main.rs

fn main() -> anyhow::Result<()> {
    let lines = vec![
        "ISS (ZARYA)",
        "1 25544U 98067A   24285.74177330  .00036177  00000-0  64514-3 0  9990",
        "2 25544  51.6390  98.0883 0008472  63.6655  27.1997 15.49693494476628",
    ];

    let home = satkit::ITRFCoord::from_geodetic_deg(0.0, 0.0, 268.9);

    // parse TLE
    let mut tle =
        satkit::TLE::load_3line(lines[0], lines[1], lines[2]).map_err(|e| anyhow::anyhow!(e))?;

    // prediction time
    let tm = satkit::AstroTime::now().map_err(|e| anyhow::anyhow!(e))?;

    // propogate orbit
    let (teme_pos, teme_vel, errs) = satkit::sgp4::sgp4(&mut tle, &[tm]);

    // move from True-Equinox Mean Equator (used in SGP4)
    // to International Terrestrial Reference Frame (ITRF) used by people
    let qteme2itrf = satkit::frametransform::qteme2itrf(&tm);
    let itrf_pos = qteme2itrf * teme_pos.column(0);
    let itrf_vel = qteme2itrf * teme_vel.column(0);

    println!("pos {:?}", itrf_pos);
    println!("vel {:?}", itrf_vel);
    println!("velmag {:?}", itrf_vel.norm());
    println!("err {:?}", errs);

    // wrap ITRF in a nicer wrapper to extract lat/long/alt
    let itrf = satkit::ITRFCoord::from_slice(itrf_pos.column(0).as_slice())
        .map_err(|e| anyhow::anyhow!(e))?;

    println!();
    println!("lat {:?}", itrf.latitude_deg());
    println!("lon {:?}", itrf.longitude_deg());
    println!("altitude {:?}", itrf.hae());

    // transform into a coordinate frame with home as origin
    // choices: East / North / UP (enu) or North / East / Down (ned)

    //let enu = itrf.to_enu(&home).normalize();
    let enu = home.q_enu2itrf().conjugate() * (itrf - home);
    let enu = enu.normalize();

    //let ned = itrf.to_ned(&home).normalize();
    //let ned = home.q_ned2itrf().conjugate() * (itrf - home);
    //let ned = ned.normalize();

    // ...why are these bugged

    println!();
    println!("enu:");
    println!("east: {:?}", enu.x);
    println!("north: {:?}", enu.y);
    println!("up: {:?}", enu.z);

    //println!("ned:");
    //println!("north: {:?}", ned.x);
    //println!("east: {:?}", ned.y);
    //println!("down: {:?}", ned.z);

    // extract elevation and azimuth

    let el = enu.z.asin() * 180.0 / std::f64::consts::PI;
    let az = enu.x.atan2(enu.y) * 180.0 / std::f64::consts::PI;

    println!();
    println!("el {:?} az {:?}", el, az);

    Ok(())
}