Anti-Jam Improvements by Combining Remotely Located Global Positioning System (GPS) Antennas on an Unpiloted/Uninhabited Aerial Vehicle (UAV) Platform

Currently, two types of antenna configurations are in use with GPS receivers; fixed reception pattern antenna (FRPA) and controlled reception pattern antenna (CRPA). FRPA is a single element antenna and, thus, can not use angle of arrival as a discriminator to suppress interfering signals or jammers. CRPA is an array of antenna elements that can use angle of arrival as a discriminator to reject interference signals and/or jammers. Many DoD platforms use FRPA due to the cost, size and weight issues. Also, a given platform may have many GPS FRPA to support various communication/ radar/ navigation systems on board the platform. Applied EM proposes a thorough performance evaluation of GPS antenna electronics when conventional antennas (GAS-1 CRPA, GAS-1N CRPA, etc.) are replaced with a set of GPS FRPA. The performance evaluation will be carried out under the jamming scenarios of interest for selected FRPA distributions on a UAV. The goal will be to come up a distribution consisting of four FRPA and another distribution of seven FRPA which lead to the best AJ performance. During Phase I, we compared the AJ performance of the many four and seven FRPA distributions with the performance obtained using regular antenna arrays (inter-element spacing of the order of half a wavelength) when the platform was assumed to be an infinite ground plane. In Phase II, the study will be extended to a UAV. The final goal will be build the antenna arrays and demonstrate their AJ performance on a UAV platform. BENEFIT: The proposed solution is based on the development of a practical GPS AJ system for DoD platforms. Our research effort will also focus on implementation techniques with realistic FRPA designs which will help toward commercialization. This technology has applications in many military systems.