm1_;
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double i_eta_;
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double i_c1_;
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double i_t2cof_;
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double i_a3ovk2_;
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double i_x1mth2_;
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double i_c4_;
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double i_xmdot_;
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double i_omgdot_;
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double i_xnodot_;
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double i_xnodcf_;
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double i_t2cof_;
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double i_xlcof_;
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double i_aycof_;
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double i_x3thm1_;
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double i_x7thm1_;
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double i_aycof_;
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double i_xlcof_;
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double i_xnodcf_;
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double i_c1_;
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double i_c4_;
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double i_omgdot_; // secular rate of omega (radians/sec)
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double i_xnodot_; // secular rate of xnode (radians/sec)
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double i_xmdot_; // secular rate of xmo (radians/sec)
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/*
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* sgp4 constant
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*/
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6
main.cpp
6
main.cpp
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@ -144,6 +144,8 @@ void RunTle(Tle tle, double start, double end, double inc) {
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void RunTest() {
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#if 0
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/*
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# ------------------ Verification test cases ----------------------
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# # TEME example
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@ -379,7 +381,7 @@ void RunTest() {
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RunTle(Tle("28350",
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"1 28350U 04020A 06167.21788666 .16154492 76267-5 18678-3 0 8894",
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"2 28350 64.9977 345.6130 0024870 260.7578 99.9590 16.47856722116490"), 0.0, 2880.0, 120.0);
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#endif
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/*
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# H-2 R/B # Deep space, perigee = 135.75 (<156) s4 mod
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@ -390,7 +392,7 @@ void RunTest() {
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"1 28623U 05006B 06177.81079184 .00637644 69054-6 96390-3 0 6000",
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"2 28623 28.5200 114.9834 6249053 170.2550 212.8965 3.79477162 12753"), 0.0, 1440.0, 120.0);
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return;
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/*
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# XM-3 # 24h resonant geo, incl < 3 deg goes
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# # negative around 1130 min
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