Browsing by Author "Welsh, Richard"

Now showing 1 - 6 of 6
  • Thumbnail Image
    ItemOpen Access
    Laboratory multistatic 3D SAR with polarimetry and sparse aperture sampling
    (Wiley, 2024-01-01) Welsh, Richard; Andre, Daniel; Finnis, Mark
    With the advent of constellations of SAR satellites, and the possibility of swarms of SAR UAV's, there is increased interest in multistatic SAR image formation. This may provide advantages including allowing three-dimensional image formation free of clutter overlay; the coherent combination of bistatic SAR geometries for improved image resolution; and the collection of additional scattering information, including polarimetric. The polarimetric collection may provide useful target information, such as its orientation, polarisability, or number of interactions with the radar signal; distributed receivers would be more likely to capture any bright specular responses from targets in the scene, making target outlines distinct. Highlight results from multistatic polarimetric SAR experiments at the Cranfield University GBSAR laboratory are presented, illustrating the utility of the approach for fully sampled 3D SAR image formation, and for sparse aperture SAR 3D point-cloud generation with a newly developed volumetric multistatic interferometry algorithm.
  • Thumbnail Image
    ItemOpen Access
    Laboratory multistatic polarimetric 3D SAR
    (IET, 2023-02-07) Andre, Daniel; Welsh, Richard; Finnis, Mark
    With the advent of constellations of SAR satellites, and the possibility of swarms of SAR UAV's, there is increased interest in multistatic SAR image formation. This may provide advantages including allowing three-dimensional image formation free of clutter overlay; the coherent combination of bistatic SAR geometries for improved image resolution; the collection of additional scattering information, including polarimetric. The polarimetric collection may provide useful target information, such as its orientation, polarizability or number of interactions with the radar signal; distributed receivers would be more likely to capture any bright specular responses from targets in the scene, making target outlines distinct. Highlight results from multistatic polarimetric SAR experiments at the Cranfield University GBSAR laboratory are presented, illustrating the utility of the approach.
  • Thumbnail Image
    ItemOpen Access
    Laboratory multistatic polarimetric sparse aperture 3D SAR investigation
    (Institute of Acoustics, 2023-12-31) Welsh, Richard; Andre, Daniel; Finnis, Mark
    Synthetic Aperture Radar (SAR) is a coherent technique that produces high quality imagery, with a finer cross-range resolution than would be possible with a stationary antenna. Radar pulses from multiple points along a flight path are combined, with return time and phase recorded for each pulse. This technique can be used to produce multidimensional 3D SAR images, with scatterers otherwise overlaid in range and azimuth separated out in height.
  • Thumbnail Image
    ItemOpen Access
    Multistatic 3D SAR imaging with coarse elevation and azimuth sampling
    (IEEE, 2022-11-10) Welsh, Richard; Andre, Daniel; Finnis, Mark
    It is advantageous to produce Synthetic Aperture Radar (SAR) renderings in three dimensions as these allow the separation of features in height, providing additional target information. A Nyquist sampled 2D SAR aperture produces high quality 3D imagery, however the large scanning time and data storage requirements make this method impractical for use in many scenarios. This paper investigates the formation of 3D target renderings from sparsely sampled 2D aperture Multistatic SAR geometries. The investigation employed both simulations and measured multistatic data collected at the Ground Based SAR (GBSAR) Laboratory at Cranfield University.
  • Thumbnail Image
    ItemOpen Access
    Polarimetry for sparse multistatic 3D SAR
    (Institution of Engineering and Technology (IET), 2025-01-01) Welsh, Richard; Andre, Daniel; Finnis, Mark
    There is significant interest in multistatic SAR image formation, due to the increased development of satellite constellations and UAV swarms for remote sensing applications. The exploitation of the finer resolution and wider coverage of these geometries has been shown to reduce the often‐impractical data collection requirements of 3D SAR imagery; this offers advantages such as improved target identification and the removal of layover artefacts. This paper presents a novel polarimetric generalisation of the SSARVI algorithm, which was previously developed to exploit sparse aperture multistatic collections for 3D SAR image formation. The new algorithm presented here, named the PolSSARVI algorithm, combines polarimetrically weighted interferograms for determining the 3D scatterer locations from sparse aperture polarimetric collections. The bistatic generalised Huynen fork polarimetric parameters are then determined for the multistatic PolSSARVI 3D SAR renderings. This new approach was tested on both simulated and experimental data. Experimental imagery was formed using measurements from the Cranfield GBSAR laboratory.
  • Thumbnail Image
    ItemOpen Access
    Volumetric interferometry for sparse 3D synthetic aperture radar with bistatic geometries
    (Institution of Engineering and Technology (IET), 2023-06-25) Welsh, Richard; Andre, Daniel; Finnis, Mark
    Synthetic Aperture Radar (SAR) renderings in 3D provide additional target information when compared to 2D by separating out features overlaid in height. However, the required 2D SAR aperture, when Nyquist sampled, necessitates large scanning times that would be impractical for most realistic collections. This research has developed a novel volumetric approach to sparse aperture 3D SAR imaging, that is applicable to bistatic SAR near-field geometries, a generalization of far-field cases. This approach is first demonstrated in simulation and then applied to a measured scene containing a model vehicle target, producing sub-Nyquist sampled 3D SAR renderings.