Julia and the GPS payload onboard Waratah Seed-1 satellite

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21

This feature will be very easy to implement! I will do this!

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22

Hi @minetest2048 !

Can you please test the main branch of SatelliteToolboxPropagators.jl? Now, you can do this:

julia> using SatelliteToolboxPropagators

julia> f = create_tle_fetcher(CelestrakTleFetcher)
CelestrakTleFetcher("https://celestrak.org/NORAD/elements/gp.php")

julia> tles = fetch_tles(f; satellite_name = "ISS (ZARYA)")
[ Info: Fetch TLEs from Celestrak using satellite name: "ISS (ZARYA)" ...
1-element Vector{TLE}:
 TLE: ISS (ZARYA) (Epoch = 2024-12-27T11:52:08.200)

julia> iss_tle = tles[1]
TLE:
                      Name : ISS (ZARYA)
          Satellite number : 25544
  International designator : 98067A
        Epoch (Year / Day) : 24 / 362.49453935 (2024-12-27T11:52:08.200)
        Element set number : 999
              Eccentricity :   0.00057970
               Inclination :  51.63830000 deg
                      RAAN :  77.61300000 deg
       Argument of perigee :  11.65550000 deg
              Mean anomaly : 348.45670000 deg
           Mean motion (n) :  15.50310083 revs / day
         Revolution number : 48853
                        B* :   0.00045083 1 / er
                     ṅ / 2 :   0.00025652 rev / day²
                     n̈ / 6 :            0 rev / day³

julia> orbp = Propagators.init(Val(:SGP4), iss_tle)
OrbitPropagatorSgp4{Float64, Float64}:
   Propagator name : SGP4 Orbit Propagator
  Propagator epoch : 2024-12-27T11:52:08.200
  Last propagation : 2024-12-27T11:52:08.200

julia> sv_teme = Propagators.propagate!(orbp, 0, OrbitStateVector)
OrbitStateVector{Float64, Float64}:
  epoch : 2.46067e6 (2024-12-27T11:52:08.200)
      r : [1456.71, 6632.76, 0.0224472]  km
      v : [-4.647, 1.0129, 6.01325]      km/s

The last argument in Propagators.propagate! is now a “sink” option and it can be Tuple (default) to obtain the old behavior or OrbitStateVector to obtain the state vector as you wanted.

I only need to add the documentation and test cases before tagging the new version.

5 Likes
23

Now with OrbitStateVector with epochs, its easy to convert ECI to ECEF without magic numbers

julia> using SatelliteToolbox

julia> f = create_tle_fetcher(CelestrakTleFetcher)
CelestrakTleFetcher("https://celestrak.org/NORAD/elements/gp.php")

julia> tles = fetch_tles(f; satellite_name = "ISS (ZARYA)")
[ Info: Fetch TLEs from Celestrak using satellite name: "ISS (ZARYA)" ...
1-element Vector{TLE}:
 TLE: ISS (ZARYA) (Epoch = 2024-12-29T04:05:28.309)

julia> iss_tle = tles[1]
TLE:
                      Name : ISS (ZARYA)
          Satellite number : 25544
  International designator : 98067A
        Epoch (Year / Day) : 24 / 364.17046654 (2024-12-29T04:05:28.309)
        Element set number : 999
              Eccentricity :   0.00059130
               Inclination :  51.63830000 deg
                      RAAN :  69.30530000 deg
       Argument of perigee :  18.67410000 deg
              Mean anomaly : 341.44630000 deg
           Mean motion (n) :  15.50400391 revs / day
         Revolution number : 48879
                        B* :   0.00043786 1 / er
                     ṅ / 2 :    0.0002498 rev / day²
                     n̈ / 6 :            0 rev / day³

julia> orbp = Propagators.init(Val(:SGP4), iss_tle)
OrbitPropagatorSgp4{Float64, Float64}:
   Propagator name : SGP4 Orbit Propagator
  Propagator epoch : 2024-12-29T04:05:28.309
  Last propagation : 2024-12-29T04:05:28.309

julia> sv_temes = Propagators.propagate!(orbp, 0:10, OrbitStateVector)
11-element Vector{OrbitStateVector{Float64, Float64}}:
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:28.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:29.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:30.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:31.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:32.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:33.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:34.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:35.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:36.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:37.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:38.309)

julia> sv_eci_to_ecef.(sv_temes, TEME(), PEF(), getfield.(sv_temes,:t))
11-element Vector{OrbitStateVector{Float64, Float64}}:
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:28.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:29.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:30.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:31.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:32.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:33.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:34.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:35.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:36.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:37.309)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46067e6 (2024-12-29T04:05:38.309)
2 Likes
24

Awesome! I will implement one new feature that, if you omit the time in sv_ functions, it will automatically use the epoch in the state vector.

5 Likes
25

Hi @minetest2048 !

With the v1.0 of SatelliteToolbox.jl, you can now suppress the time argument:

julia> using SatelliteToolbox

julia> f = create_tle_fetcher(CelestrakTleFetcher)
CelestrakTleFetcher("https://celestrak.org/NORAD/elements/gp.php")

julia> tles = fetch_tles(f; satellite_name = "ISS (ZARYA)")
[ Info: Fetch TLEs from Celestrak using satellite name: "ISS (ZARYA)" ...
1-element Vector{TLE}:
 TLE: ISS (ZARYA) (Epoch = 2025-01-06T13:47:09.406)

julia> iss_tle = tles[1]
TLE:
                      Name : ISS (ZARYA)
          Satellite number : 25544
  International designator : 98067A
        Epoch (Year / Day) : 25 /   6.57441442 (2025-01-06T13:47:09.406)
        Element set number : 999
              Eccentricity :   0.00063540
               Inclination :  51.63990000 deg
                      RAAN :  27.62390000 deg
       Argument of perigee :  52.73050000 deg
              Mean anomaly :  91.48470000 deg
           Mean motion (n) :  15.50836984 revs / day
         Revolution number : 49009
                        B* :   0.00038488 1 / er
                     ṅ / 2 :   0.00022243 rev / day²
                     n̈ / 6 :            0 rev / day³

julia> orbp = Propagators.init(Val(:SGP4), iss_tle)
OrbitPropagatorSgp4{Float64, Float64}:
   Propagator name : SGP4 Orbit Propagator
  Propagator epoch : 2025-01-06T13:47:09.406
  Last propagation : 2025-01-06T13:47:09.406

julia> sv_temes = Propagators.propagate!(orbp, 0:10, OrbitStateVector)
11-element Vector{OrbitStateVector{Float64, Float64}}:
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:09.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:10.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:11.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:12.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:13.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:14.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:15.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:16.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:17.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:18.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:19.406)

julia> sv_eci_to_ecef.(sv_temes, TEME(), PEF())
11-element Vector{OrbitStateVector{Float64, Float64}}:
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:09.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:10.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:11.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:12.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:13.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:14.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:15.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:16.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:17.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:18.406)
 OrbitStateVector{Float64, Float64}: Epoch = 2.46068e6 (2025-01-06T13:47:19.406)

In this case, it will use the epoch of the state vector.

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