Improving CRPA Anti-Jamming Performance with Virtual Array Integration

Abstract

This thesis explores the concept of integrating a virtual array into current controlled reception pattern antenna (CRPA) technology to increase performance. A four channel virtual CRPA is designed and simulated, and its anti-jamming power minimization performance is compared to that of a uniformly spaced CRPA. It is shown that a virtual array can be integrated into a controlled reception pattern antenna to increase anti-jamming performance of a static receiver tracking the GPS L1 signal. A genetic algorithm is designed to estimate an improved CRPA geometry in an arbitrary signal environment. It is shown that a genetic algorithm is an effective and efficient method of initialization of element position offsets and complex weights. The use of a virtual array enables steering of the antenna elements' phase centers, or points of effective radiation, with solely electronic means. The added flexibility in spatial diversity of the antenna elements create deeper nulls in the array factor, and thus in the overall gain pattern of the CRPA. With deeper nulls, more in-view satellites are acquired. This increases geometric diversity of satellites, which increases position accuracy. It is also shown that in identical jamming configurations, a CRPA employing a virtual array initialized with a genetic algorithm can remain viable in higher J/S environments than a CRPA with uniform spacing.