Frequency angle 2D angle estimation of wide frequency band signals with sub-Nyquist spatiotemporal sampling

A method is presented for estimation of the frequency, azimuth and elevation angles of the signal over a very wide frequency band (2-18 GHz) with sub-Nyquist spatiotemporal sampling. Using a uniform circular array and antennas time-delaying, it can provide unambiguous frequency estimation under temporal under-sampling, and provides unambiguous azimuth and elevation estimation using integer search algorithm under spatial under-sampling. The estimations of azimuth and elevation and corresponding frequency are automatically paired. It not only can use second-order statistics in element space or DFT beam-space, but also can use fourth-order cumulants to estimate the parameters of non-Gaussian sources in Gaussian white or colored noises. The variance of the azimuth and elevation estimates of this method is 1-2 orders less than that of L-shaped array algorithm under the same antenna numbers and the maximum aperture in DFT beam-space. Simulations are presented to show the capabilities of the algorithm.