Signal Processing Techniques for Anti- Jamming Global Positioning System (gps) Receivers

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden The objective of this multi-year research funding is to devise new and novel methods to suppress interferers impinging on a multi-sensor GPS receiver. The research has considered chirp-like jammers as well as wideband interference. A self-coherence anti-jamming scheme is introduced which relies on the unique structure o the coarse/acquisition (C/A) code of the satellite signals. Because of the repetition of the C/A-code within each navigation symbol, the satellite signals exhibit strong self-coherence between chip-rate samples separated by integer multiples of the spreading gain. The proposed scheme utilizes this inherent self-coherence property to excise interferes that have different temporal structures from that of the satellite signals. In addition, new approaches using subspace methods and projection techniques are proposed for effective cancellation of frequency modulated jammers with minimum distortions of the desired satellite signals. The report also considers and analyzes the effect of non-Gaussian noise on the GPS receiver delay lock loops and discriminator outputs.