Research On The Key Technology Of MMW Wideband Phased Array Digital Monopulse Radar

The millimeter-wave (MMW) wideband phased array technology has more important value in a wide range of military and civil practical applications. This paper is about the pivotal techniques researches of MMW wideband phased array digital monopulse radar, and the main work includes following aspects:1) Digital sum and difference beamforming technology were researched based on the deeply research on IF Quadrature digital detection. Equivalence was proved of conventional method and the new one. An angle estimator model was proposed based on the monopulse ratio, and a lookup table method was introduced. And these made the method become more easy realization.2) The phase and amplitude error of channel would impact the sum and difference beamfoming, and resulted of the angel estimate error. So, the influence to beamforming of the phase and amplitude error was researched and a calibration method was applied. The method based on improved Normalized Least Mean Square (NLMS) algorithm, and this method can calibrate the phase and amplitude error without reference signals. The simulation result showed its'performance, and the method would have a good future with MMW hardware technique's progress.3) The monopulse estimate performance will be degraded in interference and clutter, and it will be failed if the interference appears within the mainlobe. So the monopulse estimate in interference and clutter scene became the key technique of monopulse tracking. A subarray level space/fast-time (SFT) minimum variance adaptive monopulse technology based on diagonal loading was proposed. And these were usefully explored for monopulse estimate technique of interference scene, especially for the interference appears within the mainlobe, the result showed the method was effectual.4) The wideband Chirp signal processing based on Stretch technology and the conventional technology of Chirp Stepped-Frequency signal processing were analysied. The Stretch technology is analyzed and the chosen criterion of FFT size and interval of sample is given. And then a new two dimension FFT method for synthesizing high resolution range profile based on the Stretch technology was applied. With this method the radar system can utilize few sub-pulses and low A/D sampling rate to measure targets in large range window. An experimental system of MMW wideband signal processing was builded based on the previous's works. We did indoor and outdoor experimental of the algorithm, and obtained many useful data.5) The short range angle tracking will be serious effected by glint in MMW high range resolution system. A method of phased array radar angular tracking was proposed based on the character of synthesize broadband MMW phased array radar. The method based on frequency agility and RCS weighting combined nonlinear Gaussian mixture kalman filter (NL-GMKF). The simulation result showed the method can constrain glint effectively for the MMW high range resolution radar.