Design And Implementation Of Resolving-ambiguity Algorithm Of PD Radar

Since the 21st century,the field of radar applications continues to expand,the form of modern war changes rapidly,so the requirements of radar signal processing technologys and algorithms are getting higher and higher.Solving-ambiguity algorithms is one of the key algorithms in radar signal processing.However the error tolerance,Multi-target accuracy and the calculation amount of the traditional Solving-ambiguity algorithms can not meet the requirements.So to find a solving-ambiguity algorithm which can be applied to multiple targets,not sensitive to error,less computing and highly reliable has certain significance and is also under the support of the project of national ministries.It's difficult to design a reliable solving-ambiguous algorithm when the range ambiguity and velocity ambiguity both exit.To solve this problem,the step-by-step sliding window algorithm based on multiple frequency is designed in this paper.The advantages of low computational complexity of sliding window clustering algorithm and high reliability of one-dimensional set algorithm are combined in this algorithm.To search target the algorithm adopts step by step,narrowing the sliding window.So the area where targets are impossible to exist can be determined in advance.Then unnecessary operations can be reduced.In order to test the algorithm,a mathematical model that can generate the random ambiguous ranges and velocitys of targets is established.The simulation analysis is carried out in two aspects:reliability and computation.The results show that when the error range is large and the number of targets is normal,the algorithm can maintain the correct rate over 96%in the radar system where both two ambiguitys exit.The correct rate is over 99%for the one-ambiguity system.Compared with one-dimensional set algorithm,the computation amount of the step-by-step sliding window algorithm is about an order of magnitude lower.And it is about two orders of magnitude lower when it comes to multiplication.Compared with multiple frequency system,the time of switching PRF can be removed in single frequency radar system,making the radar system simpler and more convenient.So the Kalman Filtering differential Algorithm for solving velocity ambiguity is designed in this paper.The target measurement error is regarded as the high frequency clutter component in this algorithm.After several iterations,the target speed is calculated by differential distance.The speed threshold comparison module and velocity-cumulative module are added on purpose to increase the speed of convergence.A single target uniform motion model is established with matlab in order to test the algorithm.When the velocity of the target is 1000 m/s,after 87 iterations,a accurate target velocity can be obtained.The number of iterations is about 150 without the speed threshold comparison module and velocity-cumulative module.A framework of solving-ambiguity system is proposed with the step-by-step sliding window algorithm in this paper.According to the overall framework,the main operations include generating possible values,sorting process and solving-ambiguity.The circuit structures of the corresponding module are put forward respectively.The functional verification of the three modules are carride out respectively,proving the circuit structures and function are correct.the three modules are linked with ISE for the board-level verification.The result of the circuit operation is compared with the matlab standard operation model.When it is solving range ambiguity the magnitude of difference is 10^-3and when it is solving velocity ambiguity the magnitude of difference is 10^-5,proving that the the board structure of step-by-step sliding window algorithm is correct.