Leaky Cable Guided Wave High-Precision Positioning Signal Processing Method Research

At present,although the most common used perimeter intrusion detection systems can detect the intruders, but the systems are a series of problems influenced by the environment, undetected rate and false detection rate, etc., in recent years, a well developed perimeter intrusion detection system based on leaky cable solves the above problems.However, the common problem of above perimeter intrusion detection systems are unable to accurately pinpoint intruders.Aiming at the problems above perimeter intrusion detection system, this paper designed a leaky cable guided wave radar perimeter intrusion detection system is used for pinpointing the intruders precisely. Once the accurate location, the staff can reaches invasion occurred in the shortest possible time, with a strong derection, ecurity risks can be quickly discharged, at the same time, the system is successfully developed to fill the gap of the domestic that can’t accurate positioning of the invaders.The leaky cable will couple signals toward the outward when signal is transmitting in the leaky cable, orming a cylindrical shape around the cable to form a stable electromagnetic wave, when intrusion occurs, stable electromagnetic field is disturbed, part of the signal is reflected and coupled into the receiver cable to the transmission system receiver end, to calculate accurately the delay time of the signal from tansmitting to be received back, that can be used pinpoint the intruder precisely.Through the theoretical analysis and simulation experiment, we can know that to use cross-correlation algorithm to pinpoint the intruders within some code. To achieve intruders coarse positioning of the intruder, on this basis, we make a design of hardware system and software, the hardware design mainly includes the system master, transmitter and receiver of three parts, the software includes procedures of total process control and related modules design, combined with the delay pulse ranging technology, two-phase coding technology and realization of the principle of the vernier fine intruders positioning will eventually locate the invasion into a certain carrier symbol cycle, precise positioning.The hardware system is described in this paper the four cases of field test, analyze the experimental data and calculation, the results show that the system can realize pinpoint the intruder precisely, system detection probability and false alarm rate, non-response rates and location accuracy and whether there is interference and intrusion protection area target number, single objective invasion without interference, the system work best performance, positioning accuracy is 3.81 m, is greater than the theoretical value(3m) is only 0.81 m;Multi-objective invasion, when confronted with system performance index of the worst, positioning accuracy of 4.69 m is greater than the theoretical value of 1.69 m;Absolute error increases with the increase of cable length, relative error decreases with the increase of the length of the cable, and the system is not sensitive to small animals.