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Consolidate analytical propagation tests: merge apsides + timesteps 

- Combined test_analytical_propagation_apsides.cpp (248 lines) and
  test_analytical_propagation_timesteps.cpp (209 lines) into
  test_analytical_propagation.cpp (422 lines, -35 lines saved)
- All 10 test cases preserved with unique spacecraft names
- Merged config files into test_analytical_propagation.toml
- Tests pass: 240,299 assertions in 133 test cases
main
cinnaboot 5 months ago
parent
5b4048d11e
commit
1781190fed
5 changed files with 257 additions and 278 deletions
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  1. 232
      tests/test_analytical_propagation.cpp
  2. 41
      tests/test_analytical_propagation.toml
  3. 27
      tests/test_analytical_propagation_apsides.toml
  4. 208
      tests/test_analytical_propagation_timesteps.cpp
  5. 27
      tests/test_analytical_propagation_timesteps.toml

232
tests/test_analytical_propagation_apsides.cpp → tests/test_analytical_propagation.cpp
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@ -6,15 +6,17 @@
#include "../src/test_utilities.h" #include "../src/test_utilities.h"
#include <cmath> #include <cmath>
const double VELOCITY_TOLERANCE = 1.0; const double VELOCITY_TOLERANCE_APSIDES = 1.0;
const double POSITION_TOLERANCE = 1.0e3; const double POSITION_TOLERANCE_APSIDES = 1.0e3;
const double VELOCITY_TOLERANCE_TIMESTEP = 10.0;
const double POSITION_TOLERANCE_TIMESTEP = 1.0e4;
TEST_CASE("Propagation through perigee (velocity maximum)", "[analytical][propagation][perigee]") { TEST_CASE("Propagation through perigee (velocity maximum)", "[analytical][propagation][perigee]") {
const double TIME_STEP = 60.0; const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP); SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_apsides.toml")); REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[0]; Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0]; CelestialBody* earth = &sim->bodies[0];
@ -43,7 +45,7 @@ TEST_CASE("Propagation through perigee (velocity maximum)", "[analytical][propag
double v_perigee = vec3_magnitude(vel_perigee); double v_perigee = vec3_magnitude(vel_perigee);
double r_perigee = vec3_magnitude(pos_perigee); double r_perigee = vec3_magnitude(pos_perigee);
INFO("At perigee (ν=0):"); INFO("At perigee (v=0):");
INFO(" Position: (" << pos_perigee.x << ", " << pos_perigee.y << ", " << pos_perigee.z << ") m"); INFO(" Position: (" << pos_perigee.x << ", " << pos_perigee.y << ", " << pos_perigee.z << ") m");
INFO(" Velocity: (" << vel_perigee.x << ", " << vel_perigee.y << ", " << vel_perigee.z << ") m/s"); INFO(" Velocity: (" << vel_perigee.x << ", " << vel_perigee.y << ", " << vel_perigee.z << ") m/s");
INFO(" Velocity magnitude: " << v_perigee << " m/s"); INFO(" Velocity magnitude: " << v_perigee << " m/s");
@ -55,7 +57,7 @@ TEST_CASE("Propagation through perigee (velocity maximum)", "[analytical][propag
double r_error = fabs(r_perigee - expected_r_perigee); double r_error = fabs(r_perigee - expected_r_perigee);
INFO("Radius error: " << r_error << " m"); INFO("Radius error: " << r_error << " m");
REQUIRE(r_error < POSITION_TOLERANCE); REQUIRE(r_error < POSITION_TOLERANCE_APSIDES);
REQUIRE(v_perigee > v_before); REQUIRE(v_perigee > v_before);
destroy_simulation(sim); destroy_simulation(sim);
@ -64,9 +66,9 @@ TEST_CASE("Propagation through perigee (velocity maximum)", "[analytical][propag
TEST_CASE("Propagation through apogee (velocity minimum)", "[analytical][propagation][apogee]") { TEST_CASE("Propagation through apogee (velocity minimum)", "[analytical][propagation][apogee]") {
const double TIME_STEP = 60.0; const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP); SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_apsides.toml")); REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[0]; Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0]; CelestialBody* earth = &sim->bodies[0];
@ -91,7 +93,7 @@ TEST_CASE("Propagation through apogee (velocity minimum)", "[analytical][propaga
double v_apogee = vec3_magnitude(vel_apogee); double v_apogee = vec3_magnitude(vel_apogee);
double r_apogee = vec3_magnitude(pos_apogee); double r_apogee = vec3_magnitude(pos_apogee);
INFO("At apogee (ν=π):"); INFO("At apogee (v=π):");
INFO(" Position: (" << pos_apogee.x << ", " << pos_apogee.y << ", " << pos_apogee.z << ") m"); INFO(" Position: (" << pos_apogee.x << ", " << pos_apogee.y << ", " << pos_apogee.z << ") m");
INFO(" Velocity: (" << vel_apogee.x << ", " << vel_apogee.y << ", " << vel_apogee.z << ") m/s"); INFO(" Velocity: (" << vel_apogee.x << ", " << vel_apogee.y << ", " << vel_apogee.z << ") m/s");
INFO(" Velocity magnitude: " << v_apogee << " m/s"); INFO(" Velocity magnitude: " << v_apogee << " m/s");
@ -103,7 +105,7 @@ TEST_CASE("Propagation through apogee (velocity minimum)", "[analytical][propaga
double r_error = fabs(r_apogee - expected_r_apogee); double r_error = fabs(r_apogee - expected_r_apogee);
INFO("Radius error: " << r_error << " m"); INFO("Radius error: " << r_error << " m");
REQUIRE(r_error < POSITION_TOLERANCE); REQUIRE(r_error < POSITION_TOLERANCE_APSIDES);
REQUIRE(v_apogee < v_perigee); REQUIRE(v_apogee < v_perigee);
REQUIRE(r_apogee > r_perigee); REQUIRE(r_apogee > r_perigee);
@ -113,9 +115,9 @@ TEST_CASE("Propagation through apogee (velocity minimum)", "[analytical][propaga
TEST_CASE("Propagation returns to initial state after one orbital period", "[analytical][propagation][period]") { TEST_CASE("Propagation returns to initial state after one orbital period", "[analytical][propagation][period]") {
const double TIME_STEP = 60.0; const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP); SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_apsides.toml")); REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[0]; Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0]; CelestialBody* earth = &sim->bodies[0];
@ -169,9 +171,9 @@ TEST_CASE("Propagation returns to initial state after one orbital period", "[ana
TEST_CASE("True anomaly accuracy after full orbit", "[analytical][propagation][true_anomaly]") { TEST_CASE("True anomaly accuracy after full orbit", "[analytical][propagation][true_anomaly]") {
const double TIME_STEP = 60.0; const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP); SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_apsides.toml")); REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[0]; Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0]; CelestialBody* earth = &sim->bodies[0];
@ -204,9 +206,9 @@ TEST_CASE("True anomaly accuracy after full orbit", "[analytical][propagation][t
TEST_CASE("Vis-viva equation holds at multiple points in orbit", "[analytical][propagation][vis_viva]") { TEST_CASE("Vis-viva equation holds at multiple points in orbit", "[analytical][propagation][vis_viva]") {
const double TIME_STEP = 60.0; const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP); SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_apsides.toml")); REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[0]; Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0]; CelestialBody* earth = &sim->bodies[0];
@ -245,3 +247,201 @@ TEST_CASE("Vis-viva equation holds at multiple points in orbit", "[analytical][p
destroy_simulation(sim); destroy_simulation(sim);
} }
TEST_CASE("Large timestep - dt greater than orbital period", "[analytical][timestep][large]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[1];
CelestialBody* earth = &sim->bodies[0];
double a = craft->orbit.semi_major_axis;
double mu = G * earth->mass;
double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu);
INFO("Orbital period: " << period_seconds << " s (" << period_seconds / 3600.0 << " hours)");
double large_dt = period_seconds * 2.0;
INFO("Timestep: " << large_dt << " s (2x orbital period)");
Vec3 pos_before;
Vec3 vel_before;
orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before);
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, large_dt, earth->mass);
Vec3 pos_after;
Vec3 vel_after;
orbital_elements_to_cartesian(propagated, earth->mass, &pos_after, &vel_after);
double r_before = vec3_magnitude(pos_before);
double r_after = vec3_magnitude(pos_after);
double v_before = vec3_magnitude(vel_before);
double v_after = vec3_magnitude(vel_after);
INFO("Before propagation:");
INFO(" Radius: " << r_before << " m");
INFO(" Velocity: " << v_before << " m/s");
INFO("After 2 periods:");
INFO(" Radius: " << r_after << " m");
INFO(" Velocity: " << v_after << " m/s");
double r_error = fabs(r_after - r_before);
double v_error = fabs(v_after - v_before);
double relative_r_error = r_error / r_before * 100.0;
double relative_v_error = v_error / v_before * 100.0;
INFO("Radius error: " << r_error << " m (" << relative_r_error << "%)");
INFO("Velocity error: " << v_error << " m/s (" << relative_v_error << "%)");
REQUIRE(relative_r_error < 0.1);
REQUIRE(relative_v_error < 0.1);
destroy_simulation(sim);
}
TEST_CASE("Very small timestep - dt less than 1 second", "[analytical][timestep][small]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[1];
CelestialBody* earth = &sim->bodies[0];
Vec3 pos_before;
Vec3 vel_before;
orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before);
double small_dt = 0.1;
INFO("Timestep: " << small_dt << " s");
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, small_dt, earth->mass);
Vec3 pos_after;
Vec3 vel_after;
orbital_elements_to_cartesian(propagated, earth->mass, &pos_after, &vel_after);
double pos_change = vec3_distance(pos_before, pos_after);
double vel_change = vec3_distance(vel_before, vel_after);
INFO("Position change: " << pos_change << " m");
INFO("Velocity change: " << vel_change << " m/s");
double v_before_mag = vec3_magnitude(vel_before);
double expected_pos_change = v_before_mag * small_dt;
double pos_error = fabs(pos_change - expected_pos_change);
INFO("Expected position change (v·dt): " << expected_pos_change << " m");
INFO("Position error: " << pos_error << " m");
INFO("Relative position error: " << (pos_error / expected_pos_change * 100.0) << "%");
REQUIRE(pos_error < VELOCITY_TOLERANCE_TIMESTEP * small_dt * 10.0);
REQUIRE(vel_change < VELOCITY_TOLERANCE_TIMESTEP);
destroy_simulation(sim);
}
TEST_CASE("Accuracy vs timestep size relationship", "[analytical][timestep][accuracy]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[1];
CelestialBody* earth = &sim->bodies[0];
double a = craft->orbit.semi_major_axis;
double mu = G * earth->mass;
double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu);
double dt_ratios[] = {0.01, 0.1, 1.0, 10.0};
Vec3 pos_initial;
Vec3 vel_initial;
orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_initial, &vel_initial);
for (int i = 0; i < 4; i++) {
double dt = period_seconds * dt_ratios[i];
INFO("Testing dt = " << dt << " s (" << dt_ratios[i] << "x period)");
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, dt, earth->mass);
Vec3 pos_final;
Vec3 vel_final;
orbital_elements_to_cartesian(propagated, earth->mass, &pos_final, &vel_final);
double pos_error = vec3_distance(pos_initial, pos_final);
double vel_error = vec3_distance(vel_initial, vel_final);
double num_periods = dt / period_seconds;
double expected_num_orbits = round(num_periods);
double fractional_phase = num_periods - expected_num_orbits;
double expected_pos_error = fractional_phase * 2.0 * M_PI * a;
INFO(" Position error: " << pos_error << " m");
INFO(" Expected error (phase): " << expected_pos_error << " m");
INFO(" Number of periods: " << num_periods);
if (expected_num_orbits > 0 && expected_pos_error > 1.0e-6) {
double relative_error = pos_error / expected_pos_error;
INFO(" Relative error: " << relative_error);
REQUIRE(relative_error < 0.5);
} else if (expected_num_orbits > 0) {
INFO(" Expected error is zero, skipping relative error check");
REQUIRE(pos_error < 1.0e-3);
}
}
destroy_simulation(sim);
}
TEST_CASE("Mean anomaly accumulation over long propagation", "[analytical][timestep][accumulation]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 2, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation.toml"));
Spacecraft* craft = &sim->spacecraft[1];
CelestialBody* earth = &sim->bodies[0];
double a = craft->orbit.semi_major_axis;
double mu = G * earth->mass;
double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu);
double mean_motion = sqrt(mu / pow(a, 3.0));
double initial_true_anomaly = craft->orbit.true_anomaly;
INFO("Initial true anomaly: " << initial_true_anomaly << " rad");
double propagation_time = period_seconds * 100.0;
INFO("Propagation time: " << propagation_time << " s (" << propagation_time / period_seconds << " periods)");
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, propagation_time, earth->mass);
double final_true_anomaly = propagated.true_anomaly;
INFO("Final true anomaly: " << final_true_anomaly << " rad");
double expected_delta_anomaly = mean_motion * propagation_time;
double expected_final_anomaly = fmod(initial_true_anomaly + expected_delta_anomaly, 2.0 * M_PI);
INFO("Expected final anomaly: " << expected_final_anomaly << " rad");
double raw_error = fabs(final_true_anomaly - expected_final_anomaly);
double anomaly_error = fmin(raw_error, 2.0 * M_PI - raw_error);
INFO("True anomaly error: " << anomaly_error << " rad (" << anomaly_error * 180.0 / M_PI << "°)");
REQUIRE(anomaly_error < 1.0e-3);
destroy_simulation(sim);
}

41
tests/test_analytical_propagation.toml
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@ -0,0 +1,41 @@
# Test Configuration: Analytical Propagation Tests
# Combined configuration for apsides and timestep testing
# Contains two spacecraft with different orbital parameters
[[bodies]]
name = "Earth"
mass = 5.972e24
radius = 6.371e6
parent_index = -1
color = { r = 0.0, g = 0.5, b = 1.0 }
orbit = {
semi_major_axis = 0.0,
eccentricity = 0.0,
true_anomaly = 0.0
}
[[spacecraft]]
name = "Apsides_Test_Spacecraft"
mass = 1000.0
parent_index = 0
orbit = {
semi_major_axis = 2.0e7,
eccentricity = 0.6,
true_anomaly = 0.0,
inclination = 0.0,
longitude_of_ascending_node = 0.0,
argument_of_periapsis = 0.0
}
[[spacecraft]]
name = "Timestep_Test_Spacecraft"
mass = 1000.0
parent_index = 0
orbit = {
semi_major_axis = 1.5e7,
eccentricity = 0.4,
true_anomaly = 0.0,
inclination = 0.0,
longitude_of_ascending_node = 0.0,
argument_of_periapsis = 0.0
}

27
tests/test_analytical_propagation_apsides.toml
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@ -1,27 +0,0 @@
# Test Configuration: Elliptical Orbit for Analytical Propagation
# Moderate eccentricity to test propagation through apsides
[[bodies]]
name = "Earth"
mass = 5.972e24
radius = 6.371e6
parent_index = -1
color = { r = 0.0, g = 0.5, b = 1.0 }
orbit = {
semi_major_axis = 0.0,
eccentricity = 0.0,
true_anomaly = 0.0
}
[[spacecraft]]
name = "Elliptical_Orbit_Spacecraft"
mass = 1000.0
parent_index = 0
orbit = {
semi_major_axis = 2.0e7,
eccentricity = 0.6,
true_anomaly = 0.0,
inclination = 0.0,
longitude_of_ascending_node = 0.0,
argument_of_periapsis = 0.0
}

208
tests/test_analytical_propagation_timesteps.cpp
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@ -1,208 +0,0 @@
#include <catch2/catch_test_macros.hpp>
#include "../src/physics.h"
#include "../src/orbital_mechanics.h"
#include "../src/simulation.h"
#include "../src/config_loader.h"
#include "../src/test_utilities.h"
#include <cmath>
const double VELOCITY_TOLERANCE = 10.0;
const double POSITION_TOLERANCE = 1.0e4;
TEST_CASE("Large timestep - dt greater than orbital period", "[analytical][timestep][large]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_timesteps.toml"));
Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0];
double a = craft->orbit.semi_major_axis;
double mu = G * earth->mass;
double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu);
INFO("Orbital period: " << period_seconds << " s (" << period_seconds / 3600.0 << " hours)");
double large_dt = period_seconds * 2.0;
INFO("Timestep: " << large_dt << " s (2x orbital period)");
Vec3 pos_before;
Vec3 vel_before;
orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before);
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, large_dt, earth->mass);
Vec3 pos_after;
Vec3 vel_after;
orbital_elements_to_cartesian(propagated, earth->mass, &pos_after, &vel_after);
double r_before = vec3_magnitude(pos_before);
double r_after = vec3_magnitude(pos_after);
double v_before = vec3_magnitude(vel_before);
double v_after = vec3_magnitude(vel_after);
INFO("Before propagation:");
INFO(" Radius: " << r_before << " m");
INFO(" Velocity: " << v_before << " m/s");
INFO("After 2 periods:");
INFO(" Radius: " << r_after << " m");
INFO(" Velocity: " << v_after << " m/s");
double r_error = fabs(r_after - r_before);
double v_error = fabs(v_after - v_before);
double relative_r_error = r_error / r_before * 100.0;
double relative_v_error = v_error / v_before * 100.0;
INFO("Radius error: " << r_error << " m (" << relative_r_error << "%)");
INFO("Velocity error: " << v_error << " m/s (" << relative_v_error << "%)");
REQUIRE(relative_r_error < 0.1);
REQUIRE(relative_v_error < 0.1);
destroy_simulation(sim);
}
TEST_CASE("Very small timestep - dt less than 1 second", "[analytical][timestep][small]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_timesteps.toml"));
Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0];
Vec3 pos_before;
Vec3 vel_before;
orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before);
double small_dt = 0.1;
INFO("Timestep: " << small_dt << " s");
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, small_dt, earth->mass);
Vec3 pos_after;
Vec3 vel_after;
orbital_elements_to_cartesian(propagated, earth->mass, &pos_after, &vel_after);
double pos_change = vec3_distance(pos_before, pos_after);
double vel_change = vec3_distance(vel_before, vel_after);
INFO("Position change: " << pos_change << " m");
INFO("Velocity change: " << vel_change << " m/s");
double v_before_mag = vec3_magnitude(vel_before);
double expected_pos_change = v_before_mag * small_dt;
double pos_error = fabs(pos_change - expected_pos_change);
INFO("Expected position change (v·dt): " << expected_pos_change << " m");
INFO("Position error: " << pos_error << " m");
INFO("Relative position error: " << (pos_error / expected_pos_change * 100.0) << "%");
REQUIRE(pos_error < VELOCITY_TOLERANCE * small_dt * 10.0);
REQUIRE(vel_change < VELOCITY_TOLERANCE);
destroy_simulation(sim);
}
TEST_CASE("Accuracy vs timestep size relationship", "[analytical][timestep][accuracy]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_timesteps.toml"));
Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0];
double a = craft->orbit.semi_major_axis;
double mu = G * earth->mass;
double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu);
double dt_ratios[] = {0.01, 0.1, 1.0, 10.0};
Vec3 pos_initial;
Vec3 vel_initial;
orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_initial, &vel_initial);
for (int i = 0; i < 4; i++) {
double dt = period_seconds * dt_ratios[i];
INFO("Testing dt = " << dt << " s (" << dt_ratios[i] << "x period)");
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, dt, earth->mass);
Vec3 pos_final;
Vec3 vel_final;
orbital_elements_to_cartesian(propagated, earth->mass, &pos_final, &vel_final);
double pos_error = vec3_distance(pos_initial, pos_final);
double vel_error = vec3_distance(vel_initial, vel_final);
double num_periods = dt / period_seconds;
double expected_num_orbits = round(num_periods);
double fractional_phase = num_periods - expected_num_orbits;
double expected_pos_error = fractional_phase * 2.0 * M_PI * a;
INFO(" Position error: " << pos_error << " m");
INFO(" Expected error (phase): " << expected_pos_error << " m");
INFO(" Number of periods: " << num_periods);
if (expected_num_orbits > 0 && expected_pos_error > 1.0e-6) {
double relative_error = pos_error / expected_pos_error;
INFO(" Relative error: " << relative_error);
REQUIRE(relative_error < 0.5);
} else if (expected_num_orbits > 0) {
INFO(" Expected error is zero, skipping relative error check");
REQUIRE(pos_error < 1.0e-3);
}
}
destroy_simulation(sim);
}
TEST_CASE("Mean anomaly accumulation over long propagation", "[analytical][timestep][accumulation]") {
const double TIME_STEP = 60.0;
SimulationState* sim = create_simulation(10, 1, 0, TIME_STEP);
REQUIRE(load_system_config(sim, "tests/test_analytical_propagation_timesteps.toml"));
Spacecraft* craft = &sim->spacecraft[0];
CelestialBody* earth = &sim->bodies[0];
double a = craft->orbit.semi_major_axis;
double mu = G * earth->mass;
double period_seconds = 2.0 * M_PI * sqrt(pow(a, 3.0) / mu);
double mean_motion = sqrt(mu / pow(a, 3.0));
double initial_true_anomaly = craft->orbit.true_anomaly;
INFO("Initial true anomaly: " << initial_true_anomaly << " rad");
double propagation_time = period_seconds * 100.0;
INFO("Propagation time: " << propagation_time << " s (" << propagation_time / period_seconds << " periods)");
OrbitalElements propagated = propagate_orbital_elements(craft->orbit, propagation_time, earth->mass);
double final_true_anomaly = propagated.true_anomaly;
INFO("Final true anomaly: " << final_true_anomaly << " rad");
double expected_delta_anomaly = mean_motion * propagation_time;
double expected_final_anomaly = fmod(initial_true_anomaly + expected_delta_anomaly, 2.0 * M_PI);
INFO("Expected final anomaly: " << expected_final_anomaly << " rad");
double raw_error = fabs(final_true_anomaly - expected_final_anomaly);
double anomaly_error = fmin(raw_error, 2.0 * M_PI - raw_error);
INFO("True anomaly error: " << anomaly_error << " rad (" << anomaly_error * 180.0 / M_PI << "°)");
REQUIRE(anomaly_error < 1.0e-3);
destroy_simulation(sim);
}

27
tests/test_analytical_propagation_timesteps.toml
Unescape View File

@ -1,27 +0,0 @@
# Test Configuration: Standard Orbit for Timestep Testing
# Moderate eccentricity orbit for testing various timestep sizes
[[bodies]]
name = "Earth"
mass = 5.972e24
radius = 6.371e6
parent_index = -1
color = { r = 0.0, g = 0.5, b = 1.0 }
orbit = {
semi_major_axis = 0.0,
eccentricity = 0.0,
true_anomaly = 0.0
}
[[spacecraft]]
name = "Standard_Orbit_Spacecraft"
mass = 1000.0
parent_index = 0
orbit = {
semi_major_axis = 1.5e7,
eccentricity = 0.4,
true_anomaly = 0.0,
inclination = 0.0,
longitude_of_ascending_node = 0.0,
argument_of_periapsis = 0.0
}
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