Research On Joint Direction-finding Technology By Comparing Amplitude,Phase And Tine

The direction of the radiation source is an important basis for decision-making of combat behavior,such as signal detection,signal sorting,threat decision,interference guidance,and anti-radiation attack.The direction of the radiation source is strictly constrained by geographical conditions and athletic ability,and it has the continuity and stability of geographical location and motion.It is also an important feature and basis for target-sorting,target-identification and electronic warfare behavior guidance.Therefore,accurate direction-finding is a necessary function of electronic warfare.Now,the main direction-finding techniques that are used in electronic warfare systems are the direction-finding method by comparing amplitude and phase.With the continuous improvement of the measurement accuracy of time and time difference,the direction-finding method by comparing time difference has appeared.In some cases,the use of a single direction-finding technique may not be suitable for the actual battlefield signal environment or meet the requirements of tactical technical indicators.In order to solve these problems,a combination of multiple direction-finding technologies have emerged to achieve the best system performance.In order to adapt the direction-finding system to the actual battlefield signal environment or to meet the requirements of tactical technical indicators,this thesis proposes a joint direction-finding method that combines the direction-finding method by comparing phase and the direction-finding method by comparing phase.This method has a good application prospect.This joint direction-finding method is studied from the following aspects in this thesis.The principle of the direction-finding method by comparing amplitude is firstly introduced in this thesis,because this direction-finding method is not helpful in the study of the joint direction-finding method by comparing phase and time,so this direction-finding method is only briefly introduced.Then the direction-finding principle of comparing phase and time,system composition,constraints,key techniques and the dephasing algorithm of the direction-finding method by comparing phase,such as the remainder theorem,the long and short baseline defuzzification algorithm,the virtual baseline defuzzification algorithm,and the process of defuzzification phase algorithm of remainder theorem is secondly introduced in this thesis,and the factors affecting the defuzzification phase algorithm of remainder theorem are analyzed.Through theoretical analysis and simulation of the performance of the direction-finding system by comparing phase and the direction-finding system by comparing time are verified,and the affecting factors such as signal-to-noise ratio on the two direction-finding systems are analyzed in order to provide a basis for studying the direction-finding method by comparing phase and time.Based on the direction-finding method by comparing time,the measurement of the arrival time difference of the incident signal is studied,especially how to realize the high-precision time difference estimation.In this thesis,the time difference estimation method that is based on Fourier transform or phase difference measurement is proposed.These two methods can realize the high-precision time difference estimation,verify the performance of the two high-precision time difference estimation methods through theoretical analysis and simulation,and the factors affecting the time difference estimation accuracy of the two kinds of time difference estimation methods are analyzed.Based on the direction-finding method by comparing phase,direction-finding method by comparing time and high-precision time difference estimation method have been introduced,the workflow,system composition and signal processing method of the joint direction-finding system by comparing phase and time are studied,especially how to use the phase difference to accurately estimate the time difference and how to use the time difference to correctly solve the phase algorithm.The joint direction-finding method is simulated and verified,and the factors affecting the direction finding accuracy of the joint direction-finding method are analyzed.The results of simulation show that the joint direction-finding system by comparing phase and time can realize the phase difference and time difference measurement of the incident signal simultaneously with a set of antennas,thus achieving high-precision of direction-finding,and the direction-finding accuracy is higher than the single direction-finding by comparing phase and direction-finding by comparing time.