SBIR-STTR Award

This Phase I SBIR program will design and develop a diminutive broadband antenna element that can be used to fashion a small aperture array of several elements. The design will focus on a low-profile antenna. The antenna is inherently broadband, simple to fabricate, and requires no special feeding technique to launch the wave. In conjunction with the antenna development, pattern agility capability of small arrays is to be investigated toward designing a preliminary system architecture and array configuration. Follow-on developments in optimization of the small aperture array and the miniaturization of the anti-jam electronics package will allow the formation of a small, low-cost, airborne applique for the military and commercial marketplace. Protection of military airborne weapon systems from inadvertent or intentional spoofers and jammers is the primary goal of this project. Non-hostile environments, however, also expose military and commercial airplanes to RF interference from TV, radio, PCS, Satcom, and other communication systems. Multipath is another source of GPS performance degradation. Commercial application of this Controlled Reception Pattern Antenna can mitigate and in some cases eliminate the interference problem.

Keywords:
ANTENNA, GPS, ANTI-JAM, ARRAY, CONTROLLED RECEPTION PATTERN ANTENNA, AIRBORNE, PATTERN AGILITY, CRPA

The JPALS ORD requires GPS receivers to provide position and navigation information in the presence of jamming. Effective Anti-Jam (AJ) techniques are required to ensure continuity, integrity, and availability of the GPS service for JPALS. Current steering approaches fall short, given the need for carrier phase tracking. Radix Technologies has developed and demonstrated an effective, concurrent digital beamforming and null steering anti-jam technology called BEAMSTAR, which enables acquisition and tracking of GPS signals in highly jammed environments. The approach optimizes a seperate beam in the direction of each SV, while simultaneously minimizing the interference plus noise environment. This SV-unique optimization provides superior protection over approaches that apply a common weight vector to all SVs. A Matlab simulation was developed and used to evaluate the patented Code Gated Maximum Likelihood (CGML) technique used in BEAMSTAR and to compare the performance of CGML to other approaches and showed significant performance improvement . Under a Phase I SBIR contract, Radix has developed a suitably modified simulation of the CGML technique for inclusion in GIANT, a simulation tool used to determine system performance and operational effectiveness in a GPS/INS environment. The proposed Phase II SBIR effort will yield a demonstration AJ GPS receiver modified for JPALS purposes that incorporates the multibeam CGML technique.

Benefit:
Adding digital beamforming / null steering to the GPS receiver components of JPALS will enable operation in highly jammed environments, so that landing systems may be reliably deployed in military scenarios. The technology will enhance the GPS elements of ground and shipboard applications, as well as military aircraft. The application of this technology may also be extended to LAAS installations at over 150 airports in the U.S., as well as commercial aircraft, ensuring reliable, continuous usage of the Global Positioning System for precision approach and landing.

Keywords:
(RFI), interference, Nulling, Antenn, Multipath, Pattern, digital, beamforming, frequency, Reception, Controlled, Spatial-Temporal, radio, adaptive, processing