Photonics-assisted omnidirectional 3D positioning radar for noncooperative multi-targets by using a cross-shaped antenna array

A photonics-assisted omnidirectional 3D positioning radar for noncooperative multi-targets is proposed and demonstrated. A cross-shaped antenna array containing two linear antenna arrays (LAAs) with symmetrical structure is designed to receive echo signals. Through polarization multiplexing modulation, the received signals from the center antenna could provide overlapped reference frequencies. According to specific symmetry, de -chirped frequencies of echo signals from each target can be distinguished. Two angle-of-arrivals (AOAs) could be extracted to obtain the azimuth angle and elevation angle of multi-targets. Three-target proof-of-concept experiments are implemented, and the results verify the capability of omnidirectional 3D positioning for multi-targets, which supplies an alternative for the detection of low, small and slow (LSS) targets.