| The OFDM(orthogonal frequency division multiplexing) radar is a new system radar which has been researched recent years. OFDM radar has a lot of advantages such as large wide bandwidth product, good anti-jamming performance, high spectrum efficiency, easy to the digital processing and many other advantages, so it has attracted many attentions of the scholars in the world. According to the relationship of the frequency response of radar target and radar transmitting frequency designing appropriate OFDM waveform is very important. The appropriate OFDM waveform can improve the target detection performance. In addition, the electronic countermeasures is increasingly intense, Military radar jamming ability demand is higher and higher. The OFDM radar signals with complex time-frequency characteristics, the enemy is difficult to estimate the emission signal waveform and instantaneous frequency; therefore, the research of OFDM radar the performance of deception jamming is important. This paper studies on these two aspects, the main research content is as follows:①Introduce the basic principle of OFDM radar briefly, and present the signal model. PMEPR of OFDM radar is high which makes difficulties of OFDM radar in engineering implementation. This chapter research subcarrier weighting and the initial phase weighting on PMEPR. Compare the advantages and disadvantages of the two methods. Finally, through computer simulation verify the inhibition effect on PMEPR.②OFDM radar signals is large wide bandwidth product signal, there is some limitations when using narrowband ambiguity function to analyze it; This chapter first gives the OFDM radar echo signal model, on the basis of the model deduct the broadband LFM-OFMD ambiguity function expression. Analyze the time-frequency resolution performance of LFM-OFDM signal. The analysis results show that the ambiguity function of LFM-OFDM signal approximate the pin shape. Which means the time-frequency resolution performance of LFM-OFDM signal is improved, the results can be used in designing the OFDM radar system.③ Radar target frequency response relate to the frequency of the radar’s transmitting signal, the scattering coefficient will change when the target is moving; This chapter adopt the ideas of adaptive radar using the relationship between target scattering coefficient and frequency to improve the ambiguity function, put forward a design method of adaptive waveform based on the mean square error. Using the ambiguity function to analysis the characteristic of fixed parameters of OFDM monopulse radar signal and adaptive OFDM monopulse radar signal, the experimental results show that the adaptive OFDM monopulse radar signal on the energy distribution is more reasonable.④The deception jamming suppression ability of traditional linear frequency modulation signal is limited, as OFDM radar signals with complex time-frequency characteristics, the enemy is difficult to estimate the emission signal waveform and instantaneous frequency. Therefore, OFDM radar has a strong ability to resist deception jamming. This chapter deeply analyzes the principle of OFDM radar anti-jamming, using the OFDM-SAR imaging to verify the ability to resist deception jamming. |
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