A Practical Approach For Modelling The Electromagnetic Radar Signature Of Barefaced Terrain For Remote Sensing

Abstract

A practical approach is proposed and used to investigate the electromagnetic (EM) signature of barefaced terrain using 3D computer electromagnetic models (CEM). Six barefaced terrain types with different electrical, physical and chemical properties were investigated. They comprise homogeneous and heterogeneous terrain. The approach developed CEMs in software using refl ectance spectroscopy and dielectric permittivity data. EM signature models of the barefaced terrain are based on fi nite integration technique (FIT) solvers. The developed technique and models are valid for diverse materials under test including unconventional petroleum resources like shale rock and oil sands. The remote sensing of terrain from airborne or satellite synthetic aperture radar requires a prior determination of the EM signature for accurate classifi cation. The implementation of our new method combined empirical measurements and FIT in three steps. Geochemical properties determined using refl ectance spectroscopy in the mid-infrared region (2.5-25 µm) identifi ed the presence of bitumen, clay and moisture in Nigerian oil sands while reststrahlen effects were observed in beach sand compared with gravel and pebble. Also new information on both real, e′ r and imaginary, e′ r permittivity of terrain was experimentally obtained for frequency varying from 1 to 11 GHz. After post-processing, the results differed from expectation of complex refractive index method for petrophysics although adequate Kramers-Krönig correlation between measured real, e′ r and imaginary, e′ r permittivity data was exhibited. Our approach uses the results to improve the CEMs for superior EM signature determination. An application of our new technique to land degradation monitoring using radar is also presented.

Terrain backscatter and oil sand exploration: Average reflectivity analysis

“…ain component in pebbles and s more EM energy than both nd respectively. Similarly the or beach sand and LFS produced m reflectivity values of σ 0 in dB using (11). Results for the six w backscatter environment are average reflectivity value was e E-field observed at the rear of n HH polarization mode the reflectivity from terrain at 10λ distance was the same on both the front and rear terrain planes due to the relatively short distance (0.32m) of the samples.…”

“…This way we used the same antenna f analysis at f = 1, 7 and 10GHz. The main ch radar model and the laboratory scatterome used in an anechoic chamber are presented in The terrain models were detailed in [11] in order to variations. The simulation reflectivity (S11) for the antenn representative plane wave usi Fig.…”

“…Detailed measurement results for real and imaginary permittivity, ' and " are at [9], [10]. We use our approach developed in [11] for the 3D EM simulation system. In the next section we introduce both the radar system model and measurement system.…”

Electromagnetic characterisation of terrain for unconventional petroleum exploration

“…We represent both planar and non-planar as well as homogenous and heterogenous terrain in CEMs by their intrinsic physical and measured dielectric properties using our method developed in [17]. This method provides flexibility in representing the geometric attributes particularly surface roughness and also inclusion of other material properties such as dispersion, nonlinearity and anisotropy.…”

“…Our dielectric measurements results were also input in to the terrain models. The terrain models were developed using techniques outlined in [17]. Radar illuminates from + Z direction.…”