As you navigate SatGen 4 you have multiple ways to customize your scenario, all depending on your specific GNSS testing requirements.
Create a simple stationary or static scenario
Draw a route on the map in SatGen 4
You can use SatGen 4 to add leap-second events
The user-defined trajectory input feature is the most versatile of all scenario input methods. By building a simple list of commands a trajectory can easily be created.