scholarly journals Study Effect of Objects Orientation in the Mediums On GPR Signal Reflections Using FDTD Simulation

2018 ◽  
Vol 3 (11) ◽  
pp. 73-77
Author(s):  
Aye Mint Mohamed Mostapha ◽  
Gamil Alsharahi ◽  
Abdellah Driouach
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Ground Penetrating Radar ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Ground Surface ◽  
Propagation Path ◽  
Fdtd Simulation ◽  
Ground Penetrating ◽  
Dielectric Objects

Ground penetrating radar (GPR) is a very effective tool for detecting and identifying objects below the ground surface.  based on  the propagation and reflection of high-frequency electromagnetic waves. The GPR reflection can be affected by many things like the type of objects orientation, their shapes ..ect. The purpose of this paper is to  study by simulation the effect of objects orientation in two different mediums (dry and wet sand) on the GPR signal reflection using Reflexw software which is based on a numerical method known as finite difference in time domain (FDTD).  The simulations that have been realized included a conductor  and dielectric objects. The results obtained have led us to find that the propagation path, the reflection strength and the signal form change with the change of object orientation and nature. To confirm the validity of the results, we compared them with experimental results previously published by researchers under the same conditions.

scholarly journals GROUND PENETRATING RADAR DATA ANALYSIS BY USING MODELLING WITH FINITE DIFFERENCE METHOD: CASE STUDY IN BELAWAN PORT

2016 ◽  
Vol 11 (1) ◽  
pp. 15-24
Author(s):  
Hans Elmaury Andreas Siregar
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Data Acquisition ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Processing Technique ◽  
Radar Image ◽  
Clayey Sand ◽  
Near Surface ◽  
Ground Penetrating

Ground Penetrating Radar (GPR) is one of non destructive geophysics methods which is appropriate used to identify subsurface object with depth penetration less than 70 meter. High data resolution as well as relatively unprolonged and manageable data acquisition make this method becoming convenient supporting method to increase near surface data for other geophysics methods.  The depth penetration of GPR varies with the frequency of antenna. Getting optimum depth penetration before field acquisition data some numerical simulation should be accomplished in order to perceive antenna frequency and processing technique that used, so the depth of target zone can be achieved. The Finite Difference (FD) is one one of numerical anaysis technique that mostly used to determine differential equation. By using FD method, the solution of electromagnetic waves equation can be obtained and the image of numerical simulation can be displayed. In line with this radar image from numerical simulation, the relationship of frequency and depth penetration on the media used is acquired.  Media used in this simulation are sand, clay, sandy clay, clayey sand and concrete. Through numerical simulation from this research, we conclude that GPR method able to distinguish boundary layer among each medium. Processing technique is accomplished to comprehend suitable  processing stages for high resolution radar image that can be interpreted. Data acquisition and processing technique from simulation have been implemented in field experiment and very helpful to apprehend GPR characteristic signal in subsurface map in Belawan port.

scholarly journals Antena Spiral-dipole untuk Ground Penetrating Radar (GPR)

2016 ◽  
Vol 13 (2) ◽  
pp. 39
Author(s):  
Yuyu Wahyu ◽  
Haryanto Sachrawi S ◽  
Asep Yudi H ◽  
Heroe Wijanto
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Ground Penetrating Radar ◽  
Finite Difference Time Domain ◽  
Late Time ◽  
Ground Penetrating ◽  
Difference Time

GPR (Ground Penetrating Radar) merupakan divais yang berguna untuk proses pendeteksian objek yang terkubur di bawah permukaan tanah hingga kedalaman tertentu, tanpa perlu dilakukan penggalian tanah. Pada penelitian ini dilakukan perancangan, simulasi dan realisasi antena spiral-dipole dengan pembebanan resistif untuk aplikasi impulse GPR. Pembebanan resistif bertujuan untuk menekan late-time ringing dan memperbesar bandwidth walaupun akan mengurangi efisiensi amplitudo pulsa utama. Late-time ringing merupakan osilasi yang mengikuti pulsa yang dikirimkan. Osilasi ini dapat mengaburkan sinyal yang dipantulkan oleh objek sehingga menyulitkan untuk dilakukan proses deteksi. Dengan melakukan perubahan nilai konstanta k pada rumusan spiral Archimedes, maka didapatkan bentuk spiral dengan kerapatan yang berbeda-beda. Dalam tulisan ini, nilai konstanta k yang digunakan antara lain 0,5; 1; dan 1,5. Parameter yang dibahas dalam simulasi ini adalah amplitudo peak to peak pulsa utama maupun ringing yang dihasilkan dari masing-masing antena dengan nilai konstanta k yang digunakan. Analisis elektromagnetik dalam domain waktu digunakan metode FDTD (finite-difference time-domain) dengan software FDTD3D untuk menghitung gelombang yang ditransmisikan antena dalam domain waktu. Selanjutnya dilakukan realisasi dan pengukuran antena tersebut.

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