Algorithm Study And Circuit Implementation Of Digital Monopulse Angle-measurement

The angle-measurement of the target is the basic function of the radar and plays an important role.The monopulse method is now commonly used in angle-measurement,which can obtain angle information in one pulse cycle.Nowadays,radar system has developed from analog to digital,which greatly enhances processing capacity and operability.Correspondingly,the monopulse also develops towards the digital.Therefore,the study of digital monopulse angle-measurement is of great significance.Based on the national ministry project,the algorithm design,performance comparison and algorithm realization of digital monopulse angle-measurement are analyzed and discussed.Firstly,according to the basic theory of digital monopulse angle-measurement,the design scheme of digital monopulse angle measurement is analyzed.The sum-difference beamforming method in the digital monopulse angle-measurement algorithm is discussed,then analyzes the half-array method,the direct weighted method and the double-direction angle method formed form analysis.The three methods'sum beam produces the peak in the desired direction,the different beam produces the null and the angle curve has a certain linear range in the close to the expected direction.Finally,obtain the linear angle curve equation by least squares.Aiming at solving the problem of reducing the flexibility of the algorithm as a result of developing the numerous angle curves in the monopulse method based on sum-difference beam,a method based on beam-comparison is given.The method no longer needs to develop angle curve,but obtains the angle information by beam-comparison.The idea of method is to estimate the angle value firstly,and then use the value as the center,set up a symmetrical comparison beam.By comparing the comparison beam,adjust the comparison beam to point target position,ultimately make it point to the direction of the target and obtain the angle information of the target.Due to the need of preliminary estimation for the measured angle in the digital monopulse angle-measurement algorithm,an angle pre-processing estimation method is designed.The method is to set the reference point with DBF.Obtain preliminary estimation by looking for the largest the reference point.The analysis shows that the method can accurately measure the reference point corresponding to the target angle.According to the project demand,the model construction and circuit realization of the digital monopulse angle measuring system for azimuth of single target are carried out.Firstly,a high-speed and an array-configurable digital beamforming circuit respectively are designed.The former uses a full parallel architecture,while the latter implements configurable features by setting a dedicated coefficient memory unit.Next,using DBF circuit,a circuit system is designed based on the angle pre-processing estimation method and the beam-comparison angle-measurement method,which includes two parts:angle pre-processing estimation module and angle-measurement module.The former finishes the initial estimation for angle when the latter finish angle-measurement based on the initial estimation.Finally,modelsim and matlab are used to make functional simulation,the result of the logic synthesis shows that the frequency of the circuit can reach 200MHz with DC^TM in the SMIC 0.13?m technology library.