SBIR-STTR Award

Recent advances in Field Programmable Gate Arrays (FPGA’s) and Digital Signal Processing (DSP) devices are providing a means for the development and fielding of wideband digital receiver suites for Electronic Support (ES). Digital processing of these signals can result in significant improvements in parameter measurements such as Direction of Arrival (DOA), frequency measurement, time of arrival and signal amplitude as well as improved envelope and modulation estimation. Use of advanced digital processing also allows for the implementation of modern interference cancellation algorithms to allow processing of today’s high density signal environments containing many overlapping signals. The proposed research will study the feasibility and effectiveness of a novel wideband interference cancellation technique for separating overlapped signals. The technique is based on an extension of existing IFM techniques. It makes use of a series of co-variance matrices from which a set of eigenvectors can be found. These eigenvectors are used for signal detection, time up, frequency and angle of arrival measurements. These parameters are then used as components of typical pulse descriptor words that can be fed into existing pulse separation and association processors for further downstream processing. Use of FPGA and high speed DSP chips allows these algorithms to be implemented in real time and in a fieldable form factor and in fact, can be readily inserted into existing systems. Benefit Interference cancellation has many benefits. The first is removal of on-board interference from co-located radars and communications systems. Communications systems generally are CW signals which generate severe self jamming of existing IFM receivers and crystal video detectors and DOA units. Interference cancellation also allows for detection and processing of signals in very dense environments which are much more prevalent in today’s new littoral water deployments encountered by both the Navy and the Coast Guard. Interference cancellation also has wide application in commercial communications networks, both in terms of canceling unwanted interference and allowing for more efficient utilization of very valuable, but limited spectrum. Keywords Wideband Processing, Field Programmable Arrays (FPGA), Rotman Lens, Parameter measurement, Instantaneous Frequency Measurement (IFM), Electronic Support Measures, interference cancellation, Direction of Arrival (DF)

The increasing interference density of the modern RF environment is causing unacceptable degradation to the effectiveness of military electronic support (ES) and radar warning systems, which for economy must use wideband analog detection and discrimination devices in their front-end processing stages. A Phase I SBIR study was completed in 2004, which showed that the core technology could be upgraded to operate through relatively severe interference environments, by replacing the DSP algorithms applied to the standard digitized outputs from these analog front-ends. DSP retrofits were demonstrated on the Phase I study both for instantaneous frequency measurement (IFM) systems and wideband direction-finding (WDF) systems. Through computer modeling and simulation, the proposed DSP algorithms were shown to maintain effective operation through up to 40 dB of interference, and to be highly robust to non-ideal hardware characteristics. The Phase II program proposed herein will construct a brassboard implementation to retire the remaining technical risk, by replacing computer models with actual analog hardware. It is divided into three sub-phases as follows

Keywords:
Electronic Support Measures Wideband Pulse Detection Interference Cancellation Radar Warning Receivers Instantaneous Frequency Measurement (Ifm) Dire