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

Period of Performance: 12/23/2008 - 09/30/2009


Phase 1 SBIR

Recipient Firm

Applied EM, Inc.
100 Exploration Way, Suite 300
Hampton, VA 23666
Principal Investigator


Currently, there are two types of antenna configurations which are used with GPS receivers, fixed reception pattern antenna (FRPA) and controlled reception pattern antenna (CRPA). FRPA is a single element antenna and can not use angle of arrival as a discriminator to suppress interfering or jamming signals. CRPA is an array of antenna elements with the ability to reject interference signals. 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. The goal will be to come up a distribution consisting of four or seven FRPA which lead to the best AJ performance. The AJ performance of the two FRPA distributions will be compared with the performance obtained using a GAS-1N CRPA and a GAS-1 CRPA, respectively. In Phase II, two antenna arrays will be built and their performance will be demonstrated. 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.