Modulation techniques for GPR system radargram

• Main Author: Joret, Ariffuddin
• Format: Thesis
• Language: English; English; English
• Published: 2018
• Subjects: TK5101-6720 Telecommunication. Including telegraphy, telephone, radio, radar, television
• Online Access: http://eprints.uthm.edu.my/162/

Ground Penetrating Radar (GPR) system ability to detect embedded object underground is dependent on the ultra-wideband antenna use. Based on this antenna type, the fractional bandwidth used by the GPR system is usually greater or equal to 1. On the other hand, the GPR system using fractional bandwidth less than 1 will produce unsmooth GPR radargram, as the consequences of high signal ripples generated in the system output signals. Based on fractional bandwidth parameter, this study focuses in developing a digital signal processing of the GPR system to produce a smooth GPR radargram. The proposed GPR signal processing system is based on envelope detector technique of Asynchronous Half-Wave (AHW), Asynchronous Full-Wave (AFW) and Asynchronous Real Square Law (ARSL). The Pulse Modulation (PM), Stepped Frequency Continuous Wave (SFCW) and Hybrid GPR system simulation are modeled using CST Studio Suite and MATLAB software. The selected fractional bandwidth of the GPR system simulation modeled is 0.46 and 0.4 for Microstrip Vivaldi and Horn antennas respectively. In addition, a practical implementation of the SFCW and Hybrid GPR system using fabricated Microstrip Vivaldi antenna having a fractional bandwidth of 0.46 and VNA equipment, was conducted. Based on the analysis results of the proposed PM GPR system simulation, the AFW technique produces clearer PM GPR radargram. The detection rate for PM GPR system simulation using AFW technique is 87% and 51.3% using Horn and Microstrip Vivaldi antennas respectively. Practical implementation of SFCW and Hybrid GPR systems using AFW technique and Microstrip Vivaldi antenna can detect an iron and a bottle filled with water object.