Mitigation of radar range ambiguities via waveform diversity

The USAF is considering a number of radar systems as a method to achieve persistent intelligence, surveillance and reconnaissance (ISR) over the Earth´s surface. A comprehensive approach must be taken that identifies feasible radar system parameters, geometry, area coverage and processing approaches that will provide needed moving target indication MTI (both ground and air) performance. From the signal processing perspective, there are a number of unique technical challenges facing this concept. Issues which will need to be addressed include the restriction of antenna aperture and the need to locate and detect targets at shallow grazing angles These and other phenomenology will impact the ability of algorithms implemented by the system to perform image formation, target detection and parameter estimation. This paper presents a new approach to the problem of radar range ambiguities in synthetic aperture radar (SAR) imagery and surface moving target indication (SMTI). By using a combination a priori knowledge of the collection geometry, orthogonal waveforms and an alternative approach to traditional matched filter processing, it can be shown that the effects of the ambiguities can be mitigated and provide image quality and SMTI performance with little degradation as compared to the non-ambiguous case.