User libraries is a sub-package where useful Python modules contributed by users are stored.

GPR antenna models

Information

The module features models of antennas similar to commercial GPR antennas. The following antenna models are included:

Manufacturer/Model	Dimensions	Resolution(s)	Author/Contact	Attribution/Cite
GSSI 1.5GHz (Model 5100)	170x108x45mm	1, 2mm	Craig Warren (craig.warren@northumbria.ac.uk), Northumbria University, UK	1,2
MALA 1.2GHz	184x109x46mm	1, 2mm	Craig Warren (craig.warren@northumbria.ac.uk), Northumbria University, UK	1
GSSI 400MHz	300x300x170mm	0.5, 1, 2mm	Sam Stadler (Sam.Stadler@liag-hannover.de), Leibniz Institute for Applied Geophysics, Germany	3

License: Creative Commons Attribution-ShareAlike 4.0 International License

Attributions/citations:

1. Warren, C., Giannopoulos, A. (2011). Creating finite-difference time-domain models of commercial ground-penetrating radar antennas using Taguchi’s optimization method. Geophysics, 76(2), G37-G47. (http://dx.doi.org/10.1190/1.3548506)

2. Giannakis, I., Giannopoulos, A., & Warren, C. (2019). Realistic FDTD GPR antenna models optimised using a novel linear/non-linear Full Waveform Inversion. IEEE Transactions on Geoscience and Remote Sensing, 57(3), 1768-1778. (https://doi.org/10.1109/TGRS.2018.2869027)

3. Stadler. S., Igel J. (2018). A Numerical Study on Using Guided GPR Waves Along Metallic Cylinders in Boreholes for Permittivity Sounding. 17th International Conference on GPR. (https://tinyurl.com/y6vdab22)

Module overview

• GSSI.py is a module containing models of antennas similar to those manufactured by Geophysical Survey Systems, Inc. (GSSI).

• MALA.py is a module containing models of antennas similar to those manufactured by MALA Geoscience.

Descriptions of how the models were created can be found in the aforementioned attributions.

How to use the module

The antenna models can be accessed from within a block of Python code in an input file. The models are inserted at location x,y,z. The coordinates are relative to the geometric centre of the antenna in the x-y plane and the bottom of the antenna skid in the z direction. The models must be used with cubic spatial resolutions of either 0.5mm (GSSI 400MHz antenna only), 1mm (default), or 2mm by setting the keyword argument, e.g. resolution=0.002. The antenna models can be rotated 90 degrees counter-clockwise (CCW) in the x-y plane by setting the keyword argument rotate90=True.

Note

If you are moving an antenna model within a simulation, e.g. to generate a B-scan, you should ensure that the step size you choose is a multiple of the spatial resolution of the simulation. Otherwise when the position of antenna is converted to cell coordinates the geometry maybe altered.

Example

To include an antenna model similar to a GSSI 1.5 GHz antenna at a location 0.125m, 0.094m, 0.100m (x,y,z) using a 2mm cubic spatial resolution:

#python:
from user_libs.antennas.GSSI import antenna_like_GSSI_1500
antenna_like_GSSI_1500(0.125, 0.094, 0.100, resolution=0.002)
#end_python:

Fig. 15 FDTD geometry mesh showing an antenna model similar to a GSSI 1.5 GHz antenna (skid removed for illustrative purposes).

Fig. 16 FDTD geometry mesh showing an antenna model similar to a GSSI 400 MHz antenna (skid removed for illustrative purposes).

Fig. 17 FDTD geometry mesh showing an antenna model similar to a MALA 1.2GHz antenna (skid removed for illustrative purposes).