Studies On The Characteristice Of Interferometer Direction Finding Antenna Array For Unmanned Aerial Vehicle

In modern war, it is very important to reconnoiter and set out the location and direction of enemy radiation source rapidly, exactly and secluded. It is not only to protect our self maximum, but also it is the precondition of destroy enemy military target. The frequencies, position, angle of signals are the basic parameters for guiding disturb, active hidden, and electromagnetism disguised. The research and estimate of the above parameters are vertical in electronic warfare field. Interferometer direction finding technology keeps the merits of high sensitivity, better ability of anti-interference, excellent hidden performance, high precise, direction-finding rapidly, and high ability to survival in warfare battlefield, and attracts many attentions. Based on the project of reconnoiter and direction finding, this thesis focus on the study of the system of interferometer direction finding, and designs a small size wideband antenna and a direction finding antenna array in the use of airplane. The main work and innovations of this paper are described as follows:This paper briefly introduces some kinds of common radio direction finding methods, and focus on the research of interferometer direction finding, which is the mostly useful technology in the field of electronic warfare and communication. This paper analyses the principle of interferometer direction finding in detail, and the systems of radio direction finding are discussed. The principles, direction finding error, and characteristics of single-baseline interferometer and double-baseline interferometer, and the direction finding index have been discussed. Finally, the method of long-short baseline for solving the phase ambiguity has been analyzed.Based on the study of extra wideband and miniaturization antennas for airplane, some kinds of methods for loaded techniques used in wideband antennas are discussed. By comparing the characteristics between top loaded, medium loaded, lumped elements loaded and distributed elements loaded, the distributed elements loaded had been adopted as the design method of extra wideband and miniaturization antennas, and the theory of distributed elements loaded had been analyzed in detail. A 30MHz~400MHz extra wideband direction finding antenna for airplane had been designed by adopting distributed loaded elements. The performance of the antenna meets the demands.This paper analyses the location characteristics of the airborne antennas, and the affections of the airplane shape and airplane skin. The affection of different gap between direction finding antennas and airplane shape for direction finding antennas electric field had been simulated. Based on the consideration of the demands of direction finding system and unmanned airplane, the locations of direction finding antennas had been analyzed quantitatively and qualitatively. Finally, a reasonable antennas location for unmanned airplane had been obtained, and the testing results satisfy the demands of direction finding precision, amplitude, and phase response.