Study Of Radar Reconnaissance Digital Receiving And Signal Processing Technology

In the modern electronic warfare, electromagnetic environment became more and more serious. Under the background of broad bandwidth, various sorts of unsettled signals, and receiving task passively, the real-time signal processing ability meets unprecedentedly high demands for Radar Reconnaissance Digital Receiver(PRDR). However, in PRDR, there is a deep gap between processing speed of the high-precision and high-speed ADC devices and the processing ability of current processor. Therefore, the data processing speed of the Digital Reconnaissance Receiver has become the main limitation of developing high-speed modern PRDR.In this paper, we firstly analyzed the basic structure of digital receiver theoretically, introduced the components of the system specifically, illustrated the operating principle, and then analyzed the performance of three typical digital receivers briefly. Besides, we also made an analysis of data receiving system theory, and mainly discussed the multispeed processing technique based on the mismatch problem between digital back-end processing speed and front-end high ADC switching speed in the receivers. At last we also mentioned several digital intermediate frequency processing techniques.Based on classical radar signal, we described its feature parameters, then introduced single-carrier frequency pulse signal, linear frequency modulation pulse signal, and phase coded pulse signal. Time-frequency analytical methods of several classical radar signal are also represented. In addition, we made a specific comparison among instant autocorrelation, short-time Fourier transform, WVD distribution and wavelet transform. In this paper we used short-time Fourier transform as the quasi-best receiving processing.We discussed the short-term Fourier transform in detail, and analyzed the influences of sliding points on performance of algorithm, whole calculation process, precision in time domain. Signal detection theory, threshold analysis theory, and evaluation algorithm of narrow band energy spectra are also introduced. We also made quasi-best receiving simulations of single channel carrier frequency pulse signal, linear frequency modulation pulse signal, and phase coded pulse signal, respectively. Ideal and noise signals are also simulated, and especially we analyzed the SNR of the noise signal. At last we compared the influence of frequency error and width error on SNR.