183 lines
6.7 KiB
Rust
183 lines
6.7 KiB
Rust
//! Tests for the combined orbit type.
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//!
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//! 合并后的轨道类型的测试。
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use apsis_orbit::{GravityModel, Orbit};
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use apsis_tle::TwoLineElement;
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const ISS: &str = concat!(
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"1 25544U 98067A 08264.51782528 -.00002182 00000-0 -11606-4 0 2927\r\n",
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"2 25544 51.6416 247.4627 0006703 130.5360 325.0288 15.72125391563537\r\n",
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);
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const DEEP_SPACE: &str = concat!(
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"1 09880U 77021A 06174.85710247 .00000090 00000-0 10000-3 0 7322\r\n",
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"2 09880 64.1526 313.1296 6546925 103.4683 305.3980 2.00754276 13047\r\n",
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);
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fn orbit(text: &str) -> Orbit {
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let element = TwoLineElement::parse(text).expect("test element set parses");
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Orbit::from_element(&element, GravityModel::WGS72).expect("test element set is propagatable")
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}
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#[test]
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fn construction_succeeds_for_a_valid_element_set() {
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let orbit = orbit(ISS);
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assert!(!orbit.is_deep_space());
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assert_eq!(
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orbit.gravity_parameter(),
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apsis_orbit::GravityParameter::WGS72
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);
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}
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#[test]
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fn deep_space_orbits_are_reported() {
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assert!(orbit(DEEP_SPACE).is_deep_space());
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}
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#[test]
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fn propagation_matches_the_underlying_propagator() {
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let orbit = orbit(ISS);
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let via_orbit = orbit.propagate_minutes(360.0).expect("state exists");
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let via_satellite = orbit
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.satellite()
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.propagate_minutes(360.0)
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.expect("state exists");
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assert_eq!(via_orbit, via_satellite);
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}
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#[test]
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fn position_and_radius_accessors_agree_with_the_state() {
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let orbit = orbit(ISS);
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let state = orbit.propagate_minutes(120.0).expect("state exists");
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assert_eq!(
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orbit.position_at(120.0).expect("state exists"),
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state.position
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);
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assert!((orbit.radius_at(120.0).expect("state exists") - state.position.norm()).abs() < 1e-12);
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}
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#[test]
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fn propagate_at_uses_the_element_epoch() {
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let orbit = orbit(ISS);
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let epoch = orbit.epoch_mjd();
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let at_epoch = orbit.propagate_at(epoch).expect("state exists");
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let at_zero = orbit.propagate_minutes(0.0).expect("state exists");
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assert!((at_epoch.position - at_zero.position).norm() < 1e-6);
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// One day later is 1440 minutes.
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// 一天后是 1440 分钟。
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let next_day = orbit.propagate_at(epoch + 1.0).expect("state exists");
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let one_day = orbit.propagate_minutes(1440.0).expect("state exists");
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assert!((next_day.position - one_day.position).norm() < 1e-3);
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}
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#[test]
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fn osculating_elements_describe_a_low_earth_orbit() {
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let orbit = orbit(ISS);
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let elements = orbit.osculating_elements(0.0).expect("state exists");
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// These values were checked against an independent computation from the
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// same state vector. The inclination agrees with the catalogued value
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// closely, because the oblateness has little effect on it, while the
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// eccentricity differs from the catalogued 0.0006703. That difference
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// is expected: the element set stores mean elements and the osculating
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// eccentricity includes the short period variation the two-body model
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// does not reproduce.
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// 这些值是针对同一天量矢量的一份独立计算核对的。倾角与编目值接近，因为扁率对它
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// 影响很小，而偏心率不同于编目的 0.0006703。该差异是预期的：根数集保存的是平
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// 根数，而密切偏心率包含二体模型不复现的短周期变化。
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assert!(
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(elements.semi_major_axis - 6_725.542).abs() < 0.01,
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"semi-major axis {}",
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elements.semi_major_axis
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);
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assert!(
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(elements.eccentricity - 0.000_832_1).abs() < 1e-6,
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"eccentricity {}",
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elements.eccentricity
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);
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assert!(
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(elements.inclination - 51.6217_f64.to_radians()).abs() < 1e-4,
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"inclination {}",
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elements.inclination.to_degrees()
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);
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}
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#[test]
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fn osculating_elements_reproduce_the_state() {
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let orbit = orbit(ISS);
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let state = orbit.propagate_minutes(45.0).expect("state exists");
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let elements = orbit.osculating_elements(45.0).expect("state exists");
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let rebuilt = elements
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.to_state(orbit.gravity_parameter())
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.expect("elements are valid");
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assert!((rebuilt.position - state.position).norm() < 1e-6);
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assert!((rebuilt.velocity - state.velocity).norm() < 1e-9);
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}
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#[test]
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fn osculating_elements_change_along_the_orbit() {
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// The osculating elements are not the mean elements, so they vary
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// because the perturbations SGP4 models are absent from the two-body
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// reconstruction.
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// 密切根数不是平根数，故它们变化，因为 SGP4 所建模的摄动在二体重构中缺席。
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let orbit = orbit(ISS);
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let start = orbit.osculating_elements(0.0).expect("state exists");
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let later = orbit.osculating_elements(720.0).expect("state exists");
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assert!((start.eccentricity - later.eccentricity).abs() > 1e-7);
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}
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#[test]
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fn osculating_elements_work_for_a_deep_space_orbit() {
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let orbit = orbit(DEEP_SPACE);
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let elements = orbit.osculating_elements(0.0).expect("state exists");
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// The catalogued mean values are an eccentricity of 0.6546925 and an
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// inclination of 64.1526 degrees. The osculating values are close but
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// not identical for the reason given in the low Earth orbit test.
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// 编目的平值为偏心率 0.6546925、倾角 64.1526 度。密切值接近但不相同，理由同低轨
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// 测试中所述。
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assert!(
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(elements.eccentricity - 0.655_871_3).abs() < 1e-6,
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"eccentricity {}",
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elements.eccentricity
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);
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assert!(
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(elements.inclination - 64.1696_f64.to_radians()).abs() < 1e-4,
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"inclination {}",
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elements.inclination.to_degrees()
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);
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assert!(
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(elements.semi_major_axis - 26_543.982).abs() < 0.01,
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"semi-major axis {}",
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elements.semi_major_axis
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);
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}
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#[test]
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fn the_gravity_parameter_matches_the_model() {
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let element = TwoLineElement::parse(ISS).expect("parses");
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let wgs72 = Orbit::from_element(&element, GravityModel::WGS72).expect("propagatable");
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assert_eq!(
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wgs72.gravity_parameter(),
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apsis_orbit::GravityParameter::WGS72
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);
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let wgs84 = Orbit::from_element(&element, GravityModel::WGS84).expect("propagatable");
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assert_eq!(
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wgs84.gravity_parameter(),
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apsis_orbit::GravityParameter::WGS84
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);
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}
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#[test]
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fn the_facade_reexports_the_layer() {
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// The facade must make the element parser and the propagator types
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// reachable without a separate dependency.
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// 门面必须使根数解析器与传播器类型无需单独依赖即可达到。
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let element = apsis_orbit::TwoLineElement::parse(ISS).expect("parses");
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assert_eq!(element.satellite_number, 25544);
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let satellite =
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apsis_orbit::Satellite::from_element(&element, GravityModel::WGS72).expect("propagatable");
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assert!(satellite.propagate_minutes(0.0).is_ok());
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}
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