Simulated results on the scattering effects of targets can be derived in the form of single gathered time-domain traces and of B-scan cross sections (‘radargrams’), both in monostatic and in bistatic configurations, analogously to the typical output achievable by GPR instruments [1,2,5].
403020
E(V/m)
100-10-20-30
2
4
6
8
10
We present in Fig. 4 some examples of test cases related to the presence of buried scatterers (see figure captions and labels for all the details). In Fig. 4(a) we show the probed output signal traces (amplitudes vs. time) from an input Gaussian pulse related to various dipole antennas.
B-scan plots (received scattered signal in grey scale vs. scan position) have been simulated for different antennas and waveforms to detect buried scatterers. Examples of detection are reported for a cubic target close to the interface in Figs. 4(b) and 4(c): in Fig. 4(b) for a monopole antenna radiating a Gaussian modulated pulse, and in Fig. 4(c) for a Vivaldi antenna radiating a chirp signal.
IV. CONCLUSION
An extensive numerical study has been carried out for the accurate analysis of the features of GPR systems in realistic scenarios. The influence of the designed antenna system and of the chosen input signal features have particularly been addressed, taking into account a number of practical issues which make this type of study an efficient and versatile tool to predict the practical performance of GPRs for target detection.
ACKNOWLEDGMENTS
The authors gratefully acknowledge financial support from the Italian Space Agency through Contract ASI I/060/10/0, EXOMARS SCIENCE phase C2/D.
REFERENCES
[1] D. J. Daniels, Ed., Ground Penetrating Radar. The Institution
(a)
t (ns)
[2] [3]
[4]
(cm)
t (ns)
(b)
[5]
(cm)
[6] [7]
(c)
[8]
Fig. 4. Simulation examples of target detection with ground-coupled radars for different antenna types and input signal waveforms. A metallic cubic scatterer, having 9-cm side and 10-cm depth, buried in a dielectric ground ( r = 3.2): (a) received traces (probed output signal E, V/m, vs. time, ns) for λ/2, loaded, and folded-loaded dipoles (see labels for the colors associated to the curves); (b) B-scan plot (grey-scale amplitude along tìme, ns, vs. linear scan position, cm) for a monopole antenna with an input Gaussian modulated pulse signal; (c) B-scan plot for a Vivaldi antenna with an input chirp signal (pulse compression ratio Bτ = 100).
[9]
of Electrical Engineers (IEE), London, UK, 2nd Ed., 2004. H. M. Jol, Ed., Ground Penetrating Radar: Theory and Applications. Elsevier, Amsterdam, The Netherlands, 2009. F. Soldovieri, I. Catapano, P. M. Barone, S. E. Lauro, E. Mattei, E. Pettinelli, G. Valerio, D. Comite, and A. Galli, “GPR estimation of the geometrical features of buried metallic targets in testing conditions,” Progress in Electromagnetic Research B, vol. 49, pp. 339-362, 2013. A. Galli, D. Comite, I. Catapano, G. Gennarelli, F. Soldovieri, and E. Pettinelli, “3D imaging of buried dielectric targets with a tomographic microwave approach applied to GPR synthetic data,” Int. J. Antennas Propag., art. ID 610389, 10 pp., 2013. G. Valerio, A. Galli, P. M. Barone, S. E. Lauro, E. Mattei, and E. Pettinelli, “GPR detectability of rocks in a Martian-like shallow subsoil: A numerical approach,” Planetary Space Sci., vol. 62, pp. 31-40, 2012.
CST Microwave Studio Manual, CST, Germany, 2002.
E. Pettinelli, G. Vannaroni, E. Mattei, A. Di Matteo, F. Paolucci, A. R. Pisani, A. Cereti, D. Del Vento, P. Burghignoli, A. Galli, A. De Santis, and F. Bella, “Electromagnetic propagation features of ground-penetrating radars for the exploration of Martian subsurface,” Near Surface Geophys., vol. 4, pp. 5-11, 2006.
E. Pettinelli, P. Burghignoli, A. R. Pisani, F. Ticconi, A. Galli, G. Vannaroni, and F. Bella, “Electromagnetic propagation of GPR signals in Martian subsurface scenarios including material losses and scattering,” IEEE Trans. Geosci. Remote Sensing, vol. 45, pp. 1271-1280, May 2007.
V. Ciarletti, C. Corbel, D. Plettemeier, P. Cais, S. M. Clifford, and S.-E. Hamran, “WISDOM GPR designed for shallow and high-resolution sounding of the Martian subsurface,” Proc. IEEE, vol. 99, pp. 824-836, May 2011.