A Uniform Linear Array Self-Calibration Method for UHF River Flow Detection Radar

This letter proposes a uniform linear array (ULA) self-calibration method for ultrahigh-frequency (UHF) river flow detection radar (URFDR). URFDR usually uses ULA with less array elements, thus traditional self-calibration methods are all ineffective. This method using river echo signals with single direction of arrival as calibration sources mainly includes two steps: 1) A cost function is constructed based on eigenstructure decomposition, and the array error with Vandermonde fuzziness is estimated by minimizing the cost function using the gradient descent method. 2) The fuzzy array error estimation is corrected by nonlinear least square method based on the characteristics of river echo signals. A field experiment was conducted in the Yangtze River in October 2016, the processing results of which verify the effectiveness of the proposed method.