Short-range Radar Detection with (M, N)-Coprime Array Configurations

Abstract

An (M, N)-coprime array comprises two well-organized subarrays: an M-element and an N-element. This sparse array configuration is capable of resolving a number of remote sources up to O(MN) solely with the use of an M + N - 1 sensors, which allows the identification of more targets with fewer transceivers while main- taining high resolution. In this way, the coprime array theory can significantly help to simplify the configura- tion of traditional transceiver systems. However, to date, the coprime array approaches reported in the literat- ure rely strongly on far-field approximation, which is associated with significant error when dealing with the problem of short-range radar detection because the probed objects are nearby the sensors. To solve this prob- lem, we extend the theory of the standard coprime array to short-range detection, whereby the probed object is located NOT far away from the sensors (either the transmitter or receiver). We demonstrate that the (M, N)- coprime array configuration can retrieve the object spectrum over (-2tk0, 2tk0) with a resolution of 4tk0/MN, where k0 denotes the free space wavenumber and t is a scenario-dependent factor. As a consequence, the (M, N)-coprime array allows for the resolution of O(MN) objects nearby sensors, with a spatial resolution of l/4t. We also examined the performance of the coprime array with respect to the through-wall-imaging problem. Fi- nally, we verified the usefulness of the coprime array for short-range radar detection with a selected number of numerical experiments.