Research On Accurate Velocity Measurement Technology Of Small High-speed Target

With the development of air strike technology, defense technology need to be more advance to confront the crisis. One possible method is deploying barrage in hostile attacking aircraft`s flight route to intercept it at low altitude. With a result of that, each small high-speed target must be precise measured to get its velocity parameter for defense system to form a barrage net to destroy it. As a result of bad test environment which is full of interference, to measure the velocity of high-speed small target accurately has been always difficult.According to status of small high-speed target velocity measurement research at home and abroad, this article designed a system which is used to measure small high-speed target`s velocity in real-time. In this design, based on the principle of Doppler theory, the received Doppler echo signal is used to calculate the speed information after a series of digital signal process.Doppler echo signal algorithm is as follows. Sampled signal was processed by filter. Measuring filtered Doppler echo signal by fast Fourier transform to initially analyze the approximate data range of the velocity. A number of frequencies in the range were produced as time-domain data by Direct Digital Synthesizer module. These frequencies were calculated the correlated with original Doppler echo signal. The frequency closest to the original signal was found by comparing the correlation results. The speed was determined by the frequency. This speed is the accuracy value of small high-speed target`s velocity.Accurate velocity measurement system of small high-speed target was realized by Field-Programmable Gate Array. A signal which is similar with the Doppler echo signal of a small high-speed target is generated by MATLAB as the target signal to be tested. After the signal has been processed by the sampling module, the speed measuring module is going to finish the rest of work. The signal is sent to the speed measurement module after processed by the sampling module to verify the working of the system. Time-consuming analysis and error analysis of the results are completed and improvements are proposed.Test result shows that, velocity detection system of small high-speed target works stable, and each part works correctly. The system calculates velocity accurately, the signal processing time spends only 0.118 ms, and the speed detection accuracy is 0.161%, both reaching targets. With all above, the solution proposed by this article could solve the problem of detecting high-speed small target`s precise velocity in a short time and be used under the background of defense technology.