Broadband Interferometer System For Rbitrary Antenna Array Direction Inding Algorithm And Simulation Tudy Of Master Thesis

The direction finding antenna array based on interferometer has many advantages,such as simple form and high accuracy of DOA finding, etc. It is widely used in passivelocating and the PRS of ARM. As the spreading of radar’s working frequency spectrum,the design of the direction finding antenna array based on interferometer must take thisfactor into account. There hasn’t been effective design of interferometer directionfinding antenna array in multi-octave bandwidth. The arrangement of antenna elementand the corresponding ambiguity eliminating algorithm are the key technologies.This thesis firstly explain the direction finding principle of phase interferometerand the phenomenon of periodic ambiguity; then analyses several common ambiguityeliminating algorithms; finally gives the simulation analysis on the main factorsaffecting the direction finding effect of the interferometer. As to the phase errortolerance under phase interferometer system, this thesis uses K-search method andangle-search method to analyse and compare the error. The simulation result shows thatthe angle-search method can get the baseline length under minimum error tolerance,which at the same time is more flexible.When using two baseline for direction finding, once the length of baselines aredetermined, their phase error tolerance is determined. The only way to increase the errortolerance is to increase the number of baselines. The problem thereupon is how to makecombining use of the information generated from multi-baseline. The traditional methodis to solve the angle combining the calculation results generated from pairs of baselinesin different waveband. However, its effect on either increasing the phase error toleranceor simplifying the algorithm is very unsatisfactory. According to practical application,this thesis presents a method called “griddle”, a comparative principle in solving thedirection finding ambiguity under interferometer system. This method analyses thephase error tolerance quantitatively through comparing the minimum angle betweendifferent baselines and performs simulation verification using three-baseline antennaarrangement. The simulation results reveals that this method can eliminate angle resolution ambiguity in full view field.Finally the thesis discusses about the direction finding theory of stereo baselinesand the direction finding of random antenna arrangement along with the “griddle”comparative principle. Simulations shows that the stereo baseline direction findingalgorithm based on “griddle” principle can resolve the angle correctly within14°range.Further more, the algorithm is applicable not only in the direction finding of planararray antenna, but also in the direction finding of non-planar array antenna, whichproves its universality and practicability.