Global Navigation Satellite System (GNSS) technology such as the US Global Positioning System (GPS) is increasingly being used in many different military applications beyond navigation. For instance, soldiers can use GPS to enhance situational awareness on the battlefield with systems such as the forthcoming Dismounted Soldier System (DSS).
GPS applications for airborne soldiers provide guidance to the drop zone in night or inclement weather operations. In the case of airdrop systems GPS guidance receivers provide navigation and steering commands to guide the payload to the drop zone. GPS-enabled asset tracking may also provide current position and status of high-value assets, such as VIPs or weapons for example. In training applications, GPS technology may be used to track the participating assets, scoring the exercise and enabling a far more instructive debrief.
In all of the examples above, and in many other GPS-enabled military applications, it frequently becomes necessary for these GPS receivers to operate in locations where the GPS signals are normally not available, reducing awareness, effectiveness and survivability.
The type of environments where GPS is unavailable include inside ground vehicles such as Bulldog, Warrior, Spartan, MASTIFF 2 and future vehicles such as OCELOT and FRES. GPS-denied environments also exist inside aircraft such as C-130, C-17 and CH-47 (Chinook).