Blue Force Tracking is a GPS-enabled system that give US Military the location of “friendly” military forces. You can read more about it on Wikipedia.
Inmarsat is one of the commercial satellite providers that has a contract with the the US Military to provide coverage in certain areas. Below is a public domain image showing US Navy soldier preparing his Blue Force Tracker before departing.
Maps like the one below of Baghdad International Airport is an example of how troops show up overlaid on a map.
Below are two channels of the Blue Force Tracking waveform as discovered on one of the Inmarsat satellites. Rest assured this waveform is completely secure and highly encrypted.