Due to their cost and operating and design complexities, GPS/AJ receivers will not be deployed everywhere, but only in specific applications. To protect those systems which are not immune to jamming or interference, high power non space-based GPS transmitters called pseudo-satellites, or pseudolites could satisfy the demanding needs for anti-jam GPS navigation aids. The Pseudolite transmitter is conceptually simple, consisting of a GPS Anti-Jam reference receiver, integrated with an Inertial Measurement Unit (IMU) for position reporting, a GPS RF signal generator, an atomic frequency standard and supporting equipment such as power amplifier, power supply and datalink receiver. Rockwell Collins already demonstrated the feasibility of Pseudolites under a DARPA program. During tests, an airborne Pseudolite was deployed on US Army Hunter UAVs, emplaced as a secondary payload on the Hunter’s boom pods. In addition to its navigation support, Pseudolite can also provide ad-hoc datalink communications, supporting smart munitions with retargeting information, flexible fusing and other advanced features. Pseudolites can provide significant anti-jam GPS flexibility when deployed over a localized or wide area, without any change to existing hardware.