Ultra-Wideband MIMO Ambiguity Function and Its Factorability

Ambiguity function (AF) provides an effective way for analysis of the resolving performance of a radar system. With the development of ultra-wideband (UWB) and multiple-input-multiple-output (MIMO) radio techniques, recently, the combination of them-the concept of UWB MIMO radar has been proposed and received much attention. For a UWB MIMO radar, first, the signal waveform with an exponential expression which is widely adopted in narrowband cases is not appropriate anymore. Second, the MIMO radar sensors are typically organized in a certain spatial topology, which greatly impacts the performance of the MIMO system. In addition, for a typical MIMO radar application scenario, generally, there are relative motions existing between the radar sensors and the targets. The presence of the relative motions would further complicate the performance analysis of the system. In fact, for a MIMO radar, the overall performance of the system is jointly determined by the parameters, such as the signal waveform, the topology, and the relative motions. Each of the parameters impacts the resolving performance in a particular way. In order to evaluate the contribution of each individual parameter of interest, in this paper, a UWB MIMO AF is developed and factorized into several factors. By this means, each individual parameter can be evaluated via the corresponding factor to examine a certain specific characteristic of the system, instead of via the complicated whole MIMO AFs.