When you select Orbital Trajectory as the Routing Mode, the Orbital Trajectory window will open.
This is where you configure your orbital trajectory before you generate it.
Set the required date and time for the start of the trajectory.
Use the dropdown arrow next to the date to open the calendar view and select the required date.
Use the arrow buttons next to the time to adjust the time forward or back.
Alternatively, you can click on a value box and enter the required date and time directly.
Click on a value box and enter the required simulation length.
You can choose to use either Simple or Advanced mode for the Orbital Trajectory. Advanced mode will provide further options for the Orbital Trajectory:
This is the orbit height (in kilometres) above the WGS84 ellipsoid, measured at the equator.
Set the required height for the trajectory.
Use the arrows next to the value to increase/decrease the height.
Alternatively, you can enter the required value directly into the value box.
This is the angle between the Equator (east from the ascending node) and the orbital plane (north from the ascending node).
Set the required inclination for the trajectory and select whether to use Degrees or Radians.
Use the arrows next to the value to increase/decrease the inclination.
Alternatively, you can enter the required value directly into the value box.
The Advanced Mode will provide optional parameters that you can configure for the trajectory.
This is the reference time for Keplerian Elements.
Use the dropdown arrow to select the option you want to use from the following:
- Epoch (Date/Time)
Reference time for Keplerian Elements, expressed as date and time of day (hours, minutes, seconds).
- Epoch (Year/Day)
Reference time for Keplerian Elements, expressed as year and fractional day of year. Note that day is 1-based, for example, one minute after midnight on 1st January is day 1.00069444444444444.
Use the dropdown arrow next to the date to open the calendar view and select the required date.
Use the arrow buttons next to the time to adjust the time forward or back.
Alternatively, you can click on a value box and enter the required date and time directly.
A dimensionless parameter that determines the amount by which the orbit deviates from a perfect circle. A value of 0 defines a perfectly circular orbit, while values between 0 and 1 define elliptical orbits.
Adjust the Eccentricity by using the arrows next to the value to increase/decrease the eccentricity.
Alternatively, you can enter the required value directly into the value box.
Click the dropdown arrow to select between the following:
- Semi-Major Axis (m)
Half the distance between Perigee and Apogee.
- Revolutions per day
Fractional number of orbital revolutions made within 24 hours.
Set the required value for the selected option.
Adjust the value by using the arrows next to it to increase/decrease the eccentricity.
Alternatively, you can enter the required value directly into the value box.
The angle between the equator (east from the ascending node) and the orbital plane (north from the ascending node).
Set the required inclination for the trajectory and select whether to use Degrees or Radians.
Use the arrows next to the value to increase/decrease the inclination.
Alternatively, you can enter the required value directly into the value box.
- Longitude of Ascending Node (Epoch)
Easterly longitude of the point where the satellite passes from south to north through the equatorial plane at the reference time selected for Keplerian Elements.
- Longitude of Ascending Node (J2000/TLE)
Easterly longitude of the point where the satellite passes from south to north through the equatorial plane at the J2000 epoch (1.01.2000 12:00:00 Terrestrial Time, which is 1.01.2000 11:58:55.816 UTC). Such reference time is used in TLE (Two Line Element sets published by NORAD).
Set the required longitude for the trajectory and select whether to use Degrees or Radians.
Use the arrows next to the value to increase/decrease the value.
Alternatively, you can enter the required value directly into the value box.
The angle between the ascending node and the point of the orbit which is closest to the Earth, measured in the orbital plane in the direction of the moving satellite.
Set the required angle for the trajectory and select whether to use Degrees or Radians.
Use the arrows next to the value to increase/decrease the inclination.
Alternatively, you can enter the required value directly into the value box.
The fraction of the orbit's period that has elapsed since the satellite passed the perigee, expressed as an angle.
Set the required angle for the trajectory and select whether to use Degrees or Radians.
Use the arrows next to the value to increase/decrease the inclination.
Alternatively, you can enter the required value directly into the value box.
This section will display the orbital period for the configured trajectory.
Equatorial orbits (including geostationary) are not supported.
SatGen 4 will not simulate atmospheric drag, solar pressure, Sun and Moon pull or any other advanced effects. First and second order Earth gravitational effects are simulated.
Click the Generate button to make SatGen 4 generate the route and set the mode to Map Mode, where you can view and edit the Orbital Trajectory.
Click Cancel to close the Orbital Trajectory window without generating a route.
When you have generated the Orbital Trajectory, SatGen 4 will open the trajectory in Map Mode.
To edit the trajectory configuration, go to the Route Options.
This area will provide the same settings as the Orbital Trajectory configurator.
Change the relevant settings in the configuration. The trajectory will automatically update in the Maps and on the Graph.
You can find more information and steps for creating scenario files with Orbital Trajectories in the Creating Files chapter in the User Guide.
You can find more information and steps for playing simulations with Orbital Trajectories in the Playing Simulations chapter in the User Guide.