The Research Of Impulse Ground-penetrating Radar Signal Acquisition System Based On FPGA

GPR is a detect method which uses to obtain subsurface material information byhigh-frequency electromagnetic pulse. According to the changing information of receivedecho signal, we can inference the structure, location and morphology of subsurface materialreasonably. Impulse GPR has become the most widely used detection equipment in the marketwith the advantage of fast speed, high resolution, bandwidth, lossless etc. Its echo signalscarry a lot of subsurface information, the more information we get, the unknown regionsdetected will be more clearly. Therefore, the study on impulse GPR acquisition system hasimportant value and significance.This paper first introduces the working principle of impulse GPR. According to therequirements on characteristics and parameters of its pulse signal, we have a systematicresearch on the structure of impulse GPR. On the basis of research, we design a kind ofacquisition scheme for impulse GPR echo signal using high-speed ADC chip. FPGA is thecore of the acquisition system, controlling each part of the system. In order to ensure thestability of the signal, high-speed signals need to be collected in differential manner. Treatingcollected high-speed data to deceleration processing by using custom multi-level FIFO bufferwithin the FPGA rich block RAM resources. Eventually, the data is transmitted to PC for thenext processing work with the rate several times lower than that of the sampling frequency viaUSB bus. The system enables achieve real-time results for data acquisition by using FPGA andUSB interface.The research is the impulse GPR signal acquisition system, and the core is controllinghigh-speed ADC with FPGA and the data cache storage. By debugging the hardware circuitand software components, we have got the correct simulation on FPGA design, realizing thecollection test of narrow pulse signal with low duty cycle and high frequency sinusoidalsignal, as well as the recovery of original waveform and spectrum. The design of the system isreasonable, and we can achieve the proper collection and storage of impulse ground penetrating radar echo signal.