pub struct SpacecraftUncertainty {
pub nominal: Spacecraft,
pub frame: Option<LocalFrame>,
pub x_km: f64,
pub y_km: f64,
pub z_km: f64,
pub vx_km_s: f64,
pub vy_km_s: f64,
pub vz_km_s: f64,
pub coeff_reflectivity: f64,
pub coeff_drag: f64,
pub mass_kg: f64,
}Expand description
Builds a spacecraft uncertainty in different local frames, dispersing any of the parameters of the spacecraft state.
§Usage
Use the TypeBuilder trait, e.g SpacecraftUncertainty::builder().nominal(spacecraft).frame(LocalFrame::RIC).x_km(0.5).y_km(0.5).z_km(0.5).build()
to build an uncertainty on position in the RIC frame of 500 meters on R, I, and C, and zero on all other parameters (velocity components, Cr, Cd, mass).
Fields§
§nominal: Spacecraft§frame: Option<LocalFrame>§x_km: f64§y_km: f64§z_km: f64§vx_km_s: f64§vy_km_s: f64§vz_km_s: f64§coeff_reflectivity: f64§coeff_drag: f64§mass_kg: f64Implementations§
Source§impl SpacecraftUncertainty
impl SpacecraftUncertainty
Sourcepub fn builder() -> SpacecraftUncertaintyBuilder<((), (), (), (), (), (), (), (), (), (), ())>
pub fn builder() -> SpacecraftUncertaintyBuilder<((), (), (), (), (), (), (), (), (), (), ())>
Create a builder for building SpacecraftUncertainty.
On the builder, call .nominal(...), .frame(...)(optional), .x_km(...)(optional), .y_km(...)(optional), .z_km(...)(optional), .vx_km_s(...)(optional), .vy_km_s(...)(optional), .vz_km_s(...)(optional), .coeff_reflectivity(...)(optional), .coeff_drag(...)(optional), .mass_kg(...)(optional) to set the values of the fields.
Finally, call .build() to create the instance of SpacecraftUncertainty.
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.clone())?;
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
34fn main() -> Result<(), Box<dyn Error>> {
35 pel::init();
36
37 // ====================== //
38 // === ALMANAC SET UP === //
39 // ====================== //
40
41 let manifest_dir =
42 PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap_or(".".to_string()));
43
44 let out = manifest_dir.join("data/04_output/");
45
46 let almanac = Arc::new(
47 Almanac::new(
48 &manifest_dir
49 .join("data/01_planetary/pck08.pca")
50 .to_string_lossy(),
51 )
52 .unwrap()
53 .load(
54 &manifest_dir
55 .join("data/01_planetary/de440s.bsp")
56 .to_string_lossy(),
57 )
58 .unwrap(),
59 );
60
61 let eme2k = almanac.frame_info(EARTH_J2000).unwrap();
62 let moon_iau = almanac.frame_info(IAU_MOON_FRAME).unwrap();
63
64 let epoch = Epoch::from_gregorian_tai(2021, 5, 29, 19, 51, 16, 852_000);
65 let nrho = Orbit::cartesian(
66 166_473.631_302_239_7,
67 -274_715.487_253_382_7,
68 -211_233.210_176_686_7,
69 0.933_451_604_520_018_4,
70 0.436_775_046_841_900_9,
71 -0.082_211_021_250_348_95,
72 epoch,
73 eme2k,
74 );
75
76 let tx_nrho_sc = Spacecraft::from(nrho);
77
78 let state_luna = almanac.transform_to(nrho, MOON_J2000, None).unwrap();
79 println!("Start state (dynamics: Earth, Moon, Sun gravity):\n{state_luna}");
80
81 let bodies = vec![EARTH, SUN];
82 let dynamics = SpacecraftDynamics::new(OrbitalDynamics::point_masses(bodies));
83
84 let setup = Propagator::rk89(
85 dynamics,
86 IntegratorOptions::builder().max_step(0.5.minutes()).build(),
87 );
88
89 /* == Propagate the NRHO vehicle == */
90 let prop_time = 1.1 * state_luna.period().unwrap();
91
92 let (nrho_final, mut tx_traj) = setup
93 .with(tx_nrho_sc, almanac.clone())
94 .for_duration_with_traj(prop_time)
95 .unwrap();
96
97 tx_traj.name = Some("NRHO Tx SC".to_string());
98
99 println!("{tx_traj}");
100
101 /* == Propagate an LLO vehicle == */
102 let llo_orbit =
103 Orbit::try_keplerian_altitude(110.0, 1e-4, 90.0, 0.0, 0.0, 0.0, epoch, moon_iau).unwrap();
104
105 let llo_sc = Spacecraft::builder().orbit(llo_orbit).build();
106
107 let (_, llo_traj) = setup
108 .with(llo_sc, almanac.clone())
109 .until_epoch_with_traj(nrho_final.epoch())
110 .unwrap();
111
112 // Export the subset of the first two hours.
113 llo_traj
114 .clone()
115 .filter_by_offset(..2.hours())
116 .to_parquet_simple(out.join("05_caps_llo_truth.pq"))?;
117
118 /* == Setup the interlink == */
119
120 let mut measurement_types = IndexSet::new();
121 measurement_types.insert(MeasurementType::Range);
122 measurement_types.insert(MeasurementType::Doppler);
123
124 let mut stochastics = IndexMap::new();
125
126 let sa45_csac_allan_dev = 1e-11;
127
128 stochastics.insert(
129 MeasurementType::Range,
130 StochasticNoise::from_hardware_range_km(
131 sa45_csac_allan_dev,
132 10.0.seconds(),
133 link_specific::ChipRate::StandardT4B,
134 link_specific::SN0::Average,
135 ),
136 );
137
138 stochastics.insert(
139 MeasurementType::Doppler,
140 StochasticNoise::from_hardware_doppler_km_s(
141 sa45_csac_allan_dev,
142 10.0.seconds(),
143 link_specific::CarrierFreq::SBand,
144 link_specific::CN0::Average,
145 ),
146 );
147
148 let interlink = InterlinkTxSpacecraft {
149 traj: tx_traj,
150 measurement_types,
151 integration_time: None,
152 timestamp_noise_s: None,
153 ab_corr: Aberration::LT,
154 stochastic_noises: Some(stochastics),
155 };
156
157 // Devices are the transmitter, which is our NRHO vehicle.
158 let mut devices = BTreeMap::new();
159 devices.insert("NRHO Tx SC".to_string(), interlink);
160
161 let mut configs = BTreeMap::new();
162 configs.insert(
163 "NRHO Tx SC".to_string(),
164 TrkConfig::builder()
165 .strands(vec![Strand {
166 start: epoch,
167 end: nrho_final.epoch(),
168 }])
169 .build(),
170 );
171
172 let mut trk_sim =
173 TrackingArcSim::with_seed(devices.clone(), llo_traj.clone(), configs, 0).unwrap();
174 println!("{trk_sim}");
175
176 let trk_data = trk_sim.generate_measurements(almanac.clone()).unwrap();
177 println!("{trk_data}");
178
179 trk_data
180 .to_parquet_simple(out.clone().join("nrho_interlink_msr.pq"))
181 .unwrap();
182
183 // Run a truth OD where we estimate the LLO position
184 let llo_uncertainty = SpacecraftUncertainty::builder()
185 .nominal(llo_sc)
186 .x_km(1.0)
187 .y_km(1.0)
188 .z_km(1.0)
189 .vx_km_s(1e-3)
190 .vy_km_s(1e-3)
191 .vz_km_s(1e-3)
192 .build();
193
194 let mut proc_devices = devices.clone();
195
196 // Define the initial estimate, randomized, seed for reproducibility
197 let mut initial_estimate = llo_uncertainty.to_estimate_randomized(Some(0)).unwrap();
198 // Inflate the covariance -- https://github.com/nyx-space/nyx/issues/339
199 initial_estimate.covar *= 2.5;
200
201 // Increase the noise in the devices to accept more measurements.
202
203 for link in proc_devices.values_mut() {
204 for noise in &mut link.stochastic_noises.as_mut().unwrap().values_mut() {
205 *noise.white_noise.as_mut().unwrap() *= 3.0;
206 }
207 }
208
209 let init_err = initial_estimate
210 .orbital_state()
211 .ric_difference(&llo_orbit)
212 .unwrap();
213
214 println!("initial estimate:\n{initial_estimate}");
215 println!("RIC errors = {init_err}",);
216
217 let odp = InterlinkKalmanOD::new(
218 setup.clone(),
219 KalmanVariant::ReferenceUpdate,
220 Some(ResidRejectCrit::default()),
221 proc_devices,
222 almanac.clone(),
223 );
224
225 // Shrink the data to process.
226 let arc = trk_data.filter_by_offset(..2.hours());
227
228 let od_sol = odp.process_arc(initial_estimate, &arc).unwrap();
229
230 println!("{od_sol}");
231
232 od_sol
233 .to_parquet(
234 out.join("05_caps_interlink_od_sol.pq"),
235 ExportCfg::default(),
236 )
237 .unwrap();
238
239 let od_traj = od_sol.to_traj().unwrap();
240
241 od_traj
242 .ric_diff_to_parquet(
243 &llo_traj,
244 out.join("05_caps_interlink_llo_est_error.pq"),
245 ExportCfg::default(),
246 )
247 .unwrap();
248
249 let final_est = od_sol.estimates.last().unwrap();
250 assert!(final_est.within_3sigma(), "should be within 3 sigma");
251
252 println!("ESTIMATE\n{final_est:x}\n");
253 let truth = llo_traj.at(final_est.epoch()).unwrap();
254 println!("TRUTH\n{truth:x}");
255
256 let final_err = truth
257 .orbit
258 .ric_difference(&final_est.orbital_state())
259 .unwrap();
260 println!("ERROR {final_err}");
261
262 // Build the residuals versus reference plot.
263 let rvr_sol = odp
264 .process_arc(initial_estimate, &arc.resid_vs_ref_check())
265 .unwrap();
266
267 rvr_sol
268 .to_parquet(
269 out.join("05_caps_interlink_resid_v_ref.pq"),
270 ExportCfg::default(),
271 )
272 .unwrap();
273
274 let final_rvr = rvr_sol.estimates.last().unwrap();
275
276 println!("RMAG error {:.3} m", final_err.rmag_km() * 1e3);
277 println!(
278 "Pure prop error {:.3} m",
279 final_rvr
280 .orbital_state()
281 .ric_difference(&final_est.orbital_state())
282 .unwrap()
283 .rmag_km()
284 * 1e3
285 );
286
287 Ok(())
288}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 = [env!("CARGO_MANIFEST_DIR"), "examples", "04_lro_od"]
46 .iter()
47 .collect();
48
49 let meta = data_folder.join("lro-dynamics.dhall");
50
51 // Load this ephem in the general Almanac we're using for this analysis.
52 let mut almanac = MetaAlmanac::new(meta.to_string_lossy().as_ref())
53 .map_err(Box::new)?
54 .process(true)
55 .map_err(Box::new)?;
56
57 let mut moon_pc = almanac.get_planetary_data_from_id(MOON).unwrap();
58 moon_pc.mu_km3_s2 = 4902.74987;
59 almanac.set_planetary_data_from_id(MOON, moon_pc).unwrap();
60
61 let mut earth = almanac.get_planetary_data_from_id(EARTH).unwrap();
62 earth.mu_km3_s2 = 398600.436;
63 almanac.set_planetary_data_from_id(EARTH, earth).unwrap();
64
65 // Save this new kernel for reuse.
66 // In an operational context, this would be part of the "Lock" process, and should not change throughout the mission.
67 almanac
68 .planetary_data
69 .values()
70 .next()
71 .unwrap()
72 .save_as(&data_folder.join("lro-specific.pca"), true)?;
73
74 // Lock the almanac (an Arc is a read only structure).
75 let almanac = Arc::new(almanac);
76
77 // Orbit determination requires a Trajectory structure, which can be saved as parquet file.
78 // In our case, the trajectory comes from the BSP file, so we need to build a Trajectory from the almanac directly.
79 // To query the Almanac, we need to build the LRO frame in the J2000 orientation in our case.
80 // Inspecting the LRO BSP in the ANISE GUI shows us that NASA has assigned ID -85 to LRO.
81 let lro_frame = Frame::from_ephem_j2000(-85);
82
83 // To build the trajectory we need to provide a spacecraft template.
84 let sc_template = Spacecraft::builder()
85 .mass(Mass::from_dry_and_prop_masses(1018.0, 900.0)) // Launch masses
86 .srp(SRPData {
87 // SRP configuration is arbitrary, but we will be estimating it anyway.
88 area_m2: 3.9 * 2.7,
89 coeff_reflectivity: 0.96,
90 })
91 .orbit(Orbit::zero(MOON_J2000)) // Setting a zero orbit here because it's just a template
92 .build();
93 // Now we can build the trajectory from the BSP file.
94 // We'll arbitrarily set the tracking arc to 24 hours with a five second time step.
95 let traj_as_flown = Traj::from_bsp(
96 lro_frame,
97 MOON_J2000,
98 almanac.clone(),
99 sc_template,
100 5.seconds(),
101 Some(Epoch::from_str("2024-01-01 00:00:00 UTC")?),
102 Some(Epoch::from_str("2024-01-02 00:00:00 UTC")?),
103 Aberration::LT,
104 Some("LRO".to_string()),
105 )?;
106
107 println!("{traj_as_flown}");
108
109 // ====================== //
110 // === MODEL MATCHING === //
111 // ====================== //
112
113 // Set up the spacecraft dynamics.
114
115 // Specify that the orbital dynamics must account for the graviational pull of the Earth and the Sun.
116 // The gravity of the Moon will also be accounted for since the spaceraft in a lunar orbit.
117 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![EARTH, SUN, JUPITER_BARYCENTER]);
118
119 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
120 // We're using the GRAIL JGGRX model.
121 let mut jggrx_meta = MetaFile {
122 uri: "http://public-data.nyxspace.com/nyx/models/Luna_jggrx_1500e_sha.tab.gz".to_string(),
123 crc32: Some(0x6bcacda8), // Specifying the CRC32 avoids redownloading it if it's cached.
124 };
125 // And let's download it if we don't have it yet.
126 jggrx_meta.process(true)?;
127
128 // Build the spherical harmonics.
129 // The harmonics must be computed in the body fixed frame.
130 // We're using the long term prediction of the Moon principal axes frame.
131 let moon_pa_frame = MOON_PA_FRAME.with_orient(31008);
132 let sph_harmonics = Harmonics::from_stor(
133 almanac.frame_info(moon_pa_frame)?,
134 HarmonicsMem::from_shadr(&jggrx_meta.uri, 80, 80, true)?,
135 );
136
137 // Include the spherical harmonics into the orbital dynamics.
138 orbital_dyn.accel_models.push(sph_harmonics);
139
140 // We define the solar radiation pressure, using the default solar flux and accounting only
141 // for the eclipsing caused by the Earth and Moon.
142 // Note that by default, enabling the SolarPressure model will also enable the estimation of the coefficient of reflectivity.
143 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], almanac.clone())?;
144
145 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
146 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
147 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
148
149 println!("{dynamics}");
150
151 // Now we can build the propagator.
152 let setup = Propagator::default_dp78(dynamics.clone());
153
154 // For reference, let's build the trajectory with Nyx's models from that LRO state.
155 let (sim_final, traj_as_sim) = setup
156 .with(*traj_as_flown.first(), almanac.clone())
157 .until_epoch_with_traj(traj_as_flown.last().epoch())?;
158
159 println!("SIM INIT: {:x}", traj_as_flown.first());
160 println!("SIM FINAL: {sim_final:x}");
161 // Compute RIC difference between SIM and LRO ephem
162 let sim_lro_delta = sim_final
163 .orbit
164 .ric_difference(&traj_as_flown.last().orbit)?;
165 println!("{traj_as_sim}");
166 println!(
167 "SIM v LRO - RIC Position (m): {:.3}",
168 sim_lro_delta.radius_km * 1e3
169 );
170 println!(
171 "SIM v LRO - RIC Velocity (m/s): {:.3}",
172 sim_lro_delta.velocity_km_s * 1e3
173 );
174
175 traj_as_sim.ric_diff_to_parquet(
176 &traj_as_flown,
177 "./data/04_output/04_lro_sim_truth_error.parquet",
178 ExportCfg::default(),
179 )?;
180
181 // ==================== //
182 // === OD SIMULATOR === //
183 // ==================== //
184
185 // 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
186 // and the truth LRO state.
187
188 // Therefore, we will actually run an estimation from a dispersed LRO state.
189 // The sc_seed is the true LRO state from the BSP.
190 let sc_seed = *traj_as_flown.first();
191
192 // Load the Deep Space Network ground stations.
193 // Nyx allows you to build these at runtime but it's pretty static so we can just load them from YAML.
194 let ground_station_file: PathBuf = [
195 env!("CARGO_MANIFEST_DIR"),
196 "examples",
197 "04_lro_od",
198 "dsn-network.yaml",
199 ]
200 .iter()
201 .collect();
202
203 let devices = GroundStation::load_named(ground_station_file)?;
204
205 let mut proc_devices = devices.clone();
206
207 // Increase the noise in the devices to accept more measurements.
208 for gs in proc_devices.values_mut() {
209 if let Some(noise) = &mut gs
210 .stochastic_noises
211 .as_mut()
212 .unwrap()
213 .get_mut(&MeasurementType::Range)
214 {
215 *noise.white_noise.as_mut().unwrap() *= 3.0;
216 }
217 }
218
219 // Typical OD software requires that you specify your own tracking schedule or you'll have overlapping measurements.
220 // Nyx can build a tracking schedule for you based on the first station with access.
221 let trkconfg_yaml: PathBuf = [
222 env!("CARGO_MANIFEST_DIR"),
223 "examples",
224 "04_lro_od",
225 "tracking-cfg.yaml",
226 ]
227 .iter()
228 .collect();
229
230 let configs: BTreeMap<String, TrkConfig> = TrkConfig::load_named(trkconfg_yaml)?;
231
232 // Build the tracking arc simulation to generate a "standard measurement".
233 let mut trk = TrackingArcSim::<Spacecraft, GroundStation>::with_seed(
234 devices.clone(),
235 traj_as_flown.clone(),
236 configs,
237 123, // Set a seed for reproducibility
238 )?;
239
240 trk.build_schedule(almanac.clone())?;
241 let arc = trk.generate_measurements(almanac.clone())?;
242 // Save the simulated tracking data
243 arc.to_parquet_simple("./data/04_output/04_lro_simulated_tracking.parquet")?;
244
245 // We'll note that in our case, we have continuous coverage of LRO when the vehicle is not behind the Moon.
246 println!("{arc}");
247
248 // Now that we have simulated measurements, we'll run the orbit determination.
249
250 // ===================== //
251 // === OD ESTIMATION === //
252 // ===================== //
253
254 let sc = SpacecraftUncertainty::builder()
255 .nominal(sc_seed)
256 .frame(LocalFrame::RIC)
257 .x_km(0.5)
258 .y_km(0.5)
259 .z_km(0.5)
260 .vx_km_s(5e-3)
261 .vy_km_s(5e-3)
262 .vz_km_s(5e-3)
263 .build();
264
265 // Build the filter initial estimate, which we will reuse in the filter.
266 let mut initial_estimate = sc.to_estimate()?;
267 initial_estimate.covar *= 3.0;
268
269 println!("== FILTER STATE ==\n{sc_seed:x}\n{initial_estimate}");
270
271 // Build the SNC in the Moon J2000 frame, specified as a velocity noise over time.
272 let process_noise = ProcessNoise3D::from_velocity_km_s(
273 &[1e-10, 1e-10, 1e-10],
274 1 * Unit::Hour,
275 10 * Unit::Minute,
276 None,
277 );
278
279 println!("{process_noise}");
280
281 // We'll set up the OD process to reject measurements whose residuals are move than 3 sigmas away from what we expect.
282 let odp = SpacecraftKalmanOD::new(
283 setup,
284 KalmanVariant::ReferenceUpdate,
285 Some(ResidRejectCrit::default()),
286 proc_devices,
287 almanac.clone(),
288 )
289 .with_process_noise(process_noise);
290
291 let od_sol = odp.process_arc(initial_estimate, &arc)?;
292
293 let final_est = od_sol.estimates.last().unwrap();
294
295 println!("{final_est}");
296
297 let ric_err = traj_as_flown
298 .at(final_est.epoch())?
299 .orbit
300 .ric_difference(&final_est.orbital_state())?;
301 println!("== RIC at end ==");
302 println!("RIC Position (m): {:.3}", ric_err.radius_km * 1e3);
303 println!("RIC Velocity (m/s): {:.3}", ric_err.velocity_km_s * 1e3);
304
305 println!(
306 "Num residuals rejected: #{}",
307 od_sol.rejected_residuals().len()
308 );
309 println!(
310 "Percentage within +/-3: {}",
311 od_sol.residual_ratio_within_threshold(3.0).unwrap()
312 );
313 println!("Ratios normal? {}", od_sol.is_normal(None).unwrap());
314
315 od_sol.to_parquet(
316 "./data/04_output/04_lro_od_results.parquet",
317 ExportCfg::default(),
318 )?;
319
320 // Create the ephemeris
321 let ephem = od_sol.to_ephemeris("LRO rebuilt".to_string());
322 let ephem_start = ephem.start_epoch().unwrap();
323 let ephem_end = ephem.end_epoch().unwrap();
324 // Check that the covariance is PSD throughout the ephemeris by interpolating it.
325 for epoch in TimeSeries::inclusive(ephem_start, ephem_end, Unit::Minute * 5) {
326 ephem
327 .covar_at(
328 epoch,
329 anise::ephemerides::ephemeris::LocalFrame::RIC,
330 &almanac,
331 )
332 .unwrap_or_else(|e| panic!("covar not PSD at {epoch}: {e}"));
333 }
334 // Export as BSP!
335 ephem
336 .write_spice_bsp(-85, "./data/04_output/04_lro_rebuilt.bsp", None)
337 .expect("could not built BSP");
338 let new_almanac = Almanac::default()
339 .load("./data/04_output/04_lro_rebuilt.bsp")
340 .unwrap();
341 new_almanac.describe(None, None, None, None, None, None, None, None);
342 let (spk_start, spk_end) = new_almanac.spk_domain(-85).unwrap();
343
344 assert!((ephem_start - spk_start).abs() < Unit::Microsecond * 1);
345 assert!((ephem_end - spk_end).abs() < Unit::Microsecond * 1);
346
347 // In our case, we have the truth trajectory from NASA.
348 // So we can compute the RIC state difference between the real LRO ephem and what we've just estimated.
349 // Export the OD trajectory first.
350 let od_trajectory = od_sol.to_traj()?;
351 // Build the RIC difference.
352 od_trajectory.ric_diff_to_parquet(
353 &traj_as_flown,
354 "./data/04_output/04_lro_od_truth_error.parquet",
355 ExportCfg::default(),
356 )?;
357
358 Ok(())
359}Source§impl SpacecraftUncertainty
impl SpacecraftUncertainty
Sourcepub fn to_estimate(&self) -> PhysicsResult<KfEstimate<Spacecraft>>
pub fn to_estimate(&self) -> PhysicsResult<KfEstimate<Spacecraft>>
Builds a Kalman filter estimate for a spacecraft state, ready to ingest into an OD Process.
Note: this function will rotate from the provided local frame into the inertial frame with the same central body.
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.clone())?;
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 = [env!("CARGO_MANIFEST_DIR"), "examples", "04_lro_od"]
46 .iter()
47 .collect();
48
49 let meta = data_folder.join("lro-dynamics.dhall");
50
51 // Load this ephem in the general Almanac we're using for this analysis.
52 let mut almanac = MetaAlmanac::new(meta.to_string_lossy().as_ref())
53 .map_err(Box::new)?
54 .process(true)
55 .map_err(Box::new)?;
56
57 let mut moon_pc = almanac.get_planetary_data_from_id(MOON).unwrap();
58 moon_pc.mu_km3_s2 = 4902.74987;
59 almanac.set_planetary_data_from_id(MOON, moon_pc).unwrap();
60
61 let mut earth = almanac.get_planetary_data_from_id(EARTH).unwrap();
62 earth.mu_km3_s2 = 398600.436;
63 almanac.set_planetary_data_from_id(EARTH, earth).unwrap();
64
65 // Save this new kernel for reuse.
66 // In an operational context, this would be part of the "Lock" process, and should not change throughout the mission.
67 almanac
68 .planetary_data
69 .values()
70 .next()
71 .unwrap()
72 .save_as(&data_folder.join("lro-specific.pca"), true)?;
73
74 // Lock the almanac (an Arc is a read only structure).
75 let almanac = Arc::new(almanac);
76
77 // Orbit determination requires a Trajectory structure, which can be saved as parquet file.
78 // In our case, the trajectory comes from the BSP file, so we need to build a Trajectory from the almanac directly.
79 // To query the Almanac, we need to build the LRO frame in the J2000 orientation in our case.
80 // Inspecting the LRO BSP in the ANISE GUI shows us that NASA has assigned ID -85 to LRO.
81 let lro_frame = Frame::from_ephem_j2000(-85);
82
83 // To build the trajectory we need to provide a spacecraft template.
84 let sc_template = Spacecraft::builder()
85 .mass(Mass::from_dry_and_prop_masses(1018.0, 900.0)) // Launch masses
86 .srp(SRPData {
87 // SRP configuration is arbitrary, but we will be estimating it anyway.
88 area_m2: 3.9 * 2.7,
89 coeff_reflectivity: 0.96,
90 })
91 .orbit(Orbit::zero(MOON_J2000)) // Setting a zero orbit here because it's just a template
92 .build();
93 // Now we can build the trajectory from the BSP file.
94 // We'll arbitrarily set the tracking arc to 24 hours with a five second time step.
95 let traj_as_flown = Traj::from_bsp(
96 lro_frame,
97 MOON_J2000,
98 almanac.clone(),
99 sc_template,
100 5.seconds(),
101 Some(Epoch::from_str("2024-01-01 00:00:00 UTC")?),
102 Some(Epoch::from_str("2024-01-02 00:00:00 UTC")?),
103 Aberration::LT,
104 Some("LRO".to_string()),
105 )?;
106
107 println!("{traj_as_flown}");
108
109 // ====================== //
110 // === MODEL MATCHING === //
111 // ====================== //
112
113 // Set up the spacecraft dynamics.
114
115 // Specify that the orbital dynamics must account for the graviational pull of the Earth and the Sun.
116 // The gravity of the Moon will also be accounted for since the spaceraft in a lunar orbit.
117 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![EARTH, SUN, JUPITER_BARYCENTER]);
118
119 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
120 // We're using the GRAIL JGGRX model.
121 let mut jggrx_meta = MetaFile {
122 uri: "http://public-data.nyxspace.com/nyx/models/Luna_jggrx_1500e_sha.tab.gz".to_string(),
123 crc32: Some(0x6bcacda8), // Specifying the CRC32 avoids redownloading it if it's cached.
124 };
125 // And let's download it if we don't have it yet.
126 jggrx_meta.process(true)?;
127
128 // Build the spherical harmonics.
129 // The harmonics must be computed in the body fixed frame.
130 // We're using the long term prediction of the Moon principal axes frame.
131 let moon_pa_frame = MOON_PA_FRAME.with_orient(31008);
132 let sph_harmonics = Harmonics::from_stor(
133 almanac.frame_info(moon_pa_frame)?,
134 HarmonicsMem::from_shadr(&jggrx_meta.uri, 80, 80, true)?,
135 );
136
137 // Include the spherical harmonics into the orbital dynamics.
138 orbital_dyn.accel_models.push(sph_harmonics);
139
140 // We define the solar radiation pressure, using the default solar flux and accounting only
141 // for the eclipsing caused by the Earth and Moon.
142 // Note that by default, enabling the SolarPressure model will also enable the estimation of the coefficient of reflectivity.
143 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], almanac.clone())?;
144
145 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
146 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
147 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
148
149 println!("{dynamics}");
150
151 // Now we can build the propagator.
152 let setup = Propagator::default_dp78(dynamics.clone());
153
154 // For reference, let's build the trajectory with Nyx's models from that LRO state.
155 let (sim_final, traj_as_sim) = setup
156 .with(*traj_as_flown.first(), almanac.clone())
157 .until_epoch_with_traj(traj_as_flown.last().epoch())?;
158
159 println!("SIM INIT: {:x}", traj_as_flown.first());
160 println!("SIM FINAL: {sim_final:x}");
161 // Compute RIC difference between SIM and LRO ephem
162 let sim_lro_delta = sim_final
163 .orbit
164 .ric_difference(&traj_as_flown.last().orbit)?;
165 println!("{traj_as_sim}");
166 println!(
167 "SIM v LRO - RIC Position (m): {:.3}",
168 sim_lro_delta.radius_km * 1e3
169 );
170 println!(
171 "SIM v LRO - RIC Velocity (m/s): {:.3}",
172 sim_lro_delta.velocity_km_s * 1e3
173 );
174
175 traj_as_sim.ric_diff_to_parquet(
176 &traj_as_flown,
177 "./data/04_output/04_lro_sim_truth_error.parquet",
178 ExportCfg::default(),
179 )?;
180
181 // ==================== //
182 // === OD SIMULATOR === //
183 // ==================== //
184
185 // 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
186 // and the truth LRO state.
187
188 // Therefore, we will actually run an estimation from a dispersed LRO state.
189 // The sc_seed is the true LRO state from the BSP.
190 let sc_seed = *traj_as_flown.first();
191
192 // Load the Deep Space Network ground stations.
193 // Nyx allows you to build these at runtime but it's pretty static so we can just load them from YAML.
194 let ground_station_file: PathBuf = [
195 env!("CARGO_MANIFEST_DIR"),
196 "examples",
197 "04_lro_od",
198 "dsn-network.yaml",
199 ]
200 .iter()
201 .collect();
202
203 let devices = GroundStation::load_named(ground_station_file)?;
204
205 let mut proc_devices = devices.clone();
206
207 // Increase the noise in the devices to accept more measurements.
208 for gs in proc_devices.values_mut() {
209 if let Some(noise) = &mut gs
210 .stochastic_noises
211 .as_mut()
212 .unwrap()
213 .get_mut(&MeasurementType::Range)
214 {
215 *noise.white_noise.as_mut().unwrap() *= 3.0;
216 }
217 }
218
219 // Typical OD software requires that you specify your own tracking schedule or you'll have overlapping measurements.
220 // Nyx can build a tracking schedule for you based on the first station with access.
221 let trkconfg_yaml: PathBuf = [
222 env!("CARGO_MANIFEST_DIR"),
223 "examples",
224 "04_lro_od",
225 "tracking-cfg.yaml",
226 ]
227 .iter()
228 .collect();
229
230 let configs: BTreeMap<String, TrkConfig> = TrkConfig::load_named(trkconfg_yaml)?;
231
232 // Build the tracking arc simulation to generate a "standard measurement".
233 let mut trk = TrackingArcSim::<Spacecraft, GroundStation>::with_seed(
234 devices.clone(),
235 traj_as_flown.clone(),
236 configs,
237 123, // Set a seed for reproducibility
238 )?;
239
240 trk.build_schedule(almanac.clone())?;
241 let arc = trk.generate_measurements(almanac.clone())?;
242 // Save the simulated tracking data
243 arc.to_parquet_simple("./data/04_output/04_lro_simulated_tracking.parquet")?;
244
245 // We'll note that in our case, we have continuous coverage of LRO when the vehicle is not behind the Moon.
246 println!("{arc}");
247
248 // Now that we have simulated measurements, we'll run the orbit determination.
249
250 // ===================== //
251 // === OD ESTIMATION === //
252 // ===================== //
253
254 let sc = SpacecraftUncertainty::builder()
255 .nominal(sc_seed)
256 .frame(LocalFrame::RIC)
257 .x_km(0.5)
258 .y_km(0.5)
259 .z_km(0.5)
260 .vx_km_s(5e-3)
261 .vy_km_s(5e-3)
262 .vz_km_s(5e-3)
263 .build();
264
265 // Build the filter initial estimate, which we will reuse in the filter.
266 let mut initial_estimate = sc.to_estimate()?;
267 initial_estimate.covar *= 3.0;
268
269 println!("== FILTER STATE ==\n{sc_seed:x}\n{initial_estimate}");
270
271 // Build the SNC in the Moon J2000 frame, specified as a velocity noise over time.
272 let process_noise = ProcessNoise3D::from_velocity_km_s(
273 &[1e-10, 1e-10, 1e-10],
274 1 * Unit::Hour,
275 10 * Unit::Minute,
276 None,
277 );
278
279 println!("{process_noise}");
280
281 // We'll set up the OD process to reject measurements whose residuals are move than 3 sigmas away from what we expect.
282 let odp = SpacecraftKalmanOD::new(
283 setup,
284 KalmanVariant::ReferenceUpdate,
285 Some(ResidRejectCrit::default()),
286 proc_devices,
287 almanac.clone(),
288 )
289 .with_process_noise(process_noise);
290
291 let od_sol = odp.process_arc(initial_estimate, &arc)?;
292
293 let final_est = od_sol.estimates.last().unwrap();
294
295 println!("{final_est}");
296
297 let ric_err = traj_as_flown
298 .at(final_est.epoch())?
299 .orbit
300 .ric_difference(&final_est.orbital_state())?;
301 println!("== RIC at end ==");
302 println!("RIC Position (m): {:.3}", ric_err.radius_km * 1e3);
303 println!("RIC Velocity (m/s): {:.3}", ric_err.velocity_km_s * 1e3);
304
305 println!(
306 "Num residuals rejected: #{}",
307 od_sol.rejected_residuals().len()
308 );
309 println!(
310 "Percentage within +/-3: {}",
311 od_sol.residual_ratio_within_threshold(3.0).unwrap()
312 );
313 println!("Ratios normal? {}", od_sol.is_normal(None).unwrap());
314
315 od_sol.to_parquet(
316 "./data/04_output/04_lro_od_results.parquet",
317 ExportCfg::default(),
318 )?;
319
320 // Create the ephemeris
321 let ephem = od_sol.to_ephemeris("LRO rebuilt".to_string());
322 let ephem_start = ephem.start_epoch().unwrap();
323 let ephem_end = ephem.end_epoch().unwrap();
324 // Check that the covariance is PSD throughout the ephemeris by interpolating it.
325 for epoch in TimeSeries::inclusive(ephem_start, ephem_end, Unit::Minute * 5) {
326 ephem
327 .covar_at(
328 epoch,
329 anise::ephemerides::ephemeris::LocalFrame::RIC,
330 &almanac,
331 )
332 .unwrap_or_else(|e| panic!("covar not PSD at {epoch}: {e}"));
333 }
334 // Export as BSP!
335 ephem
336 .write_spice_bsp(-85, "./data/04_output/04_lro_rebuilt.bsp", None)
337 .expect("could not built BSP");
338 let new_almanac = Almanac::default()
339 .load("./data/04_output/04_lro_rebuilt.bsp")
340 .unwrap();
341 new_almanac.describe(None, None, None, None, None, None, None, None);
342 let (spk_start, spk_end) = new_almanac.spk_domain(-85).unwrap();
343
344 assert!((ephem_start - spk_start).abs() < Unit::Microsecond * 1);
345 assert!((ephem_end - spk_end).abs() < Unit::Microsecond * 1);
346
347 // In our case, we have the truth trajectory from NASA.
348 // So we can compute the RIC state difference between the real LRO ephem and what we've just estimated.
349 // Export the OD trajectory first.
350 let od_trajectory = od_sol.to_traj()?;
351 // Build the RIC difference.
352 od_trajectory.ric_diff_to_parquet(
353 &traj_as_flown,
354 "./data/04_output/04_lro_od_truth_error.parquet",
355 ExportCfg::default(),
356 )?;
357
358 Ok(())
359}Sourcepub fn to_estimate_randomized(
&self,
seed: Option<u128>,
) -> PhysicsResult<KfEstimate<Spacecraft>>
pub fn to_estimate_randomized( &self, seed: Option<u128>, ) -> PhysicsResult<KfEstimate<Spacecraft>>
Returns an estimation whose nominal state is dispersed. Known bug in MultiVariate dispersion: https://github.com/nyx-space/nyx/issues/339
Examples found in repository?
34fn main() -> Result<(), Box<dyn Error>> {
35 pel::init();
36
37 // ====================== //
38 // === ALMANAC SET UP === //
39 // ====================== //
40
41 let manifest_dir =
42 PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap_or(".".to_string()));
43
44 let out = manifest_dir.join("data/04_output/");
45
46 let almanac = Arc::new(
47 Almanac::new(
48 &manifest_dir
49 .join("data/01_planetary/pck08.pca")
50 .to_string_lossy(),
51 )
52 .unwrap()
53 .load(
54 &manifest_dir
55 .join("data/01_planetary/de440s.bsp")
56 .to_string_lossy(),
57 )
58 .unwrap(),
59 );
60
61 let eme2k = almanac.frame_info(EARTH_J2000).unwrap();
62 let moon_iau = almanac.frame_info(IAU_MOON_FRAME).unwrap();
63
64 let epoch = Epoch::from_gregorian_tai(2021, 5, 29, 19, 51, 16, 852_000);
65 let nrho = Orbit::cartesian(
66 166_473.631_302_239_7,
67 -274_715.487_253_382_7,
68 -211_233.210_176_686_7,
69 0.933_451_604_520_018_4,
70 0.436_775_046_841_900_9,
71 -0.082_211_021_250_348_95,
72 epoch,
73 eme2k,
74 );
75
76 let tx_nrho_sc = Spacecraft::from(nrho);
77
78 let state_luna = almanac.transform_to(nrho, MOON_J2000, None).unwrap();
79 println!("Start state (dynamics: Earth, Moon, Sun gravity):\n{state_luna}");
80
81 let bodies = vec![EARTH, SUN];
82 let dynamics = SpacecraftDynamics::new(OrbitalDynamics::point_masses(bodies));
83
84 let setup = Propagator::rk89(
85 dynamics,
86 IntegratorOptions::builder().max_step(0.5.minutes()).build(),
87 );
88
89 /* == Propagate the NRHO vehicle == */
90 let prop_time = 1.1 * state_luna.period().unwrap();
91
92 let (nrho_final, mut tx_traj) = setup
93 .with(tx_nrho_sc, almanac.clone())
94 .for_duration_with_traj(prop_time)
95 .unwrap();
96
97 tx_traj.name = Some("NRHO Tx SC".to_string());
98
99 println!("{tx_traj}");
100
101 /* == Propagate an LLO vehicle == */
102 let llo_orbit =
103 Orbit::try_keplerian_altitude(110.0, 1e-4, 90.0, 0.0, 0.0, 0.0, epoch, moon_iau).unwrap();
104
105 let llo_sc = Spacecraft::builder().orbit(llo_orbit).build();
106
107 let (_, llo_traj) = setup
108 .with(llo_sc, almanac.clone())
109 .until_epoch_with_traj(nrho_final.epoch())
110 .unwrap();
111
112 // Export the subset of the first two hours.
113 llo_traj
114 .clone()
115 .filter_by_offset(..2.hours())
116 .to_parquet_simple(out.join("05_caps_llo_truth.pq"))?;
117
118 /* == Setup the interlink == */
119
120 let mut measurement_types = IndexSet::new();
121 measurement_types.insert(MeasurementType::Range);
122 measurement_types.insert(MeasurementType::Doppler);
123
124 let mut stochastics = IndexMap::new();
125
126 let sa45_csac_allan_dev = 1e-11;
127
128 stochastics.insert(
129 MeasurementType::Range,
130 StochasticNoise::from_hardware_range_km(
131 sa45_csac_allan_dev,
132 10.0.seconds(),
133 link_specific::ChipRate::StandardT4B,
134 link_specific::SN0::Average,
135 ),
136 );
137
138 stochastics.insert(
139 MeasurementType::Doppler,
140 StochasticNoise::from_hardware_doppler_km_s(
141 sa45_csac_allan_dev,
142 10.0.seconds(),
143 link_specific::CarrierFreq::SBand,
144 link_specific::CN0::Average,
145 ),
146 );
147
148 let interlink = InterlinkTxSpacecraft {
149 traj: tx_traj,
150 measurement_types,
151 integration_time: None,
152 timestamp_noise_s: None,
153 ab_corr: Aberration::LT,
154 stochastic_noises: Some(stochastics),
155 };
156
157 // Devices are the transmitter, which is our NRHO vehicle.
158 let mut devices = BTreeMap::new();
159 devices.insert("NRHO Tx SC".to_string(), interlink);
160
161 let mut configs = BTreeMap::new();
162 configs.insert(
163 "NRHO Tx SC".to_string(),
164 TrkConfig::builder()
165 .strands(vec![Strand {
166 start: epoch,
167 end: nrho_final.epoch(),
168 }])
169 .build(),
170 );
171
172 let mut trk_sim =
173 TrackingArcSim::with_seed(devices.clone(), llo_traj.clone(), configs, 0).unwrap();
174 println!("{trk_sim}");
175
176 let trk_data = trk_sim.generate_measurements(almanac.clone()).unwrap();
177 println!("{trk_data}");
178
179 trk_data
180 .to_parquet_simple(out.clone().join("nrho_interlink_msr.pq"))
181 .unwrap();
182
183 // Run a truth OD where we estimate the LLO position
184 let llo_uncertainty = SpacecraftUncertainty::builder()
185 .nominal(llo_sc)
186 .x_km(1.0)
187 .y_km(1.0)
188 .z_km(1.0)
189 .vx_km_s(1e-3)
190 .vy_km_s(1e-3)
191 .vz_km_s(1e-3)
192 .build();
193
194 let mut proc_devices = devices.clone();
195
196 // Define the initial estimate, randomized, seed for reproducibility
197 let mut initial_estimate = llo_uncertainty.to_estimate_randomized(Some(0)).unwrap();
198 // Inflate the covariance -- https://github.com/nyx-space/nyx/issues/339
199 initial_estimate.covar *= 2.5;
200
201 // Increase the noise in the devices to accept more measurements.
202
203 for link in proc_devices.values_mut() {
204 for noise in &mut link.stochastic_noises.as_mut().unwrap().values_mut() {
205 *noise.white_noise.as_mut().unwrap() *= 3.0;
206 }
207 }
208
209 let init_err = initial_estimate
210 .orbital_state()
211 .ric_difference(&llo_orbit)
212 .unwrap();
213
214 println!("initial estimate:\n{initial_estimate}");
215 println!("RIC errors = {init_err}",);
216
217 let odp = InterlinkKalmanOD::new(
218 setup.clone(),
219 KalmanVariant::ReferenceUpdate,
220 Some(ResidRejectCrit::default()),
221 proc_devices,
222 almanac.clone(),
223 );
224
225 // Shrink the data to process.
226 let arc = trk_data.filter_by_offset(..2.hours());
227
228 let od_sol = odp.process_arc(initial_estimate, &arc).unwrap();
229
230 println!("{od_sol}");
231
232 od_sol
233 .to_parquet(
234 out.join("05_caps_interlink_od_sol.pq"),
235 ExportCfg::default(),
236 )
237 .unwrap();
238
239 let od_traj = od_sol.to_traj().unwrap();
240
241 od_traj
242 .ric_diff_to_parquet(
243 &llo_traj,
244 out.join("05_caps_interlink_llo_est_error.pq"),
245 ExportCfg::default(),
246 )
247 .unwrap();
248
249 let final_est = od_sol.estimates.last().unwrap();
250 assert!(final_est.within_3sigma(), "should be within 3 sigma");
251
252 println!("ESTIMATE\n{final_est:x}\n");
253 let truth = llo_traj.at(final_est.epoch()).unwrap();
254 println!("TRUTH\n{truth:x}");
255
256 let final_err = truth
257 .orbit
258 .ric_difference(&final_est.orbital_state())
259 .unwrap();
260 println!("ERROR {final_err}");
261
262 // Build the residuals versus reference plot.
263 let rvr_sol = odp
264 .process_arc(initial_estimate, &arc.resid_vs_ref_check())
265 .unwrap();
266
267 rvr_sol
268 .to_parquet(
269 out.join("05_caps_interlink_resid_v_ref.pq"),
270 ExportCfg::default(),
271 )
272 .unwrap();
273
274 let final_rvr = rvr_sol.estimates.last().unwrap();
275
276 println!("RMAG error {:.3} m", final_err.rmag_km() * 1e3);
277 println!(
278 "Pure prop error {:.3} m",
279 final_rvr
280 .orbital_state()
281 .ric_difference(&final_est.orbital_state())
282 .unwrap()
283 .rmag_km()
284 * 1e3
285 );
286
287 Ok(())
288}Trait Implementations§
Source§impl Clone for SpacecraftUncertainty
impl Clone for SpacecraftUncertainty
Source§fn clone(&self) -> SpacecraftUncertainty
fn clone(&self) -> SpacecraftUncertainty
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moreSource§impl Debug for SpacecraftUncertainty
impl Debug for SpacecraftUncertainty
Source§impl Display for SpacecraftUncertainty
impl Display for SpacecraftUncertainty
impl Copy for SpacecraftUncertainty
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