#[repr(C)]pub struct Epoch {
pub duration: Duration,
pub time_scale: TimeScale,
}
Expand description
Defines a nanosecond-precision Epoch.
Refer to the appropriate functions for initializing this Epoch from different time scales or representations.
Fields§
§duration: Duration
An Epoch is always stored as the duration since the beginning of its time scale
time_scale: TimeScale
Time scale used during the initialization of this Epoch.
Implementations§
§impl Epoch
impl Epoch
pub fn to_gregorian_str(&self, time_scale: TimeScale) -> String
pub fn to_gregorian_str(&self, time_scale: TimeScale) -> String
Converts the Epoch to Gregorian in the provided time scale and in the ISO8601 format with the time scale appended to the string
pub fn to_gregorian_utc(&self) -> (i32, u8, u8, u8, u8, u8, u32)
pub fn to_gregorian_utc(&self) -> (i32, u8, u8, u8, u8, u8, u32)
Converts the Epoch to the Gregorian UTC equivalent as (year, month, day, hour, minute, second). WARNING: Nanoseconds are lost in this conversion!
§Example
use hifitime::Epoch;
let dt_tai = Epoch::from_tai_parts(1, 537582752000000000);
let dt_str = "2017-01-14T00:31:55 UTC";
let dt = Epoch::from_gregorian_str(dt_str).unwrap();
let (y, m, d, h, min, s, _) = dt_tai.to_gregorian_utc();
assert_eq!(y, 2017);
assert_eq!(m, 1);
assert_eq!(d, 14);
assert_eq!(h, 0);
assert_eq!(min, 31);
assert_eq!(s, 55);
#[cfg(feature = "std")]
{
assert_eq!("2017-01-14T00:31:55 UTC", format!("{dt_tai:?}"));
// dt_tai is initialized from TAI, so the default print is the Gregorian in that time system
assert_eq!("2017-01-14T00:32:32 TAI", format!("{dt_tai}"));
// But dt is initialized from UTC, so the default print and the debug print are both in UTC.
assert_eq!("2017-01-14T00:31:55 UTC", format!("{dt}"));
}
pub fn to_gregorian_tai(&self) -> (i32, u8, u8, u8, u8, u8, u32)
pub fn to_gregorian_tai(&self) -> (i32, u8, u8, u8, u8, u8, u32)
Converts the Epoch to the Gregorian TAI equivalent as (year, month, day, hour, minute, second). WARNING: Nanoseconds are lost in this conversion!
§Example
use hifitime::Epoch;
let dt = Epoch::from_gregorian_tai_at_midnight(1972, 1, 1);
let (y, m, d, h, min, s, _) = dt.to_gregorian_tai();
assert_eq!(y, 1972);
assert_eq!(m, 1);
assert_eq!(d, 1);
assert_eq!(h, 0);
assert_eq!(min, 0);
assert_eq!(s, 0);
pub fn maybe_from_gregorian_tai(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
nanos: u32,
) -> Result<Epoch, EpochError>
pub fn maybe_from_gregorian_tai( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, nanos: u32, ) -> Result<Epoch, EpochError>
Attempts to build an Epoch from the provided Gregorian date and time in TAI.
pub fn maybe_from_gregorian(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
nanos: u32,
time_scale: TimeScale,
) -> Result<Epoch, EpochError>
pub fn maybe_from_gregorian( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, nanos: u32, time_scale: TimeScale, ) -> Result<Epoch, EpochError>
Attempts to build an Epoch from the provided Gregorian date and time in the provided time scale.
Note: The month is ONE indexed, i.e. January is month 1 and December is month 12.
pub fn from_gregorian_tai(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
nanos: u32,
) -> Epoch
pub fn from_gregorian_tai( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, nanos: u32, ) -> Epoch
Builds an Epoch from the provided Gregorian date and time in TAI. If invalid date is provided, this function will panic. Use maybe_from_gregorian_tai if unsure.
pub fn from_gregorian_tai_at_midnight(year: i32, month: u8, day: u8) -> Epoch
pub fn from_gregorian_tai_at_midnight(year: i32, month: u8, day: u8) -> Epoch
Initialize from the Gregorian date at midnight in TAI.
pub fn from_gregorian_tai_at_noon(year: i32, month: u8, day: u8) -> Epoch
pub fn from_gregorian_tai_at_noon(year: i32, month: u8, day: u8) -> Epoch
Initialize from the Gregorian date at noon in TAI
pub fn from_gregorian_tai_hms(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
) -> Epoch
pub fn from_gregorian_tai_hms( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, ) -> Epoch
Initialize from the Gregorian date and time (without the nanoseconds) in TAI
pub fn maybe_from_gregorian_utc(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
nanos: u32,
) -> Result<Epoch, EpochError>
pub fn maybe_from_gregorian_utc( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, nanos: u32, ) -> Result<Epoch, EpochError>
Attempts to build an Epoch from the provided Gregorian date and time in UTC.
pub fn from_gregorian_utc(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
nanos: u32,
) -> Epoch
pub fn from_gregorian_utc( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, nanos: u32, ) -> Epoch
Builds an Epoch from the provided Gregorian date and time in UTC. If invalid date is provided, this function will panic. Use maybe_from_gregorian_utc if unsure.
pub fn from_gregorian_utc_at_midnight(year: i32, month: u8, day: u8) -> Epoch
pub fn from_gregorian_utc_at_midnight(year: i32, month: u8, day: u8) -> Epoch
Initialize from Gregorian date in UTC at midnight
pub fn from_gregorian_utc_at_noon(year: i32, month: u8, day: u8) -> Epoch
pub fn from_gregorian_utc_at_noon(year: i32, month: u8, day: u8) -> Epoch
Initialize from Gregorian date in UTC at noon
pub fn from_gregorian_utc_hms(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
) -> Epoch
pub fn from_gregorian_utc_hms( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, ) -> Epoch
Initialize from the Gregorian date and time (without the nanoseconds) in UTC
Examples found in repository?
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fn main() -> Result<(), Box<dyn Error>> {
pel::init();
// Set up the dynamics like in the orbit raise.
let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
// Define the GEO orbit, and we're just going to maintain it very tightly.
let earth_j2000 = almanac.frame_from_uid(EARTH_J2000)?;
let orbit = Orbit::try_keplerian(42164.0, 1e-5, 0., 163.0, 75.0, 0.0, epoch, earth_j2000)?;
println!("{orbit:x}");
let sc = Spacecraft::builder()
.orbit(orbit)
.dry_mass_kg(1000.0) // 1000 kg of dry mass
.fuel_mass_kg(1000.0) // 1000 kg of fuel, totalling 2.0 tons
.srp(SrpConfig::from_area(3.0 * 6.0)) // Assuming 1 kW/m^2 or 18 kW, giving a margin of 4.35 kW for on-propulsion consumption
.thruster(Thruster {
// "NEXT-STEP" row in Table 2
isp_s: 4435.0,
thrust_N: 0.472,
})
.mode(GuidanceMode::Thrust) // Start thrusting immediately.
.build();
// Set up the spacecraft dynamics like in the orbit raise example.
let prop_time = 30.0 * Unit::Day;
// Define the guidance law -- we're just using a Ruggiero controller as demonstrated in AAS-2004-5089.
let objectives = &[
Objective::within_tolerance(StateParameter::SMA, 42_164.0, 5.0), // 5 km
Objective::within_tolerance(StateParameter::Eccentricity, 0.001, 5e-5),
Objective::within_tolerance(StateParameter::Inclination, 0.05, 1e-2),
];
let ruggiero_ctrl = Ruggiero::from_max_eclipse(objectives, sc, EclipseState::Penumbra(0.2))?;
println!("{ruggiero_ctrl}");
let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
let mut jgm3_meta = MetaFile {
uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
};
jgm3_meta.process()?;
let harmonics = Harmonics::from_stor(
almanac.frame_from_uid(IAU_EARTH_FRAME)?,
HarmonicsMem::from_cof(&jgm3_meta.uri, 8, 8, true)?,
);
orbital_dyn.accel_models.push(harmonics);
let srp_dyn = SolarPressure::default(EARTH_J2000, almanac.clone())?;
let sc_dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn)
.with_guidance_law(ruggiero_ctrl.clone());
println!("{sc_dynamics}");
// Finally, let's use the Monte Carlo framework built into Nyx to propagate spacecraft.
// Let's start by defining the dispersion.
// The MultivariateNormal structure allows us to define the dispersions in any of the orbital parameters, but these are applied directly in the Cartesian state space.
// Note that additional validation on the MVN is in progress -- https://github.com/nyx-space/nyx/issues/339.
let mc_rv = MultivariateNormal::new(
sc,
vec![StateDispersion::zero_mean(StateParameter::SMA, 3.0)],
)?;
let my_mc = MonteCarlo::new(
sc, // Nominal state
mc_rv,
"03_geo_sk".to_string(), // Scenario name
None, // No specific seed specified, so one will be drawn from the computer's entropy.
);
// Build the propagator setup.
let setup = Propagator::rk89(
sc_dynamics.clone(),
PropOpts::builder()
.min_step(10.0_f64.seconds())
.error_ctrl(RSSCartesianStep {})
.build(),
);
let num_runs = 25;
let rslts = my_mc.run_until_epoch(setup, almanac.clone(), sc.epoch() + prop_time, num_runs);
assert_eq!(rslts.runs.len(), num_runs);
// For all of the resulting trajectories, we'll want to compute the percentage of penumbra and umbra.
rslts.to_parquet(
"03_geo_sk.parquet",
Some(vec![
&EclipseLocator::cislunar(almanac.clone()).to_penumbra_event()
]),
ExportCfg::default(),
almanac,
)?;
Ok(())
}
More examples
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fn main() -> Result<(), Box<dyn Error>> {
pel::init();
// Dynamics models require planetary constants and ephemerides to be defined.
// Let's start by grabbing those by using ANISE's latest MetaAlmanac.
// This will automatically download the DE440s planetary ephemeris,
// the daily-updated Earth Orientation Parameters, the high fidelity Moon orientation
// parameters (for the Moon Mean Earth and Moon Principal Axes frames), and the PCK11
// planetary constants kernels.
// For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
// Note that we place the Almanac into an Arc so we can clone it cheaply and provide read-only
// references to many functions.
let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
// Fetch the EME2000 frame from the Almabac
let eme2k = almanac.frame_from_uid(EARTH_J2000).unwrap();
// Define the orbit epoch
let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
// Build the spacecraft itself.
// Using slide 6 of https://aerospace.org/sites/default/files/2018-11/Davis-Mayberry_HPSEP_11212018.pdf
// for the "next gen" SEP characteristics.
// GTO start
let orbit = Orbit::keplerian(24505.9, 0.725, 7.05, 0.0, 0.0, 0.0, epoch, eme2k);
let sc = Spacecraft::builder()
.orbit(orbit)
.dry_mass_kg(1000.0) // 1000 kg of dry mass
.fuel_mass_kg(1000.0) // 1000 kg of fuel, totalling 2.0 tons
.srp(SrpConfig::from_area(3.0 * 6.0)) // Assuming 1 kW/m^2 or 18 kW, giving a margin of 4.35 kW for on-propulsion consumption
.thruster(Thruster {
// "NEXT-STEP" row in Table 2
isp_s: 4435.0,
thrust_N: 0.472,
})
.mode(GuidanceMode::Thrust) // Start thrusting immediately.
.build();
let prop_time = 180.0 * Unit::Day;
// Define the guidance law -- we're just using a Ruggiero controller as demonstrated in AAS-2004-5089.
let objectives = &[
Objective::within_tolerance(StateParameter::SMA, 42_165.0, 20.0),
Objective::within_tolerance(StateParameter::Eccentricity, 0.001, 5e-5),
Objective::within_tolerance(StateParameter::Inclination, 0.05, 1e-2),
];
// Ensure that we only thrust if we have more than 20% illumination.
let ruggiero_ctrl =
Ruggiero::from_max_eclipse(objectives, sc, EclipseState::Penumbra(0.2)).unwrap();
println!("{ruggiero_ctrl}");
// Define the high fidelity dynamics
// Set up the spacecraft dynamics.
// Specify that the orbital dynamics must account for the graviational pull of the Moon and the Sun.
// The gravity of the Earth will also be accounted for since the spaceraft in an Earth orbit.
let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
// We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
// We're using the JGM3 model here, which is the default in GMAT.
let mut jgm3_meta = MetaFile {
uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
};
// And let's download it if we don't have it yet.
jgm3_meta.process()?;
// Build the spherical harmonics.
// The harmonics must be computed in the body fixed frame.
// We're using the long term prediction of the Earth centered Earth fixed frame, IAU Earth.
let harmonics = Harmonics::from_stor(
almanac.frame_from_uid(IAU_EARTH_FRAME)?,
HarmonicsMem::from_cof(&jgm3_meta.uri, 8, 8, true).unwrap(),
);
// Include the spherical harmonics into the orbital dynamics.
orbital_dyn.accel_models.push(harmonics);
// We define the solar radiation pressure, using the default solar flux and accounting only
// for the eclipsing caused by the Earth.
let srp_dyn = SolarPressure::default(EARTH_J2000, almanac.clone())?;
// Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
// acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
let sc_dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn)
.with_guidance_law(ruggiero_ctrl.clone());
println!("{:x}", orbit);
// We specify a minimum step in the propagator because the Ruggiero control would otherwise drive this step very low.
let (final_state, traj) = Propagator::rk89(
sc_dynamics.clone(),
PropOpts::builder()
.min_step(10.0_f64.seconds())
.error_ctrl(RSSCartesianStep {})
.build(),
)
.with(sc, almanac.clone())
.for_duration_with_traj(prop_time)?;
let fuel_usage = sc.fuel_mass_kg - final_state.fuel_mass_kg;
println!("{:x}", final_state.orbit);
println!("fuel usage: {:.3} kg", fuel_usage);
// Finally, export the results for analysis, including the penumbra percentage throughout the orbit raise.
traj.to_parquet(
"./03_geo_raise.parquet",
Some(vec![
&EclipseLocator::cislunar(almanac.clone()).to_penumbra_event()
]),
ExportCfg::default(),
almanac,
)?;
for status_line in ruggiero_ctrl.status(&final_state) {
println!("{status_line}");
}
ruggiero_ctrl
.achieved(&final_state)
.expect("objective not achieved");
Ok(())
}
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fn main() -> Result<(), Box<dyn Error>> {
pel::init();
// Dynamics models require planetary constants and ephemerides to be defined.
// Let's start by grabbing those by using ANISE's latest MetaAlmanac.
// This will automatically download the DE440s planetary ephemeris,
// the daily-updated Earth Orientation Parameters, the high fidelity Moon orientation
// parameters (for the Moon Mean Earth and Moon Principal Axes frames), and the PCK11
// planetary constants kernels.
// For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
// Note that we place the Almanac into an Arc so we can clone it cheaply and provide read-only
// references to many functions.
let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
// Define the orbit epoch
let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
// Define the orbit.
// First we need to fetch the Earth J2000 from information from the Almanac.
// This allows the frame to include the gravitational parameters and the shape of the Earth,
// defined as a tri-axial ellipoid. Note that this shape can be changed manually or in the Almanac
// by loading a different set of planetary constants.
let earth_j2000 = almanac.frame_from_uid(EARTH_J2000)?;
// Placing this GEO bird just above Colorado.
// In theory, the eccentricity is zero, but in practice, it's about 1e-5 to 1e-6 at best.
let orbit = Orbit::try_keplerian(42164.0, 1e-5, 0., 163.0, 75.0, 0.0, epoch, earth_j2000)?;
// Print in in Keplerian form.
println!("{orbit:x}");
let state_bf = almanac.transform_to(orbit, IAU_EARTH_FRAME, None)?;
let (orig_lat_deg, orig_long_deg, orig_alt_km) = state_bf.latlongalt()?;
// Nyx is used for high fidelity propagation, not Keplerian propagation as above.
// Nyx only propagates Spacecraft at the moment, which allows it to account for acceleration
// models such as solar radiation pressure.
// Let's build a cubesat sized spacecraft, with an SRP area of 10 cm^2 and a mass of 9.6 kg.
let sc = Spacecraft::builder()
.orbit(orbit)
.dry_mass_kg(9.60)
.srp(SrpConfig {
area_m2: 10e-4,
cr: 1.1,
})
.build();
println!("{sc:x}");
// Set up the spacecraft dynamics.
// Specify that the orbital dynamics must account for the graviational pull of the Moon and the Sun.
// The gravity of the Earth will also be accounted for since the spaceraft in an Earth orbit.
let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
// We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
// We're using the JGM3 model here, which is the default in GMAT.
let mut jgm3_meta = MetaFile {
uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
};
// And let's download it if we don't have it yet.
jgm3_meta.process()?;
// Build the spherical harmonics.
// The harmonics must be computed in the body fixed frame.
// We're using the long term prediction of the Earth centered Earth fixed frame, IAU Earth.
let harmonics_21x21 = Harmonics::from_stor(
almanac.frame_from_uid(IAU_EARTH_FRAME)?,
HarmonicsMem::from_cof(&jgm3_meta.uri, 21, 21, true).unwrap(),
);
// Include the spherical harmonics into the orbital dynamics.
orbital_dyn.accel_models.push(harmonics_21x21);
// We define the solar radiation pressure, using the default solar flux and accounting only
// for the eclipsing caused by the Earth and Moon.
let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], almanac.clone())?;
// Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
// acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
println!("{dynamics}");
// Finally, let's propagate this orbit to the same epoch as above.
// The first returned value is the spacecraft state at the final epoch.
// The second value is the full trajectory where the step size is variable step used by the propagator.
let (future_sc, trajectory) = Propagator::default(dynamics)
.with(sc, almanac.clone())
.until_epoch_with_traj(epoch + Unit::Century * 0.03)?;
println!("=== High fidelity propagation ===");
println!(
"SMA changed by {:.3} km",
orbit.sma_km()? - future_sc.orbit.sma_km()?
);
println!(
"ECC changed by {:.6}",
orbit.ecc()? - future_sc.orbit.ecc()?
);
println!(
"INC changed by {:.3e} deg",
orbit.inc_deg()? - future_sc.orbit.inc_deg()?
);
println!(
"RAAN changed by {:.3} deg",
orbit.raan_deg()? - future_sc.orbit.raan_deg()?
);
println!(
"AOP changed by {:.3} deg",
orbit.aop_deg()? - future_sc.orbit.aop_deg()?
);
println!(
"TA changed by {:.3} deg",
orbit.ta_deg()? - future_sc.orbit.ta_deg()?
);
// We also have access to the full trajectory throughout the propagation.
println!("{trajectory}");
println!("Spacecraft params after 3 years without active control:\n{future_sc:x}");
// With the trajectory, let's build a few data products.
// 1. Export the trajectory as a parquet file, which includes the Keplerian orbital elements.
let analysis_step = Unit::Minute * 5;
trajectory.to_parquet(
"./03_geo_hf_prop.parquet",
Some(vec![
&EclipseLocator::cislunar(almanac.clone()).to_penumbra_event()
]),
ExportCfg::builder().step(analysis_step).build(),
almanac.clone(),
)?;
// 2. Compute the latitude, longitude, and altitude throughout the trajectory by rotating the spacecraft position into the Earth body fixed frame.
// We iterate over the trajectory, grabbing a state every two minutes.
let mut offset_s = vec![];
let mut epoch_str = vec![];
let mut longitude_deg = vec![];
let mut latitude_deg = vec![];
let mut altitude_km = vec![];
for state in trajectory.every(analysis_step) {
// Convert the GEO bird state into the body fixed frame, and keep track of its latitude, longitude, and altitude.
// These define the GEO stationkeeping box.
let this_epoch = state.epoch();
offset_s.push((this_epoch - orbit.epoch).to_seconds());
epoch_str.push(this_epoch.to_isoformat());
let state_bf = almanac.transform_to(state.orbit, IAU_EARTH_FRAME, None)?;
let (lat_deg, long_deg, alt_km) = state_bf.latlongalt()?;
longitude_deg.push(long_deg);
latitude_deg.push(lat_deg);
altitude_km.push(alt_km);
}
println!(
"Longitude changed by {:.3} deg -- Box is 0.1 deg E-W",
orig_long_deg - longitude_deg.last().unwrap()
);
println!(
"Latitude changed by {:.3} deg -- Box is 0.05 deg N-S",
orig_lat_deg - latitude_deg.last().unwrap()
);
println!(
"Altitude changed by {:.3} km -- Box is 30 km",
orig_alt_km - altitude_km.last().unwrap()
);
// Build the station keeping data frame.
let mut sk_df = df!(
"Offset (s)" => offset_s.clone(),
"Epoch (UTC)" => epoch_str.clone(),
"Longitude E-W (deg)" => longitude_deg,
"Latitude N-S (deg)" => latitude_deg,
"Altitude (km)" => altitude_km,
)?;
// Create a file to write the Parquet to
let file = File::create("./03_geo_lla.parquet").expect("Could not create file");
// Create a ParquetWriter and write the DataFrame to the file
ParquetWriter::new(file).finish(&mut sk_df)?;
Ok(())
}
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fn main() -> Result<(), Box<dyn Error>> {
pel::init();
// Dynamics models require planetary constants and ephemerides to be defined.
// Let's start by grabbing those by using ANISE's latest MetaAlmanac.
// This will automatically download the DE440s planetary ephemeris,
// the daily-updated Earth Orientation Parameters, the high fidelity Moon orientation
// parameters (for the Moon Mean Earth and Moon Principal Axes frames), and the PCK11
// planetary constants kernels.
// For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
// Note that we place the Almanac into an Arc so we can clone it cheaply and provide read-only
// references to many functions.
let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
// Define the orbit epoch
let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
// Define the orbit.
// First we need to fetch the Earth J2000 from information from the Almanac.
// This allows the frame to include the gravitational parameters and the shape of the Earth,
// defined as a tri-axial ellipoid. Note that this shape can be changed manually or in the Almanac
// by loading a different set of planetary constants.
let earth_j2000 = almanac.frame_from_uid(EARTH_J2000)?;
let orbit =
Orbit::try_keplerian_altitude(300.0, 0.015, 68.5, 65.2, 75.0, 0.0, epoch, earth_j2000)?;
// Print in in Keplerian form.
println!("{orbit:x}");
// There are two ways to propagate an orbit. We can make a quick approximation assuming only two-body
// motion. This is a useful first order approximation but it isn't used in real-world applications.
// This approach is a feature of ANISE.
let future_orbit_tb = orbit.at_epoch(epoch + Unit::Day * 3)?;
println!("{future_orbit_tb:x}");
// Two body propagation relies solely on Kepler's laws, so only the true anomaly will change.
println!(
"SMA changed by {:.3e} km",
orbit.sma_km()? - future_orbit_tb.sma_km()?
);
println!(
"ECC changed by {:.3e}",
orbit.ecc()? - future_orbit_tb.ecc()?
);
println!(
"INC changed by {:.3e} deg",
orbit.inc_deg()? - future_orbit_tb.inc_deg()?
);
println!(
"RAAN changed by {:.3e} deg",
orbit.raan_deg()? - future_orbit_tb.raan_deg()?
);
println!(
"AOP changed by {:.3e} deg",
orbit.aop_deg()? - future_orbit_tb.aop_deg()?
);
println!(
"TA changed by {:.3} deg",
orbit.ta_deg()? - future_orbit_tb.ta_deg()?
);
// Nyx is used for high fidelity propagation, not Keplerian propagation as above.
// Nyx only propagates Spacecraft at the moment, which allows it to account for acceleration
// models such as solar radiation pressure.
// Let's build a cubesat sized spacecraft, with an SRP area of 10 cm^2 and a mass of 9.6 kg.
let sc = Spacecraft::builder()
.orbit(orbit)
.dry_mass_kg(9.60)
.srp(SrpConfig {
area_m2: 10e-4,
cr: 1.1,
})
.build();
println!("{sc:x}");
// Set up the spacecraft dynamics.
// Specify that the orbital dynamics must account for the graviational pull of the Moon and the Sun.
// The gravity of the Earth will also be accounted for since the spaceraft in an Earth orbit.
let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
// We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
// We're using the JGM3 model here, which is the default in GMAT.
let mut jgm3_meta = MetaFile {
uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
};
// And let's download it if we don't have it yet.
jgm3_meta.process()?;
// Build the spherical harmonics.
// The harmonics must be computed in the body fixed frame.
// We're using the long term prediction of the Earth centered Earth fixed frame, IAU Earth.
let harmonics_21x21 = Harmonics::from_stor(
almanac.frame_from_uid(IAU_EARTH_FRAME)?,
HarmonicsMem::from_cof(&jgm3_meta.uri, 21, 21, true).unwrap(),
);
// Include the spherical harmonics into the orbital dynamics.
orbital_dyn.accel_models.push(harmonics_21x21);
// We define the solar radiation pressure, using the default solar flux and accounting only
// for the eclipsing caused by the Earth.
let srp_dyn = SolarPressure::default(EARTH_J2000, almanac.clone())?;
// Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
// acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
println!("{dynamics}");
// Finally, let's propagate this orbit to the same epoch as above.
// The first returned value is the spacecraft state at the final epoch.
// The second value is the full trajectory where the step size is variable step used by the propagator.
let (future_sc, trajectory) = Propagator::default(dynamics)
.with(sc, almanac.clone())
.until_epoch_with_traj(future_orbit_tb.epoch)?;
println!("=== High fidelity propagation ===");
println!(
"SMA changed by {:.3} km",
orbit.sma_km()? - future_sc.orbit.sma_km()?
);
println!(
"ECC changed by {:.6}",
orbit.ecc()? - future_sc.orbit.ecc()?
);
println!(
"INC changed by {:.3e} deg",
orbit.inc_deg()? - future_sc.orbit.inc_deg()?
);
println!(
"RAAN changed by {:.3} deg",
orbit.raan_deg()? - future_sc.orbit.raan_deg()?
);
println!(
"AOP changed by {:.3} deg",
orbit.aop_deg()? - future_sc.orbit.aop_deg()?
);
println!(
"TA changed by {:.3} deg",
orbit.ta_deg()? - future_sc.orbit.ta_deg()?
);
// We also have access to the full trajectory throughout the propagation.
println!("{trajectory}");
// With the trajectory, let's build a few data products.
// 1. Export the trajectory as a CCSDS OEM version 2.0 file and as a parquet file, which includes the Keplerian orbital elements.
trajectory.to_oem_file(
"./01_cubesat_hf_prop.oem",
ExportCfg::builder().step(Unit::Minute * 2).build(),
)?;
trajectory.to_parquet_with_cfg(
"./01_cubesat_hf_prop.parquet",
ExportCfg::builder().step(Unit::Minute * 2).build(),
almanac.clone(),
)?;
// 2. Compare the difference in the radial-intrack-crosstrack frame between the high fidelity
// and Keplerian propagation. The RIC frame is commonly used to compute the difference in position
// and velocity of different spacecraft.
// 3. Compute the azimuth, elevation, range, and range-rate data of that spacecraft as seen from Boulder, CO, USA.
let boulder_station = GroundStation::from_point(
"Boulder, CO, USA".to_string(),
40.014984, // latitude in degrees
-105.270546, // longitude in degrees
1.6550, // altitude in kilometers
almanac.frame_from_uid(IAU_EARTH_FRAME)?,
);
// We iterate over the trajectory, grabbing a state every two minutes.
let mut offset_s = vec![];
let mut epoch_str = vec![];
let mut ric_x_km = vec![];
let mut ric_y_km = vec![];
let mut ric_z_km = vec![];
let mut ric_vx_km_s = vec![];
let mut ric_vy_km_s = vec![];
let mut ric_vz_km_s = vec![];
let mut azimuth_deg = vec![];
let mut elevation_deg = vec![];
let mut range_km = vec![];
let mut range_rate_km_s = vec![];
for state in trajectory.every(Unit::Minute * 2) {
// Try to compute the Keplerian/two body state just in time.
// This method occasionally fails to converge on an appropriate true anomaly
// from the mean anomaly. If that happens, we just skip this state.
// The high fidelity and Keplerian states diverge continuously, and we're curious
// about the divergence in this quick analysis.
let this_epoch = state.epoch();
match orbit.at_epoch(this_epoch) {
Ok(tb_then) => {
offset_s.push((this_epoch - orbit.epoch).to_seconds());
epoch_str.push(format!("{this_epoch}"));
// Compute the two body state just in time.
let ric = state.orbit.ric_difference(&tb_then)?;
ric_x_km.push(ric.radius_km.x);
ric_y_km.push(ric.radius_km.y);
ric_z_km.push(ric.radius_km.z);
ric_vx_km_s.push(ric.velocity_km_s.x);
ric_vy_km_s.push(ric.velocity_km_s.y);
ric_vz_km_s.push(ric.velocity_km_s.z);
// Compute the AER data for each state.
let aer = almanac.azimuth_elevation_range_sez(
state.orbit,
boulder_station.to_orbit(this_epoch, &almanac)?,
)?;
azimuth_deg.push(aer.azimuth_deg);
elevation_deg.push(aer.elevation_deg);
range_km.push(aer.range_km);
range_rate_km_s.push(aer.range_rate_km_s);
}
Err(e) => warn!("{} {e}", state.epoch()),
};
}
// Build the data frames.
let ric_df = df!(
"Offset (s)" => offset_s.clone(),
"Epoch" => epoch_str.clone(),
"RIC X (km)" => ric_x_km,
"RIC Y (km)" => ric_y_km,
"RIC Z (km)" => ric_z_km,
"RIC VX (km/s)" => ric_vx_km_s,
"RIC VY (km/s)" => ric_vy_km_s,
"RIC VZ (km/s)" => ric_vz_km_s,
)?;
println!("RIC difference at start\n{}", ric_df.head(Some(10)));
println!("RIC difference at end\n{}", ric_df.tail(Some(10)));
let aer_df = df!(
"Offset (s)" => offset_s.clone(),
"Epoch" => epoch_str.clone(),
"azimuth (deg)" => azimuth_deg,
"elevation (deg)" => elevation_deg,
"range (km)" => range_km,
"range rate (km/s)" => range_rate_km_s,
)?;
// Finally, let's see when the spacecraft is visible, assuming 15 degrees minimum elevation.
let mask = aer_df.column("elevation (deg)")?.gt(15.0)?;
let cubesat_visible = aer_df.filter(&mask)?;
println!("{cubesat_visible}");
Ok(())
}
pub fn from_gregorian(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
nanos: u32,
time_scale: TimeScale,
) -> Epoch
pub fn from_gregorian( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, nanos: u32, time_scale: TimeScale, ) -> Epoch
Builds an Epoch from the provided Gregorian date and time in the provided time scale. If invalid date is provided, this function will panic. Use maybe_from_gregorian if unsure.
pub fn from_gregorian_at_midnight(
year: i32,
month: u8,
day: u8,
time_scale: TimeScale,
) -> Epoch
pub fn from_gregorian_at_midnight( year: i32, month: u8, day: u8, time_scale: TimeScale, ) -> Epoch
Initialize from Gregorian date in UTC at midnight
pub fn from_gregorian_at_noon(
year: i32,
month: u8,
day: u8,
time_scale: TimeScale,
) -> Epoch
pub fn from_gregorian_at_noon( year: i32, month: u8, day: u8, time_scale: TimeScale, ) -> Epoch
Initialize from Gregorian date in UTC at noon
pub fn from_gregorian_hms(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
time_scale: TimeScale,
) -> Epoch
pub fn from_gregorian_hms( year: i32, month: u8, day: u8, hour: u8, minute: u8, second: u8, time_scale: TimeScale, ) -> Epoch
Initialize from the Gregorian date and time (without the nanoseconds) in UTC
pub fn from_gregorian_str(s_in: &str) -> Result<Epoch, EpochError>
pub fn from_gregorian_str(s_in: &str) -> Result<Epoch, EpochError>
Converts a Gregorian date time in ISO8601 or RFC3339 format into an Epoch, accounting for the time zone designator and the time scale.
§Definition
- Time Zone Designator: this is either a
Z
(lower or upper case) to specify UTC, or an offset in hours and minutes off of UTC, such as+01:00
for UTC plus one hour and zero minutes. - Time system (or time “scale”): UTC, TT, TAI, TDB, ET, etc.
Converts an ISO8601 or RFC3339 datetime representation to an Epoch.
If no time scale is specified, then UTC is assumed.
A time scale may be specified in addition to the format unless
The T
which separates the date from the time can be replaced with a single whitespace character (\W
).
The offset is also optional, cf. the examples below.
§Example
use hifitime::Epoch;
let dt = Epoch::from_gregorian_utc(2017, 1, 14, 0, 31, 55, 0);
assert_eq!(
dt,
Epoch::from_gregorian_str("2017-01-14T00:31:55 UTC").unwrap()
);
assert_eq!(
dt,
Epoch::from_gregorian_str("2017-01-14T00:31:55.0000 UTC").unwrap()
);
assert_eq!(
dt,
Epoch::from_gregorian_str("2017-01-14T00:31:55").unwrap()
);
assert_eq!(
dt,
Epoch::from_gregorian_str("2017-01-14 00:31:55").unwrap()
);
// Regression test for #90
assert_eq!(
Epoch::from_gregorian_utc(2017, 1, 14, 0, 31, 55, 811000000),
Epoch::from_gregorian_str("2017-01-14 00:31:55.811 UTC").unwrap()
);
assert_eq!(
Epoch::from_gregorian_utc(2017, 1, 14, 0, 31, 55, 811200000),
Epoch::from_gregorian_str("2017-01-14 00:31:55.8112 UTC").unwrap()
);
// Example from https://www.w3.org/TR/NOTE-datetime
assert_eq!(
Epoch::from_gregorian_utc_hms(1994, 11, 5, 13, 15, 30),
Epoch::from_gregorian_str("1994-11-05T13:15:30Z").unwrap()
);
assert_eq!(
Epoch::from_gregorian_utc_hms(1994, 11, 5, 13, 15, 30),
Epoch::from_gregorian_str("1994-11-05T08:15:30-05:00").unwrap()
);
§impl Epoch
impl Epoch
pub fn min(&self, other: Epoch) -> Epoch
pub fn min(&self, other: Epoch) -> Epoch
Returns the minimum of the two epochs.
use hifitime::Epoch;
let e0 = Epoch::from_gregorian_utc_at_midnight(2022, 10, 20);
let e1 = Epoch::from_gregorian_utc_at_midnight(2022, 10, 21);
assert_eq!(e0, e1.min(e0));
assert_eq!(e0, e0.min(e1));
Note: this uses a pointer to self
which will be copied immediately because Python requires a pointer.
pub fn max(&self, other: Epoch) -> Epoch
pub fn max(&self, other: Epoch) -> Epoch
Returns the maximum of the two epochs.
use hifitime::Epoch;
let e0 = Epoch::from_gregorian_utc_at_midnight(2022, 10, 20);
let e1 = Epoch::from_gregorian_utc_at_midnight(2022, 10, 21);
assert_eq!(e1, e1.max(e0));
assert_eq!(e1, e0.max(e1));
Note: this uses a pointer to self
which will be copied immediately because Python requires a pointer.
pub fn floor(&self, duration: Duration) -> Epoch
pub fn floor(&self, duration: Duration) -> Epoch
Floors this epoch to the closest provided duration
§Example
use hifitime::{Epoch, TimeUnits};
let e = Epoch::from_gregorian_tai_hms(2022, 5, 20, 17, 57, 43);
assert_eq!(
e.floor(1.hours()),
Epoch::from_gregorian_tai_hms(2022, 5, 20, 17, 0, 0)
);
let e = Epoch::from_gregorian_tai(2022, 10, 3, 17, 44, 29, 898032665);
assert_eq!(
e.floor(3.minutes()),
Epoch::from_gregorian_tai_hms(2022, 10, 3, 17, 42, 0)
);
pub fn ceil(&self, duration: Duration) -> Epoch
pub fn ceil(&self, duration: Duration) -> Epoch
Ceils this epoch to the closest provided duration in the TAI time scale
§Example
use hifitime::{Epoch, TimeUnits};
let e = Epoch::from_gregorian_tai_hms(2022, 5, 20, 17, 57, 43);
assert_eq!(
e.ceil(1.hours()),
Epoch::from_gregorian_tai_hms(2022, 5, 20, 18, 0, 0)
);
// 45 minutes is a multiple of 3 minutes, hence this result
let e = Epoch::from_gregorian_tai(2022, 10, 3, 17, 44, 29, 898032665);
assert_eq!(
e.ceil(3.minutes()),
Epoch::from_gregorian_tai_hms(2022, 10, 3, 17, 45, 0)
);
pub fn round(&self, duration: Duration) -> Epoch
pub fn round(&self, duration: Duration) -> Epoch
Rounds this epoch to the closest provided duration in TAI
§Example
use hifitime::{Epoch, TimeUnits};
let e = Epoch::from_gregorian_tai_hms(2022, 5, 20, 17, 57, 43);
assert_eq!(
e.round(1.hours()),
Epoch::from_gregorian_tai_hms(2022, 5, 20, 18, 0, 0)
);
pub fn to_time_of_week(&self) -> (u32, u64)
pub fn to_time_of_week(&self) -> (u32, u64)
Converts this epoch into the time of week, represented as a rolling week counter into that time scale and the number of nanoseconds elapsed in current week (since closest Sunday midnight). This is usually how GNSS receivers describe a timestamp.
pub fn weekday_in_time_scale(&self, time_scale: TimeScale) -> Weekday
pub fn weekday_in_time_scale(&self, time_scale: TimeScale) -> Weekday
Returns the weekday in provided time scale ASSUMING that the reference epoch of that time scale is a Monday.
You probably do not want to use this. You probably either want weekday()
or weekday_utc()
.
Several time scales do not have a reference day that’s on a Monday, e.g. BDT.
pub fn weekday_utc(&self) -> Weekday
pub fn weekday_utc(&self) -> Weekday
Returns weekday in UTC timescale
pub fn next(&self, weekday: Weekday) -> Epoch
pub fn next(&self, weekday: Weekday) -> Epoch
Returns the next weekday.
use hifitime::prelude::*;
let epoch = Epoch::from_gregorian_utc_at_midnight(1988, 1, 2);
assert_eq!(epoch.weekday_utc(), Weekday::Saturday);
assert_eq!(epoch.next(Weekday::Sunday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 3));
assert_eq!(epoch.next(Weekday::Monday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 4));
assert_eq!(epoch.next(Weekday::Tuesday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 5));
assert_eq!(epoch.next(Weekday::Wednesday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 6));
assert_eq!(epoch.next(Weekday::Thursday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 7));
assert_eq!(epoch.next(Weekday::Friday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 8));
assert_eq!(epoch.next(Weekday::Saturday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 9));
pub fn next_weekday_at_midnight(&self, weekday: Weekday) -> Epoch
pub fn next_weekday_at_noon(&self, weekday: Weekday) -> Epoch
pub fn previous(&self, weekday: Weekday) -> Epoch
pub fn previous(&self, weekday: Weekday) -> Epoch
Returns the next weekday.
use hifitime::prelude::*;
let epoch = Epoch::from_gregorian_utc_at_midnight(1988, 1, 2);
assert_eq!(epoch.previous(Weekday::Friday), Epoch::from_gregorian_utc_at_midnight(1988, 1, 1));
assert_eq!(epoch.previous(Weekday::Thursday), Epoch::from_gregorian_utc_at_midnight(1987, 12, 31));
assert_eq!(epoch.previous(Weekday::Wednesday), Epoch::from_gregorian_utc_at_midnight(1987, 12, 30));
assert_eq!(epoch.previous(Weekday::Tuesday), Epoch::from_gregorian_utc_at_midnight(1987, 12, 29));
assert_eq!(epoch.previous(Weekday::Monday), Epoch::from_gregorian_utc_at_midnight(1987, 12, 28));
assert_eq!(epoch.previous(Weekday::Sunday), Epoch::from_gregorian_utc_at_midnight(1987, 12, 27));
assert_eq!(epoch.previous(Weekday::Saturday), Epoch::from_gregorian_utc_at_midnight(1987, 12, 26));
pub fn previous_weekday_at_midnight(&self, weekday: Weekday) -> Epoch
pub fn previous_weekday_at_noon(&self, weekday: Weekday) -> Epoch
§impl Epoch
impl Epoch
pub fn with_hms(&self, hours: u64, minutes: u64, seconds: u64) -> Epoch
pub fn with_hms(&self, hours: u64, minutes: u64, seconds: u64) -> Epoch
Returns a copy of self where the time is set to the provided hours, minutes, seconds Invalid number of hours, minutes, and seconds will overflow into their higher unit. Warning: this does not set the subdivisions of second to zero.
pub fn with_hms_from(&self, other: Epoch) -> Epoch
pub fn with_hms_from(&self, other: Epoch) -> Epoch
Returns a copy of self where the hours, minutes, seconds is set to the time of the provided epoch but the sub-second parts are kept from the current epoch.
use hifitime::prelude::*;
let epoch = Epoch::from_gregorian_utc(2022, 12, 01, 10, 11, 12, 13);
let other_utc = Epoch::from_gregorian_utc(2024, 12, 01, 20, 21, 22, 23);
let other = other_utc.to_time_scale(TimeScale::TDB);
assert_eq!(
epoch.with_hms_from(other),
Epoch::from_gregorian_utc(2022, 12, 01, 20, 21, 22, 13)
);
pub fn with_time_from(&self, other: Epoch) -> Epoch
pub fn with_time_from(&self, other: Epoch) -> Epoch
Returns a copy of self where all of the time components (hours, minutes, seconds, and sub-seconds) are set to the time of the provided epoch.
use hifitime::prelude::*;
let epoch = Epoch::from_gregorian_utc(2022, 12, 01, 10, 11, 12, 13);
let other_utc = Epoch::from_gregorian_utc(2024, 12, 01, 20, 21, 22, 23);
// If the other Epoch is in another time scale, it does not matter, it will be converted to the correct time scale.
let other = other_utc.to_time_scale(TimeScale::TDB);
assert_eq!(
epoch.with_time_from(other),
Epoch::from_gregorian_utc(2022, 12, 01, 20, 21, 22, 23)
);
pub fn with_hms_strict(&self, hours: u64, minutes: u64, seconds: u64) -> Epoch
pub fn with_hms_strict(&self, hours: u64, minutes: u64, seconds: u64) -> Epoch
Returns a copy of self where the time is set to the provided hours, minutes, seconds Invalid number of hours, minutes, and seconds will overflow into their higher unit. Warning: this will set the subdivisions of seconds to zero.
pub fn with_hms_strict_from(&self, other: Epoch) -> Epoch
pub fn with_hms_strict_from(&self, other: Epoch) -> Epoch
Returns a copy of self where the time is set to the time of the other epoch but the subseconds are set to zero.
use hifitime::prelude::*;
let epoch = Epoch::from_gregorian_utc(2022, 12, 01, 10, 11, 12, 13);
let other_utc = Epoch::from_gregorian_utc(2024, 12, 01, 20, 21, 22, 23);
let other = other_utc.to_time_scale(TimeScale::TDB);
assert_eq!(
epoch.with_hms_strict_from(other),
Epoch::from_gregorian_utc(2022, 12, 01, 20, 21, 22, 0)
);
§impl Epoch
impl Epoch
pub fn now() -> Result<Epoch, EpochError>
pub fn now() -> Result<Epoch, EpochError>
Initializes a new Epoch from now
.
WARNING: This assumes that the system time returns the time in UTC (which is the case on Linux)
Uses std::time::SystemTime::now
or javascript interop under the hood
§impl Epoch
impl Epoch
pub fn to_time_scale(&self, ts: TimeScale) -> Epoch
pub fn to_time_scale(&self, ts: TimeScale) -> Epoch
Converts self to another time scale
As per the Rust naming convention, this borrows an Epoch and returns an owned Epoch.
pub const fn from_tai_duration(duration: Duration) -> Epoch
pub const fn from_tai_duration(duration: Duration) -> Epoch
Creates a new Epoch from a Duration as the time difference between this epoch and TAI reference epoch.
pub fn leap_seconds_with<L>(&self, iers_only: bool, provider: L) -> Option<f64>where
L: LeapSecondProvider,
pub fn leap_seconds_with<L>(&self, iers_only: bool, provider: L) -> Option<f64>where
L: LeapSecondProvider,
Get the accumulated number of leap seconds up to this Epoch from the provided LeapSecondProvider. Returns None if the epoch is before 1960, year at which UTC was defined.
§Why does this function return an Option
when the other returns a value
This is to match the iauDat
function of SOFA (src/dat.c). That function will return a warning and give up if the start date is before 1960.
pub const fn from_duration(duration: Duration, ts: TimeScale) -> Epoch
pub const fn from_duration(duration: Duration, ts: TimeScale) -> Epoch
Creates an epoch from given duration expressed in given timescale, i.e. since the given time scale’s reference epoch.
For example, if the duration is 1 day and the time scale is Ephemeris Time, then this will create an epoch of 2000-01-02 at midnight ET. If the duration is 1 day and the time scale is TAI, this will create an epoch of 1900-01-02 at noon, because the TAI reference epoch in Hifitime is chosen to be the J1900 epoch. In case of ET, TDB Timescales, a duration since J2000 is expected.
pub fn to_duration_since_j1900(&self) -> Duration
pub fn from_tai_parts(centuries: i16, nanoseconds: u64) -> Epoch
pub fn from_tai_parts(centuries: i16, nanoseconds: u64) -> Epoch
Creates a new Epoch from its centuries and nanosecond since the TAI reference epoch.
pub fn from_tai_seconds(seconds: f64) -> Epoch
pub fn from_tai_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the provided TAI seconds since 1900 January 01 at midnight
pub fn from_tai_days(days: f64) -> Epoch
pub fn from_tai_days(days: f64) -> Epoch
Initialize an Epoch from the provided TAI days since 1900 January 01 at midnight
pub fn from_utc_duration(duration: Duration) -> Epoch
pub fn from_utc_duration(duration: Duration) -> Epoch
Initialize an Epoch from the provided UTC seconds since 1900 January 01 at midnight
pub fn from_utc_seconds(seconds: f64) -> Epoch
pub fn from_utc_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the provided UTC seconds since 1900 January 01 at midnight
pub fn from_utc_days(days: f64) -> Epoch
pub fn from_utc_days(days: f64) -> Epoch
Initialize an Epoch from the provided UTC days since 1900 January 01 at midnight
pub fn from_gpst_duration(duration: Duration) -> Epoch
pub fn from_gpst_duration(duration: Duration) -> Epoch
Initialize an Epoch from the provided duration since 1980 January 6 at midnight
pub fn from_qzsst_duration(duration: Duration) -> Epoch
pub fn from_qzsst_duration(duration: Duration) -> Epoch
Initialize an Epoch from the provided duration since 1980 January 6 at midnight
pub fn from_gst_duration(duration: Duration) -> Epoch
pub fn from_gst_duration(duration: Duration) -> Epoch
Initialize an Epoch from the provided duration since August 21st 1999 midnight
pub fn from_bdt_duration(duration: Duration) -> Epoch
pub fn from_bdt_duration(duration: Duration) -> Epoch
Initialize an Epoch from the provided duration since January 1st midnight
pub fn from_mjd_tai(days: f64) -> Epoch
pub fn from_mjd_utc(days: f64) -> Epoch
pub fn from_mjd_gpst(days: f64) -> Epoch
pub fn from_mjd_qzsst(days: f64) -> Epoch
pub fn from_mjd_gst(days: f64) -> Epoch
pub fn from_mjd_bdt(days: f64) -> Epoch
pub fn from_jde_tai(days: f64) -> Epoch
pub fn from_jde_utc(days: f64) -> Epoch
pub fn from_jde_gpst(days: f64) -> Epoch
pub fn from_jde_qzsst(days: f64) -> Epoch
pub fn from_jde_gst(days: f64) -> Epoch
pub fn from_jde_bdt(days: f64) -> Epoch
pub fn from_tt_seconds(seconds: f64) -> Epoch
pub fn from_tt_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the provided TT seconds (approximated to 32.184s delta from TAI)
pub fn from_tt_duration(duration: Duration) -> Epoch
pub fn from_tt_duration(duration: Duration) -> Epoch
Initialize an Epoch from the provided TT seconds (approximated to 32.184s delta from TAI)
pub fn from_et_seconds(seconds_since_j2000: f64) -> Epoch
pub fn from_et_seconds(seconds_since_j2000: f64) -> Epoch
Initialize an Epoch from the Ephemeris Time seconds past 2000 JAN 01 (J2000 reference)
pub fn from_et_duration(duration_since_j2000: Duration) -> Epoch
pub fn from_et_duration(duration_since_j2000: Duration) -> Epoch
Initializes an Epoch from the duration between J2000 and the current epoch as per NAIF SPICE.
§Limitation
This method uses a Newton Raphson iteration to find the appropriate TAI duration. This method is only accuracy to a few nanoseconds.
Hence, when calling as_et_duration()
and re-initializing it with from_et_duration
you may have a few nanoseconds of difference (expect less than 10 ns).
§Warning
The et2utc function of NAIF SPICE will assume that there are 9 leap seconds before 01 JAN 1972, as this date introduces 10 leap seconds. At the time of writing, this does not seem to be in line with IERS and the documentation in the leap seconds list.
In order to match SPICE, the as_et_duration() function will manually get rid of that difference.
pub fn from_tdb_seconds(seconds_j2000: f64) -> Epoch
pub fn from_tdb_seconds(seconds_j2000: f64) -> Epoch
Initialize an Epoch from Dynamic Barycentric Time (TDB) seconds past 2000 JAN 01 midnight (difference than SPICE) NOTE: This uses the ESA algorithm, which is a notch more complicated than the SPICE algorithm, but more precise. In fact, SPICE algorithm is precise +/- 30 microseconds for a century whereas ESA algorithm should be exactly correct.
pub fn from_tdb_duration(duration_since_j2000: Duration) -> Epoch
pub fn from_tdb_duration(duration_since_j2000: Duration) -> Epoch
Initialize from Dynamic Barycentric Time (TDB) (same as SPICE ephemeris time) whose epoch is 2000 JAN 01 noon TAI.
pub fn from_jde_et(days: f64) -> Epoch
pub fn from_jde_et(days: f64) -> Epoch
Initialize from the JDE days
pub fn from_jde_tdb(days: f64) -> Epoch
pub fn from_jde_tdb(days: f64) -> Epoch
Initialize from Dynamic Barycentric Time (TDB) (same as SPICE ephemeris time) in JD days
pub fn from_gpst_seconds(seconds: f64) -> Epoch
pub fn from_gpst_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the number of seconds since the GPS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn from_gpst_days(days: f64) -> Epoch
pub fn from_gpst_days(days: f64) -> Epoch
Initialize an Epoch from the number of days since the GPS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn from_gpst_nanoseconds(nanoseconds: u64) -> Epoch
pub fn from_gpst_nanoseconds(nanoseconds: u64) -> Epoch
Initialize an Epoch from the number of nanoseconds since the GPS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29). This may be useful for time keeping devices that use GPS as a time source.
pub fn from_qzsst_seconds(seconds: f64) -> Epoch
pub fn from_qzsst_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the number of seconds since the QZSS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn from_qzsst_days(days: f64) -> Epoch
pub fn from_qzsst_days(days: f64) -> Epoch
Initialize an Epoch from the number of days since the QZSS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn from_qzsst_nanoseconds(nanoseconds: u64) -> Epoch
pub fn from_qzsst_nanoseconds(nanoseconds: u64) -> Epoch
Initialize an Epoch from the number of nanoseconds since the QZSS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29). This may be useful for time keeping devices that use QZSS as a time source.
pub fn from_gst_seconds(seconds: f64) -> Epoch
pub fn from_gst_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the number of seconds since the GST Time Epoch, starting August 21st 1999 midnight (UTC) (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS).
pub fn from_gst_days(days: f64) -> Epoch
pub fn from_gst_days(days: f64) -> Epoch
Initialize an Epoch from the number of days since the GST Time Epoch, starting August 21st 1999 midnight (UTC) (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS)
pub fn from_gst_nanoseconds(nanoseconds: u64) -> Epoch
pub fn from_gst_nanoseconds(nanoseconds: u64) -> Epoch
Initialize an Epoch from the number of nanoseconds since the GPS Time Epoch, starting August 21st 1999 midnight (UTC) (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS)
pub fn from_bdt_seconds(seconds: f64) -> Epoch
pub fn from_bdt_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the number of seconds since the BDT Time Epoch, starting on January 1st 2006 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS)
pub fn from_bdt_days(days: f64) -> Epoch
pub fn from_bdt_days(days: f64) -> Epoch
Initialize an Epoch from the number of days since the BDT Time Epoch, starting on January 1st 2006 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS)
pub fn from_bdt_nanoseconds(nanoseconds: u64) -> Epoch
pub fn from_bdt_nanoseconds(nanoseconds: u64) -> Epoch
Initialize an Epoch from the number of nanoseconds since the BDT Time Epoch, starting on January 1st 2006 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS). This may be useful for time keeping devices that use BDT as a time source.
pub fn from_unix_duration(duration: Duration) -> Epoch
pub fn from_unix_duration(duration: Duration) -> Epoch
Initialize an Epoch from the provided duration since UTC midnight 1970 January 01.
pub fn from_unix_seconds(seconds: f64) -> Epoch
pub fn from_unix_seconds(seconds: f64) -> Epoch
Initialize an Epoch from the provided UNIX second timestamp since UTC midnight 1970 January 01.
pub fn from_unix_milliseconds(millisecond: f64) -> Epoch
pub fn from_unix_milliseconds(millisecond: f64) -> Epoch
Initialize an Epoch from the provided UNIX millisecond timestamp since UTC midnight 1970 January 01.
pub fn from_str_with_format(
s_in: &str,
format: Format,
) -> Result<Epoch, EpochError>
pub fn from_str_with_format( s_in: &str, format: Format, ) -> Result<Epoch, EpochError>
Initializes an Epoch from the provided Format.
pub fn from_format_str(
s_in: &str,
format_str: &str,
) -> Result<Epoch, EpochError>
pub fn from_format_str( s_in: &str, format_str: &str, ) -> Result<Epoch, EpochError>
Initializes an Epoch from the Format as a string.
pub fn from_time_of_week(
week: u32,
nanoseconds: u64,
time_scale: TimeScale,
) -> Epoch
pub fn from_time_of_week( week: u32, nanoseconds: u64, time_scale: TimeScale, ) -> Epoch
Builds an Epoch from given week
: elapsed weeks counter into the desired Time scale, and the amount of nanoseconds within that week.
For example, this is how GPS vehicles describe a GPST epoch.
Note that this constructor relies on 128 bit integer math and may be slow on embedded devices.
pub fn from_time_of_week_utc(week: u32, nanoseconds: u64) -> Epoch
pub fn from_time_of_week_utc(week: u32, nanoseconds: u64) -> Epoch
Builds a UTC Epoch from given week
: elapsed weeks counter and “ns” amount of nanoseconds since closest Sunday Midnight.
pub fn from_day_of_year(year: i32, days: f64, time_scale: TimeScale) -> Epoch
pub fn from_day_of_year(year: i32, days: f64, time_scale: TimeScale) -> Epoch
Builds an Epoch from the provided year, days in the year, and a time scale.
§Limitations
In the TDB or ET time scales, there may be an error of up to 750 nanoseconds when initializing an Epoch this way. This is because we first initialize the epoch in Gregorian scale and then apply the TDB/ET offset, but that offset actually depends on the precise time.
§Day couting behavior
The day counter starts at 01, in other words, 01 January is day 1 of the counter, as per the GPS specificiations.
§impl Epoch
impl Epoch
pub fn leap_seconds_iers(&self) -> i32
pub fn leap_seconds_iers(&self) -> i32
Get the accumulated number of leap seconds up to this Epoch accounting only for the IERS leap seconds.
pub fn leap_seconds(&self, iers_only: bool) -> Option<f64>
pub fn leap_seconds(&self, iers_only: bool) -> Option<f64>
Get the accumulated number of leap seconds up to this Epoch accounting only for the IERS leap seconds and the SOFA scaling from 1960 to 1972, depending on flag. Returns None if the epoch is before 1960, year at which UTC was defined.
§Why does this function return an Option
when the other returns a value
This is to match the iauDat
function of SOFA (src/dat.c). That function will return a warning and give up if the start date is before 1960.
pub fn to_isoformat(&self) -> String
pub fn to_isoformat(&self) -> String
The standard ISO format of this epoch (six digits of subseconds) in the current time scale, refer to https://docs.rs/hifitime/latest/hifitime/efmt/format/struct.Format.html for format options.
Examples found in repository?
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218
fn main() -> Result<(), Box<dyn Error>> {
pel::init();
// Dynamics models require planetary constants and ephemerides to be defined.
// Let's start by grabbing those by using ANISE's latest MetaAlmanac.
// This will automatically download the DE440s planetary ephemeris,
// the daily-updated Earth Orientation Parameters, the high fidelity Moon orientation
// parameters (for the Moon Mean Earth and Moon Principal Axes frames), and the PCK11
// planetary constants kernels.
// For details, refer to https://github.com/nyx-space/anise/blob/master/data/latest.dhall.
// Note that we place the Almanac into an Arc so we can clone it cheaply and provide read-only
// references to many functions.
let almanac = Arc::new(MetaAlmanac::latest().map_err(Box::new)?);
// Define the orbit epoch
let epoch = Epoch::from_gregorian_utc_hms(2024, 2, 29, 12, 13, 14);
// Define the orbit.
// First we need to fetch the Earth J2000 from information from the Almanac.
// This allows the frame to include the gravitational parameters and the shape of the Earth,
// defined as a tri-axial ellipoid. Note that this shape can be changed manually or in the Almanac
// by loading a different set of planetary constants.
let earth_j2000 = almanac.frame_from_uid(EARTH_J2000)?;
// Placing this GEO bird just above Colorado.
// In theory, the eccentricity is zero, but in practice, it's about 1e-5 to 1e-6 at best.
let orbit = Orbit::try_keplerian(42164.0, 1e-5, 0., 163.0, 75.0, 0.0, epoch, earth_j2000)?;
// Print in in Keplerian form.
println!("{orbit:x}");
let state_bf = almanac.transform_to(orbit, IAU_EARTH_FRAME, None)?;
let (orig_lat_deg, orig_long_deg, orig_alt_km) = state_bf.latlongalt()?;
// Nyx is used for high fidelity propagation, not Keplerian propagation as above.
// Nyx only propagates Spacecraft at the moment, which allows it to account for acceleration
// models such as solar radiation pressure.
// Let's build a cubesat sized spacecraft, with an SRP area of 10 cm^2 and a mass of 9.6 kg.
let sc = Spacecraft::builder()
.orbit(orbit)
.dry_mass_kg(9.60)
.srp(SrpConfig {
area_m2: 10e-4,
cr: 1.1,
})
.build();
println!("{sc:x}");
// Set up the spacecraft dynamics.
// Specify that the orbital dynamics must account for the graviational pull of the Moon and the Sun.
// The gravity of the Earth will also be accounted for since the spaceraft in an Earth orbit.
let mut orbital_dyn = OrbitalDynamics::point_masses(vec![MOON, SUN]);
// We want to include the spherical harmonics, so let's download the gravitational data from the Nyx Cloud.
// We're using the JGM3 model here, which is the default in GMAT.
let mut jgm3_meta = MetaFile {
uri: "http://public-data.nyxspace.com/nyx/models/JGM3.cof.gz".to_string(),
crc32: Some(0xF446F027), // Specifying the CRC32 avoids redownloading it if it's cached.
};
// And let's download it if we don't have it yet.
jgm3_meta.process()?;
// Build the spherical harmonics.
// The harmonics must be computed in the body fixed frame.
// We're using the long term prediction of the Earth centered Earth fixed frame, IAU Earth.
let harmonics_21x21 = Harmonics::from_stor(
almanac.frame_from_uid(IAU_EARTH_FRAME)?,
HarmonicsMem::from_cof(&jgm3_meta.uri, 21, 21, true).unwrap(),
);
// Include the spherical harmonics into the orbital dynamics.
orbital_dyn.accel_models.push(harmonics_21x21);
// We define the solar radiation pressure, using the default solar flux and accounting only
// for the eclipsing caused by the Earth and Moon.
let srp_dyn = SolarPressure::new(vec![EARTH_J2000, MOON_J2000], almanac.clone())?;
// Finalize setting up the dynamics, specifying the force models (orbital_dyn) separately from the
// acceleration models (SRP in this case). Use `from_models` to specify multiple accel models.
let dynamics = SpacecraftDynamics::from_model(orbital_dyn, srp_dyn);
println!("{dynamics}");
// Finally, let's propagate this orbit to the same epoch as above.
// The first returned value is the spacecraft state at the final epoch.
// The second value is the full trajectory where the step size is variable step used by the propagator.
let (future_sc, trajectory) = Propagator::default(dynamics)
.with(sc, almanac.clone())
.until_epoch_with_traj(epoch + Unit::Century * 0.03)?;
println!("=== High fidelity propagation ===");
println!(
"SMA changed by {:.3} km",
orbit.sma_km()? - future_sc.orbit.sma_km()?
);
println!(
"ECC changed by {:.6}",
orbit.ecc()? - future_sc.orbit.ecc()?
);
println!(
"INC changed by {:.3e} deg",
orbit.inc_deg()? - future_sc.orbit.inc_deg()?
);
println!(
"RAAN changed by {:.3} deg",
orbit.raan_deg()? - future_sc.orbit.raan_deg()?
);
println!(
"AOP changed by {:.3} deg",
orbit.aop_deg()? - future_sc.orbit.aop_deg()?
);
println!(
"TA changed by {:.3} deg",
orbit.ta_deg()? - future_sc.orbit.ta_deg()?
);
// We also have access to the full trajectory throughout the propagation.
println!("{trajectory}");
println!("Spacecraft params after 3 years without active control:\n{future_sc:x}");
// With the trajectory, let's build a few data products.
// 1. Export the trajectory as a parquet file, which includes the Keplerian orbital elements.
let analysis_step = Unit::Minute * 5;
trajectory.to_parquet(
"./03_geo_hf_prop.parquet",
Some(vec![
&EclipseLocator::cislunar(almanac.clone()).to_penumbra_event()
]),
ExportCfg::builder().step(analysis_step).build(),
almanac.clone(),
)?;
// 2. Compute the latitude, longitude, and altitude throughout the trajectory by rotating the spacecraft position into the Earth body fixed frame.
// We iterate over the trajectory, grabbing a state every two minutes.
let mut offset_s = vec![];
let mut epoch_str = vec![];
let mut longitude_deg = vec![];
let mut latitude_deg = vec![];
let mut altitude_km = vec![];
for state in trajectory.every(analysis_step) {
// Convert the GEO bird state into the body fixed frame, and keep track of its latitude, longitude, and altitude.
// These define the GEO stationkeeping box.
let this_epoch = state.epoch();
offset_s.push((this_epoch - orbit.epoch).to_seconds());
epoch_str.push(this_epoch.to_isoformat());
let state_bf = almanac.transform_to(state.orbit, IAU_EARTH_FRAME, None)?;
let (lat_deg, long_deg, alt_km) = state_bf.latlongalt()?;
longitude_deg.push(long_deg);
latitude_deg.push(lat_deg);
altitude_km.push(alt_km);
}
println!(
"Longitude changed by {:.3} deg -- Box is 0.1 deg E-W",
orig_long_deg - longitude_deg.last().unwrap()
);
println!(
"Latitude changed by {:.3} deg -- Box is 0.05 deg N-S",
orig_lat_deg - latitude_deg.last().unwrap()
);
println!(
"Altitude changed by {:.3} km -- Box is 30 km",
orig_alt_km - altitude_km.last().unwrap()
);
// Build the station keeping data frame.
let mut sk_df = df!(
"Offset (s)" => offset_s.clone(),
"Epoch (UTC)" => epoch_str.clone(),
"Longitude E-W (deg)" => longitude_deg,
"Latitude N-S (deg)" => latitude_deg,
"Altitude (km)" => altitude_km,
)?;
// Create a file to write the Parquet to
let file = File::create("./03_geo_lla.parquet").expect("Could not create file");
// Create a ParquetWriter and write the DataFrame to the file
ParquetWriter::new(file).finish(&mut sk_df)?;
Ok(())
}
pub fn to_duration_in_time_scale(&self, ts: TimeScale) -> Duration
pub fn to_duration_in_time_scale(&self, ts: TimeScale) -> Duration
Returns this epoch with respect to the provided time scale. This is needed to correctly perform duration conversions in dynamical time scales (e.g. TDB).
pub fn to_tai_seconds(&self) -> f64
pub fn to_tai_seconds(&self) -> f64
Returns the number of TAI seconds since J1900
pub fn to_tai_duration(&self) -> Duration
pub fn to_tai_duration(&self) -> Duration
Returns this time in a Duration past J1900 counted in TAI
pub fn to_tai(&self, unit: Unit) -> f64
pub fn to_tai(&self, unit: Unit) -> f64
Returns the epoch as a floating point value in the provided unit
pub fn to_tai_parts(&self) -> (i16, u64)
pub fn to_tai_parts(&self) -> (i16, u64)
Returns the TAI parts of this duration
pub fn to_tai_days(&self) -> f64
pub fn to_tai_days(&self) -> f64
Returns the number of days since J1900 in TAI
pub fn to_utc_seconds(&self) -> f64
pub fn to_utc_seconds(&self) -> f64
Returns the number of UTC seconds since the TAI epoch
pub fn to_utc_duration(&self) -> Duration
pub fn to_utc_duration(&self) -> Duration
Returns this time in a Duration past J1900 counted in UTC
pub fn to_utc_days(&self) -> f64
pub fn to_utc_days(&self) -> f64
Returns the number of UTC days since the TAI epoch
pub fn to_mjd_tai_days(&self) -> f64
pub fn to_mjd_tai_days(&self) -> f64
as_mjd_days
creates an Epoch from the provided Modified Julian Date in days as explained
here. MJD epoch is Modified Julian Day at 17 November 1858 at midnight.
pub fn to_mjd_tai_seconds(&self) -> f64
pub fn to_mjd_tai_seconds(&self) -> f64
Returns the Modified Julian Date in seconds TAI.
pub fn to_mjd_tai(&self, unit: Unit) -> f64
pub fn to_mjd_tai(&self, unit: Unit) -> f64
Returns this epoch as a duration in the requested units in MJD TAI
pub fn to_mjd_utc_days(&self) -> f64
pub fn to_mjd_utc_days(&self) -> f64
Returns the Modified Julian Date in days UTC.
pub fn to_mjd_utc(&self, unit: Unit) -> f64
pub fn to_mjd_utc(&self, unit: Unit) -> f64
Returns the Modified Julian Date in the provided unit in UTC.
pub fn to_mjd_utc_seconds(&self) -> f64
pub fn to_mjd_utc_seconds(&self) -> f64
Returns the Modified Julian Date in seconds UTC.
pub fn to_jde_tai_days(&self) -> f64
pub fn to_jde_tai_days(&self) -> f64
Returns the Julian days from epoch 01 Jan -4713, 12:00 (noon) as explained in “Fundamentals of astrodynamics and applications”, Vallado et al. 4th edition, page 182, and on Wikipedia.
pub fn to_jde_tai(&self, unit: Unit) -> f64
pub fn to_jde_tai(&self, unit: Unit) -> f64
Returns the Julian Days from epoch 01 Jan -4713 12:00 (noon) in desired Duration::Unit
pub fn to_jde_tai_duration(&self) -> Duration
pub fn to_jde_tai_duration(&self) -> Duration
Returns the Julian Days from epoch 01 Jan -4713 12:00 (noon) as a Duration
pub fn to_jde_tai_seconds(&self) -> f64
pub fn to_jde_tai_seconds(&self) -> f64
Returns the Julian seconds in TAI.
pub fn to_jde_utc_days(&self) -> f64
pub fn to_jde_utc_days(&self) -> f64
Returns the Julian days in UTC.
pub fn to_jde_utc_duration(&self) -> Duration
pub fn to_jde_utc_duration(&self) -> Duration
Returns the Julian days in UTC as a Duration
pub fn to_jde_utc_seconds(&self) -> f64
pub fn to_jde_utc_seconds(&self) -> f64
Returns the Julian Days in UTC seconds.
pub fn to_tt_seconds(&self) -> f64
pub fn to_tt_seconds(&self) -> f64
Returns seconds past TAI epoch in Terrestrial Time (TT) (previously called Terrestrial Dynamical Time (TDT))
pub fn to_tt_duration(&self) -> Duration
pub fn to_tt_duration(&self) -> Duration
Returns Duration
past TAI epoch in Terrestrial Time (TT).
pub fn to_tt_days(&self) -> f64
pub fn to_tt_days(&self) -> f64
Returns days past TAI epoch in Terrestrial Time (TT) (previously called Terrestrial Dynamical Time (TDT))
pub fn to_tt_centuries_j2k(&self) -> f64
pub fn to_tt_centuries_j2k(&self) -> f64
Returns the centuries passed J2000 TT
pub fn to_tt_since_j2k(&self) -> Duration
pub fn to_tt_since_j2k(&self) -> Duration
Returns the duration past J2000 TT
pub fn to_jde_tt_days(&self) -> f64
pub fn to_jde_tt_days(&self) -> f64
Returns days past Julian epoch in Terrestrial Time (TT) (previously called Terrestrial Dynamical Time (TDT))
pub fn to_jde_tt_duration(&self) -> Duration
pub fn to_mjd_tt_days(&self) -> f64
pub fn to_mjd_tt_days(&self) -> f64
Returns days past Modified Julian epoch in Terrestrial Time (TT) (previously called Terrestrial Dynamical Time (TDT))
pub fn to_mjd_tt_duration(&self) -> Duration
pub fn to_gpst_seconds(&self) -> f64
pub fn to_gpst_seconds(&self) -> f64
Returns seconds past GPS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn to_gpst_duration(&self) -> Duration
pub fn to_gpst_duration(&self) -> Duration
Returns Duration
past GPS time Epoch.
pub fn to_gpst_nanoseconds(&self) -> Result<u64, EpochError>
pub fn to_gpst_nanoseconds(&self) -> Result<u64, EpochError>
Returns nanoseconds past GPS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29). NOTE: This function will return an error if the centuries past GPST time are not zero.
pub fn to_gpst_days(&self) -> f64
pub fn to_gpst_days(&self) -> f64
Returns days past GPS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn to_qzsst_seconds(&self) -> f64
pub fn to_qzsst_seconds(&self) -> f64
Returns seconds past QZSS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn to_qzsst_duration(&self) -> Duration
pub fn to_qzsst_duration(&self) -> Duration
Returns Duration
past QZSS time Epoch.
pub fn to_qzsst_nanoseconds(&self) -> Result<u64, EpochError>
pub fn to_qzsst_nanoseconds(&self) -> Result<u64, EpochError>
Returns nanoseconds past QZSS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29). NOTE: This function will return an error if the centuries past QZSST time are not zero.
pub fn to_qzsst_days(&self) -> f64
pub fn to_qzsst_days(&self) -> f64
Returns days past QZSS Time Epoch, defined as UTC midnight of January 5th to 6th 1980 (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS#GPS_Time_.28GPST.29).
pub fn to_gst_seconds(&self) -> f64
pub fn to_gst_seconds(&self) -> f64
Returns seconds past GST (Galileo) Time Epoch
pub fn to_gst_duration(&self) -> Duration
pub fn to_gst_duration(&self) -> Duration
Returns Duration
past GST (Galileo) time Epoch.
pub fn to_gst_nanoseconds(&self) -> Result<u64, EpochError>
pub fn to_gst_nanoseconds(&self) -> Result<u64, EpochError>
Returns nanoseconds past GST (Galileo) Time Epoch, starting on August 21st 1999 Midnight UT (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS). NOTE: This function will return an error if the centuries past GST time are not zero.
pub fn to_gst_days(&self) -> f64
pub fn to_gst_days(&self) -> f64
Returns days past GST (Galileo) Time Epoch, starting on August 21st 1999 Midnight UT (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS).
pub fn to_bdt_seconds(&self) -> f64
pub fn to_bdt_seconds(&self) -> f64
Returns seconds past BDT (BeiDou) Time Epoch
pub fn to_bdt_duration(&self) -> Duration
pub fn to_bdt_duration(&self) -> Duration
Returns Duration
past BDT (BeiDou) time Epoch.
pub fn to_bdt_days(&self) -> f64
pub fn to_bdt_days(&self) -> f64
Returns days past BDT (BeiDou) Time Epoch, defined as Jan 01 2006 UTC (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS).
pub fn to_bdt_nanoseconds(&self) -> Result<u64, EpochError>
pub fn to_bdt_nanoseconds(&self) -> Result<u64, EpochError>
Returns nanoseconds past BDT (BeiDou) Time Epoch, defined as Jan 01 2006 UTC (cf. https://gssc.esa.int/navipedia/index.php/Time_References_in_GNSS). NOTE: This function will return an error if the centuries past GST time are not zero.
pub fn to_unix(&self, unit: Unit) -> f64
pub fn to_unix(&self, unit: Unit) -> f64
Returns the duration since the UNIX epoch in the provided unit.
pub fn to_unix_seconds(&self) -> f64
pub fn to_unix_seconds(&self) -> f64
Returns the number seconds since the UNIX epoch defined 01 Jan 1970 midnight UTC.
pub fn to_unix_milliseconds(&self) -> f64
pub fn to_unix_milliseconds(&self) -> f64
Returns the number milliseconds since the UNIX epoch defined 01 Jan 1970 midnight UTC.
pub fn to_unix_days(&self) -> f64
pub fn to_unix_days(&self) -> f64
Returns the number days since the UNIX epoch defined 01 Jan 1970 midnight UTC.
pub fn to_et_seconds(&self) -> f64
pub fn to_et_seconds(&self) -> f64
Returns the Ephemeris Time seconds past 2000 JAN 01 midnight, matches NASA/NAIF SPICE.
pub fn to_et_duration(&self) -> Duration
pub fn to_et_duration(&self) -> Duration
Returns the duration between J2000 and the current epoch as per NAIF SPICE.
§Warning
The et2utc function of NAIF SPICE will assume that there are 9 leap seconds before 01 JAN 1972, as this date introduces 10 leap seconds. At the time of writing, this does not seem to be in line with IERS and the documentation in the leap seconds list.
In order to match SPICE, the as_et_duration() function will manually get rid of that difference.
pub fn to_tdb_duration(&self) -> Duration
pub fn to_tdb_duration(&self) -> Duration
Returns the Dynamics Barycentric Time (TDB) as a high precision Duration since J2000
§Algorithm
Given the embedded sine functions in the equation to compute the difference between TDB and TAI from the number of TDB seconds past J2000, one cannot solve the revert the operation analytically. Instead, we iterate until the value no longer changes.
- Assume that the TAI duration is in fact the TDB seconds from J2000.
- Offset to J2000 because
Epoch
stores everything in the J1900 but the TDB duration is in J2000. - Compute the offset
g
due to the TDB computation with the current value of the TDB seconds (defined in step 1). - Subtract that offset to the latest TDB seconds and store this as a new candidate for the true TDB seconds value.
- Compute the difference between this candidate and the previous one. If the difference is less than one nanosecond, stop iteration.
- Set the new candidate as the TDB seconds since J2000 and loop until step 5 breaks the loop, or we’ve done five iterations.
- At this stage, we have a good approximation of the TDB seconds since J2000.
- Reverse the algorithm given that approximation: compute the
g
offset, compute the difference between TDB and TAI, add the TT offset (32.184 s), and offset by the difference between J1900 and J2000.
pub fn to_tdb_seconds(&self) -> f64
pub fn to_tdb_seconds(&self) -> f64
Returns the Dynamic Barycentric Time (TDB) (higher fidelity SPICE ephemeris time) whose epoch is 2000 JAN 01 noon TAI (cf. https://gssc.esa.int/navipedia/index.php/Transformations_between_Time_Systems#TDT_-_TDB.2C_TCB)
pub fn to_jde_et_days(&self) -> f64
pub fn to_jde_et_days(&self) -> f64
Returns the Ephemeris Time JDE past epoch
pub fn to_jde_et_duration(&self) -> Duration
pub fn to_jde_et(&self, unit: Unit) -> f64
pub fn to_jde_tdb_duration(&self) -> Duration
pub fn to_jde_tdb_days(&self) -> f64
pub fn to_jde_tdb_days(&self) -> f64
Returns the Dynamic Barycentric Time (TDB) (higher fidelity SPICE ephemeris time) whose epoch is 2000 JAN 01 noon TAI (cf. https://gssc.esa.int/navipedia/index.php/Transformations_between_Time_Systems#TDT_-_TDB.2C_TCB)
pub fn to_tdb_days_since_j2000(&self) -> f64
pub fn to_tdb_days_since_j2000(&self) -> f64
Returns the number of days since Dynamic Barycentric Time (TDB) J2000 (used for Archinal et al. rotations)
pub fn to_tdb_centuries_since_j2000(&self) -> f64
pub fn to_tdb_centuries_since_j2000(&self) -> f64
Returns the number of centuries since Dynamic Barycentric Time (TDB) J2000 (used for Archinal et al. rotations)
pub fn to_et_days_since_j2000(&self) -> f64
pub fn to_et_days_since_j2000(&self) -> f64
Returns the number of days since Ephemeris Time (ET) J2000 (used for Archinal et al. rotations)
pub fn to_et_centuries_since_j2000(&self) -> f64
pub fn to_et_centuries_since_j2000(&self) -> f64
Returns the number of centuries since Ephemeris Time (ET) J2000 (used for Archinal et al. rotations)
pub fn duration_in_year(&self) -> Duration
pub fn duration_in_year(&self) -> Duration
Returns the duration since the start of the year
pub fn day_of_year(&self) -> f64
pub fn day_of_year(&self) -> f64
Returns the number of days since the start of the year.
pub fn year(&self) -> i32
pub fn year(&self) -> i32
Returns the number of Gregorian years of this epoch in the current time scale.
pub fn year_days_of_year(&self) -> (i32, f64)
pub fn year_days_of_year(&self) -> (i32, f64)
Returns the year and the days in the year so far (days of year).
pub fn hours(&self) -> u64
pub fn hours(&self) -> u64
Returns the hours of the Gregorian representation of this epoch in the time scale it was initialized in.
pub fn minutes(&self) -> u64
pub fn minutes(&self) -> u64
Returns the minutes of the Gregorian representation of this epoch in the time scale it was initialized in.
pub fn seconds(&self) -> u64
pub fn seconds(&self) -> u64
Returns the seconds of the Gregorian representation of this epoch in the time scale it was initialized in.
pub fn milliseconds(&self) -> u64
pub fn milliseconds(&self) -> u64
Returns the milliseconds of the Gregorian representation of this epoch in the time scale it was initialized in.
pub fn microseconds(&self) -> u64
pub fn microseconds(&self) -> u64
Returns the microseconds of the Gregorian representation of this epoch in the time scale it was initialized in.
pub fn nanoseconds(&self) -> u64
pub fn nanoseconds(&self) -> u64
Returns the nanoseconds of the Gregorian representation of this epoch in the time scale it was initialized in.
pub fn month_name(&self) -> MonthName
pub fn to_rfc3339(&self) -> String
pub fn to_rfc3339(&self) -> String
Returns this epoch in UTC in the RFC3339 format
Trait Implementations§
§impl Add<f64> for Epoch
impl Add<f64> for Epoch
WARNING: For speed, there is a possibility to add seconds directly to an Epoch. These will be added in the time scale the Epoch was initialized in. Using this is discouraged and should only be used if you have facing bottlenecks with the units.
§impl AddAssign<Duration> for Epoch
impl AddAssign<Duration> for Epoch
§fn add_assign(&mut self, duration: Duration)
fn add_assign(&mut self, duration: Duration)
+=
operation. Read more§impl AddAssign<Unit> for Epoch
impl AddAssign<Unit> for Epoch
§fn add_assign(&mut self, unit: Unit)
fn add_assign(&mut self, unit: Unit)
+=
operation. Read more§impl<'de> Deserialize<'de> for Epoch
impl<'de> Deserialize<'de> for Epoch
§fn deserialize<D>(
deserializer: D,
) -> Result<Epoch, <D as Deserializer<'de>>::Error>where
D: Deserializer<'de>,
fn deserialize<D>(
deserializer: D,
) -> Result<Epoch, <D as Deserializer<'de>>::Error>where
D: Deserializer<'de>,
§impl FromStr for Epoch
impl FromStr for Epoch
§fn from_str(s_in: &str) -> Result<Epoch, <Epoch as FromStr>::Err>
fn from_str(s_in: &str) -> Result<Epoch, <Epoch as FromStr>::Err>
Attempts to convert a string to an Epoch.
Format identifiers:
- JD: Julian days
- MJD: Modified Julian days
- SEC: Seconds past a given epoch (e.g. SEC 17.2 TAI is 17.2 seconds past TAI Epoch)
§Example
use hifitime::Epoch;
use core::str::FromStr;
assert!(Epoch::from_str("JD 2452312.500372511 TDB").is_ok());
assert!(Epoch::from_str("JD 2452312.500372511 ET").is_ok());
assert!(Epoch::from_str("JD 2452312.500372511 TAI").is_ok());
assert!(Epoch::from_str("MJD 51544.5 TAI").is_ok());
assert!(Epoch::from_str("SEC 0.5 TAI").is_ok());
assert!(Epoch::from_str("SEC 66312032.18493909 TDB").is_ok());
§type Err = EpochError
type Err = EpochError
§impl Ord for Epoch
impl Ord for Epoch
§impl PartialEq for Epoch
impl PartialEq for Epoch
Equality only checks the duration since J1900 match in TAI, because this is how all of the epochs are referenced.
§impl PartialOrd for Epoch
impl PartialOrd for Epoch
§impl Serialize for Epoch
impl Serialize for Epoch
§fn serialize<S>(
&self,
serializer: S,
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>where
S: Serializer,
fn serialize<S>(
&self,
serializer: S,
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>where
S: Serializer,
§impl SubAssign<Duration> for Epoch
impl SubAssign<Duration> for Epoch
§fn sub_assign(&mut self, duration: Duration)
fn sub_assign(&mut self, duration: Duration)
-=
operation. Read more§impl SubAssign<Unit> for Epoch
impl SubAssign<Unit> for Epoch
§fn sub_assign(&mut self, unit: Unit)
fn sub_assign(&mut self, unit: Unit)
-=
operation. Read moreimpl Copy for Epoch
impl Eq for Epoch
Auto Trait Implementations§
impl Freeze for Epoch
impl RefUnwindSafe for Epoch
impl Send for Epoch
impl Sync for Epoch
impl Unpin for Epoch
impl UnwindSafe for Epoch
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.source§impl<T> FromDhall for Twhere
T: DeserializeOwned,
impl<T> FromDhall for Twhere
T: DeserializeOwned,
fn from_dhall(v: &Value) -> Result<T, Error>
§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more§impl<T> Pointable for T
impl<T> Pointable for T
§impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
§fn to_subset(&self) -> Option<SS>
fn to_subset(&self) -> Option<SS>
self
from the equivalent element of its
superset. Read more§fn is_in_subset(&self) -> bool
fn is_in_subset(&self) -> bool
self
is actually part of its subset T
(and can be converted to it).§fn to_subset_unchecked(&self) -> SS
fn to_subset_unchecked(&self) -> SS
self.to_subset
but without any property checks. Always succeeds.§fn from_subset(element: &SS) -> SP
fn from_subset(element: &SS) -> SP
self
to the equivalent element of its superset.