| name | satellitetoolbox-sgp4 |
| description | SatelliteToolboxSgp4.jl implementing the SGP4/SDP4 orbit propagator for TLE-based orbit prediction. Use when propagating TLEs, fitting TLEs from osculating states, or updating TLE epochs. |
SatelliteToolboxSgp4.jl
SGP4/SDP4 orbit propagator for TLE-based prediction. Repo: JuliaSpace/SatelliteToolboxSgp4.jl
Basic Propagation
# One-shot: init + propagate
(r_teme, v_teme, sgp4d) = sgp4(t_min, tle)
# Two-step: init then propagate
sgp4d = sgp4_init(tle)
(r_teme, v_teme) = sgp4!(sgp4d, t_min) # t_min = minutes from TLE epoch
TLE Fitting
# Fit TLE from osculating state vectors
(fitted_tle, P) = fit_sgp4_tle(vjd, vr_teme, vv_teme;
estimate_bstar=true, max_iterations=50, atol=1e-4, rtol=1e-4)
# In-place version
(fitted_tle, P) = fit_sgp4_tle!(sgp4d, vjd, vr_teme, vv_teme)
Epoch Update
new_tle = update_sgp4_tle_epoch(tle, new_epoch_jd)
Constants
sgp4c_wgs84 # WGS-84 Float64 (default)
sgp4c_wgs84_f32 # WGS-84 Float32
sgp4c_wgs72 # WGS-72 Float64
sgp4c_wgs72_f32 # WGS-72 Float32
sgp4d = sgp4_init(tle; sgp4c=sgp4c_wgs72) # Use WGS-72
Key Conventions
- Propagation time in minutes (not seconds!)
- Output: position in km, velocity in km/s
- Output frame: TEME (True Equator, Mean Equinox)
- Returns
SVector{3, T}
- In-place
! variants for reduced allocations
- Re-exports SatelliteToolboxBase and SatelliteToolboxTle
