Synthetic Aperture Radar

This paper describes the analysis of L-band radiometric measurement data gathered with the synthetic aperture radiometer HUT-2D during several ground-based and airborne measurement campaigns. The radiometric data are analyzed from the instrument's performance point of view, aiming to verify the theoretical performance of an instrument of this kind and to assess the performance of the HUT-2D radiometer system in particular. The data sets considered for the study consist of measurements of well-known natural targets, such as cosmic background radiation, and measurements of pure water scenes, the brightness temperature of which is possible to model based on in situ measurements. We define four figures of merit, which are applicable for synthetic aperture radiometers. These are radiometric resolution, image bias, pixel-to-pixel random error, and temporal stability. Then, we use the selected data sets to assess these in the case of HUT-2D. The experimental results are discussed and compared to the theoretical values, where applicable. Also, we discuss possibilities to improve the presented performance. The main results of this paper are the consolidated performance parameters of the HUT-2D instrument. We study and discuss the properties of the error components related to the technology in a general level, and study the scalability of the errors as a function of the measured targets. In particular, the stability of the direction-dependent error component is pointed out, and a mitigation guideline is proposed.

The necessity to control all the activities within the marine environment is nowadays vital for most official authorities. Besides protecting the ecosystem and providing safety and surveillance along the transportation corridors, illegal immigration and sustainable economic activities are also issues to cover. Since early nineties, a lot of efforts have been devoted to develop monitoring systems based on transponders (VMS or AIS). Such systems use active on-board devices to track ship positions via satellite communications. Despite of their great performance, the experience has shown, however, that this approach does not have the required independency and other alternatives are necessary. Among them, the one gathering more benefits is the integration of remote sensing, specially Synthetic Aperture Radar (SAR), with operational transponders. Certainly, this solution provides redundancy, 7/24 and all-weather monitoring capability, independently from the targets to track.

Use of InSAR techniques in the study of unstable slopes has been suggested in recent works. However, in the ease of mass movements, which typically occur in high-relief terrain and are of limited areal extent, the detection of ground surface deformation is difficult. Moreover, the presence of vegetation cover and atmospheric effects introduces coherence loss and resolution problems in the analysis of interferometric pairs. Thus, extreme care must be taken in every step of interferometric SAR processing in order to obtain results that can be easily interpreted and be of practical utility in landslide hazard studies. The authors present the results of the application of InSAR and DInSAR techniques to a landslide test area located in the Southern Apennines. A number of SAR images was selected, whose dates coincide with periods of mass movement activity documented by in situ controls. DInSAR processing was conducted in order to assess the potential of satellite radar data for landslide monitoring. Coarse resolution is an important limiting factor for effective information extraction. Advanced processing approaches may help to overcome this limit

An integrated remote sensing/field ecology project was carried out to link the use of synthetic aperture radar (SAR) and other remotely sensed data to studies of landscape spatial heterogeneity and bird community ecology as a first step toward applications in predicting biodiversity. P-, L-, and C-band SAR data were collected over a section of the South Alligator River in Kakadu

This paper describes a phased incremental integration approach for application of image analysis and data fusion technologies to provide automated intelligent target tracking and identification for airborne surveillance on board an Aurora Maritime Patrol Aircraft. The sensor suite of the Aurora consists of a radar, an identification friend or foe (IFF) system, an electronic support measures (ESM) system, a spotlight

Abstract: Sensor-management in tracking consists of sensor mode control and scheduling, target selection, and situation assessment. In a dynamic environment, airborne radar necessitates active mode control for the acquisition of a synthetic aperture radar (SAR) ...

The Polarimetric Synthetic Aperture Radar technique has provided various opportunities and challenges in agricultural activities mainly on crop management. The aim of this study is to investigate the sensitivity of 10 parameters derived from multi-temporal Sentinel-1 Synthetic Aperture Radar (SAR) data, to crop height and canopy coverage (CC) of maize, sunflower, and wheat. The correlation coefficient values indicate a high correlation for maize during the early growing stage. The coefficient determinations (R2) of 0.82 and 0.81 indicate that there is a strong relationship between the maize height and SAR parameters including VV + VH and VV, respectively. The maize CC is well correlated with VV parameter (R2 = 0.73), but it is observed that at the later growing stage the correlation became weaker. This means that the sensitivity decreases with increasing vegetation cover growth. Compared to maize, the sensitivity of SAR parameters to wheat variables is often good at the early stage....

A new empirical model for the retrieval, at a field scale, of the bare soil moisture content and the surface roughness characteristics from radar measurements is proposed. The derivation of the algorithm is based on the results of three experimental radar campaigns conducted under natural conditions over agricultural areas. Radar data were acquired by means of several C-band space borne

The TerraSAR-L system is currently being designed in a Phase B definition study. The platform is optimized for and built around the 11 m x 2.9 m active phased array antenna of the L-band Synthetic Aperture Radar (L-SAR). The L-SAR features, on top of standard Stripmap and ScanSAR operations, full polarimetric capabilities, repeat-pass ScanSAR interferometry and a Wave Mode. Besides a major contribution to applications in areas of climate change and oceanography, the TerraSAR-L design responds specifically to requirements from interferometric applications. Being conceived as operational, the mission scenario is aiming at maximizing the exploitation of this SAR system. One key element of the TerraSAR-L operations strategy is a long-term systematic and repetitive acquisition scenario to ensure consistent data archives. The other important factor is a systematic processing of all acquired data to Single-look Slant-range Complex (SSC) products to facilitate higher-level product generatio...

In agriculture, there is growing interest in determining field spatial variability for implementing differential management practices, which should generate economic and environmental benefits. To date, the majority of studies involving remote sensing and differential management have focused on optical sensor systems. Less attention has been paid to synthetic aperture radar (SAR), despite the advantages of "all-weather" acquisition enabling information to

Experiments of the two-pass interferometric Synthetic Aperture Radar (IfSAR) technique shows that the method often gives poor result due to poor coherence and to different physical conditions. For this reason, the stereoscopic Synthetic Aperture Radar (SAR) method presents an important alternative for terrain mapping. To automate the image matching procedures and to reduce the requirement of GCPs is a major consideration in the generation of Digital Elevation Models (DEMs) from space-borne SAR data. This paper describes a pyramidal image matching scheme with an optimized parameter selection strategy and a region-growing technique to achieve a high level of automation for producing Digital Parallax Models (DPMs) from same-side image pairs. A DPM provides successful matched points of an image pair. The strategy is mainly based on the analysis of the maximal parallax in an image pair and a pyramidal geometry. A rigorous algorithm for space intersection is used to generate DEMs from DPM...

Abstract—The launch of high-resolution remote sensing satel-lites like TerraSAR-X, WorldView, and Ikonos has benefited the combined application of synthetic aperture radar (SAR) and optical imageries tremendously. Specifically, in case of natural calamities or ...