Research On Direction Finding Technology In Circular Array Interferometer Based On Beam Scanning

The azimuth measurement is one of the most important tasks of radar reconnaissance. And the Circle Array Interferometer (CAI) is a small Electronic Support Measures (ESM) receiver which has the advantages of high probability of intercept, wide band and high precision. And the CAI also has the advantages of small size, light weight, small equipment of volume, direction finding of high precision and low Radar Cross Section (RCS). But there is also the problems of the poor anti-interference ability, the unstable measurement of the beam signals which arrived at the same time. This article is based on these problems, analyzing the circle array interferometer which is based on the phase mode theory and can be beam scanning and direction finder.Based on previous work. We introduced the Circle Array Interferometer which can be beam scanning. The main work is as follows:(1) With using the principle of beam scanning, the scanning beams have been simulated. And this paper also proposes a possible system implementation scheme. The error caused by the inconsistency of channels has been simulated by Monte Carlo simulation, to guide the practical engineering application of parameter inconsistency of channels.(2) We have also studied the work bandwidth of the scanning beam circle array interferometer when unit antenna is omnidirectional antenna or directional antenna.(3) In order to strengthen the anti-jamming capability to the Scan Beams, we have studied the way to add the Controllable Zero Points in the Scan Beams which is synthesized under different modes. After adding the Controllable Zero Points, we have also studied the narrowest limits of scan beams.The research results show that:(1) Under the influence of the channel inconsistencies, when under certain conditions of channel inconsistency, the error of direction finding is between 3-5 degrees; (2) Compared with the original Circular Array Interferometer: when the unit antenna is omnidirectional antenna, the working band width is almost same between the original CAI and the scan beams CAI; when the antenna is directional antenna, the working band width in the scan beams CAI is lower than that in the original CAI. (3) After adding two zeroes in the scanning beams which have different combinations of phase modes, the different scanning beams has the same narrowest limits between the two zeroes.