DOA Estimation With Extended Optimum Co-Prime Sensor Array (EOCSA)

In this paper we develop a novel sparse antenna array, so-called Extended Optimum Co-Prime Sensor Array (EOCSA), for direction of arrival (DOA) estimation of received signal. Here, we use a prototype co-prime sensor array (CSA) to design the EOCSA. The prototype CSA can achieve narrow beam widths using far fewer sensors than a fully populated uniform linear array (Full ULA), but at a cost of the appearance of grating lobes. To reduce the effect of grating lobes the extended CSA (ECSA), obtained by adding more sensors to the CSA while maintaining a fixed distance between sensors, is presented in literature. The ECSA is not feasible when the size of the array is limited by the costs or the environmental constraints. The purpose of this paper is to decrease the effect of grating lobes using the EOCSA which requires much fewer sensors than ECSA. The EOCSA would be very useful in many practical applications where the number of sensors is limited. Moreover, in order to DOA estimation with EOCSA we use a new processing method based on digital beamforming at sub-array level. The results illustrate the EOSCA ability to reaches the same power pattern of a Full ULA using relatively few sensors.