satellite-tools

Simple interface for orbital propagation tools, focused on space system scenarios and access intervals between assets: either Satellites or Devices on the surface of the Earth.

Configuration

Simulation

Using the sim.properties file in classpath:

# Orbit extrapolation data folder path. Can be cloned from: https://gitlab.orekit.org/orekit/orekit-data
orekit_data_path=C:/Projects/orekit-data
# Default start date
start_date=2022-01-01T20:20:00.000
# Default end date
end_date=2022-01-01T20:45:00.000
# Default time step in seconds
time_step=60
# Minimum visibility threshold over the horizon, in degrees
visibility_threshold=5
# Access interval threshold detection in seconds (internal propagator parameter)
th_detection=0.001

Logger

To configure the Logger use the log4j2.properties in the classpath or another valid method. Refer to Log4j configuration for more information.

Install in local maven

Build the project and then install the jar in local maven:

mvn install:install-file \ 
        -Dfile=<Jar location> \
        -DgroupId=com.santiagohenn -DartifactId=satellite-tools \
        -Dversion=2.0 \ 
        -Dpackaging=jar \
        -DgeneratePom=true \

---

Basic usage

Obtain access intervals for a given scenario time-span

// Declare a satellite from its TLE
String tle1 = "1 25544U 98067A   22122.68846215  .00030457  00000-0  54086-3 0  9994";
String tle2 = "2 25544  51.6435 201.9265 0006436  54.9097 105.7177 15.49915502338120";
Satellite satellite = new Satellite(tle1, tle2);

// Declare a Device with its Latitude, Longitude and Height (deg, deg, meters)
Device device = new Device(15, 15, 3);

// Instanciate a tools.simulation with a start time, end time, devices involved, time step in seconds and 
// visibility threshold in degrees
Simulation simulation = new Simulation("2022-03-20T12:00:00.000", "2022-03-20T15:00:00.000",
device, satellite, 60, 5);

// Compute access intervals
simulation.computeAccess();

// Print intervals in Unix timestamp
System.out.println("Start,End,Duration[ms]");
simulation.getIntervals().forEach(System.out::println);

// Print intervals in yyyy-MM-dd'T'HH:mm:SS.sss format
System.out.println("Start,End,Duration[s]");
simulation.getIntervals().forEach(interval -> {
System.out.println(Utils.unix2stamp(interval.getStart()) + ","
+ Utils.unix2stamp(interval.getEnd()) + "," + interval.getDuration()/1000.0);
});

Obtain Position, Velocity and Doppler for a specific moment in time

// Declare a satellite from its orbital elements
// date of the elements, sem-maj axis, ecc, inc, RAAN, w, v
OrbitalElements orbitalElements = new OrbitalElements("2020-01-01T19:40:00.000",6978135,0,98,310,0,220);
Satellite satellite = new Satellite(orbitalElements);
Device device = new Device(15, 15, 3);
Simulation simulation = new Simulation("2022-03-20T01:00:00.000", "2022-03-20T23:00:00.000"
, device, satellite, 60, 5);

Ephemeris ephemeris = simulation.computePVDAt("2022-03-20T03:00:00.000");
System.out.println("time(unix ts),posX,posY,posZ,velX,velY,velZ,range[m],doppler[m/s]");
System.out.println(ephemeris);