The Holographic Sidelobe Canceller: Holographic Radar Processing for Interference Mitigation

ABSTRACT: Propagation Research Associates, Inc., (PRA) and the Georgia Tech Research Institute (GTRI) are teamed to propose an innovative holographic receiver and processing technology for enhanced radar electronic protection. PRA/GTRI will investigate applying holographic processing to Synthetic Aperture Radar (SAR) and Electronically Scanned Arrays (ESAs) in order to mitigate interference such as radio frequency interference (RFI) and electronic attack (EA) from noise jamming. The PRA/GTRI holographic receiver will provide enhanced dynamic range by compressing the target signal in the analog domain and, using nearly orthogonal channels that isolate the interference from the signal by implementing a holographic sidelobe cancelling algorithm. This Holographic Sidelobe Canceller (HSLC) has the advantages of (1) increasing the dynamic range of the receiver, (2) providing electronic protection (EP) against broadband noise jammers and RFI, and (3) operating recursively to adapt to changes in the interference environment. The PRA/GTRI team proposes to implement HSLC algorithms into a SAR simulation and demonstrate interference mitigation for SAR image construction and will apply HSLC algorithms to ESA architectures to demonstrate the electronic protection potential of holographic processing in a jamming environment. Finally, PRA will develop a detailed hardware design for a HSLC that can be implemented in a Phase II demonstration. BENEFIT: The PRA Holographic Sidelobe Canceller represents a paradigm shift in space-time adaptive signal processing where the target signal is holographically amplified in the amplitude channel in order to develop an adaptive sidelobe canceller using the outputs from two holographic receiver channels. This holographic approach avoids time averaging covariance statistics as in determining the array covariance matrix in a General Sidelobe Canceller (GLC). Significant time averaging will not account for highly dynamic interference environments and may be prohibitive in certain SAR applications due to the moving radar platform. On the other hand, the proposed PRA Holographic Sidelobe Canceller can cancel interference on a pulse-by-pulse or dwell-by-dwell basis and can readily adapt to changing interference dynamics. In addition, a Generalized Sidelobe Canceller can be used on the output of the holographic receiver where the receiver is creating two orthogonal channels for the GLC. In that sense, the holographic receiver can improve the performance of existing STAP and GLC techniques. The successful completion of Phase I will result in the design and evaluation of an innovative holographic radar processing technology. Specifically, PRA/GTRI will design and evaluate a Holographic Receiver and Processor that implement the PRA Holographic Sidelobe Canceller. The PRA/GTRI team will evaluate the performance of the PRA Holographic Sidelobe Canceller for both SAR and ESA applications. PRA/GTRI will demonstrate the performance of holographic approaches using existing simulations that incorporate realistic error models to finalize the hardware design for a Phase II demonstration. In Phase II, PRA proposes to build and demonstrate the PRA Holographic Sidelobe Canceller. PRA expects to have a complete design of the preferred Holographic Receiver approach at the completion of the Phase I Option and begin production of the Phase II hardware very shortly after the start of Phase II. The commercialization opportunities for the PRA Holographic Sidelobe Canceller are vast. In addition to applications in SAR and ESAs the Phase I technology has application to cancel interference in Robust GPS Networks. The first opportunity is the continued development of a set of standalone navigation products, such as proprietary chip sets or software IP cores, for use in tactical military radios. The second is the leveraging of military applications in developing a commercial product specifically targeted at first responders where position information indoors and out is a life safety critical piece of information. The focus of near-term commercialization efforts is the marketing and deployment of the Robust GPS Network family of technologies to the tactical radio community.