Design And Implementation Of Ground Penetrating Radar System For Road Detection

In recent years,the rapid development of domestic road traffic has promoted the tremendous progress of the national economy.However,the gradual aging of roads and bridges will bring more and more potential traffic hazards.To ensure the safety of transportation and daily travel,it is extremely urgent to carry out high-standard and strict quality inspection of traffic facilities.The 13 th Five-Year Plan of the Ministry of Communications puts forward the principle of insisting on construction,operation and maintenance in the process of transportation development,and emphasizes the development of non-destructive testing technology for transportation facilities.This paper mainly researches and develops an ultra-wideband pulsed ground penetrating radar system,which can be applied to real-time non-destructive testing of expressways.The ultra-wideband pulsed ground penetrating radar system designed in this paper consists of transmitting circuit,receiving circuit,equivalent sampling circuit,FPGA control system,transmitting and receiving antenna,host computer system and power supply circuit.The ultra-wideband radar pulse transmitting circuit is composed of an avalanche transistor and a differential shaping network,and can generate a narrow pulse signal of 2 ns and 10 V.The research realizes the equivalent sampling circuit of two different principles.The equivalent sampling rate of the continuous equivalent sampling circuit is 10 GSPS,which can reduce the frequency of the 2ns pulse signal by a factor of 1000 and maintain the original waveform.This circuit can use a low speed ADC to acquire high frequency signals.On the other hand,this paper studies an equivalent sampling scheme for quadrature phase control.We adjust the trigger clock phase of the high speed ADC through the FPGA and then recover the original signal.The equivalent sampling rate of this method is 5GSPS.The simulation results show that this structure can collect 65 K frame echo signals per second,and each frame signal consists of 800 discrete values.The circuit has higher sampling efficiency and more flexible control.In addition,this paper designs the power circuit and radar control system,and the data can be transmitted to the host computer system by Ethernet at a very high speed.This paper chooses the equivalent sampling technique of quadrature phase control to design the ground penetrating radar system.The design process mainly includes high-speed PCB layout and development of FPGA control programs.The article completed the integrated transmission and reception of radar signals,the synchronization of each circuit module,and the final image in combination with the host computer system.The experimental data shows that the system detects the fastest echo data of 45,000 points per second,and the radar detection accuracy is about 0.62 mm at a speed of 100 km.Compared with the traditional road detection system,the system has the advantages of non-destructive testing,high coverage,high resolution,good real-time performance and fast detection speed.