Research On Key Techniques And Anti-Jamming Performance And Implementation Of Simulation Software System For Phase Coded OFDM Radar

In rencent years, new anti jamming radar system and high resolution imaging technique have become the general concerns in the field of radar research, being able to achieve both high range resolution and good anti-jamming performance by using a single signal form, therefore, it is of practical value to study the key technology of phase coded OFDM radar and to build its visual simulation software system. Phase coded OFDM signal, as its name implies, refers to make phase encoding into each sub carrier of the OFDM signal, therefore the IFFT and FFT algorithm can be used to realize fast digital modulation and demodulation for its signal generation. Possessing of big product of time and bandwidth, makes the phase coded OFDM radar abtain the ability of high range resolution. A variety of phase encoding mode makes the waveform design of phase coded OFDM radar flexible, therefore the phase coded OFDM radar could obtained high anti-interference performance and adapt to complex and changeable working environment better.This paper could be separated into two parts, the first part is the research and simulation validation of the key algorithms to the construct the phase coded OFDM radar simulation software system, mainly includeing the following three aspects:In waveform design, this paper firstly describes the specific structural characteristics of phase coded OFDM signal and its ambiguity function. Then, the methods to increase self-correlation performance and to reduce the envelope peak average ratio for barker phase coded OFDM signal and chaotic binary-phase coded OFDM signal are analysed. Finally, a feasible design method of phase coded OFDM transmission signal is presented.In signal processing, this paper firstly introduces the process flow of signal transmitting and receiving for phase coded OFDM radar. Then, the method of pulse compression based on two-stage compression in frequency domain with lower computational complexity and its corresponding target detection algorithms are introduced. Finally, the way of how to avoid the range ambiguity by reducing the side lobe of ambiguity function and how to estimate the velocity of target by the least mean square estimation method are discussed.In anti-jamming performance, the main research of this paper is the chaotic phase coded OFDM radar signal. The fact of chaotic sequences’sensitive dependence on starting conditions provides a possibility to generate a considerable number of chaotic binary-codes which are both different and uncorrelated form each other, the different pulse of the radar transmitting signal is coded by the chaotic binary code sequence of different initial values, therefore, differences between transmitting pulses have been increased, and the anti jamming performances of chaotic binary-phase coded OFDM radar under noise suppression jamming and deception jamming condition are analyzed by simulation experiments at last.The second part mainly introduces the major construction of the simulation system for phase coded OFDM radar, which is developed with the component based methods on the VC++platform. Firstly, the functional components and classes at each level of the simulation software system are designed and encapsulated by using the algorithms which have been validated in the first part of this paper. Finally, the debugging and simulation of each main module and the whole system are finished.