SGP4.jl

NOTE: Consider using the pure-julia SGP4 implementation in SatelliteToolbox.jl.

This package enables satellite orbit propagation using the SGP4 models, given the satellites two-line element set (TLE). For now, this is a simple wrapper of python-sgp4 using PyCall.jl. There are several small changes from python-sgp4:

1. Gravity coefficients are loaded into a GravityModel type. For instance, to load the WGS-72 coefficients, just do GravityModel("wgs72"). The other two options are "wgs72old" and "wgs84".

2. Propagation is a standalone function, as opposed to a satellite member function. So, propagation is accomplished by propagate( sat, year, month, day, hour, min, sec).

Usage

Following the example given here, the TEME position and velocity for Vanguard 1 at 12:50:19 on 29 June 2000 may be calculated by:

using SGP4
line1 = "1 00005U 58002B   00179.78495062  .00000023  00000-0  28098-4 0  4753"
line2 = "2 00005  34.2682 348.7242 1859667 331.7664  19.3264 10.82419157413667"
wgs72 = GravityModel("wgs72")
satellite = twoline2rv(line1, line2, wgs72)
(position, velocity) = propagate(satellite, 2000, 6, 29, 12, 50, 19)

satellite attributes, such as the TLE epoch, may be accessed as satellite[:epoch].

You can also generate an ephemeris, given a TLE, start date/time, stop date/time, and time step:

(positions, velocities) = propagate(satellite, Dates.DateTime("2000-06-29T12:50:19.000"), Dates.DateTime("2000-06-30T12:50:19.000"), Dates.Second(60))

For more examples, see test/runtests.jl.

For other documentation, see this page.