Frequency Domain Panoramic Imaging Algorithm for Ground-Based ArcSAR.

Ground-based Synthetic Aperture Radar (GBSAR) is a tremendous example of the extended applications of Synthetic Aperture Radar (SAR). GBSAR is extremely useful in human-made structure observations, terrain mapping, landslide monitoring and many more. However, the process of designing and developing the GBSAR system is rather costly and time-consuming. It would be of a great advantage for system designers to have a realistic simulation and designing tool to anticipate the results before the implementation of the final design. In this paper, we are going to present the integrated simulation and designing tool that we have developed for a generic GBSAR system. We named it iSIM v2.0

The task of detecting and locating landmines, unexploded ordnances (UXO) and improvised explosive devices (IEDs) is still a major challenge up to the present day. Problems such as the distance between the hazardous area and the measurement system as well as the differentiation between the target of interest and the surrounding soil are of importance in the development of the sensor system. Various types of radar based systems have been developed over the last decades to solve these problems. Compared to other methods ground penetrating synthetic aperture radar (SAR) has the ability to scan large areas from a safe standoff distance in a relatively short time. In this paper, two different imaging radar systems are compared. The first one is a ground-based SAR (GB-SAR) developed at German Aerospace Center (DLR). The other system is an unmanned aerial vehicle-based SAR (UAV-SAR) from the University of Ulm. The presented data originates from a joint campaign using the same measurement scenarios.

Hazards due to ground movements and instability in man-made structures can lead to considerable human and economic losses. The decrease of permafrost areas, changes in precipitation patterns and increase of extreme weather which due to the recent climate change is actually influencing the weather-related mass movement activities. In Malaysia, landslide is the most commonly seen land deformation issue for the past few years. Therefore, an efficient tool to monitor the potential land deformation area is needed. In this study a ground-based synthetic aperture radar (GBSAR) is used to continuous monitor the high risk area which prone to landslide in Malaysia. Preliminary testing of the GBSAR has been conducted in Cameron Highland, Malaysia to verify the performance of the GBSAR and its capability of detecting landslide. The paper introduces the GBSAR system used in this study as well as the preliminary field experiments using this new system.

The ground based arc-scanning synthetic aperture radar (ArcSAR) is a kind of novel ground-based synthetic aperture radar (GBSAR) that has received increasing attention in recent years. The ArcSAR system can cover a wide range of 360-degree scenes by the antenna attached to the rotating boom. Compared with the linear scanning GBSAR, it can effectively overcome the limit of the field of view. Since the ArcSAR system scans along the arc track. The special motion track causes its imaging accuracy is affected by the terrain of the scenes. Traditional ArcSAR imaging algorithms achieve imaging on the reference plane. If the height of the reference plane is inconsistent with the actual height of the target in the scenes, the quality of the imaging result will decrease or even image defocusing will occur. In order to obtain high precision ArcSAR image, we propose a high precision imaging method for ArcSAR based on DEM-assist. We apply the DEM data to assist ArcSAR imaging, which enables the target in the scenes image on its actual height. In this paper, the ArcSAR geometric model and signal model are first introduced. Then the error model of ArcSAR imaging on the reference plane error is analyzed. Besides, the principle of the proposed high precision imaging method for ArcSAR is also given. Finally, the experiments are performed to verify the effectiveness of the proposed method.

Ground based synthetic aperture radar (GB-SAR) is used to effectively mitigate natural disasters and monitor social infrastructure such as bridges, dams, and airport pavement surfaces. This book explains the fundamentals of radar technology, the principles of synthetic aperture radar (SAR) image generation, and interferometric SAR (InSAR) processing for observing small ground surface deformation less than 1 mm. More advanced multiple-input multiple-output (MIMO) radar for ground surface observation is introduced. The authors also provide examples of GB-SAR used for monitoring landslide and vegetation to show its potential and limitations. Understanding this advanced technology and its applications will help readers plan and install GB-SAR systems in real-life projects. Features: Introduces GB-SAR, an advanced tool that measures in-millimeter ground surface displacement. Explains how the GB-SAR system can be installed for landslide monitoring. Provides a new radar technology that monitors vibrations of infrastructure remotely. Discusses the advanced radar technology related to polarimetry and interferometry. Includes several case studies applying the tools and techniques discussed to natural disasters, such as landslides, volcanoes, glaciers, and so on. This book is intended for civil professionals who deal with disaster mitigation and infrastructure monitoring and those in electrical engineering, including radar technology. It is also an excellent resource for upper-level undergraduate and graduate students taking courses in remote sensing and photogrammetry, geography, geodesy, information science, engineering, and geology, as well as researchers and scientists interested in learning the techniques and technologies for collecting, analyzing, managing, and visualizing geospatial data sets.

Aimed at improving the imaging efficiency of frequency-modulation continuous-wave (FMCW) ground-based synthetic aperture radar (SAR) characterized with lots of data, high resolution and burden processing of imaging algorithm, a real-time imaging processing software architecture based on TMS320C6678 signal processor is proposed in this paper. The multicore parallel processing technology is adopted to resolve the problem of real time imaging and the polar coordinates back-projection algorithm is realized efficiently. Experimental results demonstrate that the real-time processing software can reduce the time consumption significantly and keep the correctness of the imaging results of ground-based SAR.

The aim of this paper is to describe how ground-based radar interferometry can provide displacement measurements of earth dam surfaces and of vibration frequencies of its main concrete infrastructures. In many cases, dams were built many decades ago and, at that time, were not equipped with in situ sensors embedded in the structure when they were built. Earth dams have scattering properties similar to landslides for which the Ground-Based Synthetic Aperture Radar (GBSAR) technique has been so far extensively applied to study ground displacements. In this work, SAR and Real Aperture Radar (RAR) configurations are used for the measurement of earth dam surface displacements and vibration frequencies of concrete structures, respectively. A methodology for the acquisition of SAR data and the rendering of results is described. The geometrical correction factor, needed to transform the Line-of-Sight (LoS) displacement measurements of GBSAR into an estimate of the horizontal displacement vector of the dam surface, is derived. Furthermore, a methodology for the acquisition of RAR data and the representation of displacement temporal profiles and vibration frequency spectra of dam concrete structures is presented. For this study a Ku-band ground-based radar, equipped with horn antennas having different radiation patterns, has been used. Four case studies, using different radar acquisition strategies specifically developed for the monitoring of earth dams, are examined. The results of this work show the information that a Ku-band ground-based radar can provide to structural engineers for a non-destructive seismic assessment of earth dams.

A new type of monitoring technology - Ground-based Synthetic Aperture Radar (GBSAR) - has been proven in mining applications and shows promise for monitoring deformation of infrastructure or slope movement with accuracy of better than one millimeter (0.040 in.). This project was thus devised to test the utility of this technology for monitoring above-ground gas pipeline infrastructure that is being impacted by ground subsidence. The infrastructure monitored included: a compressor building, a segment of pipeline, pipe supports and foundations. The first objective of this project was to demonstrate the logistics involved to operate the system both on site and remotely, the measurements and output products of the GBSAR for monitoring pipeline-related infrastructure. The second objective is to compare the GBSAR results to satellite Interferometric Synthetic Aperture Radar (InSAR) ground movement estimates. A four month monitoring program was successfully executed in Blythe, California, at a compressor station. This report documents the monitoring trial and the successful outcomes of the project.

Ground-based synthetic aperture radar (GBSAR) systems are widely used for monitoring slopes, especially in quarries and open pits. Unfortunately, the movement of the machinery (cranes, trucks, shovels, and excavators) in the radar field of view often prevents to correctly focus large circular sections of the radar images, producing a characteristic artifact, often named “blurring.” Therefore, the aim of this article is to propose both an acquisition modality and an image processing technique able to mitigate the blurring due to moving clutter. The proposed acquisition modality (named “free-running” or “on-the-fly”) allows to filter out the high-frequency clutter, which is often noticeable in GBSAR images, but it is not effective with low-frequency clutter caused by slow movement of machinery like heavy trucks or large cranes. For this reason, the authors propose even a suitable processing method that can be used in combination with high-frequency sampling. The application of these two methods has been proved to be very effective in realistic quarry scenario.

Ground-based synthetic aperture radar (GB-SAR)is known as a powerful tool for monitoring ground displacement. Fault creep is important to understand diastrophism. Particularly, Marikina fault in Manila, Philippine is known as a place where fault creep has often occurred. In this paper, we demonstrate a prototype GB-SAR, which we developed, which is suitable for environmental monitoring. As a first step, we developed a GB-SAR with a simple structure, which uses a frequency not limited by a location by law. We conducted some experiments for generating SAR images by the developed GB-SAR. In the experiments, we showed we could image several targets under various conditions by SARs.

India boasts a rich heritage of monuments that are of historical and cultural significance. These monuments are continuously subjected to environmental degradation, human activity, and structural aging. Traditional structural health monitoring (SHM) techniques, such as visual inspection and contact sensors, are often invasive, localized, and ineffective for Indian Heritage sites, which are architecturally complex. Ground-Based Synthetic Aperture Radar (GBSAR) is a remote sensing technique that offers a non-contact, weather-independent, and highresolution microwave imaging alternative for SHM. This paper proposes a multistatic GBSAR framework designed specifically for the SHM of Indian monuments. By leveraging multiple spatially distributed transmit and receive nodes, the proposed system enhances spatial resolution and enables full-field deformation monitoring, even in occluded or inaccessible areas. Simulation results presented here indicate that the multistatic configuration significantly improves imaging quality compared to monostatic GBSAR. This framework provides improved deformation maps, making it a viable early warning tool for non-invasive SHM.

A Ground-Based Synthetic Aperture Radar (GB-SAR) is an important technology in a variety of application felds including of land deformation and landslide. In a landslide, this technology can be utilized to detect the movement of soil as an indicator of landslide. The fundamental aspects of the GB-SAR are controlling system of the devices. In this work, the interfacing software for controlling the GB-SAR system is developed. A C-band horn antenna is operated in the system with center frequency of 4 GHz. The transmitting and receiving radar wave is performed using 1-port portable VNA that can be operated in the frequency range of 85 MHz to 5.4 GHz. One meter linear slide is implemented as path to capture the backscattering wave from a point target. The performance of the interfacing system in term of captured data and movement step accuracy of the antenna will be discussed in this paper.

Ground-based synthetic aperture radar (GB-SAR) interferometry has already been recognized as a powerful tool for remote sensing deformation monitoring. However, the accuracy and reliability of the deformation retrieval using GB-SAR instrument is severely affected by atmospheric phase disturbances. In this paper, an improved two-dimentional polynomial regression model (2D-PRM) based atmospheric phase compensation (APC) algorithm, in collaboration with the permanent scatterer (PS) technique, is developed in GB-SAR interferometry. In order to obtain the aliasing-free data required for the APC procedure, an efficient two-stage spatial phase unwrapping method is utilized. Then the reliable PS points are selected by jointly exploiting the amplitude, coherence and amplitude deviation index (ADI) information. After that, the appropriate APC is carried out by virtue of a 2D-PRM based least square (LS) method. Finally, we conduct the atmospheric correction experiments on a real campaign to verify the performance of the proposed scheme.

This work presents a novel aspect for measurement and implementation of a radar cross section (RCS) using the polarimetric backscattered power under ground-based Synthetic Aperture Radar (GB-SAR) environment. Special attention is given to combine the GB-SAR principle with RCS measurement in order to determine the polarimetric backscatter characteristics of canonical targets along the azimuth direction. In this paper, the polarimetric measurement concept using GB-SAR environment for the movement of pyramidal horn antennas in the azimuthal direction are developed. The experimental results are presented with implementation of dihedral and trihedral corner reflectors. The results based on this methodology allow to generate the backscattered characteristics of canonical targets with reference to measurement geometry under GB-SAR environment. Consequently, the measurement concept and the experimental results can be used to determine and to identify the specific geometry of the objects in searching applications.

In short-range monitoring of tall buildings, the phenomenon of pitch angle ambiguity always appears in the process of 3D terrain matching of ground-based synthetic aperture radar (GB-SAR) based on grid projection, which affects the interpretation of projection results. To mitigate these issues, in this paper, we propose a method designed to deal with the phenomenon of pitch angle ambiguity. Firstly, the transformation relationship between the image range-azimuth coordinate system and the north-east-up coordinate system under any GB-SAR observation geometry is derived. Furthermore, we realize the 3D terrain matching of GB-SAR based on the method of grid projection. Then, we analyze the causes of the phenomenon of pitch angle ambiguity. In addition, by judging whether there is effective laser point cloud data in each grid of 3D terrain grid matrix, the false image in the projection result is eliminated and the phenomenon of pitch angle ambiguity is corrected. The experiment results indicate that the false images in the projection results are effectively removed and the proposed method has a good performance in processing the phenomenon of pitch angle ambiguity.