Browsing Research Articles (Electrical, Electronic and Computer Engineering) by UP Author "Du Plessis, W.P. (Warren Paul)"

Browsing Research Articles (Electrical, Electronic and Computer Engineering) by UP Author "Du Plessis, W.P. (Warren Paul)"

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  • Analysis and exploitation of landforms for improved optimisation of camera-based wildfire detection systems 
    Heyns, Andries M.; Du Plessis, W.P. (Warren Paul); Curtin, Kevin M.; Kosch, Michael; Hough, Gavin (Springer, 2021-09)
    Tower-mounted camera-based wildfire detection systems provide an effective means of early forest fire detection. Historically, tower sites have been identified by foresters and locals with intimate knowledge of the terrain ...
  • Analysis of path-length effects in multiloop cross-eye jamming 
    Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2017-10)
    The effect of path-length differences on multiloop retrodirective cross-eye jammers is evaluated. It is shown that such jammers may act as beacons, and the conditions under which this occurs are investigated for two-loop ...
  • A checkered network for implementing arbitrary overlapped feed networks 
    Laue, Heinrich Edgar Arnold; Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2019-11)
    Existing overlapped subarray techniques for beamforming arrays aim to realize flat-topped subarray radiation patterns, where pattern synthesis is constrained by the hardware configuration. A generalized framework for ...
  • A coherence-based algorithm for optimizing rank-1 Grassmannian codebooks 
    Laue, Heinrich Edgar Arnold; Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2017-06)
    An iterative algorithm for the numerical optimization of rank-1 Grassmannian codebooks is presented. This algorithm achieves the same results as the current state-of-the-art algorithm, but requires a median of 9.52 times ...
  • Cross-eye gain in multiloop retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2016-04)
    The simultaneous use of multiple retrodirective cross-eye jammers is analysed for both the case where the jammer loops point in different directions and when they point in the same direction. In both cases, the use of ...
  • Definition of a quality factor for single site location estimates 
    Coetzee, Petrus J.; Du Plessis, W.P. (Warren Paul) (Radio Science American Geophysical Union (AGU), 2016-06)
    A technique to estimate the performance of Single Site Location (SSL) based on High Frequency (HF) direction finding (DF) for reigning ionospheric propagation conditions is described. This technique is based on classic ...
  • Efficient computation of array factor and sidelobe level of linear arrays 
    Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2016-12)
    The implementation of code to efficiently compute the array factor and sidelobe level (SLL) of linear antenna arrays in MATLAB and GNU Octave is considered. The use of a fast Fourier transform (FFT) to compute the array ...
  • Efficient modeling of missile RCS magnitude responses by Gaussian processes 
    Jacobs, Jan Pieter; Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2017-11)
    An efficient technique for modeling radar cross section magnitude responses versus frequency is presented. The technique is based on Gaussian process regression and makes it possible to significantly reduce the number of ...
  • Experimental simulation of retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul); Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Aerospace & Electronic Systems Society, 2011-01)
    Experimental measurements that accurately simulate the effect of a retrodirective cross-eye jammer on a monopulse radar are described. The accuracy of a recently published extended analysis of retrodirective cross-eye ...
  • Extended analysis of retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul); Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Institute of Electrical and Electronics Engineers, 2009-09)
    An extended and rigorous analysis of retrodirective cross-eye jamming in a radar system scenario is presented. This analysis removes the approximations that limit the validity of other analyses of cross-eye jamming. These ...
  • Improved seeding schemes for interleaved thinned array synthesis 
    Du Plessis, W.P. (Warren Paul); Bin Ghannam, A. (Institute of Electrical and Electronics Engineers, 2014-11)
    This communication considers the synthesis of interleaved antenna arrays with shared and inactive elements. A hybrid genetic algorithm (GA) where the initial population is seeded with good solutions is proposed. A number ...
  • Limiting apparent target position in skin-return influenced cross-eye jamming 
    Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2013)
    It is desirable to limit the apparent target to one side of a retrodirective cross-eye jammer despite the variation caused by platform skin return. The relationship between the jammer parameters and the jammer-to-signal ...
  • Metrics to evaluate compression algorithms for raw SAR data 
    Pieterse, Chane; Du Plessis, W.P. (Warren Paul); Focke, Richard W. (Institution of Engineering and Technology, 2019-02)
    Modern synthetic aperture radar (SAR) systems have size, weight, power and cost (SWAP-C) limitations since platforms are becoming smaller while SAR operating modes are becoming more complex. Thus, SAR systems are producing ...
  • Numerical optimisation of compressive array feed networks 
    Laue, Heinrich Edgar Arnold; Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2018-07)
    Compressive antenna arrays reduce the number of beamforming controls by taking a limited number of weighted combinations of the element signals. A compressive array sidelobe level (SLL)-minimisation algorithm, inspired by ...
  • Optimisation of tower site locations for camera-based wildfire detection systems 
    Heyns, Andries M.; Du Plessis, W.P. (Warren Paul); Kosch, Michael; Hough, Gavin (CSIRO Publishing, 2019-08)
    Early forest fire detection can effectively be achieved by systems of specialised tower-mounted cameras. With the aim of maximising system visibility of smoke above a prescribed region, the process of selecting multiple ...
  • Path-length compensation in multi-loop retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2019-02)
    Multiloop retrodirective cross-eye jammers offer the possibility of both simplifying system implementation and improving system performance. However, the signals for each jammer loop propagate along different paths, leading ...
  • Performance limiters of near-vertical-incidence skywave propagation : a scientific approach 
    Coetzee, Petrus J.; Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2020-06)
    Near-vertical-incidence skywave (NVIS) propagation is defined as providing continuous coverage from nearly 0 km (just beyond the line of sight) to a couple hundred kilometers from the transmitter with no skip or dead zones. ...
  • Specific emitter identification for enhanced access control security 
    Samuel, J.N.; Du Plessis, W.P. (Warren Paul) (South African Institute of Electrical Engineers, 2017-06)
    This paper presents the application of specific emitter identification (SEI) to access control and points out the security caveats of current radio-based access remotes. Specifically, SEI is applied to radio frequency ...
  • Statistical skin-return results for retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2019-10)
    The effect of the radar skin return from the platform on which a cross-eye jammer is mounted is significant in many practical cross-eye jamming scenarios. However, all published analyses of skin-return affected cross-eye ...
  • Statistical skin-return results for retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul) (Institute of Electrical and Electronics Engineers, 2017-01)
    The effect of the return from the platform on which a cross-eye jammer is mounted is significant in many practical cross-eye jamming scenarios. However, all published analyses of skin-return affected cross-eye jamming ...