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: .. code-block:: none #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: .. figure:: images/antenna_like_GSSI_1500.png :width: 600 px FDTD geometry mesh showing an antenna model similar to a GSSI 1.5 GHz antenna (skid removed for illustrative purposes). .. figure:: images/antenna_like_GSSI_400.png :width: 600 px FDTD geometry mesh showing an antenna model similar to a GSSI 400 MHz antenna (skid removed for illustrative purposes). .. figure:: images/antenna_like_MALA_1200.png :width: 600 px FDTD geometry mesh showing an antenna model similar to a MALA 1.2GHz antenna (skid removed for illustrative purposes).