Computationally efficient waveform diversity

In this paper, a new signal processing approach referred to as simultaneous range-Doppler (SRD^reg) is presented. It applies fractional Fourier transforms in a manner that yields projections and slices of the cross-ambiguity function (CAF). Waveform diversity (WD) techniques often require extensive processing resources, thus precluding WD from smaller, more mobile systems, or applications with limited resources. By employing SRD^reg, the feasibility of WD in these applications is greatly increased. The projection and slice processing is used to detect targets and estimate their unambiguous range and Doppler in the CAF range-Doppler space. SRD^reg detects peaks of the CAF in a processor-efficient manner, thereby reducing the computational load associated with traditional approaches since computing the entire CAF is avoided. The number of required operations is reduced to O(Nlog₂(N)) as opposed to O(N²log₂(N)). Since SRD* processing load is insensitive to waveform modulation and coding, orthogonal waveforms can be exploited to confer temporal, spatial, and spectral diversity to a sensor system, without incurring any processing penalty. Fundamentally, SRD^reg offers waveform flexibility and increased processing efficiency, which can be applied to broaden the scope of applicability of WD to sensor systems.