Structural Parameter Estimation of Australian Flora with a Ground-based Polarimetric Radar Interferometer

Abstract

Abstract-The application of polarimetric SAR interferometry technology is extended to ground based radar imaging (GBPOLInSAR), which has a limited field of view but provides wide band coverage. It also provides for easier deployment of broadband and multi-baseline techniques, from which we can estimate vegetation structure and extinction propagation using model based techniques. This micro-scale multi-parameter combination with good temporal resolution is a unique feature of groundbased sensors.In this paper we present both polarimetric and interferometric coherence calibration results for such a GB-POLInSAR system we have developed at the University of Adelaide. We then show an initial study of height estimation of Australian native plants based on the coherence parameter retrieval models of the polarimetric SAR interferometry technique using the broadband GB-POLInSAR system.

Application of Polarization Coherence Tomography to GB-POLInSAR Data

“…As mentioned in [7], this by itself generally underestimates height and so needs augmenting by the second term, which is based on inversion of the coherence amplitude. Hence h v is given by According to [7,9], choosing 4 . 0 = ε leads to robust height estimation in varying forest density and structure environments.…”

“…The vegetation sample is placed on a rotating turntable so that measurements can be made over 360 degrees of azimuth for a given angle of incidence. Wide-band POLInSAR data were acquired across the frequency range 3 to 6 GHz at 70.8 degrees of the incident angle with a baseline of 10 cm, as detailed in [9]. Note finally that the focus for the sensor (zero phase position for interferometry) is located around 2 cm lower than the ground surface of the sample which is 40 cm above the floor level of the chamber.…”

“…SINGLE BASELINE PCT AND GB-POLINSAR DATA In [9] we investigated the ability of single baseline POLInSAR to retrieve vegetation height for short native Australian plants. Here we extend the analysis to investigate the ability of PCT to estimate variations in vertical profile due to density variations in the medium.…”

The Development and Comparison of Two Polarimetric Calibration Techniques for Ground-Based Circularly Polarized Radar System

“…In addition, Whitt et al, Chen et al, and Wiesbeck et al proposed a calibration technique without making any assumption about the distortion matrix by utilizing three reflector targets [24][25][26][27]. These well-developed point target-based calibration techniques have frequently been used for GB-SAR systems [5][6][7][8][9][10][11].…”

“…Pol-SAR systems exploit polarimetric backscattering behavior of manmade and natural scatters for the derivation of bio-and geo-physical information of targets such as land, snow and ice, ocean, vegetation, and urban area [1][2][3][4]. In addition to its traditional use in airborne and spaceborne SAR systems, Pol-SAR is also increasingly used in various ground-based (GB) SAR applications such as vegetation monitoring, damage assessment of wooden building structure, and buried target detection [5][6][7][8][9][10][11].…”