Research Of High Rate Radar Way Communication On High Speed Mobile Platform

With the developmemt and progress of technology, exploring the integrateddesign of a variety of electronic devices and signal processing techniques, removingthe influence of Doppler shift stemming from high-speed by the correlationtechnique, realizing the high-rate radar way communication on high-speed mobileplatform in real time have been a hot spot.On the basis of feasibility in radar way communication, communication signalis loaded into radar system, which not only makes the integrated system achieve thedetection and location of goals, but also realizes data transmission. High spectrumefficiency of Orthogonal Frequency Division Multiplexing(OFDM) technology canrealize high-rate communication. However, high-speed motion of mobile platform isprone to produce severely large Doppler shift, which would lead to amplitudeattenuation, phase shift, and Inter-Carrier Interference of OFDM signal. Through theanalysis of Double Differential Phase Shift Keying(DDPSK) technology, it is foundthat DDPSK technology can remove the infulence of Doppler shift effectively, eventhough it demands high in Signal to Noise Radio(SNR). Therefore, the combinationof DDPSK and OFDM technology is proposed so that the real-time high-ratetransmission on high-speed mobile platform can be achieved.By analyzing OFDM technology as well as the comparison and verification ofrelevant algorithm performance, this paper utilizes DDPSK technology to realizecarrier synchronization, the Park algorithm to realize timing synchronization, andthe Nyquist pulse shaping to reduce PAPR. For the OFDM system combined withDDPSK, when Doppler shift is fixed, the higher coding bases of digital basebandmodulation is, the higher SNR is needed, whereas the data transmission rate is muchhigher in the case of the same bandwidth with higher coding bases of OFDM systembenefitting from its higher spectrum efficiency.The DDPSK processed OFDM signal is loaded in radar subsystem. Taking theS-band, X-band and K-band radar communicaition systems as examples, when thecarrier spacing is much larger than the Doppler shift, the information transmissionof system without DDPSK can be realized. However, in some special applications,the mobile platform moves at the speed of first cosmic velocity, causing a Doppler shift which is large enough to result in deterioration of system performance. In thiscase when Doppler shift is fixed, once the requirement of SNR is met, the radarcommunication system with DDPSK can remove the effects of fairly large Dopplershift and provide a reasonably high data transmission rate, realizing real-timehigh-rate information transmission.Combination of radar system and communication system, OFDM and DDPSK,can achieve real-time high-rate radar way communication effectively on thehigh-speed mobile platform.