pub struct TrackingArcSim<MsrIn, D>where
D: TrackingDevice<MsrIn>,
MsrIn: State + Interpolatable,
DefaultAllocator: Allocator<<MsrIn as State>::Size> + Allocator<<MsrIn as State>::Size, <MsrIn as State>::Size> + Allocator<<MsrIn as State>::VecLength>,{
pub devices: BTreeMap<String, D>,
pub trajectory: Traj<MsrIn>,
pub configs: BTreeMap<String, TrkConfig>,
/* private fields */
}Fields§
§devices: BTreeMap<String, D>Map of devices from their names.
trajectory: Traj<MsrIn>Receiver trajectory
configs: BTreeMap<String, TrkConfig>Configuration of each device
Implementations§
Source§impl<MsrIn, D> TrackingArcSim<MsrIn, D>where
D: TrackingDevice<MsrIn>,
MsrIn: State + Interpolatable,
DefaultAllocator: Allocator<<MsrIn as State>::Size> + Allocator<<MsrIn as State>::Size, <MsrIn as State>::Size> + Allocator<<MsrIn as State>::VecLength>,
impl<MsrIn, D> TrackingArcSim<MsrIn, D>where
D: TrackingDevice<MsrIn>,
MsrIn: State + Interpolatable,
DefaultAllocator: Allocator<<MsrIn as State>::Size> + Allocator<<MsrIn as State>::Size, <MsrIn as State>::Size> + Allocator<<MsrIn as State>::VecLength>,
Sourcepub fn with_rng(
devices: BTreeMap<String, D>,
trajectory: Traj<MsrIn>,
configs: BTreeMap<String, TrkConfig>,
rng: Pcg64Mcg,
) -> Result<Self, ConfigError>
pub fn with_rng( devices: BTreeMap<String, D>, trajectory: Traj<MsrIn>, configs: BTreeMap<String, TrkConfig>, rng: Pcg64Mcg, ) -> Result<Self, ConfigError>
Constructs a deterministic tracking simulator initialized with a specific random number generator.
Evaluates the configuration of all provided devices, filtering out invalid definitions via sanity checks. Computes the greatest common denominator (GCD) of all configured sampling rates to construct a unified, high-fidelity time series encompassing the entire trajectory span. This ensures that interpolation artifacts are minimized when extracting state vectors at non-uniform station sampling intervals.
Sourcepub fn with_seed(
devices: BTreeMap<String, D>,
trajectory: Traj<MsrIn>,
configs: BTreeMap<String, TrkConfig>,
seed: u64,
) -> Result<Self, ConfigError>
pub fn with_seed( devices: BTreeMap<String, D>, trajectory: Traj<MsrIn>, configs: BTreeMap<String, TrkConfig>, seed: u64, ) -> Result<Self, ConfigError>
Build a new tracking arc simulator using the provided seed to initialize the random number generator.
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 = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
42
43 let out = manifest_dir.join("data/04_output/");
44
45 let almanac = Arc::new(
46 Almanac::new(
47 &manifest_dir
48 .join("data/01_planetary/pck08.pca")
49 .to_string_lossy(),
50 )
51 .unwrap()
52 .load(
53 &manifest_dir
54 .join("data/01_planetary/de440s.bsp")
55 .to_string_lossy(),
56 )
57 .unwrap(),
58 );
59
60 let eme2k = almanac.frame_info(EARTH_J2000).unwrap();
61 let moon_iau = almanac.frame_info(IAU_MOON_FRAME).unwrap();
62
63 let epoch = Epoch::from_gregorian_tai(2021, 5, 29, 19, 51, 16, 852_000);
64 let nrho = Orbit::cartesian(
65 166_473.631_302_239_7,
66 -274_715.487_253_382_7,
67 -211_233.210_176_686_7,
68 0.933_451_604_520_018_4,
69 0.436_775_046_841_900_9,
70 -0.082_211_021_250_348_95,
71 epoch,
72 eme2k,
73 );
74
75 let tx_nrho_sc = Spacecraft::from(nrho);
76
77 let state_luna = almanac.transform_to(nrho, MOON_J2000, None).unwrap();
78 println!("Start state (dynamics: Earth, Moon, Sun gravity):\n{state_luna}");
79
80 let bodies = vec![EARTH, SUN];
81 let dynamics = SpacecraftDynamics::new(OrbitalDynamics::point_masses(bodies));
82
83 let setup = Propagator::rk89(
84 dynamics,
85 IntegratorOptions::builder().max_step(0.5.minutes()).build(),
86 );
87
88 /* == Propagate the NRHO vehicle == */
89 let prop_time = 1.1 * state_luna.period().unwrap();
90
91 let (nrho_final, mut tx_traj) = setup
92 .with(tx_nrho_sc, almanac.clone())
93 .for_duration_with_traj(prop_time)
94 .unwrap();
95
96 tx_traj.name = Some("NRHO Tx SC".to_string());
97
98 println!("{tx_traj}");
99
100 /* == Propagate an LLO vehicle == */
101 let llo_orbit =
102 Orbit::try_keplerian_altitude(110.0, 1e-4, 90.0, 0.0, 0.0, 0.0, epoch, moon_iau).unwrap();
103
104 let llo_sc = Spacecraft::builder().orbit(llo_orbit).build();
105
106 let (_, llo_traj) = setup
107 .with(llo_sc, almanac.clone())
108 .until_epoch_with_traj(nrho_final.epoch())
109 .unwrap();
110
111 // Export the subset of the first two hours.
112 llo_traj
113 .clone()
114 .filter_by_offset(..2.hours())
115 .to_parquet_simple(out.join("05_caps_llo_truth.pq"))?;
116
117 /* == Setup the interlink == */
118
119 let mut measurement_types = IndexSet::new();
120 measurement_types.insert(MeasurementType::Range);
121 measurement_types.insert(MeasurementType::Doppler);
122
123 let mut stochastics = IndexMap::new();
124
125 let sa45_csac_allan_dev = 1e-11;
126
127 stochastics.insert(
128 MeasurementType::Range,
129 StochasticNoise::from_hardware_range_km(
130 sa45_csac_allan_dev,
131 10.0.seconds(),
132 link_specific::ChipRate::StandardT4B(),
133 link_specific::SN0::Average(),
134 ),
135 );
136
137 stochastics.insert(
138 MeasurementType::Doppler,
139 StochasticNoise::from_hardware_doppler_km_s(
140 sa45_csac_allan_dev,
141 10.0.seconds(),
142 link_specific::CarrierFreq::SBand(),
143 link_specific::CN0::Average(),
144 ),
145 );
146
147 let interlink = InterlinkTxSpacecraft {
148 traj: tx_traj,
149 measurement_types,
150 integration_time: None,
151 timestamp_noise_s: None,
152 ab_corr: Aberration::LT,
153 stochastic_noises: Some(stochastics),
154 };
155
156 // Devices are the transmitter, which is our NRHO vehicle.
157 let mut devices = BTreeMap::new();
158 devices.insert("NRHO Tx SC".to_string(), interlink);
159
160 let mut configs = BTreeMap::new();
161 configs.insert(
162 "NRHO Tx SC".to_string(),
163 TrkConfig::builder()
164 .strands(vec![Strand {
165 start: epoch,
166 end: nrho_final.epoch(),
167 }])
168 .build(),
169 );
170
171 let mut trk_sim =
172 TrackingArcSim::with_seed(devices.clone(), llo_traj.clone(), configs, 0).unwrap();
173 println!("{trk_sim}");
174
175 let trk_data = trk_sim.generate_measurements(&almanac).unwrap();
176 println!("{trk_data}");
177
178 trk_data
179 .to_parquet_simple(out.clone().join("nrho_interlink_msr.pq"))
180 .unwrap();
181
182 // Run a truth OD where we estimate the LLO position
183 let llo_uncertainty = SpacecraftUncertainty::builder()
184 .nominal(llo_sc)
185 .x_km(1.0)
186 .y_km(1.0)
187 .z_km(1.0)
188 .vx_km_s(1e-3)
189 .vy_km_s(1e-3)
190 .vz_km_s(1e-3)
191 .build();
192
193 let mut proc_devices = devices.clone();
194
195 // Define the initial estimate, randomized, seed for reproducibility
196 let mut initial_estimate = llo_uncertainty.to_estimate_randomized(Some(0)).unwrap();
197 // Inflate the covariance -- https://github.com/nyx-space/nyx/issues/339
198 initial_estimate.covar *= 2.5;
199
200 // Increase the noise in the devices to accept more measurements.
201
202 for link in proc_devices.values_mut() {
203 for noise in &mut link.stochastic_noises.as_mut().unwrap().values_mut() {
204 *noise.white_noise.as_mut().unwrap() *= 3.0;
205 }
206 }
207
208 let init_err = initial_estimate
209 .orbital_state()
210 .ric_difference(&llo_orbit)
211 .unwrap();
212
213 println!("initial estimate:\n{initial_estimate}");
214 println!("RIC errors = {init_err}",);
215
216 let odp = InterlinkKalmanOD::new(
217 setup.clone(),
218 KalmanVariant::ReferenceUpdate,
219 Some(SigmaRejection::default()),
220 proc_devices,
221 almanac.clone(),
222 );
223
224 // Shrink the data to process.
225 let arc = trk_data.filter_by_offset(..2.hours());
226
227 let od_sol = odp.process_arc(initial_estimate, &arc).unwrap();
228
229 println!("{od_sol}");
230
231 od_sol
232 .to_parquet(
233 out.join("05_caps_interlink_od_sol.pq"),
234 ExportCfg::default(),
235 )
236 .unwrap();
237
238 let od_traj = od_sol.to_traj().unwrap();
239
240 od_traj
241 .ric_diff_to_parquet(
242 &llo_traj,
243 out.join("05_caps_interlink_llo_est_error.pq"),
244 ExportCfg::default(),
245 )
246 .unwrap();
247
248 let final_est = od_sol.estimates.last().unwrap();
249 assert!(final_est.within_3sigma(), "should be within 3 sigma");
250
251 println!("ESTIMATE\n{final_est:x}\n");
252 let truth = llo_traj.at(final_est.epoch()).unwrap();
253 println!("TRUTH\n{truth:x}");
254
255 let final_err = truth
256 .orbit
257 .ric_difference(&final_est.orbital_state())
258 .unwrap();
259 println!("ERROR {final_err}");
260
261 // Build the residuals versus reference plot.
262 let rvr_sol = odp
263 .process_arc(initial_estimate, &arc.resid_vs_ref_check())
264 .unwrap();
265
266 rvr_sol
267 .to_parquet(
268 out.join("05_caps_interlink_resid_v_ref.pq"),
269 ExportCfg::default(),
270 )
271 .unwrap();
272
273 let final_rvr = rvr_sol.estimates.last().unwrap();
274
275 println!("RMAG error {:.3} m", final_err.rmag_km() * 1e3);
276 println!(
277 "Pure prop error {:.3} m",
278 final_rvr
279 .orbital_state()
280 .ric_difference(&final_est.orbital_state())
281 .unwrap()
282 .rmag_km()
283 * 1e3
284 );
285
286 Ok(())
287}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}34fn main() -> Result<(), Box<dyn Error>> {
35 pel::init();
36
37 // ====================== //
38 // === ALMANAC SET UP === //
39 // ====================== //
40
41 // Dynamics models require planetary constants and ephemerides to be defined.
42 // Let's start by grabbing those by using ANISE's MetaAlmanac.
43
44 let output_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "../data", "04_output"]
45 .iter()
46 .collect();
47
48 let data_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "examples", "04_lro_od"]
49 .iter()
50 .collect();
51
52 let meta = data_folder.join("lro-dynamics.dhall");
53
54 // Load this ephem in the general Almanac we're using for this analysis.
55 let almanac = Arc::new(
56 MetaAlmanac::new(meta.to_string_lossy().as_ref())
57 .map_err(Box::new)?
58 .process(true)
59 .map_err(Box::new)?,
60 );
61
62 // Orbit determination requires a Trajectory structure, which can be saved as parquet file.
63 // In our case, the trajectory comes from the BSP file, so we need to build a Trajectory from the almanac directly.
64 // To query the Almanac, we need to build the LRO frame in the J2000 orientation in our case.
65 // Inspecting the LRO BSP in the ANISE GUI shows us that NASA has assigned ID -85 to LRO.
66 let lro_frame = Frame::from_ephem_j2000(-85);
67
68 // To build the trajectory we need to provide a spacecraft template.
69 let sc_template = Spacecraft::builder()
70 .mass(Mass::from_dry_and_prop_masses(1018.0, 900.0)) // Launch masses
71 .srp(SRPData {
72 // SRP configuration is arbitrary, but we will be estimating it anyway.
73 area_m2: 3.9 * 2.7,
74 coeff_reflectivity: 0.96,
75 })
76 .orbit(Orbit::zero(MOON_J2000)) // Setting a zero orbit here because it's just a template
77 .build();
78 // Now we can build the trajectory from the BSP file.
79 // We'll arbitrarily set the tracking arc to 24 hours with a five second time step.
80 let traj_as_flown = Traj::from_bsp(
81 lro_frame,
82 MOON_J2000,
83 &almanac,
84 sc_template,
85 5.seconds(),
86 Some(Epoch::from_str("2024-01-01 01:00:00 UTC")?),
87 Some(Epoch::from_str("2024-01-02 01:00:00 UTC")?),
88 None,
89 Some("LRO".to_string()),
90 )?;
91
92 println!("{traj_as_flown}");
93
94 // ====================== //
95 // === MODEL MATCHING === //
96 // ====================== //
97
98 // Set up the spacecraft dynamics.
99
100 // Specify that the orbital dynamics must account for the graviational pull of the Earth and the Sun.
101 // The gravity of the Moon will also be accounted for since the spaceraft in a lunar orbit.
102 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![EARTH, SUN, JUPITER_BARYCENTER]);
103
104 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
105 // We're using the GRAIL JGGRX model.
106 let mut jggrx_meta = MetaFile {
107 uri: "http://public-data.nyxspace.com/nyx/models/Luna_jggrx_1500e_sha.tab.gz".to_string(),
108 crc32: Some(0x6bcacda8), // Specifying the CRC32 avoids redownloading it if it's cached.
109 };
110 // And let's download it if we don't have it yet.
111 jggrx_meta.process(true)?;
112
113 // Build the spherical harmonics.
114 // The harmonics must be computed in the body fixed frame.
115 // We're using the long term prediction of the Moon principal axes frame.
116 let moon_pa_frame = MOON_PA_FRAME.with_orient(31008);
117 let sph_harmonics = GravityField::new(GravityFieldData::from_shadr(
118 &jggrx_meta.uri,
119 81,
120 81,
121 almanac.frame_info(moon_pa_frame)?,
122 )?);
123
124 // Include the spherical harmonics into the orbital dynamics.
125 orbital_dyn.accel_models.push(sph_harmonics);
126
127 // We define the solar radiation pressure, using the default solar flux and accounting only
128 // for the eclipsing caused by the Earth and Moon.
129 // Note that by default, enabling the SolarPressure model will also enable the estimation of the coefficient of reflectivity.
130 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], &almanac)?;
131
132 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
133 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
134 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
135
136 println!("{dynamics}");
137
138 // Now we can build the propagator.
139 let setup = Propagator::default_dp78(dynamics.clone());
140
141 // For reference, let's build the trajectory with Nyx's models from that LRO state.
142 let (sim_final, traj_as_sim) = setup
143 .with(*traj_as_flown.first(), almanac.clone())
144 .until_epoch_with_traj(traj_as_flown.last().epoch())?;
145
146 println!("SIM INIT: {:x}", traj_as_flown.first());
147 println!("SIM FINAL: {sim_final:x}");
148 // Compute RIC difference between SIM and LRO ephem
149 let sim_lro_delta = sim_final
150 .orbit
151 .ric_difference(&traj_as_flown.last().orbit)?;
152 println!("{traj_as_sim}");
153 println!(
154 "SIM v LRO - RIC Position (m): {:.3}",
155 sim_lro_delta.radius_km * 1e3
156 );
157 println!(
158 "SIM v LRO - RIC Velocity (m/s): {:.3}",
159 sim_lro_delta.velocity_km_s * 1e3
160 );
161
162 traj_as_sim.ric_diff_to_parquet(
163 &traj_as_flown,
164 output_folder.join("./04_lro_sim_truth_error.parquet"),
165 ExportCfg::default(),
166 )?;
167
168 // ==================== //
169 // === OD SIMULATOR === //
170 // ==================== //
171
172 // 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
173 // and the truth LRO state.
174
175 // Therefore, we will actually run an estimation from a dispersed LRO state.
176 // The sc_seed is the true LRO state from the BSP.
177 let sc_seed = *traj_as_flown.first();
178
179 // Load the Deep Space Network ground stations.
180 // Nyx allows you to build these at runtime but it's pretty static so we can just load them from YAML.
181 let ground_station_file: PathBuf = [
182 env!("CARGO_MANIFEST_DIR"),
183 "examples",
184 "04_lro_od",
185 "dsn-network.yaml",
186 ]
187 .iter()
188 .collect();
189
190 let devices = GroundStation::load_named(ground_station_file)?;
191
192 let proc_devices = devices.clone();
193
194 // Typical OD software requires that you specify your own tracking schedule or you'll have overlapping measurements.
195 // Nyx can build a tracking schedule for you based on the first station with access.
196 let trkconfg_yaml: PathBuf = [
197 env!("CARGO_MANIFEST_DIR"),
198 "examples",
199 "04_lro_od",
200 "tracking-cfg.yaml",
201 ]
202 .iter()
203 .collect();
204
205 let configs: BTreeMap<String, TrkConfig> = TrkConfig::load_named(trkconfg_yaml)?;
206
207 // Build the tracking arc simulation to generate a "standard measurement".
208 let mut trk = TrackingArcSim::<Spacecraft, GroundStation>::with_seed(
209 devices.clone(),
210 traj_as_flown.clone(),
211 configs,
212 123, // Set a seed for reproducibility
213 )?;
214
215 trk.build_schedule(&almanac)?;
216 let arc = trk.generate_measurements(&almanac)?;
217 // Save the simulated tracking data
218 arc.to_parquet_simple(output_folder.join("04_lro_simulated_tracking.parquet"))?;
219
220 // We'll note that in our case, we have continuous coverage of LRO when the vehicle is not behind the Moon.
221 println!("{arc}");
222
223 // Now that we have simulated measurements, we'll run the orbit determination.
224
225 // ===================== //
226 // === OD ESTIMATION === //
227 // ===================== //
228
229 let sc = SpacecraftUncertainty::builder()
230 .nominal(sc_seed)
231 .frame(LocalFrame::RIC)
232 .x_km(0.5)
233 .y_km(0.5)
234 .z_km(0.5)
235 .vx_km_s(5e-3)
236 .vy_km_s(5e-3)
237 .vz_km_s(5e-3)
238 .build();
239
240 // Build the filter initial estimate, which we will reuse in the filter.
241 let mut initial_estimate = sc.to_estimate()?;
242 initial_estimate.covar *= 1.5;
243
244 println!("== FILTER STATE ==\n{sc_seed:x}\n{initial_estimate}");
245
246 // Build the SNC in the Moon J2000 frame, specified as a velocity noise over time.
247 let process_noise = ProcessNoise3D::from_velocity_km_s(
248 &[5e-13, 5e-13, 5e-13],
249 1 * Unit::Hour,
250 10 * Unit::Minute,
251 None,
252 );
253
254 println!("{process_noise}");
255
256 // We'll set up the OD process to reject measurements whose residuals are move than 3 sigmas away from what we expect.
257 let odp = SpacecraftKalmanOD::new(
258 setup,
259 KalmanVariant::ReferenceUpdate,
260 Some(SigmaRejection::default()),
261 proc_devices,
262 almanac.clone(),
263 )
264 .with_process_noise(process_noise);
265
266 let od_sol = odp.process_arc(initial_estimate, &arc)?;
267
268 let final_est = od_sol.estimates.last().unwrap();
269
270 println!("{final_est}");
271
272 let ric_err = traj_as_flown
273 .at(final_est.epoch())?
274 .orbit
275 .ric_difference(&final_est.orbital_state())?;
276 println!("== RIC at end ==");
277 println!("RIC Position (m): {:.3}", ric_err.radius_km * 1e3);
278 println!("RIC Velocity (m/s): {:.3}", ric_err.velocity_km_s * 1e3);
279
280 println!(
281 "Num residuals rejected: #{}",
282 od_sol.rejected_residuals().len()
283 );
284 println!(
285 "Percentage within +/-3: {}",
286 od_sol.residual_ratio_within_threshold(3.0).unwrap()
287 );
288 println!("Ratios normal? {}", od_sol.is_normal(None).unwrap());
289 od_sol.nis_consistency(None)?.log();
290
291 od_sol.to_parquet(
292 output_folder.join("04_lro_od_results.parquet"),
293 ExportCfg::default(),
294 )?;
295
296 // Create the ephemeris
297 let ephem = od_sol.to_ephemeris("LRO rebuilt".to_string());
298 let ephem_start = ephem.start_epoch().unwrap();
299 let ephem_end = ephem.end_epoch().unwrap();
300 // Check that the covariance is PSD throughout the ephemeris by interpolating it.
301 for epoch in TimeSeries::inclusive(ephem_start, ephem_end, Unit::Minute * 5) {
302 ephem
303 .covar_at(
304 epoch,
305 anise::ephemerides::ephemeris::LocalFrame::RIC,
306 &almanac,
307 )
308 .unwrap_or_else(|e| panic!("covar not PSD at {epoch}: {e}"));
309 }
310 // Export as BSP!
311 ephem
312 .write_spice_bsp(
313 -85,
314 output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap(),
315 None,
316 )
317 .expect("could not built BSP");
318 let new_almanac = Almanac::default()
319 .load(output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap())
320 .unwrap();
321 new_almanac.describe(None, None, None, None, None, None, None, None);
322 let (spk_start, spk_end) = new_almanac.spk_domain(-85).unwrap();
323
324 assert!((ephem_start - spk_start).abs() < Unit::Microsecond * 1);
325 assert!((ephem_end - spk_end).abs() < Unit::Microsecond * 1);
326
327 // In our case, we have the truth trajectory from NASA.
328 // So we can compute the RIC state difference between the real LRO ephem and what we've just estimated.
329 // Export the OD trajectory first.
330 let od_trajectory = od_sol.to_traj()?;
331 // Build the RIC difference.
332 od_trajectory.ric_diff_to_parquet(
333 &traj_as_flown,
334 output_folder.join("04_lro_od_truth_error.parquet"),
335 ExportCfg::default(),
336 )?;
337
338 Ok(())
339}Sourcepub fn new(
devices: BTreeMap<String, D>,
trajectory: Traj<MsrIn>,
configs: BTreeMap<String, TrkConfig>,
) -> Result<Self, ConfigError>
pub fn new( devices: BTreeMap<String, D>, trajectory: Traj<MsrIn>, configs: BTreeMap<String, TrkConfig>, ) -> Result<Self, ConfigError>
Build a new tracking arc simulator using the system entropy to seed the random number generator.
Sourcepub fn generate_measurements(
&mut self,
almanac: &Almanac,
) -> Result<TrackingDataArc, ConfigError>
pub fn generate_measurements( &mut self, almanac: &Almanac, ) -> Result<TrackingDataArc, ConfigError>
Generates measurements for the tracking arc using the defined strands
§Warning
This function will return an error if any of the devices defines as a scheduler.
You must create the schedule first using build_schedule first.
§Notes
Although mutable, this function may be called several times to generate different measurements.
§Algorithm
For each tracking device, and for each strand within that device, sample the trajectory at the sample rate of the tracking device, adding a measurement whenever the spacecraft is visible. Build the measurements as a vector, ordered chronologically.
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 = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
42
43 let out = manifest_dir.join("data/04_output/");
44
45 let almanac = Arc::new(
46 Almanac::new(
47 &manifest_dir
48 .join("data/01_planetary/pck08.pca")
49 .to_string_lossy(),
50 )
51 .unwrap()
52 .load(
53 &manifest_dir
54 .join("data/01_planetary/de440s.bsp")
55 .to_string_lossy(),
56 )
57 .unwrap(),
58 );
59
60 let eme2k = almanac.frame_info(EARTH_J2000).unwrap();
61 let moon_iau = almanac.frame_info(IAU_MOON_FRAME).unwrap();
62
63 let epoch = Epoch::from_gregorian_tai(2021, 5, 29, 19, 51, 16, 852_000);
64 let nrho = Orbit::cartesian(
65 166_473.631_302_239_7,
66 -274_715.487_253_382_7,
67 -211_233.210_176_686_7,
68 0.933_451_604_520_018_4,
69 0.436_775_046_841_900_9,
70 -0.082_211_021_250_348_95,
71 epoch,
72 eme2k,
73 );
74
75 let tx_nrho_sc = Spacecraft::from(nrho);
76
77 let state_luna = almanac.transform_to(nrho, MOON_J2000, None).unwrap();
78 println!("Start state (dynamics: Earth, Moon, Sun gravity):\n{state_luna}");
79
80 let bodies = vec![EARTH, SUN];
81 let dynamics = SpacecraftDynamics::new(OrbitalDynamics::point_masses(bodies));
82
83 let setup = Propagator::rk89(
84 dynamics,
85 IntegratorOptions::builder().max_step(0.5.minutes()).build(),
86 );
87
88 /* == Propagate the NRHO vehicle == */
89 let prop_time = 1.1 * state_luna.period().unwrap();
90
91 let (nrho_final, mut tx_traj) = setup
92 .with(tx_nrho_sc, almanac.clone())
93 .for_duration_with_traj(prop_time)
94 .unwrap();
95
96 tx_traj.name = Some("NRHO Tx SC".to_string());
97
98 println!("{tx_traj}");
99
100 /* == Propagate an LLO vehicle == */
101 let llo_orbit =
102 Orbit::try_keplerian_altitude(110.0, 1e-4, 90.0, 0.0, 0.0, 0.0, epoch, moon_iau).unwrap();
103
104 let llo_sc = Spacecraft::builder().orbit(llo_orbit).build();
105
106 let (_, llo_traj) = setup
107 .with(llo_sc, almanac.clone())
108 .until_epoch_with_traj(nrho_final.epoch())
109 .unwrap();
110
111 // Export the subset of the first two hours.
112 llo_traj
113 .clone()
114 .filter_by_offset(..2.hours())
115 .to_parquet_simple(out.join("05_caps_llo_truth.pq"))?;
116
117 /* == Setup the interlink == */
118
119 let mut measurement_types = IndexSet::new();
120 measurement_types.insert(MeasurementType::Range);
121 measurement_types.insert(MeasurementType::Doppler);
122
123 let mut stochastics = IndexMap::new();
124
125 let sa45_csac_allan_dev = 1e-11;
126
127 stochastics.insert(
128 MeasurementType::Range,
129 StochasticNoise::from_hardware_range_km(
130 sa45_csac_allan_dev,
131 10.0.seconds(),
132 link_specific::ChipRate::StandardT4B(),
133 link_specific::SN0::Average(),
134 ),
135 );
136
137 stochastics.insert(
138 MeasurementType::Doppler,
139 StochasticNoise::from_hardware_doppler_km_s(
140 sa45_csac_allan_dev,
141 10.0.seconds(),
142 link_specific::CarrierFreq::SBand(),
143 link_specific::CN0::Average(),
144 ),
145 );
146
147 let interlink = InterlinkTxSpacecraft {
148 traj: tx_traj,
149 measurement_types,
150 integration_time: None,
151 timestamp_noise_s: None,
152 ab_corr: Aberration::LT,
153 stochastic_noises: Some(stochastics),
154 };
155
156 // Devices are the transmitter, which is our NRHO vehicle.
157 let mut devices = BTreeMap::new();
158 devices.insert("NRHO Tx SC".to_string(), interlink);
159
160 let mut configs = BTreeMap::new();
161 configs.insert(
162 "NRHO Tx SC".to_string(),
163 TrkConfig::builder()
164 .strands(vec![Strand {
165 start: epoch,
166 end: nrho_final.epoch(),
167 }])
168 .build(),
169 );
170
171 let mut trk_sim =
172 TrackingArcSim::with_seed(devices.clone(), llo_traj.clone(), configs, 0).unwrap();
173 println!("{trk_sim}");
174
175 let trk_data = trk_sim.generate_measurements(&almanac).unwrap();
176 println!("{trk_data}");
177
178 trk_data
179 .to_parquet_simple(out.clone().join("nrho_interlink_msr.pq"))
180 .unwrap();
181
182 // Run a truth OD where we estimate the LLO position
183 let llo_uncertainty = SpacecraftUncertainty::builder()
184 .nominal(llo_sc)
185 .x_km(1.0)
186 .y_km(1.0)
187 .z_km(1.0)
188 .vx_km_s(1e-3)
189 .vy_km_s(1e-3)
190 .vz_km_s(1e-3)
191 .build();
192
193 let mut proc_devices = devices.clone();
194
195 // Define the initial estimate, randomized, seed for reproducibility
196 let mut initial_estimate = llo_uncertainty.to_estimate_randomized(Some(0)).unwrap();
197 // Inflate the covariance -- https://github.com/nyx-space/nyx/issues/339
198 initial_estimate.covar *= 2.5;
199
200 // Increase the noise in the devices to accept more measurements.
201
202 for link in proc_devices.values_mut() {
203 for noise in &mut link.stochastic_noises.as_mut().unwrap().values_mut() {
204 *noise.white_noise.as_mut().unwrap() *= 3.0;
205 }
206 }
207
208 let init_err = initial_estimate
209 .orbital_state()
210 .ric_difference(&llo_orbit)
211 .unwrap();
212
213 println!("initial estimate:\n{initial_estimate}");
214 println!("RIC errors = {init_err}",);
215
216 let odp = InterlinkKalmanOD::new(
217 setup.clone(),
218 KalmanVariant::ReferenceUpdate,
219 Some(SigmaRejection::default()),
220 proc_devices,
221 almanac.clone(),
222 );
223
224 // Shrink the data to process.
225 let arc = trk_data.filter_by_offset(..2.hours());
226
227 let od_sol = odp.process_arc(initial_estimate, &arc).unwrap();
228
229 println!("{od_sol}");
230
231 od_sol
232 .to_parquet(
233 out.join("05_caps_interlink_od_sol.pq"),
234 ExportCfg::default(),
235 )
236 .unwrap();
237
238 let od_traj = od_sol.to_traj().unwrap();
239
240 od_traj
241 .ric_diff_to_parquet(
242 &llo_traj,
243 out.join("05_caps_interlink_llo_est_error.pq"),
244 ExportCfg::default(),
245 )
246 .unwrap();
247
248 let final_est = od_sol.estimates.last().unwrap();
249 assert!(final_est.within_3sigma(), "should be within 3 sigma");
250
251 println!("ESTIMATE\n{final_est:x}\n");
252 let truth = llo_traj.at(final_est.epoch()).unwrap();
253 println!("TRUTH\n{truth:x}");
254
255 let final_err = truth
256 .orbit
257 .ric_difference(&final_est.orbital_state())
258 .unwrap();
259 println!("ERROR {final_err}");
260
261 // Build the residuals versus reference plot.
262 let rvr_sol = odp
263 .process_arc(initial_estimate, &arc.resid_vs_ref_check())
264 .unwrap();
265
266 rvr_sol
267 .to_parquet(
268 out.join("05_caps_interlink_resid_v_ref.pq"),
269 ExportCfg::default(),
270 )
271 .unwrap();
272
273 let final_rvr = rvr_sol.estimates.last().unwrap();
274
275 println!("RMAG error {:.3} m", final_err.rmag_km() * 1e3);
276 println!(
277 "Pure prop error {:.3} m",
278 final_rvr
279 .orbital_state()
280 .ric_difference(&final_est.orbital_state())
281 .unwrap()
282 .rmag_km()
283 * 1e3
284 );
285
286 Ok(())
287}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}34fn main() -> Result<(), Box<dyn Error>> {
35 pel::init();
36
37 // ====================== //
38 // === ALMANAC SET UP === //
39 // ====================== //
40
41 // Dynamics models require planetary constants and ephemerides to be defined.
42 // Let's start by grabbing those by using ANISE's MetaAlmanac.
43
44 let output_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "../data", "04_output"]
45 .iter()
46 .collect();
47
48 let data_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "examples", "04_lro_od"]
49 .iter()
50 .collect();
51
52 let meta = data_folder.join("lro-dynamics.dhall");
53
54 // Load this ephem in the general Almanac we're using for this analysis.
55 let almanac = Arc::new(
56 MetaAlmanac::new(meta.to_string_lossy().as_ref())
57 .map_err(Box::new)?
58 .process(true)
59 .map_err(Box::new)?,
60 );
61
62 // Orbit determination requires a Trajectory structure, which can be saved as parquet file.
63 // In our case, the trajectory comes from the BSP file, so we need to build a Trajectory from the almanac directly.
64 // To query the Almanac, we need to build the LRO frame in the J2000 orientation in our case.
65 // Inspecting the LRO BSP in the ANISE GUI shows us that NASA has assigned ID -85 to LRO.
66 let lro_frame = Frame::from_ephem_j2000(-85);
67
68 // To build the trajectory we need to provide a spacecraft template.
69 let sc_template = Spacecraft::builder()
70 .mass(Mass::from_dry_and_prop_masses(1018.0, 900.0)) // Launch masses
71 .srp(SRPData {
72 // SRP configuration is arbitrary, but we will be estimating it anyway.
73 area_m2: 3.9 * 2.7,
74 coeff_reflectivity: 0.96,
75 })
76 .orbit(Orbit::zero(MOON_J2000)) // Setting a zero orbit here because it's just a template
77 .build();
78 // Now we can build the trajectory from the BSP file.
79 // We'll arbitrarily set the tracking arc to 24 hours with a five second time step.
80 let traj_as_flown = Traj::from_bsp(
81 lro_frame,
82 MOON_J2000,
83 &almanac,
84 sc_template,
85 5.seconds(),
86 Some(Epoch::from_str("2024-01-01 01:00:00 UTC")?),
87 Some(Epoch::from_str("2024-01-02 01:00:00 UTC")?),
88 None,
89 Some("LRO".to_string()),
90 )?;
91
92 println!("{traj_as_flown}");
93
94 // ====================== //
95 // === MODEL MATCHING === //
96 // ====================== //
97
98 // Set up the spacecraft dynamics.
99
100 // Specify that the orbital dynamics must account for the graviational pull of the Earth and the Sun.
101 // The gravity of the Moon will also be accounted for since the spaceraft in a lunar orbit.
102 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![EARTH, SUN, JUPITER_BARYCENTER]);
103
104 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
105 // We're using the GRAIL JGGRX model.
106 let mut jggrx_meta = MetaFile {
107 uri: "http://public-data.nyxspace.com/nyx/models/Luna_jggrx_1500e_sha.tab.gz".to_string(),
108 crc32: Some(0x6bcacda8), // Specifying the CRC32 avoids redownloading it if it's cached.
109 };
110 // And let's download it if we don't have it yet.
111 jggrx_meta.process(true)?;
112
113 // Build the spherical harmonics.
114 // The harmonics must be computed in the body fixed frame.
115 // We're using the long term prediction of the Moon principal axes frame.
116 let moon_pa_frame = MOON_PA_FRAME.with_orient(31008);
117 let sph_harmonics = GravityField::new(GravityFieldData::from_shadr(
118 &jggrx_meta.uri,
119 81,
120 81,
121 almanac.frame_info(moon_pa_frame)?,
122 )?);
123
124 // Include the spherical harmonics into the orbital dynamics.
125 orbital_dyn.accel_models.push(sph_harmonics);
126
127 // We define the solar radiation pressure, using the default solar flux and accounting only
128 // for the eclipsing caused by the Earth and Moon.
129 // Note that by default, enabling the SolarPressure model will also enable the estimation of the coefficient of reflectivity.
130 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], &almanac)?;
131
132 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
133 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
134 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
135
136 println!("{dynamics}");
137
138 // Now we can build the propagator.
139 let setup = Propagator::default_dp78(dynamics.clone());
140
141 // For reference, let's build the trajectory with Nyx's models from that LRO state.
142 let (sim_final, traj_as_sim) = setup
143 .with(*traj_as_flown.first(), almanac.clone())
144 .until_epoch_with_traj(traj_as_flown.last().epoch())?;
145
146 println!("SIM INIT: {:x}", traj_as_flown.first());
147 println!("SIM FINAL: {sim_final:x}");
148 // Compute RIC difference between SIM and LRO ephem
149 let sim_lro_delta = sim_final
150 .orbit
151 .ric_difference(&traj_as_flown.last().orbit)?;
152 println!("{traj_as_sim}");
153 println!(
154 "SIM v LRO - RIC Position (m): {:.3}",
155 sim_lro_delta.radius_km * 1e3
156 );
157 println!(
158 "SIM v LRO - RIC Velocity (m/s): {:.3}",
159 sim_lro_delta.velocity_km_s * 1e3
160 );
161
162 traj_as_sim.ric_diff_to_parquet(
163 &traj_as_flown,
164 output_folder.join("./04_lro_sim_truth_error.parquet"),
165 ExportCfg::default(),
166 )?;
167
168 // ==================== //
169 // === OD SIMULATOR === //
170 // ==================== //
171
172 // 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
173 // and the truth LRO state.
174
175 // Therefore, we will actually run an estimation from a dispersed LRO state.
176 // The sc_seed is the true LRO state from the BSP.
177 let sc_seed = *traj_as_flown.first();
178
179 // Load the Deep Space Network ground stations.
180 // Nyx allows you to build these at runtime but it's pretty static so we can just load them from YAML.
181 let ground_station_file: PathBuf = [
182 env!("CARGO_MANIFEST_DIR"),
183 "examples",
184 "04_lro_od",
185 "dsn-network.yaml",
186 ]
187 .iter()
188 .collect();
189
190 let devices = GroundStation::load_named(ground_station_file)?;
191
192 let proc_devices = devices.clone();
193
194 // Typical OD software requires that you specify your own tracking schedule or you'll have overlapping measurements.
195 // Nyx can build a tracking schedule for you based on the first station with access.
196 let trkconfg_yaml: PathBuf = [
197 env!("CARGO_MANIFEST_DIR"),
198 "examples",
199 "04_lro_od",
200 "tracking-cfg.yaml",
201 ]
202 .iter()
203 .collect();
204
205 let configs: BTreeMap<String, TrkConfig> = TrkConfig::load_named(trkconfg_yaml)?;
206
207 // Build the tracking arc simulation to generate a "standard measurement".
208 let mut trk = TrackingArcSim::<Spacecraft, GroundStation>::with_seed(
209 devices.clone(),
210 traj_as_flown.clone(),
211 configs,
212 123, // Set a seed for reproducibility
213 )?;
214
215 trk.build_schedule(&almanac)?;
216 let arc = trk.generate_measurements(&almanac)?;
217 // Save the simulated tracking data
218 arc.to_parquet_simple(output_folder.join("04_lro_simulated_tracking.parquet"))?;
219
220 // We'll note that in our case, we have continuous coverage of LRO when the vehicle is not behind the Moon.
221 println!("{arc}");
222
223 // Now that we have simulated measurements, we'll run the orbit determination.
224
225 // ===================== //
226 // === OD ESTIMATION === //
227 // ===================== //
228
229 let sc = SpacecraftUncertainty::builder()
230 .nominal(sc_seed)
231 .frame(LocalFrame::RIC)
232 .x_km(0.5)
233 .y_km(0.5)
234 .z_km(0.5)
235 .vx_km_s(5e-3)
236 .vy_km_s(5e-3)
237 .vz_km_s(5e-3)
238 .build();
239
240 // Build the filter initial estimate, which we will reuse in the filter.
241 let mut initial_estimate = sc.to_estimate()?;
242 initial_estimate.covar *= 1.5;
243
244 println!("== FILTER STATE ==\n{sc_seed:x}\n{initial_estimate}");
245
246 // Build the SNC in the Moon J2000 frame, specified as a velocity noise over time.
247 let process_noise = ProcessNoise3D::from_velocity_km_s(
248 &[5e-13, 5e-13, 5e-13],
249 1 * Unit::Hour,
250 10 * Unit::Minute,
251 None,
252 );
253
254 println!("{process_noise}");
255
256 // We'll set up the OD process to reject measurements whose residuals are move than 3 sigmas away from what we expect.
257 let odp = SpacecraftKalmanOD::new(
258 setup,
259 KalmanVariant::ReferenceUpdate,
260 Some(SigmaRejection::default()),
261 proc_devices,
262 almanac.clone(),
263 )
264 .with_process_noise(process_noise);
265
266 let od_sol = odp.process_arc(initial_estimate, &arc)?;
267
268 let final_est = od_sol.estimates.last().unwrap();
269
270 println!("{final_est}");
271
272 let ric_err = traj_as_flown
273 .at(final_est.epoch())?
274 .orbit
275 .ric_difference(&final_est.orbital_state())?;
276 println!("== RIC at end ==");
277 println!("RIC Position (m): {:.3}", ric_err.radius_km * 1e3);
278 println!("RIC Velocity (m/s): {:.3}", ric_err.velocity_km_s * 1e3);
279
280 println!(
281 "Num residuals rejected: #{}",
282 od_sol.rejected_residuals().len()
283 );
284 println!(
285 "Percentage within +/-3: {}",
286 od_sol.residual_ratio_within_threshold(3.0).unwrap()
287 );
288 println!("Ratios normal? {}", od_sol.is_normal(None).unwrap());
289 od_sol.nis_consistency(None)?.log();
290
291 od_sol.to_parquet(
292 output_folder.join("04_lro_od_results.parquet"),
293 ExportCfg::default(),
294 )?;
295
296 // Create the ephemeris
297 let ephem = od_sol.to_ephemeris("LRO rebuilt".to_string());
298 let ephem_start = ephem.start_epoch().unwrap();
299 let ephem_end = ephem.end_epoch().unwrap();
300 // Check that the covariance is PSD throughout the ephemeris by interpolating it.
301 for epoch in TimeSeries::inclusive(ephem_start, ephem_end, Unit::Minute * 5) {
302 ephem
303 .covar_at(
304 epoch,
305 anise::ephemerides::ephemeris::LocalFrame::RIC,
306 &almanac,
307 )
308 .unwrap_or_else(|e| panic!("covar not PSD at {epoch}: {e}"));
309 }
310 // Export as BSP!
311 ephem
312 .write_spice_bsp(
313 -85,
314 output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap(),
315 None,
316 )
317 .expect("could not built BSP");
318 let new_almanac = Almanac::default()
319 .load(output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap())
320 .unwrap();
321 new_almanac.describe(None, None, None, None, None, None, None, None);
322 let (spk_start, spk_end) = new_almanac.spk_domain(-85).unwrap();
323
324 assert!((ephem_start - spk_start).abs() < Unit::Microsecond * 1);
325 assert!((ephem_end - spk_end).abs() < Unit::Microsecond * 1);
326
327 // In our case, we have the truth trajectory from NASA.
328 // So we can compute the RIC state difference between the real LRO ephem and what we've just estimated.
329 // Export the OD trajectory first.
330 let od_trajectory = od_sol.to_traj()?;
331 // Build the RIC difference.
332 od_trajectory.ric_diff_to_parquet(
333 &traj_as_flown,
334 output_folder.join("04_lro_od_truth_error.parquet"),
335 ExportCfg::default(),
336 )?;
337
338 Ok(())
339}Source§impl TrackingArcSim<Spacecraft, GroundStation>
impl TrackingArcSim<Spacecraft, GroundStation>
Sourcepub fn generate_schedule(
&self,
almanac: &Almanac,
) -> Result<BTreeMap<String, TrkConfig>, AnalysisError>
pub fn generate_schedule( &self, almanac: &Almanac, ) -> Result<BTreeMap<String, TrkConfig>, AnalysisError>
Builds the schedule provided the config. Requires the tracker to be a ground station.
§Algorithm
- For each tracking device:
- Find when the vehicle trajectory has an elevation greater or equal to zero, and use that as the first start of the first tracking arc for this station
- Find when the vehicle trajectory has an elevation less than zero (i.e. disappears below the horizon), after that initial epoch
- Repeat 2, 3 until the end of the trajectory
- Build each of these as “tracking strands” for this tracking device.
- Organize all of the built tracking strands chronologically.
- Iterate through all of the strands:
7.a. if that tracker is marked as
Greedyand it ends after the start of the next strand, change the start date of the next strand. 7.b. if that tracker is marked asEagerand it ends after the start of the next strand, change the end date of the current strand.
Sourcepub fn build_schedule(&mut self, almanac: &Almanac) -> Result<(), AnalysisError>
pub fn build_schedule(&mut self, almanac: &Almanac) -> Result<(), AnalysisError>
Sets the schedule to that built in build_schedule
Examples found in repository?
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}More examples
34fn main() -> Result<(), Box<dyn Error>> {
35 pel::init();
36
37 // ====================== //
38 // === ALMANAC SET UP === //
39 // ====================== //
40
41 // Dynamics models require planetary constants and ephemerides to be defined.
42 // Let's start by grabbing those by using ANISE's MetaAlmanac.
43
44 let output_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "../data", "04_output"]
45 .iter()
46 .collect();
47
48 let data_folder: PathBuf = [env!("CARGO_MANIFEST_DIR"), "examples", "04_lro_od"]
49 .iter()
50 .collect();
51
52 let meta = data_folder.join("lro-dynamics.dhall");
53
54 // Load this ephem in the general Almanac we're using for this analysis.
55 let almanac = Arc::new(
56 MetaAlmanac::new(meta.to_string_lossy().as_ref())
57 .map_err(Box::new)?
58 .process(true)
59 .map_err(Box::new)?,
60 );
61
62 // Orbit determination requires a Trajectory structure, which can be saved as parquet file.
63 // In our case, the trajectory comes from the BSP file, so we need to build a Trajectory from the almanac directly.
64 // To query the Almanac, we need to build the LRO frame in the J2000 orientation in our case.
65 // Inspecting the LRO BSP in the ANISE GUI shows us that NASA has assigned ID -85 to LRO.
66 let lro_frame = Frame::from_ephem_j2000(-85);
67
68 // To build the trajectory we need to provide a spacecraft template.
69 let sc_template = Spacecraft::builder()
70 .mass(Mass::from_dry_and_prop_masses(1018.0, 900.0)) // Launch masses
71 .srp(SRPData {
72 // SRP configuration is arbitrary, but we will be estimating it anyway.
73 area_m2: 3.9 * 2.7,
74 coeff_reflectivity: 0.96,
75 })
76 .orbit(Orbit::zero(MOON_J2000)) // Setting a zero orbit here because it's just a template
77 .build();
78 // Now we can build the trajectory from the BSP file.
79 // We'll arbitrarily set the tracking arc to 24 hours with a five second time step.
80 let traj_as_flown = Traj::from_bsp(
81 lro_frame,
82 MOON_J2000,
83 &almanac,
84 sc_template,
85 5.seconds(),
86 Some(Epoch::from_str("2024-01-01 01:00:00 UTC")?),
87 Some(Epoch::from_str("2024-01-02 01:00:00 UTC")?),
88 None,
89 Some("LRO".to_string()),
90 )?;
91
92 println!("{traj_as_flown}");
93
94 // ====================== //
95 // === MODEL MATCHING === //
96 // ====================== //
97
98 // Set up the spacecraft dynamics.
99
100 // Specify that the orbital dynamics must account for the graviational pull of the Earth and the Sun.
101 // The gravity of the Moon will also be accounted for since the spaceraft in a lunar orbit.
102 let mut orbital_dyn = OrbitalDynamics::point_masses(vec![EARTH, SUN, JUPITER_BARYCENTER]);
103
104 // We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
105 // We're using the GRAIL JGGRX model.
106 let mut jggrx_meta = MetaFile {
107 uri: "http://public-data.nyxspace.com/nyx/models/Luna_jggrx_1500e_sha.tab.gz".to_string(),
108 crc32: Some(0x6bcacda8), // Specifying the CRC32 avoids redownloading it if it's cached.
109 };
110 // And let's download it if we don't have it yet.
111 jggrx_meta.process(true)?;
112
113 // Build the spherical harmonics.
114 // The harmonics must be computed in the body fixed frame.
115 // We're using the long term prediction of the Moon principal axes frame.
116 let moon_pa_frame = MOON_PA_FRAME.with_orient(31008);
117 let sph_harmonics = GravityField::new(GravityFieldData::from_shadr(
118 &jggrx_meta.uri,
119 81,
120 81,
121 almanac.frame_info(moon_pa_frame)?,
122 )?);
123
124 // Include the spherical harmonics into the orbital dynamics.
125 orbital_dyn.accel_models.push(sph_harmonics);
126
127 // We define the solar radiation pressure, using the default solar flux and accounting only
128 // for the eclipsing caused by the Earth and Moon.
129 // Note that by default, enabling the SolarPressure model will also enable the estimation of the coefficient of reflectivity.
130 let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], &almanac)?;
131
132 // Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
133 // acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
134 let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
135
136 println!("{dynamics}");
137
138 // Now we can build the propagator.
139 let setup = Propagator::default_dp78(dynamics.clone());
140
141 // For reference, let's build the trajectory with Nyx's models from that LRO state.
142 let (sim_final, traj_as_sim) = setup
143 .with(*traj_as_flown.first(), almanac.clone())
144 .until_epoch_with_traj(traj_as_flown.last().epoch())?;
145
146 println!("SIM INIT: {:x}", traj_as_flown.first());
147 println!("SIM FINAL: {sim_final:x}");
148 // Compute RIC difference between SIM and LRO ephem
149 let sim_lro_delta = sim_final
150 .orbit
151 .ric_difference(&traj_as_flown.last().orbit)?;
152 println!("{traj_as_sim}");
153 println!(
154 "SIM v LRO - RIC Position (m): {:.3}",
155 sim_lro_delta.radius_km * 1e3
156 );
157 println!(
158 "SIM v LRO - RIC Velocity (m/s): {:.3}",
159 sim_lro_delta.velocity_km_s * 1e3
160 );
161
162 traj_as_sim.ric_diff_to_parquet(
163 &traj_as_flown,
164 output_folder.join("./04_lro_sim_truth_error.parquet"),
165 ExportCfg::default(),
166 )?;
167
168 // ==================== //
169 // === OD SIMULATOR === //
170 // ==================== //
171
172 // 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
173 // and the truth LRO state.
174
175 // Therefore, we will actually run an estimation from a dispersed LRO state.
176 // The sc_seed is the true LRO state from the BSP.
177 let sc_seed = *traj_as_flown.first();
178
179 // Load the Deep Space Network ground stations.
180 // Nyx allows you to build these at runtime but it's pretty static so we can just load them from YAML.
181 let ground_station_file: PathBuf = [
182 env!("CARGO_MANIFEST_DIR"),
183 "examples",
184 "04_lro_od",
185 "dsn-network.yaml",
186 ]
187 .iter()
188 .collect();
189
190 let devices = GroundStation::load_named(ground_station_file)?;
191
192 let proc_devices = devices.clone();
193
194 // Typical OD software requires that you specify your own tracking schedule or you'll have overlapping measurements.
195 // Nyx can build a tracking schedule for you based on the first station with access.
196 let trkconfg_yaml: PathBuf = [
197 env!("CARGO_MANIFEST_DIR"),
198 "examples",
199 "04_lro_od",
200 "tracking-cfg.yaml",
201 ]
202 .iter()
203 .collect();
204
205 let configs: BTreeMap<String, TrkConfig> = TrkConfig::load_named(trkconfg_yaml)?;
206
207 // Build the tracking arc simulation to generate a "standard measurement".
208 let mut trk = TrackingArcSim::<Spacecraft, GroundStation>::with_seed(
209 devices.clone(),
210 traj_as_flown.clone(),
211 configs,
212 123, // Set a seed for reproducibility
213 )?;
214
215 trk.build_schedule(&almanac)?;
216 let arc = trk.generate_measurements(&almanac)?;
217 // Save the simulated tracking data
218 arc.to_parquet_simple(output_folder.join("04_lro_simulated_tracking.parquet"))?;
219
220 // We'll note that in our case, we have continuous coverage of LRO when the vehicle is not behind the Moon.
221 println!("{arc}");
222
223 // Now that we have simulated measurements, we'll run the orbit determination.
224
225 // ===================== //
226 // === OD ESTIMATION === //
227 // ===================== //
228
229 let sc = SpacecraftUncertainty::builder()
230 .nominal(sc_seed)
231 .frame(LocalFrame::RIC)
232 .x_km(0.5)
233 .y_km(0.5)
234 .z_km(0.5)
235 .vx_km_s(5e-3)
236 .vy_km_s(5e-3)
237 .vz_km_s(5e-3)
238 .build();
239
240 // Build the filter initial estimate, which we will reuse in the filter.
241 let mut initial_estimate = sc.to_estimate()?;
242 initial_estimate.covar *= 1.5;
243
244 println!("== FILTER STATE ==\n{sc_seed:x}\n{initial_estimate}");
245
246 // Build the SNC in the Moon J2000 frame, specified as a velocity noise over time.
247 let process_noise = ProcessNoise3D::from_velocity_km_s(
248 &[5e-13, 5e-13, 5e-13],
249 1 * Unit::Hour,
250 10 * Unit::Minute,
251 None,
252 );
253
254 println!("{process_noise}");
255
256 // We'll set up the OD process to reject measurements whose residuals are move than 3 sigmas away from what we expect.
257 let odp = SpacecraftKalmanOD::new(
258 setup,
259 KalmanVariant::ReferenceUpdate,
260 Some(SigmaRejection::default()),
261 proc_devices,
262 almanac.clone(),
263 )
264 .with_process_noise(process_noise);
265
266 let od_sol = odp.process_arc(initial_estimate, &arc)?;
267
268 let final_est = od_sol.estimates.last().unwrap();
269
270 println!("{final_est}");
271
272 let ric_err = traj_as_flown
273 .at(final_est.epoch())?
274 .orbit
275 .ric_difference(&final_est.orbital_state())?;
276 println!("== RIC at end ==");
277 println!("RIC Position (m): {:.3}", ric_err.radius_km * 1e3);
278 println!("RIC Velocity (m/s): {:.3}", ric_err.velocity_km_s * 1e3);
279
280 println!(
281 "Num residuals rejected: #{}",
282 od_sol.rejected_residuals().len()
283 );
284 println!(
285 "Percentage within +/-3: {}",
286 od_sol.residual_ratio_within_threshold(3.0).unwrap()
287 );
288 println!("Ratios normal? {}", od_sol.is_normal(None).unwrap());
289 od_sol.nis_consistency(None)?.log();
290
291 od_sol.to_parquet(
292 output_folder.join("04_lro_od_results.parquet"),
293 ExportCfg::default(),
294 )?;
295
296 // Create the ephemeris
297 let ephem = od_sol.to_ephemeris("LRO rebuilt".to_string());
298 let ephem_start = ephem.start_epoch().unwrap();
299 let ephem_end = ephem.end_epoch().unwrap();
300 // Check that the covariance is PSD throughout the ephemeris by interpolating it.
301 for epoch in TimeSeries::inclusive(ephem_start, ephem_end, Unit::Minute * 5) {
302 ephem
303 .covar_at(
304 epoch,
305 anise::ephemerides::ephemeris::LocalFrame::RIC,
306 &almanac,
307 )
308 .unwrap_or_else(|e| panic!("covar not PSD at {epoch}: {e}"));
309 }
310 // Export as BSP!
311 ephem
312 .write_spice_bsp(
313 -85,
314 output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap(),
315 None,
316 )
317 .expect("could not built BSP");
318 let new_almanac = Almanac::default()
319 .load(output_folder.join("04_lro_rebuilt.bsp").to_str().unwrap())
320 .unwrap();
321 new_almanac.describe(None, None, None, None, None, None, None, None);
322 let (spk_start, spk_end) = new_almanac.spk_domain(-85).unwrap();
323
324 assert!((ephem_start - spk_start).abs() < Unit::Microsecond * 1);
325 assert!((ephem_end - spk_end).abs() < Unit::Microsecond * 1);
326
327 // In our case, we have the truth trajectory from NASA.
328 // So we can compute the RIC state difference between the real LRO ephem and what we've just estimated.
329 // Export the OD trajectory first.
330 let od_trajectory = od_sol.to_traj()?;
331 // Build the RIC difference.
332 od_trajectory.ric_diff_to_parquet(
333 &traj_as_flown,
334 output_folder.join("04_lro_od_truth_error.parquet"),
335 ExportCfg::default(),
336 )?;
337
338 Ok(())
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