Research And Application Of Data Acquisition System For Full-Polarimetric Ground Penetrating Radar

Ground penetrating radar(GPR)is a non-destructive detection tool based on electromagnetic reflection information,which is very suitable for shallow target detection.Conventional ground penetrating radars are mostly single-polarized radars.Due to the limitation of acquisition methods,only one kind of co-polarized information can be collected,and the amount of information obtained is very limited,and it is difficult to meet the needs of some complex environments.Full-polarimetric GPR can not only collect co-polarized information,but also cross-polarized information.The amount of information collected is three times more than that of single-polarized GPR.Therefore,the full-polarimetric GPR has been gradually developed in recent years.Full-polarimetric GPR works in four antenna combinations,which can obtain not only rich target information but also comprehensive polarization attributes of the target.The ability of target recognition can be improved by using polarization attributes,and the image resolution can be improved by using data fusion technology.Therefore,the research on full-polarimetric GPR is of great significance.However,most commercial radars are single-polarized radars,and the radar systems imported from abroad are expensive,so the development of full-polarimetric GPR data acquisition system has become an urgent problem to be solved.In this paper,a Vivaldi antenna array(VAA)with full polarization mode is designed,and a horn antenna(HA)array with full polarization mode is constructed.Rich full polarization information can be obtained by using these two antenna arrays.On this basis,a data acquisition system of full-polarimetric GPR with different antennas is established,which is mainly composed of PC control terminal,network analyzer,switch driver and antenna.In this system,the automatic control of each part is realized by one key of PC control terminal,so as to achieve convenient and fast acquisition of full-polarimetric common reflection information of target.The dihedral detection experiment of the system is carried out in the laboratory,and good results are obtained,which verifies the detection effectiveness of the system.The system carries out the surface subsidence experiment with Vivaldi antenna array.Through the measured radar polarization profile and data fusion section,the information of collapse location and the risk of collapse around the collapsed road can be obtained.The ice crack detection experiment is carried out by using the horn antenna.The experimental results show that the system can locate the ice crack accurately,and the data fusion results can improve the imaging quality of ice crack.The main purpose of this paper is to build an effective full-polarimetric GPR data acquisition system,and provide some ideas for the subsequent development of full-polarimetric GPR data acquisition system.The main contents of this paper are as follows:1.The basic theory of the antenna is introduced,and the radiation principle of the antenna is introduced by taking the electric short dipole as an example.Then,some performance parameters and their definitions of the antenna are introduced,Vivaldi antenna array and horn antenna are designed,and full-polarimetric measurement is realized according to the designed antenna.2.The data acquisition system of full-polarimetric GPR is built,which is mainly composed of PC control terminal,vector network analyzer,switch driver and antenna.Then it introduces each part of the system and analyzes the function of each part in the system.Finally,according to the characteristics of the two kinds of antennas,the working principle of the data acquisition system of full-polarimetric GPR built in this paper is described.3.The flow of GPR data processing is introduced.The data processing method is proposed for the full-polarimetric GPR system,and the specific measurement matrix is given.Finally,the weighted average data fusion method is introduced and applied to the data processing of subsequent experiments.4.The metal dihedral angle detection experiment of the full-polarimetric GPR data acquisition system is carried out in the laboratory,and the full-polarized radar profile and single channel signal are analyzed to verify the effectiveness of the system.In addition,the system is applied to the surface subsidence and ice crack detection experiments respectively,and good results are achieved.