Anti-Jam Antennas for GPS Pseudolites and Blue Force Electronic Attack (BFEA) Interference Sources

The prevalence of radio frequency (RF) transmissions in the GPS frequency band has grown significantly in recent years. Typically, these interference sources transmit at much higher power levels and experience much lower propagation loss than the low-power transmission from satellites in the GPS constellation, resulting in scenarios where GPS receivers are overwhelmed by these high-power signals. In recent years, the military has begun to use GPS pseudo-satellites (pseudolites) to augment the ability of military GPS receivers to reliably generate accurate location and heading solutions ? especially in environments where conventional GPS signals are disadvantaged by geography and/or RF interference. However, because the signals from these pseudolites have many of the same signal characteristics as GPS interference sources, it is common for current military GPS antenna systems to mistake these friendly signals as being hostile in nature, and to incorrectly take actions to prevent them from reaching the receiver. To prevent this problem FIRST RF proposes a state-of-the-art GPS antenna system that is capable of detecting and neutralizing both hostile and friendly sources of interference while simultaneously maintaining adequate sensitivity to detect and utilize desired GPS signals originating from both the GPS satellite constellation and GPS pseudolites.