Crate sgp4

This crate implements the SGP4 algorithm for satellite propagation.

It also provides methods to parse both 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 stations OMMs from Celestrak and predicts the stations' positions and velocities after 12 h and 24 h.

fn main() -> sgp4::Result<()> {
    let response = ureq::get("https://celestrak.com/NORAD/elements/gp.php")
        .query("GROUP", "stations")
        .query("FORMAT", "json")
        .call();
    if response.error() {
        Err(sgp4::Error::new(format!(
            "network error {}: {}",
            response.status(),
            response.into_string()?
        )))
    } else {
        let elements_group: Vec<sgp4::Elements> = response.into_json_deserialize()?;
        for elements in &elements_group {
            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((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.

Structs

Constants	Propagator variables calculated from epoch quantities and used during propagation
Elements	General perturbations orbital data parsed from a TLE or OMM
Error	Represents an SGP4 error
Geopotential	Model of the Earth radius and gravitational field
Orbit	The Brouwer orbital elements
Prediction	Predicted satellite position and velocity after SGP4 propagation
ResonanceState	Represents the state of the deep space resonnance integrator

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
parse_2les	Parses a multi-line TL/2LE string into a list of Elements
parse_3les	Parses a multi-line TL/3LE string into a list of Elements

Type Definitions

Result

The result type returned by SGP4 functions