The Modeling And Simulation Of Linear Frequency Modulation Radar Echoes

Radar simulation technology can be used to do system analysis and performance evaluation for complex radar, and also can help for the integrated design of radar. This technology has several advantages, such as conserving resources, easily realized, high efficiency, repeatability, etc. and it has become an important technology of building virtual battlefield system and doing research of radar system. The radar echoes obtained in real working environment provide reliable data to the target recognition system.In this dissertation, the linear frequency coded radar echoes were processed by coherent video signal simulation, and the key job is simulating linear frequency coded radar echoes and land clutters in real simulation.The main contents of this dissertation are as follows:1. Various methods of calculating Radar Cross Section (RCS) have been studied, such as Methods of Moment (MOM), Multilevel Fast Multi-pole Method (MLFMM), Physical Optics (PO), etc. Based on FEKO software, the optimize mesh split by ANSYS was used to simulate these methods and verify their efficiency.2. The radar clutters were analyzed. First, the clutters were introduced, containing amplitude distribution model and frequency spectrum distribution model. Second, the methods of generating relevant Gaussian sequences were studied, which contain frequency domain transformation method and modified power spectrum method. Third, the methods of producing relevant non-Gaussian random sequences were studied, which contain Zero Memory Nonlinearity (ZMNL) and Specifically Invariant Random Process(SIRP). And at last, various relevant clutters whose amplitude subjecting to different distribution were simulated.3. Linear frequency coded radar echoes were modeled and simulated, especially the targets echoes and land clutters. Radar coherent video signal was studied, LFM pulse signal and the processing of pulse compressing were analyzed, and two different methods were used to simulate targets echoes. The first one is to assume the targets echoes were superimposed by echoes of several scattering center. While the second one is regarding targets echoes as the convolution of radar transmitted signal and targets scattering function. The electromagnetic analysis software (FEKO) was used to calculate targets wideband electromagnetic response in the range of radar working frequency, based on which the targets echoes were calculated and simulated. Using the second method, the radar echoes of two aircraft models were modeled, and their high resolution range profile (HRRP) were achieved and simulated. In the end of this dissertation the land clutters were considered and simulated based on real situation.