The Research On The Multi-Frequency Pulse Ground Penetrating Radar System

GPR(Ground Penetrating Radar) is the detection technique which is accurate, convenient and efficient. Now the detection depth is limited due to single-frenquency antenna and the detection efficiency is low with single channel. To cope with the above problems, this paper studies the structure of the multi-frequency GPR, proposes a new controlling stratege for multi-channels, designs the working process and finishes the design of the harware and software of the master control system of GPR.The equivalent sampling is adopted to process the echos with high frequency and large dynamic range. And then the structure of the multi-frequency GPR composed of the upper computer, the master control system and the antenna system is elaboratly designed. The working process of GPR is designed and a new controlling stratege used in multi-channel detection is proposed, decreasing the interval time between channels from 10 us to 1us.The master control system receives the control commands from the upper computer, thus triggering the transmitting antenna to radiate electromagnetic wave to underground and triggering the receiving antenna to sample the echoes. The master control system is divided into two moduals, the delay-control modual and the data-acquisition modual according to its functionality. The delay circuit of the delay-control modual is designed for the sampling of echoes with three different center frequencies. The design of the multi-channel sampling ciucuit, the data storage part and the communication interface are implemented within the data acquisition modual.The communication protocol between the master control system and the upper computer is designed elaborately. The working process of the multi-frequency GPR is implemented by the means of Finite State Machine. The software of the master control system is also developed based on the working process.Finally, the hardware and software of the master control system are debugged by the means of modual testing and system integration. According to the debugging results, the design goals of the multi-frequency GPR are realized.