Study On High Accuracy Velocity Measurement Based On Millimeter Wave Radar Of High-speed Moving Targets

High-speed weapons are more and more popular in modern military war, such as intercontinental missiles which speed can be up to 10 kilometers per second; unmanned reconnaissance aircraft which speed can be up to 10 Mach. So the high-speed weapons play a significant role in modern military war. It is a bottleneck on how to detect, trace, and estimate the velocity, image and precise attack. Compared with traditional radar, the millimeter wave (MMW) radar has been widely used because of many advantages. Because of the development of microwave, especially the progress of component technological, the millimeter wave radar’s antenna size can be smaller and smaller. And the millimeter wave radar can transmit signal with narrow band which leads to higher resolution. Because the millimeter wave has a good anti-jamming ability and a good anti-stealth ability, and it is seldom affected by environment. The millimeter wave radar has a good anti-disturbing ability.The high accuracy velocity measurement based on millimeter wave radar of high-speed target is studied in this dissertation, with emphasis on the three methods of high accuracy velocity measurement. The main contents and results of this dissertation can be summarized as follows:1. The cross-correlation velocity measurement based on fractional delay estimation for high speed targets is studied. Firstly, the cross-correlation velocity measurement method is described. And then considering the limitation of measurement accuracy due to the range cell, this paper proposes an improved method based on fractional delay estimation is proposed. The idea of this improved method is to extend the range cell from fractional delay to get a higher accuracy. Simulations are also carried out in this paper and the result shows that the velocity error of the proposed method is about 1 m/s.2. A method for velocity measurement by using the second differential phase is proposed. The intermediate frequency (IF) signal is used in the difference processing in both the fast time domain and slow time domain, in order to get the second differential phase. And the second differential phase is a constant value which contains the information of velocity. So the velocity estimation can be got through this constant value. This paper introduces the method’s basic principle and realization process. Through the simulations, it can be seen that the velocity error of the proposed method is about 1 m/s when SNR exceeds 3dB. Also this method uses the average of constant value which results this method has robustness of bandwidth.3. This paper proposes the velocity measurement based on Keystone transform. In the traditional radar, there is serious range migration between adjacent echoes causes phase wrapping. The Keystone transform can deal with this problem and the ambiguity degree can be got. Then a new method based on entropy minimization is proposed which is calculated the ambiguity degree while the traditional method needs high SNR. Through the simulations, it can be seen that the method of entropy minimization performs better than the traditional method which decreases 10 dB. Also the simulations show the velocity error of the proposed method is about 0.042 m/s.