GNSS Antenna Arrays for Situational Awareness

ABSTRACT: FIRST RF proposes a 4- and 7-element Controlled Reception Pattern Antenna (CRPA) covering the full L-band GNSS radio navigation spectrum, offering simultaneous anti-jam (A/J) and situational awareness (SA) functionality. Both the 4- and 7-element configurations are backwards compatible with ADAP/GAS-1N and GAS-1 standard military CRPA configurations, offering full GNSS coverage and the ability to geolocate signals of interest. The key to the proposed design is an antenna element which maintains vector RF pattern performance over the full frequency band and over the full field of view. Element-to-element uniformity is also maintained in terms of vector performance over frequency and angle, which is a key performance discriminator for both anti-jam nullforming as well as amplitude and phase based direction finding systems. The CRPA is compatible with NAVWAR Trinity requirements, and is suitable for aircraft, ground mobile and maritime environments. BENEFIT: The proposed technology is a one-for-one drop-in replacement of existing military CRPAs, but with full GNSS coverage. This increased capability without an increase in size or footprint, and maintaining compatibility with existing designs, avoids modifications to existing airframes and other vehicles. The cost savings is substantial. Furthermore, the ability to navigate using the radio navigation signals of all satellite services offers increased resistance to jamming in the GPS degraded or denied environment. The near term application of this technology includes the NAVWAR Trinity program for airborne platforms, as well as a number of Army initiatives aimed at improving the performance of ground-based platforms. Commercial sales are motivated by increased usage of UAVs in domestic airspace with a need for more robust, jam resistant and lower cost navigation systems. The elements demonstrated in this program can also be utilized in commercial GNSS receiver systems.