Direct Position Determination for Distributed Opportunistic Array

In this paper, a direct position determination (DPD) algorithm based on distributed opportunistic arrays is proposed in the cases of known and unknown signal, respectively. Opportunistic array radar (OAR) is a new type of digital radar recently proposed, with its array antennas randomly and densely arranged on accessible space. DPD algorithm using maximum likelihood (ML) principle directly estimates the location of the emitter, and thus avoids information loss caused by separately processing the emitted signals in respective receiving stations. First, we selectively activate some array antennas to form each opportunistic array, so that the pattern of the opportunistic arrays has a narrower mainlobe width and a lower sidelobe level. Then, we derive a DPD algorithm based on the above-mentioned opportunistic array in the cases of known and unknown signal, respectively. Numerical results show that the proposed DPD algorithm based on distributed opportunistic arrays can effectively locate the emitter at high signal-to-noise ratio (SNR), and the root mean squared error(RMSE) is lower than that of the two-step method at low SNR.