Adaptive Orthogonal Waveform Set

To address the Army’s need for advanced stationary target indicator (STI) waveforms for fire control radar (FCR) on Apache attack helicopters, Intellisense Systems, Inc. (Intellisense) proposes to develop a new Adaptive Orthogonal Waveform Set (AROWS) with simulation and demonstration of the capabilities of a theoretical Active Electronically Scanned Array (AESA) antenna to improve detection of the stationary ground targets. AROWS comprises a set of STI waveforms and a new software tool set that enables optimization of these waveforms for complex target engagements to completely test the optimized STI waveforms before integration with the Apache attack helicopter FCR and other radars for detection of stationary ground targets. The novel AROWS approach supports multiple-input multiple-output (MIMO) radar configurations and allows significant improvement to the MIMO channels’ orthogonality and reduces both range and cross-range sidelobes. Specifically, AROWS uses an innovative modulation technique with code diversity combined with optimized filtering. The waveform optimization, depending on radar mode, radar platform velocity, expected range to target, and other radar/target conditions, allows for highly effective operation in a MIMO radar configuration and enhanced orthogonality of the wideband radar waveforms with significant reduction of sidelobes in the STI application. Introducing use of very long codes in pulsed radars provides AROWS waveforms with clear and unique advantages over competition and adversaries. MIMO radar configurations are considered digital extensions of the AESA approach, which allows improved radar angular resolution in the real-beam imaging (RBI) mode and increased area of surveillance in the synthetic-aperture radar (SAR) mode. Additionally, polarization and carrier frequency diversities will be applied to enable diversity gain for fluctuated target detection and reduce ground clutter speckle. As a result, the AROWS approach will allow high resolution radar images of the target scene in both RBI and SAR modes to improve stationary targets’ detectability. In Phase I, Intellisense will develop an initial concept design for prototype STI waveforms for both RBI and SAR modes and demonstrate the expected results from each waveform by using modeling and simulation (M&S) tools. In Phase II, the adapted M&S tools used in Phase I will be optimized into a standalone software tool set to support the enhancement of the prototype STI waveforms and demonstrate it for targets and clutter models by using signal simulation, signature databases, or collected data.