Study Of The Methods Of Radio Direction Finding

The radio direction finding is widely used in military and civilian fields and it can locate the wireless signal,track the signal, finally the azimuth information in which we are interested is obtained in real time. The radio direction finding system is composed of two parts,the direction finding equipments and algorithms:on the one hand a piece of signal receiving device which can receive the wireless signal through wide-band antenna to achieve the function of direction finding is needed,on the other hand the DSP and FPGA digital module are applied,the direc-tion can be find with direction finding algorithm finding function. This article focuses on the introduction finding algorithm part.The algorithm of interferometer as a fast algorithm of direction finding has significan-t advantages such as high speed,simplicity and high sensitivity. Therein phase interferome-ter(for example,short-long baseline method)is adopted in most direction finding equipments since it could be actualized both easily and fast. However this algorithm is sensitive to chan-nel amplitude phase error,and the noise immunity is poor. Corresponding strategies are put forward,improved algorithm is proposed:T-array antenna method can improve direction finding accuracy in low SNR by reducing phase ambiguity range that phase ambiguity value is calculat-ed,using K-Medoids algorithm to cluster. The improved algorithm of correlation interferometer direction finding improves accuracy and reduces effects of noise and antenna amplitude phase unbalance by counting the correlation coefficients of the reference sample and the output sig-nal array. In order to test these improved methods,MATLAB is used for simulation,which is compared with traditional algorithm of direction finding.