Multipath effects on F-15 and F-16 multi-channel GPS antenna performance

GPS jamming has been identified as the most serious threat to fully utilizing GPS capabilities during hostile engagements. Adaptive transforming has been proposed as a method for mitigating GPS jamming, and a 7-element array (the controlled reception pattern antenna, or CRPA) is in production for military aircraft. This paper describes experiments conducted by Lincoln Laboratory at the Newport, NY antenna range of the Air Force Research Laboratory (AFRL) Rome Research Site. We illuminated both F-15 and F-16 CRPA-equipped aircraft with broadband jamming signals, producing the first measurements of in-situ CRPA array responses to broadband jamming. The measurements are used to show performance of various adaptive beamforming algorithms, including spatial-only and space-time algorithms. The results clearly demonstrate the advantages of space-time adaptive processing for GPS adaptive beamforming.