Design And Implementation Of Impulse Ground-Penetrating Radar System

At present, the most widely used underground detection equipment on the market is Impulse Ground-penetrating Radar. It’s use of high-frequency electromagnetic waves to detect shallow, middle, or deep underground geological structure or target body. Impulse GPR repeat transmitted to underground the nanosecond narrow pulse, with the advantages of fast, high-voltage and ultra-wide band. Echo signal contains so much informative that it’s easy to identify underground targets. Impulse GPR with the advantages of high resolution, non-destructive nature, high detection efficiency, wide bandwidth, small size and etc. So it is widely used in geological exploration, subgrade testing, bridge inspection and other engineering. In domestic, the development of Impulse GPR system later than abroad, and technology is not perfect, so it is greatly significance to study in-depth.Firstly, this paper according to the basic principles, the selection of parameters and technical characteristics of the impulse GPR system then propose the system’s structure of impulse GPR. Secondly, studied in detail of the pulse signal generation circuit and receiver cicuit, and produce of the actual circuit. Finally, in-depth studied and designed the control system. The circuit of signal generator is use of the avalanche effect instant release of high-pressure and rapid pulse. And the generation of the Avalanche Impulse Signal is simulated by simulation software, according to the parameters of each component in the circuit, then maked the actual circuit and debugged. Echo signal is high frequency and narrow pulse width signal, the data acquisition method is based on equivalent-time sampling technique, and high-frequency of echo signal is converted to low-frequency signal by the receiver circuit, and then sent to the A / D converter for data acquisition. A method of uses the programmable logic device CPLD and MCU to control the system of Impulse GPR. Step delay pulse generator, and the data are stored in memory is converted by A/D converter are controled by CPLD. The MCU read data from memory and transmit to PC via a serial communication interface, and subsequent processing these data by PC.This paper focuses on cresearched and designed the hardware system of Impulse GPR. Designed and produced PCB, and then welded and debugged the hardware circuit. The Impulse GPR system can launch the pulse, and receive echo signal, and then acquisition and storage the data of echo signal.