Research On Testing Technology Of Optical-electro Tracking Equipment

With the development of photoelectric detection and artificial intelligence technology,the application of optical-electro tracking equipment is more and more widely.The online detection of optical-electro tracking equipment covers a wider range,and the requirements for the testability of optical-electro tracking equipment are higher and higher.But the traditional optical-electro tracking equipment online detection is rarely involved in the cable detection of equipment,and the number and types of cables in advanced equipment are increasing.The traditional method of detecting the cable fault of optical-electro tracking equipment is to dismantle the equipment,the cable through the detection instrument and from both ends of the cable.The detection speed is low,and it is easy to cause human error.The equipment may also have secondary failure during the disassembly.The cable fault detection method of equipment is mainly divided into traditional cable fault detection method and cable fault detection method based on reflection method.The traditional cable fault detection method is suitable for relatively simple system;while in the cable fault detection method based on reflection method,test signal of Time Domain Reflection(TDR)is high-speed pulse signal,the fault type is determined by obvious impedance change of fault point,but the delay is difficult to measure and is easy to be disturbed by noise.The test signal of Frequency Domain Reflection(FDR)is broadband sine wave,and is easy to be affected by noise and can not identify cable failure type;the test signal of Time Frequency Domain Reflection(TFDR)is Gaussian envelope FM signal,which has influence on communication and can not determine fault type;Spread Spectrum Time Domain Reflection(SSDTR)may cause multiple autocorrelation peaks,which are confused with fault related peaks,resulting in misjudgment.Therefore,the research on cable fault detection method with little noise interference,no influence on communication and strong self correlation is a key point of the current research on the fault detection of optical-electro tracking equipment.This paper studies the cable fault detection method of optical-electro tracking equipment.Based on the Spread Spectrum Time Domain Reflection(SSTDR),the selection of test signals and the optimization of signal processing methods are made.In order to facilitate the determination of cable fault type and location of fault,the test signal needs to have strong correlation characteristics;secondly,in the process of online cable test,there is noise interference,and the test signal needs to have strong anti-interference.Even if the collected reflected signal has noise interference,it still has obvious correlation characteristics.Finally,when the collected signal is processed,a cross term will be generated,which will interfere with the location of the fault,and there will be multiple autocorrelation peaks in SSTDR,which will be confused with the fault related peak,resulting in misjudgment.In this paper,the characteristic of the m-sequence is similar to white noise,and the test signal is generated by modulation of m-sequence,which eliminates the second wave peak of the self correlation of m-sequence,and makes it convenient to use Pseudo Wigner Ville Distribution(PWVD)to analyze the collected signals,eliminate the cross items in the collected signals,and then determine the fault type and obtain the fault location by correlation analysis.Finally,the feasibility of the method is verified by experiments,and the performance of the method is compared with the SSTDR test results,which verifies the detection performance,stability performance and engineering practicability of the method.