Study On Range Ambiguous Clutter Suppression Method Of FDA-MIMO Radar On Fast Moving Platform

Due to the high pulse repetition frequency of the high-speed platform,the range ambiguity problem is serious,which inevitably leads to the deterioration of the clutter suppression effect and the ambiguious estimation of the parameters.When the high-speed platform radar works in the forward-looking array state,since the clutter doppler is related to the range,the range ambiguious clutter echo will seriously deteriorate the performance of the adaptive processing.The FDA-MIMO radar is a new radar system that has been proposed in recent years.Compared with the traditional MIMO radar,the FDA-MIMO radar has the ability to solve range ambiguity by introducing the carrier frequency increment on the transmitting array element.This article starts with the basic principles of FDA-MIMO radar,and a series of research work is done in several respects:1.The beam characteristics of the FDA-MIMO radar are studied.Starting from the basic FDA and MIMO technology,the characteristics of the virtual joint transceiver beam at the receiving end of the FDA-MIMO radar are studied.Illuminated by the technique of sub-array MIMO technology,a sub-array FDA-MIMO radar is proposed.The advantage of this kind of sub-array FDA-MIMO radar is that the transmitting electric field does not change with time,avoiding the difficulty of signal processing,and the angular resolution can be greatly improved by transmitting the coherent waveform inside the sub-array.2.The performance of FDA-MIMO radar clutter and the dimension reduction adaptive method are studied.Starting from the modeling and simulation of clutter spectrum characteristics under the working conditions of side-looking and forward-looking,the transmit-receive domain clutter spectrum and the transmit-receive-doppler domain clutter spectrum are analyzed.Because of the IID characteristics required for the samples of adaptive processing,the transmit frequency range dependent compensation technique is studied.A three-dimensional angular doppler compensation method is proposed for the doppler frequency range dependent in the forward-looking stage.By designing the compensation matrix for a specific range region,the clutter spectrum can be converged in the three-dimensional space,which is beneficial to the clutter suppression performance.Some dimension reduced adaptive method are simulated to analyze their performance,such as JDL(joint domain localised)method,sum and difference beam method,and the method of selecting auxiliary channel across the clutter ridge.3.The robust adaptive method under the condition of the amplitude-phase error of array element and carrier frequency error is studied.The characteristics of clutter spectrum are studied in the existence of the two kind of errors.The carrier frequency error estimation method has high precision and is relatively stable when there is array element error.The adaptive performance after carrier frequency error estimation can be greatly improved.The principle of auxiliary pulse technology in FDA-MIMO radar is studied,and a robust adaptive processing method is proposed based on this technology.The simulation analysis verifies that the performance of the JDL method combined with the auxiliary pulse technique is the best among all the proposed methods.