Surface Parameter Estimation Using Bistatic Polarimetric X-Band Measurements

Abstract

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

Critical Analysis of Microwave Specular Scattering Response on Roughness Parameter and Moisture Content for Bare Periodic Rough Surfaces and Its Retrieval

“…The stationary phase approximation or more widely known as the geometric optics approach assumes that scattering can occur only along directions for which there are specular points on the surface. For a rough surface with Gaussian height distribution, the incoherent scattering coefficient of the geometric optic approach is given by [1,6,7]:…”

“…(B3) are obtained. Q is defined as: As mentioned in [4,6] for specular direction U pq takes the form U hh (θ) = 2R h (θ) cos θ U hv (θ) = 0 U vv (θ) = −2R v cos θ…”

“…In a view of deficiency of data aimed at the investigation of the bistatic active remote sensing, few outdoor bistatic measurements have been reported [6]. Three substantial indoor experiments have been carried in the recent past [7,8].…”

Numerical and Experimental Study of the Hydrodynamic Phenomena in Heterogeneous Sea Surface, Em Bistatic Scattering

“…An important aspect during the calibration process is to filter the noise or errors without losing useful information. An effective calibration technique has been chosen for our anechoic chamber to reduce these errors to acceptable levels and to calibrate the full polarimetric scattering matrix [11][12][13][14].…”

Numerical and experimental study of the hydrodynamic phenomena in heterogeneous sea surface EM bistatic scattering

“…Other works and measures on rough surfaces observed in bistatic configuration were performed on stamp of soil with different textures, including allowing the estimation of parameters of natural surfaces from measurements made in an anechoic chamber [5]. However, the surface scattering by breaking waves "nonBragg" is not enough studied and especially in the bistatic configuration.…”