Ambiguity Function of MIMO Radar Based on Quasi-Orthogonal Ultrawideband-Throb Signals

Multiple-input-multiple-output (MIMO)-radar systems employing ultrawideband (UWB) signals promise enhanced imaging performance. In this article, the generalized ambiguity function (GAF) for an MIMO-radar system is derived by using a set of quasi-orthogonal step-frequency UWB-throb signals. The effect of the step-frequency increment on the orthogonality property of the step-frequency UWB-throb signals is first analyzed. The properties of the UWB-GAF are also described. Computer simulation plots are generated for the delay-Doppler resolution function, delay-angle resolution function, Doppler-angle resolution function, delay profile, Doppler profile, and power beampattern for various design parameters of the MIMO-radar system and the employed UWB-throb signals. For the purpose of comparison, the same resolution functions and profiles are also generated for UWB linear-frequency-modulated (LFM) chirp signals. Performance analysis is conducted to demonstrate the resolution and the clutter-suppression capabilities of the GAF of an MIMO-radar system using UWB-throb signals in comparison with that of an MIMO-radar system using UWB-LFM-chirp signals. In principle, the UWB-GAF of an MIMO-radar system offers many degrees of freedom and allows for tradeoffs between the various signal-and-system design parameters. Such tradeoffs are of importance in practice for reducing the system complexity, enhancing the performance, and achieving the cost-effectiveness.