Browsing by Author "Inggs, M R"

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    A spaceborne Synthetic Aperture Radar (SAR) processor design
    (1991) Kritzinger, Paul Johan; Inggs, M R
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    Detection and monitoring of surface subsidence associated with mining activities in the Witbank Coalfields South Africa using differential radar interferometry
    (2011) Engelbrecht, J; Inggs, M R; Mukusha, G
    Surface subsidence associated with coal mining activities in the Mpumalanga Province, South Africa, changes the natural environment in several ways and current challenges for mining companies lie in rehabilitation of the natural environment and the prevention of further degradation. To monitor the spatial and temporal evolution of surface subsidence, traditional field-based monitoring approaches, including GPS and spirit levelling, are employed at a number of locations. However, the resulting measurements are point-based and frequent visitations are necessary to map the evolution of surface subsidence basins over time. To address these limitations, differential interferograms derived from repeat-pass satellite-borne synthetic aperture radar (SAR) systems were tested for their ability to measure and monitor surface deformation. The resulting interferograms revealed several features indicative of surface subsidence. Ground truth data confirmed the presence of a subsidence basin detected using differential interferometry techniques during the 35 day period between April 12, 2008 and May 17, 2008, with a maximum vertical deformation of 3.2 cm being recorded. Interferometric monitoring revealed an eastward migration of the subsidence basin between June 2, 2008 and September 15, 2008, with an additional 4.7 cm of subsidence being observed. This migration coincides with the advance of the working face of the mine during this period. The results demonstrate the ability of interferometric synthetic aperture radar techniques to measure surface subsidence as well as the monitoring of the evolution of subsidence basins over time. This implies that the technique could be included, together with traditional field-based surveying techniques, in an operational monitoring system.
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    Inverse synthetic aperture imaging using 140 kHz ultrasonic laboratory sonar
    (2004) Wilkinson, A J; Mukhopadhyay, P K; Lewitton, N; Inggs, M R
    A sonar system operating at 40 kHz in air has been developed to allow the capture of acoustic data in a laboratory environment. The system can serve as a teaching tool for students in seismology, sonar and radar, as well as a useful tool for the development and testing of signal and image processing algorithms. The system can be used for monostatic or bistatic modes of imaging. Range compression is achieved by deconvolution filtering which compensates for the linear system effects of the transducers and other components. A deconvolution filter is generated via a calibration technique in which the system response is measured by pointing the transmitting transducer directly at the receiving transducer. Results are presented which demonstrate the capability of the system for range profiling and 2-D imaging, using the inverse synthetic aperture technique whereby the scene to be imaged is moved across the beam of the sensor. The focused image is obtained by synthetic aperture azimuth focusing / migration techniques. The range and azimuth resolutions achieved with system are discussed.
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    RHINO ARM cluster control management system
    (2014) Chiriseri, Valerie Edith; Winberg, Simon; Inggs, M R