scholarly journals Calibration of a Ground-Based Array Radar for Tomographic Imaging of Natural Media

2019 ◽  
Vol 11 (24) ◽  
pp. 2924
Author(s):  
Albert R. Monteith ◽  
Lars M. H. Ulander ◽  
Stefano Tebaldini
Keyword(s):  
Electromagnetic Scattering ◽  
Systematic Errors ◽  
Temporal Variations ◽  
Synthetic Aperture ◽  
Tomographic Images ◽  
Phase Errors ◽  
Antenna Coupling ◽  
Calibration Methods ◽  
Radar Measurements ◽  
Radar Antennas

Ground-based tomographic radar measurements provide valuable knowledge about the electromagnetic scattering mechanisms and temporal variations of an observed scene and are essential in preparation for space-borne tomographic synthetic aperture radar (SAR) missions. Due to the short range between the radar antennas and a scene being observed, the tomographic radar observations are affected by several systematic errors. This article deals with the modelling and calibration of three systematic errors: mutual antenna coupling, magnitude and phase errors and the pixel-variant impulse response of the tomographic image. These errors must be compensated for so that the tomographic images represent an undistorted rendering of the scene reflectivity. New calibration methods were described, modelled and validated using experimental data. The proposed methods will be useful for future ground-based tomographic radar experiments in preparation for space-borne SAR missions.

Interpretation of synthetic aperture radar measurements of ocean currents

1983 ◽  
Vol 88 (C3) ◽  
pp. 1867 ◽  
Author(s):  
Clifford L. Rufenach ◽  
Robert A. Shuchman ◽  
David R. Lyzenga
Keyword(s):  
Synthetic Aperture Radar ◽  
Ocean Currents ◽  
Synthetic Aperture ◽  
Radar Measurements ◽  
Aperture Radar

Analytical and Calibration Models for Slot Antennas

2019 ◽  
pp. 57-100
Author(s):  
Kok Yeow You
Keyword(s):  
Numerical Simulation ◽  
Analytical Calculation ◽  
Computation Time ◽  
Systematic Errors ◽  
Simulation Software ◽  
Slot Antenna ◽  
Slot Antennas ◽  
Long Period ◽  
Calibration Models ◽  
Calibration Methods

In this chapter, the background, analytical formulations, and calibration routines for slot antennas are briefly reviewed. Performance and operating frequency of the slot antenna are strongly dependent on the dimension and shape of the slot or slotted array on the antenna. Nowadays, most antennas are designed using numerical simulation software for accuracy in analysis. However, analytical formulations still play an important role in the pre-design of the antenna due to the numerical simulation which still requires relatively long period of computation time compared to the analytical calculation. The predicted dimension of the antenna from analytical calculations will only require minor adjustment to optimize its performance in numerical simulation. Hence, the time spent for the antenna design can be shortened. Besides the performance of antenna, the antenna calibration process is crucial as well for releasing systematic errors in the antenna measurements. Some one-port calibration methods are described in detail.

scholarly journals Comparative Analysis of Polarimetric SAR Calibration Methods

2018 ◽  
Vol 10 (12) ◽  
pp. 2060 ◽  
Author(s):  
Yoon Jung ◽  
Sang-Eun Park
Keyword(s):  
Comparative Analysis ◽  
Calibration Method ◽  
System Model ◽  
Synthetic Aperture ◽  
Polarimetric Sar ◽  
Alos Palsar ◽  
Polarimetric Synthetic Aperture Radar ◽  
System Parameters ◽  
Calibration Methods ◽  
Polarimetric Calibration

In the diverse applications of polarimetric Synthetic Aperture Radar (SAR) systems, it is a crucial to conduct polarimetric calibration, which aims to remove the radar system distortion effects prior to utilizing polarimetric SAR observations. The objective of this study is to evaluate the performance of different polarimetric calibration methods. Two widely used methods, the Van Zyl and Quegan methods, and one recently proposed method, such as the Villa method, have been selected among various calibration methods in literature. The selected methods have basic differences in their assumptions that are applied to the polarimetric system model. In order to evaluate the calibration performances under different system parameters and ground characteristics, comparative analysis of the calibration results were conducted on synthetic polarimetric SAR data and ALOS PALSAR quad-pol mode data. Based on the experimental results, the advantages and limitations of different methods were clarified, and a simple hybrid calibration method is presented to further improve the polarimetric calibration performance.

scholarly journals On The Estimation of Temporal Changes of Snow Water Equivalent by Spaceborne Sar Interferometry: A New Application for the Sentinel-1 Mission

2019 ◽  
Vol 67 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Vasco Conde ◽  
Giovanni Nico ◽  
Pedro Mateus ◽  
João Catalão ◽  
Anna Kontu ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Snow Water Equivalent ◽  
Temporal Variations ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Snow Layer ◽  
Illumination Condition ◽  
Interferometric Phase ◽  
Snow Water

Abstract In this work we present a methodology for the mapping of Snow Water Equivalent (SWE) temporal variations based on the Synthetic Aperture Radar (SAR) Interferometry technique and Sentinel-1 data. The shift in the interferometric phase caused by the refraction of the microwave signal penetrating the snow layer is isolated and exploited to generate maps of temporal variation of SWE from coherent SAR interferograms. The main advantage of the proposed methodology with respect to those based on the inversion of microwave SAR backscattering models is its simplicity and the reduced number of required in-situ SWE measurements. The maps, updated up to every 6 days, can attain a spatial resolution up to 20 m with sub-centimetre ΔSWE measurement accuracy in any weather and sun illumination condition. We present results obtained using the proposed methodology over a study area in Finland. These results are compared with in-situ measurements of ΔSWE, showing a reasonable match with a mean accuracy of about 6 mm.

scholarly journals On the Use of Single-, Dual-, and Quad-Polarimetric SAR Observation for Landslide Detection

2019 ◽  
Vol 8 (9) ◽  
pp. 384 ◽  
Author(s):  
Park ◽  
Lee
Keyword(s):  
Remote Sensing ◽  
Detection Rate ◽  
Detection Method ◽  
Incidence Angle ◽  
Accuracy Assessment ◽  
Temporal Variations ◽  
The Other ◽  
Synthetic Aperture ◽  
False Alarms ◽  
Simple Change

Remote sensing technologies, particularly with Synthetic Aperture Radar (SAR) system, can provide timely and critical information to assess landslide distributions over large areas. Most space-borne SAR systems have been operating in different polarimetric modes to meet various operational requirements. This study aims to discuss how much detectability can be expected in the landslide map produced from the single-, dual-, and quad-polarization modes of observation. The experimental analysis of the characteristic changes of PALSAR-2 signals showed that quad-polarization parameters indicating signal depolarization properties revealed noticeable landslide-induced temporal changes for all local incidence angle ranges. To produce a landslide map, a simple change detection method based on characteristic scattering properties of landslide areas was proposed. The accuracy assessment results showed that the depolarization parameters, such as the co-pol coherence and polarizing contribution, can identify areas affected by landslides with a detection rate of 60%, and a false-alarm rate of 5%. On the other hand, the single- or dual-pol parameters can only be expected to provide half the accuracy with significant false-alarms in areas with temporal variations independent of landslides.

A parametric model for synthetic aperture radar measurements

1999 ◽  
Vol 47 (7) ◽  
pp. 1179-1188 ◽  
Author(s):  
M.J. Gerry ◽  
L.C. Potter ◽  
I.J. Gupta ◽  
A. Van Der Merwe
Keyword(s):  
Synthetic Aperture Radar ◽  
Parametric Model ◽  
Synthetic Aperture ◽  
Radar Measurements ◽  
Aperture Radar
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