3.2.6. Available software for PassPredict simple mode
| Package | Capabilities | |
|---|---|---|
| Main candidates for orbit calculations | GMAT (NASA) | TLE propagation, OEM interpolation, frame conversion, position prediction (GMAT, n.d.) |
| Orekit | OEM interpolation, frame conversion. The code is from a French company (CSGroup). OreKIT is used in Moriba Jah’s Orbit DetPy (Iyer, 2019). | |
| OrbitDetPy | Wrapper on OreKIT with useful functionality, from UT Austin group https://github.com/ut-astria/orbdetpy (Iyer, 2019) and https://github.com/IBM/arcade (IBM/U of Texas). | |
| Wrappers for observation requests | Astropy.astroplan | Observation planning |
| TOM Toolkit | Observation planning (Street at al 2018) | |
| Other packages of interest | STK | AGI; not free or open source |
| Freeflyer | A.i.-solutions; not free or open source | |
| ERFA | Astropy; frame conversion routines | |
| Slrfield | Satellite laser ranging pass predictions https://pypi.org/project/slrfield | |
| PROOF | ESA; uses GP/TLE to compute individual topocentric pass predictions with configurable observatory parameters, including instrument field of view, etc. It is an open source Fortran code with a Java interface. | |
| Monte | JPL (not open source) |
Notes: STK and Freeflyer are widely-used industry-standard packages of particular note. R. Street (Las Cumbres Observatory) noted an interest in building a component to the LCO TOM Toolkit to wrap the U. Texas OrbitDetPy work.
3.2.7. PassPredict advanced mode — considerations
In order to predict the apparent brightness of satellites a model for the reflectance distribution must be provided. The brightness can be predicted in a deterministic way using a satellite model or some approximation (e.g., a look-up table) assuming knowledge of the attitude state. Operators could be encouraged to share their attitude states using, e.g., the CCSDS ADM formats (similarly to ephemeris files). Many operators also follow some attitude law which could be considered in the code. Alternatively, the brightness can be bounded statistically irrespective of the attitude state, e.g. based solely on Sunphase angle.
It would be helpful if operators made available BRDFs, satellite models, and attitude control profiles to allow us to make detailed brightness predictions.
