Theoretical Research On The Key Technology Of Ultra-Wide Band Radar

Ultra-Wide band (UWB) radar shows great potential in the field of target distinguish and detection of hidden targets. More and more attention is paid to UWB radar by the scholars all over the world. It plays an important role in improving survival and fighting ability of the army under the modern war's situation. This paper investigates and discusses some key techniques in the process of dealing with UWB radar signals, such as signal selecting, target modeling and receiver design. The dissertation has great reference value for developing the UWB radar. The main content and conclusions of this paper have shown as follows.Through simulating the wave figures of four kinds of usual UWB radar signals, the results indicate that most power of the single-pole pulse is in the low frequency section, and the trend of it is down with frequency rising, which is disadvantageous to radiate the signal. Single cyclic wave's energy mainly concentrates focus on the center frequency. However, there is a gap between the polarity of sine shake and the delayed signal. The linear frequency modulation (LFM) signal is insensitive to Doppler shift, but the side lobes are very high. The non-linear frequency modulation (NLFM) signal has a performance of side lobe suppression, and signal to noise ratio (SNR) isn't lost. Stepped Frequency Wave form (SFW) can reach high distinguishing ability, but there is the distance-Doppler coupling. Phase Codes signal is sensitive to Doppler shift.The general model of UWB radar target's impulse response is built, also simulating result is provided. Through simulating the echo of four kinds of typical UWB radar signals under the designated condition, the results show that the impulse signal is simple and practical, however, it is easy to result a great loss of energy when it is radiated; single cyclic wave lacks the ability to suppress miscellaneous wave; LFM pulse is insensitive to Doppler shift, which can simplify the receiver structure greatly and reduce the system's sensitivity; at the same time, it is complex to process SFW signal. Phase Codes signal is very suitable to use as pulse-compress signal, but the specialty of its sensitivity to Doppler confines it, so it only can be applied in the situation which Doppler shift changes in a narrow range.By means of comparing the quality between the frequency channel and the time delay channel, a new kind of UWB radar design is presented. Discussing the imbalance question of I/Q perpendicularity sampling channels in the design procession of UWB radar receiver, the corresponding correcting scheme is mentioned.