App: SatTracker
Developer: GerSpatial
Genres: Bildung, Nachschlagewerke

SatTracker is designed for real-world prediction of Earth-orbiting satellite ground tracks. It is very accurate and, with fresh sets of orbital elements downloaded from within the application, it will keep that accuracy indefinitely. It provides ground tracks for multiple satellites, like some other applications, but unlike any others, it will compute visibility for multiple ground stations. 

SatTracker has been used during real satellite operations at the European Space Operations Centre, ESOC, in Germany!

SatTracker uses the SGP4 algorithms which are ideally tuned to the publicly-available orbital elements and, as a result, generates the most accurate orbits possible with these orbital elements.

As well as ground tracks, SatTracker calculates daytime, twilight and nighttime regions as well as calculating when each satellite is in sunlight so that it is visible – assuming there’s no cloud. To help with this, SatTrackerBasic can also display global cloud cover updated hourly (though this requires a paid subscription to a third-party data-provider). The various items which can be plotted are configurable, and so is the representation. The map can be displayed in two map projections: a simple rectangular projection or as a pair of azimuthal projections centred on the North and South poles.

Powerful database functionality is built-in to allow the management of thousands of satellites and ground stations.

Features of SatTracker v. 1.0:

 - plots Earth-orbiting satellite positions and ground tracks;
 - Sun and Moon position (and Moon phase) are plotted;
 - maps show the day and night coverage on the Earth;
 - the time can be adjusted freely forwards and backwards, and run in simulated future or past times;
 - current cloud cover is optionally downloaded and displayed;
 - the location of the South Atlantic Anomaly (which can affect satellite operations) is shown for a given satellite;
 - ground station horizons are plotted, taking account of the real horizon obstructions, for both transmit and receive links;
 - ground stations are grouped into related sets;
 - plots are either on a rectangular grid or a pair of polar projections;
 - dark mode, retina display and Apple Silicon.

For features of v. 2.0, see “What’s New”

Note also that SatTracker is a not a video-games quality, 3d graphics simulation, and was never intended to be. It was designed with the needs of satellite professionals in mind, particularly those in Mission Control Rooms who need to see where relatively few satellites are with respect to the visibility horizons of the available ground stations. Specifically for these engineers, the location of the South Atlantic Anomaly is shown (as requested during the development phase of the App).

For a full explanation of what SatTracker v2.0 can do (and a useful tutorial on satellites, orbits, TLEs, satellite radio links etc), please download the User Manual available at https://www.gersastronomie.com/sattracker.

Release notes:
SatTracker 2.0 adds significant new features:
 - Sky View, showing satellite positions and tracks across the sky from the selected ground station;
 - View Pass, showing a set of timelines with satellite passes plotted as elevation against time;
 - both the Sky View and Pass View windows include sky shading to indicate time of day (and the Sky View can include stars and constellation lines too);
 - on-screen and printed lists of satellite passes for a given ground station, or ground station passes for a given satellite;
 - full support for ground station time zones;
 - a database of commercial ground station antennas which can be used to populate new or existing ground stations;
 - many more networks of ground stations, including the networks offering “Ground Station as a Service”, GSaaS, for SmallSats;
 - extension of ground station communications records to VHF, UHF and L-Band (of interest for direct broadcast of meteorological and other Earth observation data);
 - great expansion of the contents of the default ground station database, including horizon profiles for most stations.

It enables the User to manage migration of databases from older versions, where necessary.

The User Manual (available at www.gersastronomie.com/sattracker) has been greatly expanded and now includes some general material for anybody who’s interested in satellites.