Crate sgp4

This crate implements the SGP4 algorithm for satellite propagation

It also provides methods to parse Two-Line Element Set (TLE) and Orbit Mean-Elements Message (OMM) data.

A UTF-8 transcript of the mathematical expressions that compose SGP4 can be found in the repository https://github.com/neuromorphicsystems/sgp4.

Example

The following standalone program downloads the lastest Galileo OMMs from Celestrak and predicts the satellites’ positions and velocities after 12 h and 24 h.

fn main() -> anyhow::Result<()> {
    let response = ureq::get("https://celestrak.com/NORAD/elements/gp.php")
        .query("GROUP", "galileo")
        .query("FORMAT", "json")
        .call()?;
    let elements_vec: Vec<sgp4::Elements> = response.into_json()?;
    for elements in &elements_vec {
        println!("{}", elements.object_name.as_ref().unwrap());
        let constants = sgp4::Constants::from_elements(elements)?;
        for hours in &[12, 24] {
            println!("    t = {} min", hours * 60);
            let prediction = constants.propagate(sgp4::MinutesSinceEpoch((hours * 60) as f64))?;
            println!("        r = {:?} km", prediction.position);
            println!("        ṙ = {:?} km.s⁻¹", prediction.velocity);
        }
    }
    Ok(())
}

More examples can be found in the repository https://github.com/neuromorphicsystems/sgp4/tree/master/examples.

Re-exports

• pub use chrono;

Structs

• Constants
  Propagator variables calculated from epoch quantities and used during propagation
• DatetimeToMinutesSinceEpochError
  Nanoseconds overflow while converting from datetime to minutes since epoch
• Elements
  General perturbations orbital data parsed from a TLE or OMM
• Geopotential
  Model of the Earth radius and gravitational field
• MinutesSinceEpoch
  Minutes ellapsed since the elements’ epoch
• Orbit
  The Brouwer orbital elements
• OutOfRangeEpochEccentricity
  The orbit used to generate epoch constants has an invalid eccentricity
• Prediction
  Predicted satellite position and velocity after SGP4 propagation
• ResonanceState
  Represents the state of the deep space resonnance integrator
• TleError
  Represents a TLE parse error

Enums

• Classification
  A satellite’s elements classification
• ElementsError
  Errors returned when creating epoch contants from elements
• Error
  Represents a propagation error caused by orbital elements divergence
• KozaiElementsError
  Represents a propagation error caused by orbital elements divergence
• MinutesSinceEpochToDatetimeError
  Nanoseconds overflow while converting from minutes since epoch to datetime
• TleErrorLine
  Input line where a parse error was found
• TleErrorWhat
  TLE error type

Constants

• WGS72
  The geopotential model used in the AFSPC implementation
• WGS84
  The geopotential model recommended by the IAU

Functions

• afspc_epoch_to_sidereal_time
  Converts an epoch to sidereal time using the AFSPC expression
• iau_epoch_to_sidereal_time
  Converts an epoch to sidereal time using the IAU expression
• julian_years_since_j2000
  Returns the number of years since UTC 1 January 2000 12h00 (J2000)
• julian_years_since_j2000_afspc_compatibility_mode
  Returns the number of years since UTC 1 January 2000 12h00 (J2000) using the AFSPC expression
• parse_2lesalloc
  Parses a multi-line TL/2LE string into a list of Elements
• parse_3lesalloc
  Parses a multi-line TL/3LE string into a list of Elements