User libraries is a sub-package where useful Python modules contributed by users are stored.
GPR antenna models
The module features models of antennas similar to commercial GPR antennas. The following antenna models are included:
|GSSI 1.5GHz (Model 5100)||170x108x45mm||1, 2mm||Craig Warren (email@example.com), Northumbria University, UK||1,2|
|MALA 1.2GHz||184x109x46mm||1, 2mm||Craig Warren (firstname.lastname@example.org), 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|
- 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)
- Giannakis, I., Giannopoulos, A., & Warren, C. (2018). Realistic FDTD GPR antenna models optimised using a novel linear/non-linear Full Waveform Inversion. IEEE Transactions on Geoscience and Remote Sensing, . ()
- Stadler, S. (2017). A Forward Modeling Study for the Investigation of the Vertical Water-Content Distribution of Using Guided GPR Waves (Master's Thesis, Freiberg University of Mining and Technology, Germany). (https://tinyurl.com/y6vdab22)
GSSI.pyis a module containing models of antennas similar to those manufactured by Geophysical Survey Systems, Inc. (GSSI).
MALA.pyis 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
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.
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:
FDTD geometry mesh showing an antenna model similar to a GSSI 1.5 GHz antenna (skid removed for illustrative purposes).
FDTD geometry mesh showing an antenna model similar to a GSSI 400 MHz antenna (skid removed for illustrative purposes).