A precise time sequency match method of GPR high resolution step system

When GPR is used for sub-bottom survey, the echo signal not only contains very high frequency, but also lasts for only several nanoseconds. These are the two difficulties in GPR signal sampling. Meanwhile, the step system which is responsible for the data sampling has an inherent minimum transmission delay. This delay will cause the failure of data collecting. In this paper, a new type of step system which is based on cascaded AD9500 is presented. This step system can realize high resolution of 0.0125ns, it can also counteract the influence of minimum transmission delay. This method can realize adaptivity to all GPR sampling systems through setting up parameters. The experimental results show the step system can remove the minimum transmission delay and realize high resolution detection.