GNSS Antenna Arrays for Situational Awareness

ABSTRACT: In the Phase-I program, Toyon explored the capability of antenna arrays to perform direction finding (DF) of jammers in the Global Navigation Satellite System (GNSS) band (1.1-1.6 GHz). Antennas included controlled radiation pattern antennas (CRPAs) consisting of four to seven elements, plus a distributed aperture array with four asymmetrically arranged elements. The distributed array provided the best accuracy because it provides the largest effective aperture. The proposed Phase-II effort will design, build, test, and deliver distributed aperture arrays with up to 12 GNSS-band elements, off-the-shelf 12-channel digital receivers covering the GPS L1 and L2 bands, and a data processing/display/user-interface system to DF one or more jammers and to display and track the jammer location through a Windows based GUI. The array and receiver system will be suitable for testing on a UAV or ground vehicle. The system will be tested in Toyons anechoic chamber, but will ultimately be field tested at Government sites such as White Sands Missile Range. We also plan to test CRPA antennas from Phase I, since they will be plug compatible with our receiver and processing system and may be useful themselves as anti-jam GPS antennas in conjunction with jammer-location platforms. BENEFIT: Toyons approach to this SBIR focuses on developing a distributed aperture array, an accompanying set of receiver and signal processing electronics, and a user friendly GUI to display the estimated jammer locations. Toyons distributed aperture array has the potential to provide geolocation estimation accuracies that are higher quality compared to if a conventional CRPA were used. Toyons multi-channel electronics system is compatible with both distributed aperture arrays and conventional CRPAs. Toyons plan to also experiment with conventional off-the-shelf CRPAs will allow for high levels of flexibility in the development of a GPS jammer geolocating tool.