Experimental evaluation of coprime sampler in direction of arrival estimation

Direction of arrival (DOA) estimation has many applications in beam-steering to improve signal reception and interference suppression. The number of sources in the scene of interest is usually very small. Thus, sparse reconstruction becomes a good candidate to work with reduced data sets. Recently, coprime arrays have been proposed for source localization. In this paper, a moving coprime array configuration is implemented for DOA estimation under sparse reconstruction framework. The proposed array uses only one antenna element. The antenna moves along the array axis to cover certain locations specified by the conventional coprime array. A stepped frequency continuous wave (SFCW) signal over ultra-wideband (UWB) is used. A microcontroller is used to control the movement and the data acquisition from the vector network analyzer to the computer. Two main advantages arise out of this approach. First, the complexity in terms of the total number of antenna elements and receivers needed to implement the array is reduced. Second, the mutual coupling effect is eliminated since only one antenna is active at a time. Experimental results in real scenarios were conducted to validate the proposed configuration. It is shown that coprime sampling is superior to uniform sampling with the same number of elements. The impact of the antenna directivity is highlighted.