pub struct SolarPressure {
pub phi: f64,
pub shadow_model: ShadowModel,
pub estimate: bool,
}Expand description
Computation of solar radiation pressure is based on STK: http://help.agi.com/stk/index.htm#gator/eq-solar.htm .
:type shadow_bodies: listFrame :type almanac: Almanac :type flux_w_m2: float :type estimate: bool
Fields§
§phi: f64solar flux at 1 AU, in W/m^2
shadow_model: ShadowModel§estimate: boolSet to true to estimate the coefficient of reflectivity
Implementations§
Source§impl SolarPressure
impl SolarPressure
Sourcepub fn default_flux_raw(
shadow_bodies: Vec<Frame>,
almanac: &Almanac,
) -> Result<Self, DynamicsError>
pub fn default_flux_raw( shadow_bodies: Vec<Frame>, almanac: &Almanac, ) -> Result<Self, DynamicsError>
Will set the solar flux at 1 AU to: Phi = 1367.0
Sourcepub fn default_flux(
shadow_body: Frame,
almanac: &Almanac,
) -> Result<Arc<Self>, DynamicsError>
pub fn default_flux( shadow_body: Frame, almanac: &Almanac, ) -> Result<Arc<Self>, DynamicsError>
Accounts for the shadowing of only one body and will set the solar flux at 1 AU to: Phi = 1367.0
Examples found in repository?
28fn main() -> Result<(), Box<dyn Error>> {
29 pel::init();
30 // Set up the dynamics like in the orbit raise.
31 let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
32 let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
33
34 // Define the GEO orbit, and we're just going to maintain it very tightly.
35 let earth_j2000 = almanac.frame_info(EARTH_J2000)?;
36 let orbit = Orbit::try_keplerian(42164.0, 1e-5, 0., 163.0, 75.0, 0.0, epoch, earth_j2000)?;
37 println!("{orbit:x}");
38
39 let sc = Spacecraft::builder()
40 .orbit(orbit)
41 .mass(Mass::from_dry_and_prop_masses(1000.0, 1000.0)) // 1000 kg of dry mass and prop, totalling 2.0 tons
42 .srp(SRPData::from_area(3.0 * 6.0)) // Assuming 1 kW/m^2 or 18 kW, giving a margin of 4.35 kW for on-propulsion consumption
43 .thruster(Thruster {
44 // "NEXT-STEP" row in Table 2
45 isp_s: 4435.0,
46 thrust_N: 0.472,
47 })
48 .mode(GuidanceMode::Thrust) // Start thrusting immediately.
49 .build();
50
51 // Set up the spacecraft dynamics like in the orbit raise example.
52
53 let prop_time = 30.0 * Unit::Day;
54
55 // Define the guidance law -- we're just using a Ruggiero controller as demonstrated in AAS-2004-5089.
56 let objectives = &[
57 Objective::within_tolerance(
58 StateParameter::Element(OrbitalElement::SemiMajorAxis),
59 42_165.0,
60 20.0,
61 ),
62 Objective::within_tolerance(
63 StateParameter::Element(OrbitalElement::Eccentricity),
64 0.001,
65 5e-5,
66 ),
67 Objective::within_tolerance(
68 StateParameter::Element(OrbitalElement::Inclination),
69 0.05,
70 1e-2,
71 ),
72 ];
73
74 let ruggiero_ctrl = Ruggiero::from_max_eclipse(objectives, sc, 0.2)?;
75 println!("{ruggiero_ctrl}");
76
77 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
78
79 let mut jgm3_meta = MetaFile {
80 uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
81 crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
82 };
83 jgm3_meta.process(true)?;
84
85 let harmonics = GravityField::new(GravityFieldData::from_cof(
86 &jgm3_meta.uri,
87 8,
88 8,
89 almanac.frame_info(IAU_EARTH_FRAME)?,
90 )?);
91 orbital_dyn.accel_models.push(harmonics);
92
93 let srp_dyn = SolarPressure::default_flux(EARTH_J2000, &almanac)?;
94 let sc_dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn)
95 .with_guidance_law(ruggiero_ctrl.clone());
96
97 println!("{sc_dynamics}");
98
99 // Finally, let's use the Monte Carlo framework built into Nyx to propagate spacecraft.
100
101 // Let's start by defining the dispersion.
102 // The MultivariateNormal structure allows us to define the dispersions in any of the orbital parameters, but these are applied directly in the Cartesian state space.
103 // Note that additional validation on the MVN is in progress -- https://github.com/nyx-space/nyx/issues/339.
104 let mc_rv = MvnSpacecraft::new(
105 sc,
106 vec![StateDispersion::zero_mean(
107 StateParameter::Element(OrbitalElement::SemiMajorAxis),
108 3.0,
109 )],
110 )?;
111
112 let my_mc = MonteCarlo::new(
113 sc, // Nominal state
114 mc_rv,
115 "03_geo_sk".to_string(), // Scenario name
116 None, // No specific seed specified, so one will be drawn from the computer's entropy.
117 );
118
119 // Build the propagator setup.
120 let setup = Propagator::rk89(
121 sc_dynamics.clone(),
122 IntegratorOptions::builder()
123 .min_step(10.0_f64.seconds())
124 .error_ctrl(ErrorControl::RSSCartesianStep)
125 .build(),
126 );
127
128 let num_runs = 25;
129 let rslts = my_mc.run_until_epoch(setup, almanac.clone(), sc.epoch() + prop_time, num_runs);
130
131 assert_eq!(rslts.runs.len(), num_runs);
132
133 rslts.to_parquet("03_geo_sk.parquet", ExportCfg::default())?;
134
135 Ok(())
136}More examples
27fn main() -> Result<(), Box<dyn Error>> {
28 pel::init();
29
30 // Dynamics models require planetary constants and ephemerides to be defined.
31 // Let's start by grabbing those by using ANISE's latest MetaAlmanac.
32 // This will automatically download the DE440s planetary ephemeris,
33 // the daily-updated Earth Orientation Parameters, the high fidelity Moon orientation
34 // parameters (for the Moon Mean Earth and Moon Principal Axes frames), and the PCK11
35 // planetary constants kernels.
36 // For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
37 // Note that we place the Almanac into an Arc so we can clone it cheaply and provide read-only
38 // references to many functions.
39 let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
40 // Fetch the EME2000 frame from the Almabac
41 let eme2k = almanac.frame_info(EARTH_J2000).unwrap();
42 // Define the orbit epoch
43 let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
44
45 // Build the spacecraft itself.
46 // Using slide 6 of https://aerospace.org/sites/default/files/2018-11/Davis-Mayberry_HPSEP_11212018.pdf
47 // for the "next gen" SEP characteristics.
48
49 // GTO start
50 let orbit = Orbit::keplerian(24505.9, 0.725, 7.05, 0.0, 0.0, 0.0, epoch, eme2k);
51
52 let sc = Spacecraft::builder()
53 .orbit(orbit)
54 .mass(Mass::from_dry_and_prop_masses(1000.0, 1000.0)) // 1000 kg of dry mass and prop, totalling 2.0 tons
55 .srp(SRPData::from_area(3.0 * 6.0)) // Assuming 1 kW/m^2 or 18 kW, giving a margin of 4.35 kW for on-propulsion consumption
56 .thruster(Thruster {
57 // "NEXT-STEP" row in Table 2
58 isp_s: 4435.0,
59 thrust_N: 0.472,
60 })
61 .mode(GuidanceMode::Thrust) // Start thrusting immediately.
62 .build();
63
64 let prop_time = 180.0 * Unit::Day;
65
66 // Define the guidance law -- we're just using a Ruggiero controller as demonstrated in AAS-2004-5089.
67 let objectives = &[
68 Objective::within_tolerance(
69 StateParameter::Element(OrbitalElement::SemiMajorAxis),
70 42_165.0,
71 20.0,
72 ),
73 Objective::within_tolerance(
74 StateParameter::Element(OrbitalElement::Eccentricity),
75 0.001,
76 5e-5,
77 ),
78 Objective::within_tolerance(
79 StateParameter::Element(OrbitalElement::Inclination),
80 0.05,
81 1e-2,
82 ),
83 ];
84
85 // Ensure that we only thrust if we have more than 20% illumination.
86 let ruggiero_ctrl = Ruggiero::from_max_eclipse(objectives, sc, 0.2).unwrap();
87 println!("{ruggiero_ctrl}");
88
89 // Define the high fidelity dynamics
90
91 // Set up the spacecraft dynamics.
92
93 // Specify that the orbital dynamics must account for the graviational pull of the Moon and the Sun.
94 // The gravity of the Earth will also be accounted for since the spaceraft in an Earth orbit.
95 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
96
97 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
98 // We're using the JGM3 model here, which is the default in GMAT.
99 let mut jgm3_meta = MetaFile {
100 uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
101 crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
102 };
103 // And let's download it if we don't have it yet.
104 jgm3_meta.process(true)?;
105
106 // Build the spherical harmonics.
107 // The harmonics must be computed in the body fixed frame.
108 // We're using the long term prediction of the Earth centered Earth fixed frame, IAU Earth.
109 let harmonics = GravityField::new(
110 GravityFieldData::from_cof(&jgm3_meta.uri, 8, 8, almanac.frame_info(IAU_EARTH_FRAME)?)
111 .unwrap(),
112 );
113
114 // Include the spherical harmonics into the orbital dynamics.
115 orbital_dyn.accel_models.push(harmonics);
116
117 // We define the solar radiation pressure, using the default solar flux and accounting only
118 // for the eclipsing caused by the Earth.
119 let srp_dyn = SolarPressure::default_flux(EARTH_J2000, &almanac)?;
120
121 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
122 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
123 let sc_dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn)
124 .with_guidance_law(ruggiero_ctrl.clone());
125
126 println!("{orbit:x}");
127
128 // We specify a minimum step in the propagator because the Ruggiero control would otherwise drive this step very low.
129 let (final_state, traj) = Propagator::rk89(
130 sc_dynamics.clone(),
131 IntegratorOptions::builder()
132 .min_step(10.0_f64.seconds())
133 .error_ctrl(ErrorControl::RSSCartesianStep)
134 .build(),
135 )
136 .with(sc, almanac.clone())
137 .for_duration_with_traj(prop_time)?;
138
139 let prop_usage = sc.mass.prop_mass_kg - final_state.mass.prop_mass_kg;
140 println!("{:x}", final_state.orbit);
141 println!("prop usage: {prop_usage:.3} kg");
142
143 // Finally, export the results for analysis, including the penumbra percentage throughout the orbit raise.
144 traj.to_parquet("./03_geo_raise.parquet", ExportCfg::default())?;
145
146 for status_line in ruggiero_ctrl.status(&final_state) {
147 println!("{status_line}");
148 }
149
150 ruggiero_ctrl
151 .achieved(&final_state)
152 .expect("objective not achieved");
153
154 Ok(())
155}30fn main() -> Result<(), Box<dyn Error>> {
31 pel::init();
32 // Dynamics models require planetary constants and ephemerides to be defined.
33 // Let's start by grabbing those by using ANISE's latest MetaAlmanac.
34 // This will automatically download the DE440s planetary ephemeris,
35 // the daily-updated Earth Orientation Parameters, the high fidelity Moon orientation
36 // parameters (for the Moon Mean Earth and Moon Principal Axes frames), and the PCK11
37 // planetary constants kernels.
38 // For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
39 // Note that we place the Almanac into an Arc so we can clone it cheaply and provide read-only
40 // references to many functions.
41 let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
42 // Define the orbit epoch
43 let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
44
45 // Define the orbit.
46 // First we need to fetch the Earth J2000 from information from the Almanac.
47 // This allows the frame to include the gravitational parameters and the shape of the Earth,
48 // defined as a tri-axial ellipoid. Note that this shape can be changed manually or in the Almanac
49 // by loading a different set of planetary constants.
50 let earth_j2000 = almanac.frame_info(EARTH_J2000)?;
51
52 let orbit =
53 Orbit::try_keplerian_altitude(300.0, 0.015, 68.5, 65.2, 75.0, 0.0, epoch, earth_j2000)?;
54 // Print in in Keplerian form.
55 println!("{orbit:x}");
56
57 // There are two ways to propagate an orbit. We can make a quick approximation assuming only two-body
58 // motion. This is a useful first order approximation but it isn't used in real-world applications.
59
60 // This approach is a feature of ANISE.
61 let future_orbit_tb = orbit.at_epoch(epoch + Unit::Day * 3)?;
62 println!("{future_orbit_tb:x}");
63
64 // Two body propagation relies solely on Kepler's laws, so only the true anomaly will change.
65 println!(
66 "SMA changed by {:.3e} km",
67 orbit.sma_km()? - future_orbit_tb.sma_km()?
68 );
69 println!(
70 "ECC changed by {:.3e}",
71 orbit.ecc()? - future_orbit_tb.ecc()?
72 );
73 println!(
74 "INC changed by {:.3e} deg",
75 orbit.inc_deg()? - future_orbit_tb.inc_deg()?
76 );
77 println!(
78 "RAAN changed by {:.3e} deg",
79 orbit.raan_deg()? - future_orbit_tb.raan_deg()?
80 );
81 println!(
82 "AOP changed by {:.3e} deg",
83 orbit.aop_deg()? - future_orbit_tb.aop_deg()?
84 );
85 println!(
86 "TA changed by {:.3} deg",
87 orbit.ta_deg()? - future_orbit_tb.ta_deg()?
88 );
89
90 // Nyx is used for high fidelity propagation, not Keplerian propagation as above.
91 // Nyx only propagates Spacecraft at the moment, which allows it to account for acceleration
92 // models such as solar radiation pressure.
93
94 // Let's build a cubesat sized spacecraft, with an SRP area of 10 cm^2 and a mass of 9.6 kg.
95 let sc = Spacecraft::builder()
96 .orbit(orbit)
97 .mass(Mass::from_dry_mass(9.60))
98 .srp(SRPData {
99 area_m2: 10e-4,
100 coeff_reflectivity: 1.1,
101 })
102 .build();
103 println!("{sc:x}");
104
105 // Set up the spacecraft dynamics.
106
107 // Specify that the orbital dynamics must account for the graviational pull of the Moon and the Sun.
108 // The gravity of the Earth will also be accounted for since the spaceraft in an Earth orbit.
109 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
110
111 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
112 // We're using the JGM3 model here, which is the default in GMAT.
113 let mut jgm3_meta = MetaFile {
114 uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
115 crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
116 };
117 // And let's download it if we don't have it yet.
118 jgm3_meta.process(true)?;
119
120 // Build the spherical harmonics.
121 // The harmonics must be computed in the body fixed frame.
122 // We're using the long term prediction of the Earth centered Earth fixed frame, IAU Earth.
123 let harmonics_21x21 = GravityField::new(
124 GravityFieldData::from_cof(&jgm3_meta.uri, 21, 21, almanac.frame_info(IAU_EARTH_FRAME)?)
125 .unwrap(),
126 );
127
128 // Include the spherical harmonics into the orbital dynamics.
129 orbital_dyn.accel_models.push(harmonics_21x21);
130
131 // We define the solar radiation pressure, using the default solar flux and accounting only
132 // for the eclipsing caused by the Earth.
133 let srp_dyn = SolarPressure::default_flux(EARTH_J2000, &almanac)?;
134
135 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
136 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
137 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
138
139 println!("{dynamics}");
140
141 // Finally, let's propagate this orbit to the same epoch as above.
142 // The first returned value is the spacecraft state at the final epoch.
143 // The second value is the full trajectory where the step size is variable step used by the propagator.
144 let (future_sc, trajectory) = Propagator::default(dynamics)
145 .with(sc, almanac.clone())
146 .until_epoch_with_traj(future_orbit_tb.epoch)?;
147
148 println!("=== High fidelity propagation ===");
149 println!(
150 "SMA changed by {:.3} km",
151 orbit.sma_km()? - future_sc.orbit.sma_km()?
152 );
153 println!(
154 "ECC changed by {:.6}",
155 orbit.ecc()? - future_sc.orbit.ecc()?
156 );
157 println!(
158 "INC changed by {:.3e} deg",
159 orbit.inc_deg()? - future_sc.orbit.inc_deg()?
160 );
161 println!(
162 "RAAN changed by {:.3} deg",
163 orbit.raan_deg()? - future_sc.orbit.raan_deg()?
164 );
165 println!(
166 "AOP changed by {:.3} deg",
167 orbit.aop_deg()? - future_sc.orbit.aop_deg()?
168 );
169 println!(
170 "TA changed by {:.3} deg",
171 orbit.ta_deg()? - future_sc.orbit.ta_deg()?
172 );
173
174 // We also have access to the full trajectory throughout the propagation.
175 println!("{trajectory}");
176
177 // With the trajectory, let's build a few data products.
178
179 // 1. Export the trajectory as a CCSDS OEM version 2.0 file and as a parquet file, which includes the Keplerian orbital elements.
180
181 trajectory.to_oem_file(
182 "./01_cubesat_hf_prop.oem",
183 "CUBESAT-ID".to_string(),
184 Some("Nyx Space".to_string()),
185 Some("CUBESAT".to_string()),
186 ExportCfg::builder().step(Unit::Minute * 2).build(),
187 )?;
188
189 trajectory.to_parquet_with_cfg(
190 "./01_cubesat_hf_prop.parquet",
191 ExportCfg::builder().step(Unit::Minute * 2).build(),
192 )?;
193
194 // 2. Compare the difference in the radial-intrack-crosstrack frame between the high fidelity
195 // and Keplerian propagation. The RIC frame is commonly used to compute the difference in position
196 // and velocity of different spacecraft.
197 // 3. Compute the azimuth, elevation, range, and range-rate data of that spacecraft as seen from Boulder, CO, USA.
198
199 let boulder_station = GroundStation::from_point(
200 "Boulder, CO, USA".to_string(),
201 40.014984, // latitude in degrees
202 -105.270546, // longitude in degrees
203 1.6550, // altitude in kilometers
204 almanac.frame_info(IAU_EARTH_FRAME)?,
205 );
206
207 // We iterate over the trajectory, grabbing a state every two minutes.
208 let mut offset_s = vec![];
209 let mut epoch_str = vec![];
210 let mut ric_x_km = vec![];
211 let mut ric_y_km = vec![];
212 let mut ric_z_km = vec![];
213 let mut ric_vx_km_s = vec![];
214 let mut ric_vy_km_s = vec![];
215 let mut ric_vz_km_s = vec![];
216
217 let mut azimuth_deg = vec![];
218 let mut elevation_deg = vec![];
219 let mut range_km = vec![];
220 let mut range_rate_km_s = vec![];
221 for state in trajectory.every(Unit::Minute * 2) {
222 // Try to compute the Keplerian/two body state just in time.
223 // This method occasionally fails to converge on an appropriate true anomaly
224 // from the mean anomaly. If that happens, we just skip this state.
225 // The high fidelity and Keplerian states diverge continuously, and we're curious
226 // about the divergence in this quick analysis.
227 let this_epoch = state.epoch();
228 match orbit.at_epoch(this_epoch) {
229 Ok(tb_then) => {
230 offset_s.push((this_epoch - orbit.epoch).to_seconds());
231 epoch_str.push(format!("{this_epoch}"));
232 // Compute the two body state just in time.
233 let ric = state.orbit.ric_difference(&tb_then)?;
234 ric_x_km.push(ric.radius_km.x);
235 ric_y_km.push(ric.radius_km.y);
236 ric_z_km.push(ric.radius_km.z);
237 ric_vx_km_s.push(ric.velocity_km_s.x);
238 ric_vy_km_s.push(ric.velocity_km_s.y);
239 ric_vz_km_s.push(ric.velocity_km_s.z);
240
241 // Compute the AER data for each state.
242 let aer = almanac.azimuth_elevation_range_sez(
243 state.orbit,
244 boulder_station.to_orbit(this_epoch, &almanac)?,
245 None,
246 None,
247 )?;
248 azimuth_deg.push(aer.azimuth_deg);
249 elevation_deg.push(aer.elevation_deg);
250 range_km.push(aer.range_km);
251 range_rate_km_s.push(aer.range_rate_km_s);
252 }
253 Err(e) => warn!("{} {e}", state.epoch()),
254 };
255 }
256
257 // Build the data frames.
258 let ric_df = df!(
259 "Offset (s)" => offset_s.clone(),
260 "Epoch" => epoch_str.clone(),
261 "RIC X (km)" => ric_x_km,
262 "RIC Y (km)" => ric_y_km,
263 "RIC Z (km)" => ric_z_km,
264 "RIC VX (km/s)" => ric_vx_km_s,
265 "RIC VY (km/s)" => ric_vy_km_s,
266 "RIC VZ (km/s)" => ric_vz_km_s,
267 )?;
268
269 println!("RIC difference at start\n{}", ric_df.head(Some(10)));
270 println!("RIC difference at end\n{}", ric_df.tail(Some(10)));
271
272 let aer_df = df!(
273 "Offset (s)" => offset_s.clone(),
274 "Epoch" => epoch_str.clone(),
275 "azimuth (deg)" => azimuth_deg,
276 "elevation (deg)" => elevation_deg,
277 "range (km)" => range_km,
278 "range rate (km/s)" => range_rate_km_s,
279 )?;
280
281 // Finally, let's see when the spacecraft is visible, assuming 15 degrees minimum elevation.
282 let mask = aer_df
283 .column("elevation (deg)")?
284 .gt(&Column::Scalar(ScalarColumn::new(
285 "elevation mask (deg)".into(),
286 Scalar::new(DataType::Float64, AnyValue::Float64(15.0)),
287 offset_s.len(),
288 )))?;
289 let cubesat_visible = aer_df.filter(&mask)?;
290
291 println!("{cubesat_visible}");
292
293 Ok(())
294}Sourcepub fn default_no_estimation(
shadow_bodies: Vec<Frame>,
almanac: &Almanac,
) -> Result<Arc<Self>, DynamicsError>
pub fn default_no_estimation( shadow_bodies: Vec<Frame>, almanac: &Almanac, ) -> Result<Arc<Self>, DynamicsError>
Accounts for the shadowing of only one body and will set the solar flux at 1 AU to: Phi = 1367.0
Sourcepub fn with_flux(
flux_w_m2: f64,
shadow_bodies: Vec<Frame>,
almanac: &Almanac,
) -> Result<Arc<Self>, DynamicsError>
pub fn with_flux( flux_w_m2: f64, shadow_bodies: Vec<Frame>, almanac: &Almanac, ) -> Result<Arc<Self>, DynamicsError>
Must provide the flux in W/m^2
Sourcepub fn new(
shadow_bodies: Vec<Frame>,
almanac: &Almanac,
) -> Result<Arc<Self>, DynamicsError>
pub fn new( shadow_bodies: Vec<Frame>, almanac: &Almanac, ) -> Result<Arc<Self>, DynamicsError>
Solar radiation pressure force model accounting for the provided shadow bodies.
Examples found in repository?
26fn main() -> Result<(), Box<dyn Error>> {
27 pel::init();
28 // Dynamics models require planetary constants and ephemerides to be defined.
29 // Let's start by grabbing those by using ANISE's latest MetaAlmanac.
30 // For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
31
32 // Download the regularly update of the James Webb Space Telescope reconstucted (or definitive) ephemeris.
33 // Refer to https://naif.jpl.nasa.gov/pub/naif/JWST/kernels/spk/aareadme.txt for details.
34 let mut latest_jwst_ephem = MetaFile {
35 uri: "https://naif.jpl.nasa.gov/pub/naif/JWST/kernels/spk/jwst_rec.bsp".to_string(),
36 crc32: None,
37 };
38 latest_jwst_ephem.process(true)?;
39
40 // Load this ephem in the general Almanac we're using for this analysis.
41 let almanac = Arc::new(
42 MetaAlmanac::latest()
43 .map_err(Box::new)?
44 .load_from_metafile(latest_jwst_ephem, true)?,
45 );
46
47 // By loading this ephemeris file in the ANISE GUI or ANISE CLI, we can find the NAIF ID of the JWST
48 // in the BSP. We need this ID in order to query the ephemeris.
49 const JWST_NAIF_ID: i32 = -170;
50 // Let's build a frame in the J2000 orientation centered on the JWST.
51 const JWST_J2000: Frame = Frame::from_ephem_j2000(JWST_NAIF_ID);
52
53 // Since the ephemeris file is updated regularly, we'll just grab the latest state in the ephem.
54 let (earliest_epoch, latest_epoch) = almanac.spk_domain(JWST_NAIF_ID)?;
55 println!("JWST defined from {earliest_epoch} to {latest_epoch}");
56 // Fetch the state, printing it in the Earth J2000 frame.
57 let jwst_orbit = almanac.transform(JWST_J2000, EARTH_J2000, latest_epoch, None)?;
58 println!("{jwst_orbit:x}");
59
60 // Build the spacecraft
61 // SRP area assumed to be the full sunshield and mass if 6200.0 kg, c.f. https://webb.nasa.gov/content/about/faqs/facts.html
62 // SRP Coefficient of reflectivity assumed to be that of Kapton, i.e. 2 - 0.44 = 1.56, table 1 from https://amostech.com/TechnicalPapers/2018/Poster/Bengtson.pdf
63 let jwst = Spacecraft::builder()
64 .orbit(jwst_orbit)
65 .srp(SRPData {
66 area_m2: 21.197 * 14.162,
67 coeff_reflectivity: 1.56,
68 })
69 .mass(Mass::from_dry_mass(6200.0))
70 .build();
71
72 // Build up the spacecraft uncertainty builder.
73 // We can use the spacecraft uncertainty structure to build this up.
74 // We start by specifying the nominal state (as defined above), then the uncertainty in position and velocity
75 // in the RIC frame. We could also specify the Cr, Cd, and mass uncertainties, but these aren't accounted for until
76 // Nyx can also estimate the deviation of the spacecraft parameters.
77 let jwst_uncertainty = SpacecraftUncertainty::builder()
78 .nominal(jwst)
79 .frame(LocalFrame::RIC)
80 .x_km(0.5)
81 .y_km(0.3)
82 .z_km(1.5)
83 .vx_km_s(1e-4)
84 .vy_km_s(0.6e-3)
85 .vz_km_s(3e-3)
86 .build();
87
88 println!("{jwst_uncertainty}");
89
90 // Build the Kalman filter estimate.
91 // Note that we could have used the KfEstimate structure directly (as seen throughout the OD integration tests)
92 // but this approach requires quite a bit more boilerplate code.
93 let jwst_estimate = jwst_uncertainty.to_estimate()?;
94
95 // Set up the spacecraft dynamics.
96 // We'll use the point masses of the Earth, Sun, Jupiter (barycenter, because it's in the DE440), and the Moon.
97 // We'll also enable solar radiation pressure since the James Webb has a huge and highly reflective sun shield.
98
99 let orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN, JUPITER_BARYCENTER]);
100 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], &almanac)?;
101
102 // Finalize setting up the dynamics.
103 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
104
105 // Build the propagator set up to use for the whole analysis.
106 let setup = Propagator::default(dynamics);
107
108 // All of the analysis will use this duration.
109 let prediction_duration = 6.5 * Unit::Day;
110
111 // === Covariance mapping ===
112 // For the covariance mapping / prediction, we'll use the common orbit determination approach.
113 // This is done by setting up a spacecraft Kalman filter OD process, and predicting for the analysis duration.
114
115 // Build the propagation instance for the OD process.
116 let odp = SpacecraftKalmanOD::new(
117 setup.clone(),
118 KalmanVariant::DeviationTracking,
119 None,
120 BTreeMap::new(),
121 almanac.clone(),
122 );
123
124 // The prediction step is 1 minute by default, configured in the OD process, i.e. how often we want to know the covariance.
125 assert_eq!(odp.max_step, 1_i64.minutes());
126 // Finally, predict, and export the trajectory with covariance to a parquet file.
127 let od_sol = odp.predict_for(jwst_estimate, prediction_duration)?;
128 od_sol.to_parquet("./02_jwst_covar_map.parquet", ExportCfg::default())?;
129
130 // === Monte Carlo framework ===
131 // Nyx comes with a complete multi-threaded Monte Carlo frame. It's blazing fast.
132
133 let my_mc = MonteCarlo::new(
134 jwst, // Nominal state
135 jwst_estimate.to_random_variable()?,
136 "02_jwst".to_string(), // Scenario name
137 None, // No specific seed specified, so one will be drawn from the computer's entropy.
138 );
139
140 let num_runs = 5_000;
141 let rslts = my_mc.run_until_epoch(
142 setup,
143 almanac.clone(),
144 jwst.epoch() + prediction_duration,
145 num_runs,
146 );
147
148 assert_eq!(rslts.runs.len(), num_runs);
149 // Finally, export these results, computing the eclipse percentage for all of these results.
150
151 rslts.to_parquet("02_jwst_monte_carlo.parquet", ExportCfg::default())?;
152
153 Ok(())
154}More examples
35fn main() -> Result<(), Box<dyn Error>> {
36 pel::init();
37
38 // ====================== //
39 // === ALMANAC SET UP === //
40 // ====================== //
41
42 // Dynamics models require planetary constants and ephemerides to be defined.
43 // Let's start by grabbing those by using ANISE's MetaAlmanac.
44
45 let data_folder: PathBuf = [
46 env!("CARGO_MANIFEST_DIR"),
47 "examples",
48 "06_lunar_orbit_determination",
49 ]
50 .iter()
51 .collect();
52
53 let meta = data_folder.join("metaalmanac.dhall");
54
55 // Load this ephem in the general Almanac we're using for this analysis.
56 let almanac = MetaAlmanac::new(meta.to_string_lossy().as_ref())
57 .map_err(Box::new)?
58 .process(true)
59 .map_err(Box::new)?;
60
61 // Lock the almanac (an Arc is a read only structure).
62 let almanac = Arc::new(almanac);
63
64 // Build a nominal trajectory
65 // TODO: Switch this to a sequence once the OD over a spacecraft sequence is implemented.
66
67 let epoch = Epoch::from_gregorian_utc_at_noon(2024, 2, 29);
68 let moon_j2000 = almanac.frame_info(MOON_J2000)?;
69
70 // To build the trajectory we need to provide a spacecraft template.
71 let orbiter = Spacecraft::builder()
72 .mass(Mass::from_dry_and_prop_masses(1018.0, 900.0))
73 .srp(SRPData {
74 area_m2: 3.9 * 2.7,
75 coeff_reflectivity: 0.96,
76 })
77 .orbit(Orbit::try_keplerian_altitude(
78 150.0, 0.00212, 33.6, 45.0, 45.0, 0.0, epoch, moon_j2000,
79 )?) // Setting a zero orbit here because it's just a template
80 .build();
81
82 // ========================== //
83 // === BUILD NOMINAL TRAJ === //
84 // ========================== //
85
86 // Set up the spacecraft dynamics.
87
88 // Specify that the orbital dynamics must account for the graviational pull of the Earth and the Sun.
89 // The gravity of the Moon will also be accounted for since the spaceraft in a lunar orbit.
90 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![EARTH, SUN, JUPITER_BARYCENTER]);
91
92 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
93 // We're using the GRAIL JGGRX model.
94 let mut jggrx_meta = MetaFile {
95 uri: "http://public-data.nyxspace.com/nyx/models/Luna_jggrx_1500e_sha.tab.gz".to_string(),
96 crc32: Some(0x6bcacda8), // Specifying the CRC32 avoids redownloading it if it's cached.
97 };
98 // And let's download it if we don't have it yet.
99 jggrx_meta.process(true)?;
100
101 // Build the spherical harmonics.
102 // The harmonics must be computed in the body fixed frame.
103 // We're using the long term prediction of the Moon principal axes frame.
104 let moon_pa_frame = MOON_PA_FRAME.with_orient(31008);
105 let sph_harmonics = GravityField::new(GravityFieldData::from_shadr(
106 &jggrx_meta.uri,
107 80,
108 80,
109 almanac.frame_info(moon_pa_frame)?,
110 )?);
111
112 // Include the spherical harmonics into the orbital dynamics.
113 orbital_dyn.accel_models.push(sph_harmonics);
114
115 // We define the solar radiation pressure, using the default solar flux and accounting only
116 // for the eclipsing caused by the Earth and Moon.
117 // Note that by default, enabling the SolarPressure model will also enable the estimation of the coefficient of reflectivity.
118 let srp_dyn = SolarPressure::new(vec![MOON_J2000], &almanac)?;
119
120 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
121 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
122 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
123
124 println!("{dynamics}");
125
126 let setup = Propagator::rk89(dynamics.clone(), IntegratorOptions::default());
127
128 let truth_traj = setup
129 .with(orbiter, almanac.clone())
130 .for_duration_with_traj(Unit::Day * 2)?
131 .1;
132
133 // ==================== //
134 // === OD SIMULATOR === //
135 // ==================== //
136
137 // Load the Deep Space Network ground stations.
138 // Nyx allows you to build these at runtime but it's pretty static so we can just load them from YAML.
139 let ground_station_file = data_folder.join("dsn-network.yaml");
140 let devices = GroundStation::load_named(ground_station_file)?;
141
142 let proc_devices = devices.clone();
143
144 // Typical OD software requires that you specify your own tracking schedule or you'll have overlapping measurements.
145 // Nyx can build a tracking schedule for you based on the first station with access.
146 let configs: BTreeMap<String, TrkConfig> =
147 TrkConfig::load_named(data_folder.join("tracking-cfg.yaml"))?;
148
149 // Build the tracking arc simulation to generate a "standard measurement".
150 let mut trk = TrackingArcSim::<Spacecraft, GroundStation>::with_seed(
151 devices.clone(),
152 truth_traj.clone(),
153 configs,
154 123, // Set a seed for reproducibility
155 )?;
156
157 trk.build_schedule(&almanac)?;
158 let arc = trk.generate_measurements(&almanac)?;
159 // Save the simulated tracking data
160 arc.to_parquet_simple("./data/04_output/06_lunar_simulated_tracking.parquet")?;
161
162 // We'll note that in our case, we have continuous coverage of LRO when the vehicle is not behind the Moon.
163 println!("{arc}");
164
165 // Now that we have simulated measurements, we'll run the orbit determination.
166
167 // ===================== //
168 // === OD ESTIMATION === //
169 // ===================== //
170
171 let sc = SpacecraftUncertainty::builder()
172 .nominal(orbiter)
173 .frame(LocalFrame::RIC)
174 .x_km(0.5)
175 .y_km(0.5)
176 .z_km(0.5)
177 .vx_km_s(5e-3)
178 .vy_km_s(5e-3)
179 .vz_km_s(5e-3)
180 .build();
181
182 // Build the filter initial estimate, which we will reuse in the filter.
183 let initial_estimate = sc.to_estimate()?;
184
185 println!("== FILTER STATE ==\n{orbiter:x}\n{initial_estimate}");
186
187 // Build the SNC in the Moon J2000 frame, specified as a velocity noise over time.
188 let process_noise = ProcessNoise3D::from_velocity_km_s(
189 &[1e-14, 1e-14, 1e-14],
190 1 * Unit::Hour,
191 10 * Unit::Minute,
192 None,
193 );
194
195 println!("{process_noise}");
196
197 // We'll set up the OD process to reject measurements whose residuals are move than 3 sigmas away from what we expect.
198 let odp = SpacecraftKalmanScalarOD::new(
199 setup,
200 KalmanVariant::ReferenceUpdate,
201 Some(SigmaRejection::default()),
202 proc_devices,
203 almanac.clone(),
204 )
205 .with_process_noise(process_noise);
206
207 let od_sol = odp.process_arc(initial_estimate, &arc)?;
208
209 let final_est = od_sol.estimates.last().unwrap();
210
211 println!("{final_est}");
212
213 let ric_err = truth_traj
214 .at(final_est.epoch())?
215 .orbit
216 .ric_difference(&final_est.orbital_state())?;
217 println!("== RIC at end ==");
218 println!("RIC Position (m): {:.3}", ric_err.radius_km * 1e3);
219 println!("RIC Velocity (m/s): {:.3}", ric_err.velocity_km_s * 1e3);
220
221 println!(
222 "Num residuals rejected: #{}",
223 od_sol.rejected_residuals().len()
224 );
225 println!(
226 "Percentage within +/-3: {}",
227 od_sol.residual_ratio_within_threshold(3.0).unwrap()
228 );
229 println!("Whitened residuals normal? {}", od_sol.is_normal(None)?);
230 println!("NIS consistency: {}", od_sol.nis_consistency(None)?);
231
232 od_sol.to_parquet(
233 "./data/04_output/06_lunar_od_results.parquet",
234 ExportCfg::default(),
235 )?;
236
237 let od_trajectory = od_sol.to_traj()?;
238 // Build the RIC difference.
239 od_trajectory.ric_diff_to_parquet(
240 &truth_traj,
241 "./data/04_output/06_lunar_od_truth_error.parquet",
242 ExportCfg::default(),
243 )?;
244
245 Ok(())
246}26fn main() -> Result<(), Box<dyn Error>> {
27 pel::init();
28 // Dynamics models require planetary constants and ephemerides to be defined.
29 // Let's start by grabbing those by using ANISE's latest MetaAlmanac.
30 // This will automatically download the DE440s planetary ephemeris,
31 // the daily-updated Earth Orientation Parameters, the high fidelity Moon orientation
32 // parameters (for the Moon Mean Earth and Moon Principal Axes frames), and the PCK11
33 // planetary constants kernels.
34 // For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
35 // Note that we place the Almanac into an Arc so we can clone it cheaply and provide read-only
36 // references to many functions.
37 let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
38 // Define the orbit epoch
39 let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
40
41 // Define the orbit.
42 // First we need to fetch the Earth J2000 from information from the Almanac.
43 // This allows the frame to include the gravitational parameters and the shape of the Earth,
44 // defined as a tri-axial ellipoid. Note that this shape can be changed manually or in the Almanac
45 // by loading a different set of planetary constants.
46 let earth_j2000 = almanac.frame_info(EARTH_J2000)?;
47
48 // Placing this GEO bird just above Colorado.
49 // In theory, the eccentricity is zero, but in practice, it's about 1e-5 to 1e-6 at best.
50 let orbit = Orbit::try_keplerian(42164.0, 1e-5, 0., 163.0, 75.0, 0.0, epoch, earth_j2000)?;
51 // Print in in Keplerian form.
52 println!("{orbit:x}");
53
54 let state_bf = almanac.transform_to(orbit, IAU_EARTH_FRAME, None)?;
55 let (orig_lat_deg, orig_long_deg, orig_alt_km) = state_bf.latlongalt()?;
56
57 // Nyx is used for high fidelity propagation, not Keplerian propagation as above.
58 // Nyx only propagates Spacecraft at the moment, which allows it to account for acceleration
59 // models such as solar radiation pressure.
60
61 // Let's build a cubesat sized spacecraft, with an SRP area of 10 cm^2 and a mass of 9.6 kg.
62 let sc = Spacecraft::builder()
63 .orbit(orbit)
64 .mass(Mass::from_dry_mass(9.60))
65 .srp(SRPData {
66 area_m2: 10e-4,
67 coeff_reflectivity: 1.1,
68 })
69 .build();
70 println!("{sc:x}");
71
72 // Set up the spacecraft dynamics.
73
74 // Specify that the orbital dynamics must account for the graviational pull of the Moon and the Sun.
75 // The gravity of the Earth will also be accounted for since the spaceraft in an Earth orbit.
76 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
77
78 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
79 // We're using the JGM3 model here, which is the default in GMAT.
80 let mut jgm3_meta = MetaFile {
81 uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
82 crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
83 };
84 // And let's download it if we don't have it yet.
85 jgm3_meta.process(true)?;
86
87 // Build the spherical harmonics.
88 // The harmonics must be computed in the body fixed frame.
89 // We're using the long term prediction of the Earth centered Earth fixed frame, IAU Earth.
90 let harmonics_21x21 = GravityField::new(
91 GravityFieldData::from_cof(&jgm3_meta.uri, 21, 21, almanac.frame_info(IAU_EARTH_FRAME)?)
92 .unwrap(),
93 );
94
95 // Include the spherical harmonics into the orbital dynamics.
96 orbital_dyn.accel_models.push(harmonics_21x21);
97
98 // We define the solar radiation pressure, using the default solar flux and accounting only
99 // for the eclipsing caused by the Earth and Moon.
100 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], &almanac)?;
101
102 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
103 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
104 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
105
106 println!("{dynamics}");
107
108 // Finally, let's propagate this orbit to the same epoch as above.
109 // The first returned value is the spacecraft state at the final epoch.
110 // The second value is the full trajectory where the step size is variable step used by the propagator.
111 let (future_sc, trajectory) = Propagator::default(dynamics)
112 .with(sc, almanac.clone())
113 .until_epoch_with_traj(epoch + Unit::Century * 0.03)?;
114
115 println!("=== High fidelity propagation ===");
116 println!(
117 "SMA changed by {:.3} km",
118 orbit.sma_km()? - future_sc.orbit.sma_km()?
119 );
120 println!(
121 "ECC changed by {:.6}",
122 orbit.ecc()? - future_sc.orbit.ecc()?
123 );
124 println!(
125 "INC changed by {:.3e} deg",
126 orbit.inc_deg()? - future_sc.orbit.inc_deg()?
127 );
128 println!(
129 "RAAN changed by {:.3} deg",
130 orbit.raan_deg()? - future_sc.orbit.raan_deg()?
131 );
132 println!(
133 "AOP changed by {:.3} deg",
134 orbit.aop_deg()? - future_sc.orbit.aop_deg()?
135 );
136 println!(
137 "TA changed by {:.3} deg",
138 orbit.ta_deg()? - future_sc.orbit.ta_deg()?
139 );
140
141 // We also have access to the full trajectory throughout the propagation.
142 println!("{trajectory}");
143
144 println!("Spacecraft params after 3 years without active control:\n{future_sc:x}");
145
146 // With the trajectory, let's build a few data products.
147
148 // 1. Export the trajectory as a parquet file, which includes the Keplerian orbital elements.
149
150 let analysis_step = Unit::Minute * 5;
151
152 trajectory.to_parquet(
153 "./03_geo_hf_prop.parquet",
154 ExportCfg::builder().step(analysis_step).build(),
155 )?;
156
157 // 2. Compute the latitude, longitude, and altitude throughout the trajectory by rotating the spacecraft position into the Earth body fixed frame.
158
159 // We iterate over the trajectory, grabbing a state every two minutes.
160 let mut offset_s = vec![];
161 let mut epoch_str = vec![];
162 let mut longitude_deg = vec![];
163 let mut latitude_deg = vec![];
164 let mut altitude_km = vec![];
165
166 for state in trajectory.every(analysis_step) {
167 // Convert the GEO bird state into the body fixed frame, and keep track of its latitude, longitude, and altitude.
168 // These define the GEO stationkeeping box.
169
170 let this_epoch = state.epoch();
171
172 offset_s.push((this_epoch - orbit.epoch).to_seconds());
173 epoch_str.push(this_epoch.to_isoformat());
174
175 let state_bf = almanac.transform_to(state.orbit, IAU_EARTH_FRAME, None)?;
176 let (lat_deg, long_deg, alt_km) = state_bf.latlongalt()?;
177 longitude_deg.push(long_deg);
178 latitude_deg.push(lat_deg);
179 altitude_km.push(alt_km);
180 }
181
182 println!(
183 "Longitude changed by {:.3} deg -- Box is 0.1 deg E-W",
184 orig_long_deg - longitude_deg.last().unwrap()
185 );
186
187 println!(
188 "Latitude changed by {:.3} deg -- Box is 0.05 deg N-S",
189 orig_lat_deg - latitude_deg.last().unwrap()
190 );
191
192 println!(
193 "Altitude changed by {:.3} km -- Box is 30 km",
194 orig_alt_km - altitude_km.last().unwrap()
195 );
196
197 // Build the station keeping data frame.
198 let mut sk_df = df!(
199 "Offset (s)" => offset_s.clone(),
200 "Epoch (UTC)" => epoch_str.clone(),
201 "Longitude E-W (deg)" => longitude_deg,
202 "Latitude N-S (deg)" => latitude_deg,
203 "Altitude (km)" => altitude_km,
204
205 )?;
206
207 // Create a file to write the Parquet to
208 let file = File::create("./03_geo_lla.parquet").expect("Could not create file");
209
210 // Create a ParquetWriter and write the DataFrame to the file
211 ParquetWriter::new(file).finish(&mut sk_df)?;
212
213 Ok(())
214}35fn main() -> Result<(), Box<dyn Error>> {
36 pel::init();
37
38 // ====================== //
39 // === ALMANAC SET UP === //
40 // ====================== //
41
42 // Dynamics models require planetary constants and ephemerides to be defined.
43 // Let's start by grabbing those by using ANISE's MetaAlmanac.
44
45 let output_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "../data", "04_output"]
46 .iter()
47 .collect();
48
49 let data_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "examples", "04_lro_od"]
50 .iter()
51 .collect();
52
53 let meta = data_folder.join("lro-dynamics.dhall");
54
55 // Load this ephem in the general Almanac we're using for this analysis.
56 let mut almanac = MetaAlmanac::new(meta.to_string_lossy().as_ref())
57 .map_err(Box::new)?
58 .process(true)
59 .map_err(Box::new)?;
60
61 let mut moon_pc = almanac.get_planetary_data_from_id(MOON).unwrap();
62 moon_pc.mu_km3_s2 = 4902.74987;
63 almanac.set_planetary_data_from_id(MOON, moon_pc).unwrap();
64
65 let mut earth = almanac.get_planetary_data_from_id(EARTH).unwrap();
66 earth.mu_km3_s2 = 398600.436;
67 almanac.set_planetary_data_from_id(EARTH, earth).unwrap();
68
69 // Save this new kernel for reuse.
70 // In an operational context, this would be part of the "Lock" process, and should not change throughout the mission.
71 almanac
72 .planetary_data
73 .values()
74 .next()
75 .unwrap()
76 .save_as(&data_folder.join("lro-specific.pca"), true)?;
77
78 // Lock the almanac (an Arc is a read only structure).
79 let almanac = Arc::new(almanac);
80
81 // Orbit determination requires a Trajectory structure, which can be saved as parquet file.
82 // In our case, the trajectory comes from the BSP file, so we need to build a Trajectory from the almanac directly.
83 // To query the Almanac, we need to build the LRO frame in the J2000 orientation in our case.
84 // Inspecting the LRO BSP in the ANISE GUI shows us that NASA has assigned ID -85 to LRO.
85 let lro_frame = Frame::from_ephem_j2000(-85);
86
87 // To build the trajectory we need to provide a spacecraft template.
88 let sc_template = Spacecraft::builder()
89 .mass(Mass::from_dry_and_prop_masses(1018.0, 900.0)) // Launch masses
90 .srp(SRPData {
91 // SRP configuration is arbitrary, but we will be estimating it anyway.
92 area_m2: 3.9 * 2.7,
93 coeff_reflectivity: 0.96,
94 })
95 .orbit(Orbit::zero(MOON_J2000)) // Setting a zero orbit here because it's just a template
96 .build();
97 // Now we can build the trajectory from the BSP file.
98 // We'll arbitrarily set the tracking arc to 24 hours with a five second time step.
99 let traj_as_flown = Traj::from_bsp(
100 lro_frame,
101 MOON_J2000,
102 &almanac,
103 sc_template,
104 5.seconds(),
105 Some(Epoch::from_str("2024-01-01 00:00:00 UTC")?),
106 Some(Epoch::from_str("2024-01-02 00:00:00 UTC")?),
107 Aberration::LT,
108 Some("LRO".to_string()),
109 )?;
110
111 println!("{traj_as_flown}");
112
113 // ====================== //
114 // === MODEL MATCHING === //
115 // ====================== //
116
117 // Set up the spacecraft dynamics.
118
119 // Specify that the orbital dynamics must account for the graviational pull of the Earth and the Sun.
120 // The gravity of the Moon will also be accounted for since the spaceraft in a lunar orbit.
121 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![EARTH, SUN, JUPITER_BARYCENTER]);
122
123 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
124 // We're using the GRAIL JGGRX model.
125 let mut jggrx_meta = MetaFile {
126 uri: "http://public-data.nyxspace.com/nyx/models/Luna_jggrx_1500e_sha.tab.gz".to_string(),
127 crc32: Some(0x6bcacda8), // Specifying the CRC32 avoids redownloading it if it's cached.
128 };
129 // And let's download it if we don't have it yet.
130 jggrx_meta.process(true)?;
131
132 // Build the spherical harmonics.
133 // The harmonics must be computed in the body fixed frame.
134 // We're using the long term prediction of the Moon principal axes frame.
135 let moon_pa_frame = MOON_PA_FRAME.with_orient(31008);
136 let sph_harmonics = GravityField::new(GravityFieldData::from_shadr(
137 &jggrx_meta.uri,
138 80,
139 80,
140 almanac.frame_info(moon_pa_frame)?,
141 )?);
142
143 // Include the spherical harmonics into the orbital dynamics.
144 orbital_dyn.accel_models.push(sph_harmonics);
145
146 // We define the solar radiation pressure, using the default solar flux and accounting only
147 // for the eclipsing caused by the Earth and Moon.
148 // Note that by default, enabling the SolarPressure model will also enable the estimation of the coefficient of reflectivity.
149 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], &almanac)?;
150
151 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
152 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
153 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
154
155 println!("{dynamics}");
156
157 // Now we can build the propagator.
158 let setup = Propagator::default_dp78(dynamics.clone());
159
160 // For reference, let's build the trajectory with Nyx's models from that LRO state.
161 let (sim_final, traj_as_sim) = setup
162 .with(*traj_as_flown.first(), almanac.clone())
163 .until_epoch_with_traj(traj_as_flown.last().epoch())?;
164
165 println!("SIM INIT: {:x}", traj_as_flown.first());
166 println!("SIM FINAL: {sim_final:x}");
167 // Compute RIC difference between SIM and LRO ephem
168 let sim_lro_delta = sim_final
169 .orbit
170 .ric_difference(&traj_as_flown.last().orbit)?;
171 println!("{traj_as_sim}");
172 println!(
173 "SIM v LRO - RIC Position (m): {:.3}",
174 sim_lro_delta.radius_km * 1e3
175 );
176 println!(
177 "SIM v LRO - RIC Velocity (m/s): {:.3}",
178 sim_lro_delta.velocity_km_s * 1e3
179 );
180
181 traj_as_sim.ric_diff_to_parquet(
182 &traj_as_flown,
183 output_folder.join("./04_lro_sim_truth_error.parquet"),
184 ExportCfg::default(),
185 )?;
186
187 // ==================== //
188 // === OD SIMULATOR === //
189 // ==================== //
190
191 // After quite some time trying to exactly match the model, we still end up with an oscillatory difference on the order of 150 meters between the propagated state
192 // and the truth LRO state.
193
194 // Therefore, we will actually run an estimation from a dispersed LRO state.
195 // The sc_seed is the true LRO state from the BSP.
196 let sc_seed = *traj_as_flown.first();
197
198 // Load the Deep Space Network ground stations.
199 // Nyx allows you to build these at runtime but it's pretty static so we can just load them from YAML.
200 let ground_station_file: PathBuf = [
201 env!("CARGO_MANIFEST_DIR"),
202 "examples",
203 "04_lro_od",
204 "dsn-network.yaml",
205 ]
206 .iter()
207 .collect();
208
209 let devices = GroundStation::load_named(ground_station_file)?;
210
211 let mut proc_devices = devices.clone();
212
213 // Increase the noise in the devices to accept more measurements.
214 for gs in proc_devices.values_mut() {
215 if let Some(noise) = &mut gs
216 .stochastic_noises
217 .as_mut()
218 .unwrap()
219 .get_mut(&MeasurementType::Range)
220 {
221 *noise.white_noise.as_mut().unwrap() *= 3.0;
222 }
223 }
224
225 // Typical OD software requires that you specify your own tracking schedule or you'll have overlapping measurements.
226 // Nyx can build a tracking schedule for you based on the first station with access.
227 let trkconfg_yaml: PathBuf = [
228 env!("CARGO_MANIFEST_DIR"),
229 "examples",
230 "04_lro_od",
231 "tracking-cfg.yaml",
232 ]
233 .iter()
234 .collect();
235
236 let configs: BTreeMap<String, TrkConfig> = TrkConfig::load_named(trkconfg_yaml)?;
237
238 // Build the tracking arc simulation to generate a "standard measurement".
239 let mut trk = TrackingArcSim::<Spacecraft, GroundStation>::with_seed(
240 devices.clone(),
241 traj_as_flown.clone(),
242 configs,
243 123, // Set a seed for reproducibility
244 )?;
245
246 trk.build_schedule(&almanac)?;
247 let arc = trk.generate_measurements(&almanac)?;
248 // Save the simulated tracking data
249 arc.to_parquet_simple(output_folder.join("04_lro_simulated_tracking.parquet"))?;
250
251 // We'll note that in our case, we have continuous coverage of LRO when the vehicle is not behind the Moon.
252 println!("{arc}");
253
254 // Now that we have simulated measurements, we'll run the orbit determination.
255
256 // ===================== //
257 // === OD ESTIMATION === //
258 // ===================== //
259
260 let sc = SpacecraftUncertainty::builder()
261 .nominal(sc_seed)
262 .frame(LocalFrame::RIC)
263 .x_km(0.5)
264 .y_km(0.5)
265 .z_km(0.5)
266 .vx_km_s(5e-3)
267 .vy_km_s(5e-3)
268 .vz_km_s(5e-3)
269 .build();
270
271 // Build the filter initial estimate, which we will reuse in the filter.
272 let mut initial_estimate = sc.to_estimate()?;
273 initial_estimate.covar *= 3.0;
274
275 println!("== FILTER STATE ==\n{sc_seed:x}\n{initial_estimate}");
276
277 // Build the SNC in the Moon J2000 frame, specified as a velocity noise over time.
278 let process_noise = ProcessNoise3D::from_velocity_km_s(
279 &[1e-12, 1e-12, 1e-12],
280 1 * Unit::Hour,
281 10 * Unit::Minute,
282 None,
283 );
284
285 println!("{process_noise}");
286
287 // We'll set up the OD process to reject measurements whose residuals are move than 3 sigmas away from what we expect.
288 let odp = SpacecraftKalmanOD::new(
289 setup,
290 KalmanVariant::ReferenceUpdate,
291 Some(SigmaRejection::default()),
292 proc_devices,
293 almanac.clone(),
294 )
295 .with_process_noise(process_noise);
296
297 let od_sol = odp.process_arc(initial_estimate, &arc)?;
298
299 let final_est = od_sol.estimates.last().unwrap();
300
301 println!("{final_est}");
302
303 let ric_err = traj_as_flown
304 .at(final_est.epoch())?
305 .orbit
306 .ric_difference(&final_est.orbital_state())?;
307 println!("== RIC at end ==");
308 println!("RIC Position (m): {:.3}", ric_err.radius_km * 1e3);
309 println!("RIC Velocity (m/s): {:.3}", ric_err.velocity_km_s * 1e3);
310
311 println!(
312 "Num residuals rejected: #{}",
313 od_sol.rejected_residuals().len()
314 );
315 println!(
316 "Percentage within +/-3: {}",
317 od_sol.residual_ratio_within_threshold(3.0).unwrap()
318 );
319 println!("Ratios normal? {}", od_sol.is_normal(None).unwrap());
320
321 od_sol.to_parquet(
322 output_folder.join("04_lro_od_results.parquet"),
323 ExportCfg::default(),
324 )?;
325
326 // Create the ephemeris
327 let ephem = od_sol.to_ephemeris("LRO rebuilt".to_string());
328 let ephem_start = ephem.start_epoch().unwrap();
329 let ephem_end = ephem.end_epoch().unwrap();
330 // Check that the covariance is PSD throughout the ephemeris by interpolating it.
331 for epoch in TimeSeries::inclusive(ephem_start, ephem_end, Unit::Minute * 5) {
332 ephem
333 .covar_at(
334 epoch,
335 anise::ephemerides::ephemeris::LocalFrame::RIC,
336 &almanac,
337 )
338 .unwrap_or_else(|e| panic!("covar not PSD at {epoch}: {e}"));
339 }
340 // Export as BSP!
341 ephem
342 .write_spice_bsp(
343 -85,
344 output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap(),
345 None,
346 )
347 .expect("could not built BSP");
348 let new_almanac = Almanac::default()
349 .load(output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap())
350 .unwrap();
351 new_almanac.describe(None, None, None, None, None, None, None, None);
352 let (spk_start, spk_end) = new_almanac.spk_domain(-85).unwrap();
353
354 assert!((ephem_start - spk_start).abs() < Unit::Microsecond * 1);
355 assert!((ephem_end - spk_end).abs() < Unit::Microsecond * 1);
356
357 // In our case, we have the truth trajectory from NASA.
358 // So we can compute the RIC state difference between the real LRO ephem and what we've just estimated.
359 // Export the OD trajectory first.
360 let od_trajectory = od_sol.to_traj()?;
361 // Build the RIC difference.
362 od_trajectory.ric_diff_to_parquet(
363 &traj_as_flown,
364 output_folder.join("04_lro_od_truth_error.parquet"),
365 ExportCfg::default(),
366 )?;
367
368 Ok(())
369}Trait Implementations§
Source§impl Clone for SolarPressure
impl Clone for SolarPressure
Source§fn clone(&self) -> SolarPressure
fn clone(&self) -> SolarPressure
1.0.0 (const: unstable) · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moreSource§impl Debug for SolarPressure
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Source§impl Default for SolarPressure
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impl DerefToPyAny for SolarPressure
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impl<'de> Deserialize<'de> for SolarPressure
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Source§impl Display for SolarPressure
impl Display for SolarPressure
Source§impl ForceModel for SolarPressure
impl ForceModel for SolarPressure
Source§fn estimation_index(&self) -> Option<usize>
fn estimation_index(&self) -> Option<usize>
Source§fn eom(
&self,
ctx: &Spacecraft,
almanac: &Almanac,
) -> Result<Vector3<f64>, DynamicsError>
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Source§impl<'a, 'py> FromPyObject<'a, 'py> for SolarPressurewhere
Self: Clone,
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impl<'py> IntoPyObject<'py> for SolarPressure
Source§type Target = SolarPressure
type Target = SolarPressure
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type Output = Bound<'py, <SolarPressure as IntoPyObject<'py>>::Target>
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self,
py: Python<'py>,
) -> Result<<Self as IntoPyObject<'_>>::Output, <Self as IntoPyObject<'_>>::Error>
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Source§impl PyClass for SolarPressure
impl PyClass for SolarPressure
Source§impl PyClassImpl for SolarPressure
impl PyClassImpl for SolarPressure
Source§const MODULE: Option<&str> = ::core::option::Option::None
const MODULE: Option<&str> = ::core::option::Option::None
Source§const IS_BASETYPE: bool = false
const IS_BASETYPE: bool = false
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const IS_SUBCLASS: bool = false
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const IS_MAPPING: bool = false
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const IS_SEQUENCE: bool = false
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Source§const RAW_DOC: &'static CStr = /// Computation of solar radiation pressure is based on STK: <http://help.agi.com/stk/index.htm#gator/eq-solar.htm> .
///
/// :type shadow_bodies: list[Frame]
/// :type almanac: Almanac
/// :type flux_w_m2: float
/// :type estimate: bool
const RAW_DOC: &'static CStr = /// Computation of solar radiation pressure is based on STK: <http://help.agi.com/stk/index.htm#gator/eq-solar.htm> . /// /// :type shadow_bodies: list[Frame] /// :type almanac: Almanac /// :type flux_w_m2: float /// :type estimate: bool
Source§const DOC: &'static CStr
const DOC: &'static CStr
text_signature if a constructor is defined. Read moreSource§type Layout = <<SolarPressure as PyClassImpl>::BaseNativeType as PyClassBaseType>::Layout<SolarPressure>
type Layout = <<SolarPressure as PyClassImpl>::BaseNativeType as PyClassBaseType>::Layout<SolarPressure>
Source§type ThreadChecker = NoopThreadChecker
type ThreadChecker = NoopThreadChecker
type Inventory = Pyo3MethodsInventoryForSolarPressure
Source§type PyClassMutability = <<PyAny as PyClassBaseType>::PyClassMutability as PyClassMutability>::MutableChild
type PyClassMutability = <<PyAny as PyClassBaseType>::PyClassMutability as PyClassMutability>::MutableChild
Source§type BaseNativeType = PyAny
type BaseNativeType = PyAny
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#[pyclass(extends=PyDict)], it’s PyDict.fn items_iter() -> PyClassItemsIter
fn lazy_type_object() -> &'static LazyTypeObject<Self>
§fn dict_offset() -> Option<PyObjectOffset>
fn dict_offset() -> Option<PyObjectOffset>
§fn weaklist_offset() -> Option<PyObjectOffset>
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Source§impl PyClassNewTextSignature for SolarPressure
impl PyClassNewTextSignature for SolarPressure
const TEXT_SIGNATURE: &'static str = "(shadow_bodies, almanac, flux_w_m2=..., estimate=True)"
Source§impl PyTypeInfo for SolarPressure
impl PyTypeInfo for SolarPressure
Source§const NAME: &str = <Self as ::pyo3::PyClass>::NAME
const NAME: &str = <Self as ::pyo3::PyClass>::NAME
prefer using ::type_object(py).name() to get the correct runtime value
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§fn is_type_of(object: &Bound<'_, PyAny>) -> bool
fn is_type_of(object: &Bound<'_, PyAny>) -> bool
object is an instance of this type or a subclass of this type.§fn is_exact_type_of(object: &Bound<'_, PyAny>) -> bool
fn is_exact_type_of(object: &Bound<'_, PyAny>) -> bool
object is an instance of this type.Source§impl Serialize for SolarPressure
impl Serialize for SolarPressure
Source§impl StaticType for SolarPressure
impl StaticType for SolarPressure
Source§fn static_type() -> SimpleType
fn static_type() -> SimpleType
Auto Trait Implementations§
impl Freeze for SolarPressure
impl RefUnwindSafe for SolarPressure
impl Send for SolarPressure
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impl Unpin for SolarPressure
impl UnsafeUnpin for SolarPressure
impl UnwindSafe for SolarPressure
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