| Perimeter intrusion detection technology has been widely used in railways,airport runways,military bases and other places where safety requirements are high.The existing perimeter intrusion detection technologies mainly include infrared intrusion detectors,video detectors,electronic fences,and microwave detectors.However,these techniques have the common drawback of low concealment and vulnerable to weather and terrain.The leaky cable can be installed in the wall or buried in the ground,is hardly to be detected.and not affected by the weather,which can well solve the above defects.Therefore,the intrusion detection guided radar technology based on leaky cable has become a research hotspot in the field of perimeter intrusion detection.Chaotic signal have characteristics such as random waveform,wide frequency band and autocorrelation curve in the form of ? function.They are widely used as radar detection signals in ranging,through-wall imaging and life detection.The use of broadband chaotic signals for leaky cable guided radar can achieve centimeter-scale range resolution,which is superior to the existing guided radar meters,and also has stronger anti-electromagnetic interference capability.Therefore,this paper introduces broadband Boolean chaotic signal into the field of guided radar for perimeter intrusion detection,proposes chaotic guided wave radar system.Design and complete chaotic guided radar prototype.The main research work includes:1.The existing perimeter intrusion detection technologies were summarized and their advantages and defects were analyzed.Then we decided to use the guided radar based on the leaky cable to detect the intruder.Moreover we analyzed research status of intrusion detection guided radar technologies.2.Two ways to generate Boolean-chaos signal was introduced,and the characteristics such as time series,spectrum,autocorrelation and ambiguity function of Boolean-chaos signal was analyzed.Based on this,the application advantages of Boolean-chaos signal in the field of intrusion detection guided radar were described.In addition,the characteristics and radiation mode of the leaky cable were summarized.To achieve high-resolution detection,we chosen wideband sparsely woven leaky cable as antennas.3.The chaotic guided radar intrusion detection system was constructed.The measurement principle was introduced in detail,that is,the intruder is located by comparing the change of the cross-correlation curve between the reference signal and the echo signal before and after the intrusion.Experimental results showed that the proposed system can detect multiple intruders with a range resolution of 30 cm.In order to estimate the detection range,the dynamic range of the system was measured.The results showed that the dynamic range can reach 50 dB.Furthermore,the anti-electromagnetic interference performance of this radar system were demonstrated.The results showed that under the same transmitting power,the system can resist the interference of noise signal and Boolean-chaos signal to locate the intruder.4.Designed and completed the chaotic guided radar prototype.The hardware system and software system of the prototype were introduced in detail.Signal acquisition and processing flow based on chaos correlation algorithm in the software system were expounded.Secondary development of digital acquisition card with LabVIEW software.Finally,the performance of the chaotic guided radar prototype was tested.The experimental results showed that the chaotic guided radar prototype can locate single or multiple intruders.Limited by the capture card bandwidth,the distance resolution was 50 cm and the dynamic range is 35 dB.In addition,in order to verify the anti-interference performance of this prototype,five kinds of interference signals were selected,which were sinusoidal signal,noise signal,Boolean chaotic signal,phase coded signal and RF pulse signal.The results showed that the chaotic guided radar prototype could still obtain the intruder's position information accurately under the interference of these five kinds of electromagnetic signals,it had good anti-electromagnetic interference performance,which was suitable for complex electromagnetic environment. |
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