volume | PIER Journals

Abstract

The main purpose of this paper is to separately estimate the important surface parameters (soil moisture and roughness) by using full polarimetric bistatic measurements. The results provide a basis for new satellite application of future bistatic measurement systems such as the TanDEM-X satellite mission. Initially, bistatic X-band measurements, which have been recorded in the Bistatic Measurement Facility (BMF) at the DLR Oberpfaffenhofen, Microwaves and Radar Institute, will be presented. The bistatic measurement sets are composed of soils with different well-known statistical roughness scales and different moistures. The BMF has been calibrated using the Isolated Antenna Calibration Technique (IACT). The validation of the calibration was achieved by measuring the reflectivity of fresh water. In the second part, the assessment of the surface parameters (soil moisture and surface roughness) using the well calibrated data introduced in the former related part, will be detailed. The validation of the specular algorithm by estimating the soil moisture of two surfaces with different roughness scales will be reported. Additionally, a new technique using the coherent term of the Integral Equation Method (IEM) to estimate the soil roughness will be presented, as well as the sensitivity of phase and reflectivity with regard to moisture variation and therefore the penetration depth was evaluated. Current results demonstrate a non-linear relationship between the signal phase and the soil moisture, as expected, confirming the possibility of using DInSAR to measure variations in soil moisture.

1. Krieger, G., A. Moreira, H. Fiedler, I. Hajnsek, M. Werner, M. Younis, and M. Zink, "TanDEM-X: A satellite formation for high-resolution SAR interferometry," IEEE Trans. Geosci. Remote Sensing, Vol. 45, No. 11, 3317-334, Nov. 2007.
doi:10.1109/TGRS.2007.900693

2. Oh, Y., K. Sarabandi, and F. T. Ulaby, "An empirical model and aninversion technique for radar scattering from bare soil surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 30, No. 2, 370-381, 1992.
doi:10.1109/36.134086

3. Dubois, P. C., J. J. van Zyl, and T. Engman, "Bistatic scattering and emissivities of lossy dielectric surfaces with exponential correlation functions," IEEE Trans. Geosci. Remote Sensing, Vol. 33, No. 4, 916-926, 1995.
doi:10.1109/36.406677

4. Xu, P. and L. Tsnag, "Measuring soil moisture with imaging radars," IEEE Trans. Geosci. Remote Sensing, Vol. 45, No. 1, Jan. 2007.
doi:10.1109/TGRS.2006.883458

5. Wu, T. D., K. S. Chen, J. Shi, H. W. Lee, and A. K. Fung, "A study of an AIEM model for bistatic scattering from randomly rough surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 46, No. 9, Sep. 2008.

6. Cost, S. T., "Measurements of the bistatic echo area of terrain of X-band,", Ohio State University, Antenna Lab., Rept. 1822-2, May 1965.

7. Domville, A. R., "The bistatic reflection from land and sea of X-band radio waves,", pt. I, GEC (Electronics) Ltd., Memo. SLM 1802, Stanmore, England, Jul. 1967.

8. Domville, A. R., "The bistatic reflection from land and sea of X-band radio waves,", pt. II, GEC (Electronics) Ltd., Memo. SLM 2116, Stanmore, England, Jul. 1968.

9. Domville, A. R., "The bistatic reflection from land and sea of X-band radio waves,", pt. II Suppl., GEC-AEI (Electronics) Ltd., Memo. SLM 2116 (Suppl.), Stanmore, England, Jul. 1969.

10. De Roo, R. D., "Theory and measurement of bistatic scattering of X-band microwaves from rough dielectric surfaces,", Ph.D. Thesis, Michigan University, USA, 1996.

11. Macelloni, G., G. Nesti, P. Pampaloni, S. Sigismmondi, D. Tarchi, and S. Lolli, "Experimental validation of surface scattering and emission models," IEEE Trans. Geosci. Remote Sensing, Vol. 38, No. 1, Jan. 2000.
doi:10.1109/36.823941

12. Thorsos, E. I., "The validity of the Kirchhoff approximation for rough surface scattering using a Gaussian roughness spectrum," Journal Acoust. Soc. AM., Vol. 83, No. 1, 78-92, Jan. 1988.
doi:10.1121/1.396188

13. Boerner, T., "Development of a coherent scattering model for polarimetric SAR interferometry applications,", Ph.D. Thesis, Munich University, Germany, 2000.

14. Dobson, G. C., J. L. Davis, and A. P. Annan, "Electromagnetic determination of soil water content: Measurements in coaxial transmission lines," Water Resour. Res., Vol. 16, No. 3, 574-582, 1980.
doi:10.1029/WR016i003p00574

15. Dobson, M. C., F. T. Ulaby, M. T. Hallikainen, and M. El-Rayes, "Microwave dielectric behaviour of wet soil - Part II: Dielectric mixing models," IEEE Trans. Geosci. Remote Sensing, Vol. 23.1, 35-46, 1985.
doi:10.1109/TGRS.1985.289498

16. Hallikainen, M. T., M. C. Ulaby, M. C. Dobson, and M. El-Rayes, "Microwave dielectricbehavior of wet soil - Part I: Empirical models and experimental observations," IEEE Trans. Geosci. Remote Sensing, Vol. 23.1, 25-34, 1985.
doi:10.1109/TGRS.1985.289497

17. Wiesbeck, W., "A complete error model for polarimetric RCS- and antenna measurements,", Institut fuer Hoechstfrequentechnik und Elektronik,-University Karlsruhe, Kaiserstr, 12 7500 Karlsruhe, Federal Republic of Germany, 1992.

18. Jersak, B. D., "Bistatic, fully polarimetric radar cross-section calibration techniques and measurement error analysis,", Ph.D. Thesis, The University of Texas at Arlington, 1993.

19. Sarabandi, K. and F. Ulaby, "A convenient technique for polarimetric calibration of single-antenna radar systems," IEEE Trans. Geosci. Remote Sensing, Vol. 28, No. 6, 1022-1033, Nov. 1990.
doi:10.1109/36.62627

20. Sarabandi, K., F. T. Ulaby, and M. A. Tassoudji, "Calibration of polarimetric radarsystems with good polarization isolation," IEEE Trans. Geosci. Remote Sensing, Vol. 28, No. 1, 70-75, Jan. 1990.
doi:10.1109/36.45747

21. Hauck, B., F. T. Ulaby, and R. DeRoo, "Polarimetric bistatic-measurement facility for point and distributed targets," IEEE Transaction on Antennas and Propagations, Vol. 40, No. 1, Feb. 1998.

22. Fung, A. K. and G. W. Pan, "Backscattering from a randomly rough dielectric surface," IEEE Trans. Geosci. Remote Sensing, Vol. 30, No. 2, Mar. 1992.
doi:10.1109/36.134085

23. Koufogbo, F., "Modelling of rough natural and manmade surfaces at millimetre-wave frequencies - Study of the interactions between a target and its natural environment,", Ph.D. Thesis, The Paul Sabatier University, Toulouse, France, 2002.

24. Tsang, L., J. A. Kong, and R. T. Shin, Theory of Microwave Remote Sensing, Wiley-Interscience Publication, 1985.

25. Alvarez, J. L., "Two novel studies of electromagnetic scattering in randommedia in the context of radar remote sensing,", Ph.D. Thesis, University of Nottingham, UK, Mar. 2002.

26. Alvarez, J. L., "An extension of the IEM/IEMM surface scattering model," Waves Random Media, Vol. 11, Mar. 2001.

27. Ceraldi, E., G. Franceschetti, A. Iodice, and D. Riccio, "Estimating the soil dielectric constant via scattering measurements along the specular direction," IEEE Trans. Geosci. Remote Sensing, Vol. 43, No. 2, 295-305, Feb. 2005.
doi:10.1109/TGRS.2004.841357

28. Shi, J., J. Wang, A. Y. Hsu, P. E. O'Neill, and E. Engman, "Estimation ofbare surface soil moisture and surface roughness parameter using L-band SAR image data," IEEE Trans. Geosci. Remote Sensing, Vol. 35, No. 5, 1254-1266, Sep. 1997.
doi:10.1109/36.628792

29. Franceschetti, G., A. Iodice, S. Maddaluno, and D. Riccio, "A fractal based theoretical framework for the retrieval of surface parameters from electromagnetic backscattering data," IEEE Trans. Geosci. Remote Sensing, Vol. 38, No. 2, 641-650, Sep. 2000.
doi:10.1109/36.841994

30. Nolan, M., D. R. Fatland, and L. Hinzman, "DInSAR measurements of soil moisture," IEEE Trans. Geosci. Remote Sensing, Vol. 41, No. 12, Dec. 2003.
doi:10.1109/TGRS.2003.817211

31. Nolan, M. and D. R. Fatland, "New DEMs may stimulate signi¯cant advancements in remote sensing of soil moisture," EOS Trans. AGU, Vol. 84, No. 25, 233-240, Jun. 24, 2003.
doi:10.1029/2003EO250001

32. Nolan, M. and D. R. Fatland, "Penetration depth as a DInSAR observable and proxy for soil moisture," IEEE Trans. Geosci. Remote Sensing, Vol. 41, No. 3, 532-537, Mar. 2003.
doi:10.1109/TGRS.2003.809931

33. Despan, D., "Modles thoriques et mesures de la diffusion du rayonnement lectromagntique dans le domaine optique et radar par des sol avec dessurfaces lisses et rugueuses alatoires,", Ph.D. Thesis, Universit de Marne-la-Valle, Feb. 1999.

34. Wait, J. R., Electromagnetic Waves in Stratified Media, Pergamon Press, Oxford, 1996.

35. Rudant, J. R., A. Bedidi, D. Massonet, G. Nesti, and R. Calonne, "Decorrelation of back scattered signal due to soil moisture changes," Conference CNES, Toulouse, Oct. 1995.

36. Arya, L. M., J. C. Richter, and J. F. Paris, "Estimating profile waterstorage from surface zone soil moisture measurements under bare field conditions," Water Resour. Res., Vol. 19, No. 2, 403-412, 1983.
doi:10.1029/WR019i002p00403

37. Rudant, J. R., A. Bedidi, D. Massonet, G. Nesti, and R. Calonne, "Near surface soil moisture estimation from microwave measurements," Remote Sens. Environ., Vol. 26, 101-121, Oct. 1988.

38. Engman, E. T. and N. Chauhan, "Status of microwave soil moisture measurements with remote sensing," Remote Sens. Environ., Vol. 51, No. 1, 189-198, 1995.
doi:10.1016/0034-4257(94)00074-W

39. Ulaby, F. T., R. K. Moore, and A. K. Fung, Microwave Remote Sensing: Active and Passive, Vol. II - Radar Remote Sensing and Surface Scattering and Emission Theory, 609, Addison-Wesley, Advanced Book Program, Reading, Massachusetts, 1982.

40. Ben Khadhra, K., "Surface parameter estimation using bistatic polarimetric X-band measurements,"-Ph.D. Thesis, German Aerospace Centre (DLR), Microwaves and Radar Institute, Oberpfaffenhofen, Germany, 2008.

Dr. Kais Khadhra

Dr. Thomas Boerner

Dr. David Hounam

Dr. Madhu Chandra