The Angle of Arrival Estimation of Frequency-Hopping Cooperative Object Based on Software-Defined Radio

Abstract This study aims to investigate and propose a methodology for determining the azimuth angle of cooperative objects with fast processing, more accuracy, and safety. The proposed methodology encompasses the utilization of a transmitter emitting a continuous wave with a hopping frequency, in conjunction with measuring the Angle of Arrival (AOA) between two antennas through the application of interferometry techniques. Furthermore, this study presents an efficient AOA estimation method, which incorporates a sophisticated coarse-to-fine strategy, designed to enhance the processing speed and azimuth angle precision. Additionally, a Fourier bandpass filter is implemented to effectively filter out any signal interference. The Fast Fourier Transform (FFT) algorithm is employed for coarse estimation, whereas the Multiple Signal Classification (MUSIC) algorithms, utilizing coarse angle input and a scan limit of 2.5 degrees, is utilized for fine estimation. The proposed method has been analyzed through modeling and validated through outdoor testing based on Software Defined Radio (SDR), yielding an RMSE of less than 1 degree, utilizing the Blade-RF as the transmitter and the USRP B210 as the receiver.