Incorporation of anti-jamming techniques in a GPS receiver

GPS guidance uses low power signals from satellites which are 11000 NMI away. The satellite transmitter power is modest nearly 10 W orders of magnitude. Neither satellite nor receivers have the luxury of very high antenna gain since both entities have significant field of view requirements. These factors result in a very low power density incident on a GPS receiver antenna. The signal received is generally 165 dB down than the thermal noise level. Such signals are notoriously easy to jam either by intentional noise sources (Jammer) or unintentionally from harmonics of broadcasting stations or other out of band sources. Here in this paper we will show how a nulling antenna or controlled reception pattern antenna with adaptive spatial filtering technique efficiently mitigate the intentional and non intentional interferences.