Browsing by Author "Corbett, Brandon"

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    Analysis and exploitation of complex SAR phenomena produced from vibrating targets
    (Institute of Acoustics, 2018-12-31) Corbett, Brandon; Andre, Daniel; Muff, D.; Finnis, Mark V.; Blacknell, D.
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    Diamond From the Sky
    (Cranfield University, 2018-11-15 13:15) Corbett, Brandon
    Digital image presented at the 2018 Defence and Security Doctoral Symposium.The image presented is an example of a high resolution airborne Synthetic Aperture Radar (SAR) collection, covering a 1km x 0.6km area above the Harwell Science and Innovation Campus, and includes the UK’s synchrotron Diamond Light Source. The data was collected using Airbus’ X-band quad-polarised SAR airborne platform. In total there were 55609 measurements along the aircraft trajectory, equating to 14GB of measurement data. This raw data was then processed into SAR imagery using parallel processing of the back-projection image formation algorithm using "Cranfield University"’s High Performance Computing facility. The image is a colour composite combining all 4 polarisations. Red represent the vertical polarisation (VV), green represents the horizontal polarisation (HH) and blue is the sum of the cross polarisations (VH and HV). The result is an extremely detailed 30000x18000 pixel SAR image. High resolution datasets like this aid in the development of new image formation and analysis algorithms and provide the user with a clean and clear reference to work with.
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    Exploiting Synthetic Aperture Radar Signal Processing to Reveal Concealed Building Features and Phenomena
    (Cranfield University, 2018-11-15 13:15) Corbett, Brandon
    3MT presented at the 2018 Defence and Security Doctoral Symposium.There has been an increased research interest in the techniques needed to exploit accurate remotely sensed data of the activities within buildings, closed/sealed areas, underground bunkers, etc. One example area which could be influenced by such research includes the detection of illegal or nefarious activities. Low frequency synthetic aperture radar (LF-SAR) can provide one such solution to this remote sensing problem. It has been shown that LF-SAR can be used to generate images of objects located behind a variety of mediums, including within buildings. However, the current literature shows that obtaining a clear picture of the structure and contents of buildings is difficult. It is well known that SAR imagery can be affected by various physical phenomena, which can produce a range of artefacts within the images. These artefacts can lead to confusion and difficulty in analysis, as they can be mistaken for targets. A vibrating scatterer is one such example, as it produces a paired echo signature in the SAR image. On the other hand, these phenomena are of particular interest for the detection of running machinery within a building. It has been shown that a vibrating scatterer can represent aspects of a running machine, e.g. a generator or fan. Therefore understanding the effects produced within a SAR image from a vibrating object behind a wall, could lead to the ability to identify and recognise running machinery within a building from a stand-off location. The intention of this research is to investigate these phenomena and the techniques required for imaging the interiors of buildings and to develop the necessary SAR tools and analysis methods required for extracting crucial intelligence information from this data.
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    Imaging SAR phenomenology of concealed vibrating targets
    (IEEE, 2018-08-16) Corbett, Brandon; Andre, Daniel; Muff, Darren; Morrow, Ivor L.; Finnis, Mark V.
    This paper describes the novel imaging of SAR phenomena produced from vibrating targets with multipath effects. It has been established, through numerical SAR experiments, that different physical mechanisms interact to produce new artefacts. The computations demonstrated that the edges of a dielectric medium can act as a source for multipath effects to emanate from, leading to the hypothesis that SAR artefacts can arise from through-wall SAR imagery. This deduction and mechanism of origin were validated through several experimental measurements, undertaken at Cranfield University’s Antennas and Ground-based SAR laboratory, yielding results that closely match those predicted.
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    Localising vibrating scatterer phenomena in synthetic aperture radar imagery
    (IET, 2020-01-21) Corbett, Brandon; Andre, Daniel; Finnis, Mark V.
    Artefact phenomena resulting from synthetic aperture radar (SAR) image formation can pose a challenge for image interpretation. One such artefact is produced when a vibrating target is imaged. Suppression of these artefacts has previously been described, however little has been developed in the area of modelling the location and shape of such artefacts. The authors present an experimentally validated model that provides accurate location and shape of vibrating target paired echoes in both SAR near-field and SAR far-field imagery.
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    Remote intelligence of building interiors, using synthetic aperture radar
    (2020-06) Corbett, Brandon; Andre, Daniel
    With most criminal and nefarious activity occurring underground or within buildings, intelligence gathering on the nature and activities of concealed areas is key for both defence and civilian sectors, leading to the formation of the “Remote Intelligence of Building Interiors” (RIBI) project. Synthetic aperture radar (SAR) systems have become fundamental in the remote sensing field, and their ability to complete inter-medium measurements makes them well suited for the RIBI project. Firstly, vibrating target phenomenology within buildings was investigated. If you can identify this phenomenon, you could infer the possibility of manufacturing equipment within the building. This topic presented several novel contributions to the field including an understanding of the localisation of vibrating target artefacts, a new experimental measurement methodology to capture this phenomenon, and the identification of a new multipath-vibration artefact. Following this a comprehensive analysis of the Bright-Sapphire II data-dome trials was conducted. This is a volumetric airborne SAR collection designed to allow for investigations into how different building types affect the detectability of targets positioned within them. An assessment of the SAR image quality across the full azimuthal and vertical extents was examined, revealing extensive radio frequency interference (RFI) and image alignment issues. This in turn reduced the overall quality and focusing of any SAR image produced from the data. To address these image alignment problems, the development of a new autofocus algorithm based on a hybrid map drift (MD) - prominent point processing (PPP) solution was completed. The solution was developed on simulated data and validated using AFRL’s Gotcha dataset. When applied to the Bright-Sapphire II dataset, the solution yielded successful results in improving scatterer alignment along the ground plane. However, volumetric imagery of the scene was not as successful. It was determined if one wants to unlock the full potential of the Bright-Sapphire II dataset, increasing the usable bandwidth will be key to accomplishing this, which will require resolving the challenging RFI contaminating the data.
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    Synthetic Aperture Radar for Through-Wall Detection and Imaging of Complex Vibrating Targets
    (Cranfield University, 2017-11-15 11:56) Corbett, Brandon; Andre, Daniel; Muff, Darren; Morrow, Ivor; Finnis, Mark
    Poster presented at the 2017 Defence and Security Doctoral Symposium.Low frequency Synthetic Aperture Radar (SAR) is a proven solution for generating through-wall images, although obtaining a clear picture of the structure and contents of buildings has proven to be difficult. Whilst the effects created by moving objects within a SAR image have been investigated before, the complex effects moving objects have upon a SAR image when located behind a wall, are less known. This is especially the case when the motion of the object being imaged is of vibration and when multipath effects influence the artefacts produced within the SAR image. This occurs when the transmitted SAR microwaves reflect from other objects within the imaged scene, before being detected by the receive antenna. The research presented, investigates these complex SAR phenomena with multistatic radar geometries, using the Cranfield University Antennas and Ground Based SAR (AGBSAR) laboratory. This research is conducted in support of the Dstl Remote Intelligence of Building Interiors (RIBI) programme, and addresses the problem of the detection of running machinery within buildings, amongst other challenging scenarios.
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    Through-Wall Detection and Imaging of a Vibrating Target Using Synthetic Aperture Radar
    (IET, 2017-06-02) Corbett, Brandon; Andre, Daniel; Finnis, Mark V.
    This paper explains the development of a through-wall synthetic aperture radar (SAR) simulator, which is being used to investigate the SAR artefacts originating from vibrating target’s, known as paired echoes. The simulation and experimental results both show that paired echoes can be detected and imaged through a wall, with a noticeable reduction in intensity, resulting in the number of visible echoes to be reduced in brightness and appear shifted in location in a through-wall SAR image
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    Using synthetic aperture radar data-dome collections for building feature analysis
    (Cranfield University, 2018-11-15) Corbett, Brandon; Andre, Daniel
    Low-frequency synthetic aperture radar (LF-SAR) is a remote sensing measurement technique that can aid in covert intelligence gathering capabilities for detecting concealed targets in building, and obscured phenomena in general. The Airbus Defence and Space Ltd LF-SAR data dome project has provided a coherently collected three-dimensional data set using airborne circular SAR (CSAR) trajectories, with the potential of providing volumetric SAR imagery of obscured regions inside buildings. Preliminary results of this collection are presented. Both the linear strip-map and CSAR datasets provided contain a great deal of information. Early results show promise, but have revealed the fundamental challenge with low-frequency remote sensing, that being the presence of radio-frequency interference, which reduces the quality of SAR image products.
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    Utilising Synthetic Aperture Radar Data-dome Collections for Building Feature Analysis
    (Cranfield University, 2018-11-15 13:15) Corbett, Brandon
    Technical paper presented at the 2018 Defence and Security Doctoral Symposium.Low-frequency synthetic aperture radar (LF-SAR) is a remote sensing measurement technique that can aid in covert intelligence gathering capabilities for detecting concealed targets in building, and obscured phenomena in general. The Airbus Defence and Space Ltd LF-SAR data dome project has provided a coherently collected three-dimensional data set using airborne circular SAR (CSAR) trajectories, with the potential of providing volumetric SAR imagery of obscured regions inside buildings. Preliminary results of this collection are presented. Both the linear strip-map and CSAR datasets provided contain a great deal of information. Early results show promise, but have revealed the fundamental challenge with low-frequency remote sensing, that being the presence of radio-frequency interference, which reduces the quality of SAR image products.