GNSS-R Land Remote Sensing about Reflected Signal’s Polarization Characteristics
Received date: 2012-03-07
Revised date: 2012-05-22
Online published: 2012-08-10
GNSS-R is a new promising remote sensing technique due to the advantages of low cost, small power and high spatial and time resolutions. GNSS constellation transmits the Right Hand Circular Polarization (RHCP) signals, which bring some useful information of the earth surface properties and reflect from it. They are received by the special designed GNSS-R receiver. Compared with the direct signals, the reflected ones are weaker and their polarizations have been changed, so a suitable receiver should be designed using the corresponding polarizations antenna to reduce polarized loss and increase the strength of received reflected signals. In principal, GNSS-R is a kind of bistatic radar. This paper provides some research based on the microwave scattering model. Bare surface and vegetation theoretical simulations were taken as the transmitted signals is RHCP and the received ones are RHCP, LHCP, H and V polarizations. As for bare surface, specular reflectivity model and PO model are used, the Bistatic mimics (Bimimics) is developed based on the backscattering model Mimics (Michigan Microwave Canopy Scattering Model) by adding the azimuth and zenith scattering angles. The simulations indicate that there is scattering values only at large incident angles (small elevation angles) as for the received polarization is LHCP. But linear polarizations exist for all the scattering angles(10°~70°). Scattering response of V polarization is the largest one.Therefore, it is good for surface characteristics research. In theory, our theoretical simulations provide some useful information for receiver’s polarization design.
Key words：
GNSS-R; PO; Bi-mimics; Spec-mimcis; Polarizations.
Li Ying , Wu Xuerui . GNSS-R Land Remote Sensing about Reflected Signal’s Polarization Characteristics[J]. Advances in Earth Science, 2012 , 27(8) : 895 -900 . DOI: 10.11867/j.issn.1001-8166.2012.08.0895
[1]Kavak A, Xu G, Vogel W.GPS multipath fade measurements to determine L-band ground reflectivity properties[C]∥Twentieth NASA Propagation Experimenters Meeting. National Aeronautics and Space Administration, Fairbanks, Alaska,1996: 257-263.
[2]SMEX02 Experiment Plan[EB/OL].http:∥hydrolab.arsusda.gov/smex02/smex60302.pdf,2012.
[3]Masters D, Axelrad P, Katzberg S. Initial results of land-reflected GPS biostatic radar measurements in SMEX02[J]. Remote Sensing of Environment,2004, 92(4): 507-520.
[4]Rodriguez-Alvarez N, Bosch-Lluis A, Camps M,et al.Soil moisture retrieval using GNSS-R techniques: Experimental results over a bare soil field[J]. IEEE Geoscience and Remote Sensing Society, 2009,47(11): 3 616-3 624,doi:10.1109/TGRS.2009.2030672.
[5]Rodriguez-Alvarez N, Camps A,Vall-llossera M.Land geophysical parameters retrieva using the interference pattern GNSS-R technique[J]. IEEE Geoscience and Remote Sensing Society, 2011,49(1):71-84, doi:10.1109/TGRS.2010.2049023.
[6]Zavorotny V,Voronovich A. Scattering of GPS signals from the ocean with wind remote sensing application[J]. IEEE Geoscience and Remote Sensing Society, 2000,38(2):951-964.
[7]Zavorotny V, Masters D, Gasiewski A, et al. Seasonal polarimetric measurements of soil moisture using tower-based GPS bistatic radar[J].Proceeding of the IEEE International Geoscience and Remote Seas, 2003, 2:781-783.
[8]Ulaby F T, Sarabandi K, McDonald K, et al. Dobson, Michigan Microwave Canopy Scattering Model (MIMICS)[R]. University of Michigan, Ann Arbor, Tech. Rep. 022486-T-1, Jul. 1988.
[9]Liang P, Pierce L E, Moghaddam M. Radiative transfer model for microwave bistatic scattering from forest canopies[J]. Transactions on Geoscience and Remote Sensing, 2005,43(11): 2 470-2 483.
[10]Katzberg S J, Torres O, Grant M S, et al. Utilizing calibrated GPS reflected signals to estimate soil reflectivity and dielectric constant: Results from SMEX02[J]. Remote Sensing of Environment,2005, 100(1): 17-28.
[11]Ruck G, Barrick D, Stuart W, et al. Radar Cross Section Handbook, vol. II[M]. New York, NY: Plenum,1970.
/
| 〈 |
|
〉 |
甘公网安备62010202000687
