Ship Detection Direction Finding And Rectification For HFSWR

High frequency ground wave radar has the ability of over-the-horizon detection, becauseof low cost, large observation range and all-weather work, etc, it is becoming more and morepopular. Because the radar wavelength of the system is long, it is not sensitive to the bearingof the target, and this leads to the low accuracy of the target direction finding. In addition, theprecision of the target bearing affects the tracking results, so we need to research on the targetdirection finding algorithm of ground wave radar. In the condition of not increasing the radararray scales, we should improve the performance of the direction finding algorithms as far aspossible. The work of this paper mainly includes the following aspects:(1) With regard to the typical direction finding methods, the comparative analysis of twotypical measuring methods were carried out, that is the DBF direction finding and amplitudecomparison direction finding. Combined with the measured data of the ground wave radar, wecompared the direction-finding precision of two algorithms. According to the principle of thetwo methods, we analyzed the main factors affecting the accuracy, and provided a theoreticalbasis for the work of direction finding rectification.(2) With regard to super resolution direction findings, the research of MUSIC algorithmwas carried out in the thesis, and we analyzed the factors affecting the precision of traditionalMUSIC by simulations. On this basis, three improved methods for MUSIC were put forward.By applying improved algorithms to the practice, it is able to overcome problems existing inthe traditional MUSIC algorithm, and it improves the―super resolution‖performance of theMUSIC algorithm effectively in the practical application.(3)Aiming at errors of DBF direction finding and amplitude comparison in the practicalapplication, two rectification methods for the direction finding were carried out based on theAIS data: the Amplitude comparison direction finding rectification method based on AIS andthe channel phase rectification of the DBF direction finding based on AIS, the first method ismainly for correcting the target amplitude, which can eliminate the effect of amplitude errorsfor the direction finding results. The second method aimed at processing the original channeldata, we can achieve the goal of calibrating DBF direction finding results by calibrating the initial phase. By carrying out the rectification research of two methods in the thesis, it canreduce the error effect in the actual processing, and ensure its reliability in the practicalapplication.