Study Of Technologies On Broadband Radar Real-time Signal Processing

An important development trend of modern radar is to obtain more detail information about the target. The range resolution of radar becomes so high that the targets can be imaged and recognized by enhancing the signal bandwidth of radar. The broadband radar signals reflected from targets have characteristics of random parameters. They are different from narrowband radar signals even reflected from the same target. So, it has been a new research field to suppress clutters and detect targets just using one broadband radar signals and then to realize the integration of detection, tracing, imaging and recognizing of targets. The research work on broadband radar signal detection establishes a foundation to further develop broadband radar signal processing further more. In addition, it has been a new important field to design "General-purpose Radar Real-time Signal Processing System" by using several high speed DSPs that has the characteristics of modular design, flexible structure, large calculation capability and general-purpose appliance.The main creative points and main contents in this dissertation are as follows:1. Study of key technologies on broadband radar signal detection. It is including:After analyzing the characteristics of broadband radar signals reflected from target, it is shown that the reflected signals are pulse sequences with random parameters. When the radial velocity of the target does not equal zero, the reflected signals in different repetition periods have range shift and Doppler frequency. The amplitudes of the pulse sequences reflected from the target in next two repetition periods are similar. The above study works provide the basis of broadband radar signal detection.The characteristics of reflected signals from broadband radar and narrowband radar are compared when it is assumed that the emission power, the noise coefficient of the receiver and the target are all the same while the signals reflected from narrowband radar are generated by combing the signals reflected from broadband radar. Statistic simulating results prove that, the performance of broadband radar is lower than narrowband radar while detecting just using one reflected signal.The methods to accumulate and detect broadband radar signals are studied. The omnidistance correlation detection method based on position information in all range distance and several sliding window detection method are compared. The characteristic and the conditions to use them in broadband radars are analyzed. The detection ability of the Energy Accumulate Detection (EDA) sliding window method is studied as the length of the window changes. On this basis, a new parameter detection method is proposed. That is Interleaved Period Correlation Detection (IPCD). It can enhance the detection ability about than EAD method when pulses in several repetition periods are accumulated. The characteristics of clutters in broadband radar are analyzed. The Weibull-distribution Gauss spectrum clutters are used to simulate ground clutter, named as Clutter Model â… . The Rayleigh-distribution Gauss spectrum clutters are used to simulate weather clutter, named as Clutter Model â…¡. The MTI,MTD and NMTI clutter suppression methods are studied while using these two clutter models.2. The method to design "General-purpose Radar High-speed Realtime Signal Processing System" using several independent Processing Elements (PEs) is presented. Each Processing Element has four general-purpose ADSP-21160s. In different radars, their signal processing systems can be designed by using several PEs according to the best network structure. Then the signal processing system can have strong real-time processing ability and can be extended easily.3. After studying the key technologies in broadband radar signal detection and the methods to suppress the clutter of broadband radar, the schemes of "Broadband Radar Real-time Signal Processing" are designed and realized. As an another applying example, after studying the key technologies in Synthetic Ape...