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@ -19,42 +19,37 @@ TEST_CASE("orbit construction", "[orbits]")
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// NOTE: example 4.6 in "Space Flight Dynamics" by Craig A. Kluever
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TEST_CASE("orbit propagation", "[orbits]") |
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{ |
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orbital_elements orbit = {}; |
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double a = 26564.5; // kilometers
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double e = 0.7411; |
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ellipse_parameters ep = ellipseInitAE(a, e); |
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orbit.ep = ep; |
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double initial_anom = 260 * M_PI / 180; // radians
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unsigned int time_step = 60 * 50; // seconds
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// NOTE: solve for gravitational parameter from mean motion
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double mean_motion = 0.00014582; // rad/s
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orbit.mu = pow(mean_motion, 2) * pow(ep.a, 3); |
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double E1 = getEccAnomFromTrueAnom(ep.e, initial_anom); |
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double a = 26564.5; // NOTE: semi-major axis in km
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double e = 0.7411; // NOTE: eccentricity
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double mu = 398601.68; // NOTE: gravitational parameter
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double r = 6378; // NOTE: body radius in km
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double initial_anom = 260 * M_PI / 180; // NOTE: radians
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unsigned int time_step = 60 * 50; // NOTE: seconds
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system_2body sys = systemInit(gravBodyInit(mu, r), orbitInit(a, e)); |
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double E1 = getEccAnomFromTrueAnom(sys.ep.e, initial_anom); |
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REQUIRE_THAT(E1, WithinAbs(-0.8615, 1e-4)); |
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double M1 = getMeanAnomFromEccAnom(E1, ep.e); |
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double M1 = getMeanAnomFromEccAnom(E1, sys.ep.e); |
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REQUIRE_THAT(M1, WithinAbs(-0.2992, 1e-4)); |
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double n = getMeanMotion(orbit.mu, orbit.ep.a); |
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double n = getMeanMotion(sys.body.mu, sys.ep.a); |
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REQUIRE_THAT(n, WithinAbs(0.00014582, 1e-8)); |
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double M2 = getPropagatedMeanAnom(M1, n, time_step); |
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REQUIRE_THAT(M2, WithinAbs(0.1383, 1e-5)); |
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// TODO: could also test for the other trial values listed in table 4.1
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double E2_1 = getInitialTrialValue(M2, ep.e); |
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double E2_1 = getInitialTrialValue(M2, sys.ep.e); |
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REQUIRE_THAT(E2_1, WithinAbs(0.315452, 1e-5)); |
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double ecc_anom = getPropagatedEccAnomaly(orbit, initial_anom, time_step); |
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double ecc_anom = getPropagatedEccAnomaly(sys, initial_anom, time_step); |
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REQUIRE_THAT(ecc_anom, WithinAbs(0.481518, 1e-5)); |
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double true_anom = getPropagatedTrueAnomaly(orbit, initial_anom, time_step); |
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double true_anom = getPropagatedTrueAnomaly(sys, initial_anom, time_step); |
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REQUIRE_THAT(true_anom, WithinAbs(1.1339, 1e-4)); |
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double r2 = getRadialDistance(ep.e, ep.p, true_anom); |
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double r2 = orbitGetRadialDistance(sys.ep.e, sys.ep.p, true_anom); |
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REQUIRE_THAT(r2, WithinAbs(9116.1, 0.1)); |
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glm::vec2 pos = polarToRect(true_anom, r2); |
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