The Design And Implementation Of Chaotic Stepped Frequency Radar For Through-the-wall Detection

Through-the-wall detection radar is a kind of novel ultra-wideband radar which can penetratenonmetallic walls. It is widely used in military, anti-terrorism, disaster relief and other fields.Chaotic signal, generated by deterministic systems, can be easily implemented by a simplecircuit and controlled to the desired states. In this thesis, stepped frequency radar is combined withchaos to generate chaotic stepped frequency radar, which has advantages of bothsteppedfrequencyradar and wideband noise radar. It not only canobtainhigh resolution while reducing the instantaneousbandwidthof the transmitter andsampling rate, but also has low probability of intercept, excellentanti-jamming capability and electromagnetic compatibility. Furthermore, it has the ability to inhibitthe single-frequency interference andrealize fast matchedfiltering. Therefore, itis suitable forthrough-the-wall detection.This paper mainly describes the design of chaoticsteppedfrequency radar for through-the-walldetection and the locating algorithm for moving targets; the primary work is as follows:1. The basic principle of through-the-wall detection and the locating method of moving targetsbehind walls are introduced. The scheme of through-the-wall radar is also designed.2. Chaotic stepped frequency radar is presented, its principle and characteristics are analyzed,and the average ambiguity function is derived. The simulation results demonstrate that this radar hasthe inhibitory to single-frequency interference, and the range profile can be realized by fast Fouriertransform.3. The genetic algorithm has been used tooptimize the FM series of the chaotic steppedfrequency waveform, so that the detector output of the direct wave remains in low frequency, then itcan be eliminatedby an analog filter before A/D sampling,which reduces the dynamic range of theecho signals.4. The conventional back projection algorithm has been improved to generatethe coherentaccumulation-fast BP algorithm based on dual channels for moving target location, which improvesthe performance of moving targets detection and the efficiency of location.5. Each function module of the chaotic stepped frequency radar prototype and DSP configurationare introduced in detail. The proposed locating algorithm for moving targets is implemented on thehardware platform of the proposed chaotic stepped frequency radar for through-the-wall application.