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Radar, Sonar and Navigation, IEE Proceedings -

Issue 2 • Date Apr 1994

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Displaying Results 1 - 9 of 9
  • Radar detection in K-distributed clutter

    Publication Year: 1994 , Page(s): 116 - 118
    Cited by:  Papers (11)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    The paper compares two newly proposed detection schemes for targets in K-distributed clutter: the first implements generalised likelihood ratio test, and the second represents a discrete realisation of the classical Neymann-Pearson detector. Results indicate that the two optimisation strategies yield substantially equivalent performance, but the generalised likelihood ratio test is simpler in its structure and offers some additional advantages both at the design and at the analysis stage View full abstract»

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  • Multisensor, multisite tracking filter

    Publication Year: 1994 , Page(s): 75 - 82
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    A fusion filter has been designed for the tracking of airborne targets over a spherical Earth which can accommodate different sensor types at different geographical sites. It is assumed that sensor contacts are exchanged between sites in a timely fashion and all sensor contacts from the same object update the track filter. Registration and correlation mechanisms are assumed to be in place so that only sensor contacts derived from target A update the master track associated with target A. The filter is updated by one scalar measurement quantity at a time: either slant range, bearing angle, elevation angle or Doppler (i.e. range rate) from a local or remote sensor. This feature considerably simplifies the filter equations and allows the easy mixture of different sensor types. Performance of this filter is demonstrated with 2D, 3D and 4D sensors at either one or two sites and manoeuvring or nonmanoeuvring target trajectories. The filter is general enough to allow the localisation of a target in three dimensions with only contacts from a single unstabilised 2D sensor on a rolling and pitching marine platform View full abstract»

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  • Aircraft geometric height computation using secondary surveillance radar range differences

    Publication Year: 1994 , Page(s): 119 - 124
    Cited by:  Papers (4)  |  Patents (27)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    A new system for accurate geometric height measurement based on secondary surveillance radar (SSR) equipment is presented. The system includes an interrogator and receiver station, and three receiving-only stations. The aircraft responds to interrogations, and the time differences of signal arrival (TDOA) at the four receiving stations are used to estimate the vertical position of the aircraft. The use of time differences eliminates the biases caused by the systematic errors in the aircraft SSR transponder delay View full abstract»

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  • Power spectrum of wind-influenced vegetation backscatter at X-band

    Publication Year: 1994 , Page(s): 125 - 131
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (420 KB)  

    The baseband power spectral density characteristics of X-band radar backscatter from wind-influenced vegetation were investigated using a short-range continuous wave radar system. Radar reflectance and concurrent wind-speed data were gathered from various individual trees from a distance of approximately 30 m. The power spectral density was observed to drop off at a rate slower than the widely-used single-peak Gaussian model. An empirical model which characterises the power spectrum as a combination of Gaussian functions with different peak locations is proposed. The model postulates that (i) the spectral broadening of the central peak is attributable to branch sway, (ii) the location of non-central peaks is attributable to leaf flutter, and (iii) the spectral broadening of the non-central peaks is attributable to a combination of branch sway and leaf flutter. The model shows satisfactory agreement with measured data. It is shown that realistic estimates of MTI improvement factors for delay-line cancellers can be obtained by knowledge of the type of vegetative clutter environment View full abstract»

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  • Analysis and comparison of two order statistics CFAR systems

    Publication Year: 1994 , Page(s): 109 - 115
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    Constant false alarm rate (CFAR) processors based on order statistics (OS) are considered. The classical OSCFAR and its greatest-of (OSGO) version are compared in the presence of a Weibull distributed (and Rayleigh distributed as a particular case) background, for a design false alarm probability equal to 10-6. The effects of interfering targets and background discontinuities are evaluated by Monte Carlo and importance sampling computer simulations. The advantages of the OSGO processor in these significant conditions are shown View full abstract»

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  • Split spread-spectrum technique for flexible use of frequency bands

    Publication Year: 1994 , Page(s): 65 - 74
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    The paper investigates methods to minimise interference between spread-spectrum (SS) radio-location systems and other radio services. Methods to control the power spectral density (PSD) of SS signals are reviewed. A novel technique, called `split-signal', is described which minimises mutual interference. The technique exploits the noncontinuous use of the radio spectrum by splitting the SS signals into several lower-rate, narrower-bandwidth components. These are transmitted independently in gaps in the radio spectrum and recombined at the receiver. It is shown, by analysis and simulation, that the performance of split-signal SS radio-location systems in comparable to that of conventional wideband SS systems View full abstract»

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  • M-sweeps detection analysis of cell-averaging CFAR processors in multiple-target situations

    Publication Year: 1994 , Page(s): 103 - 108
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    The performances of the conventional cell-averaging (CA), greatest-of (GO) and smallest-of (SO) constant false alarm rate (CFAR) detectors are analysed for the case where one or more interfering target returns are present in the set of cells used in estimating the clutter-plus-noise level. Exact expressions are derived for the detection probability of these detectors when noncoherent integration is used under the chi-square target fluctuation model. Results are depicted for a Swerling I target model. As M increases, better performances are obtained for the CA, GO and SO detectors under both homogeneous and nonhomogeneous background models. For the same parameters, the SO scheme gives the best performance in the case of a multiple-target environment View full abstract»

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  • QRD-based MVDR algorithm for adaptive multipulse antenna array signal processing

    Publication Year: 1994 , Page(s): 93 - 102
    Cited by:  Papers (8)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (708 KB)  

    A numerically robust, computationally efficient processing scheme for adaptive multipulse radar is described. Its purpose is to detect a target embedded in clutter and directive electromagnetic (EM) interference by processing the echoes received by an array of antennas on-board an aircraft or satellite. The algorithm which performs an efficient QR decomposition of the underlying space-time data matrix, may be implemented in parallel on either a triangular array of processors or using a novel lattice-type structure of smaller triangular array processors. A Monte Carlo simulation study has been performed to evaluate the performance of the processing scheme in terms of steady-state improvement factor, transient response, 2D filtering capability, and numerical robustness View full abstract»

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  • Study of the detection and resolution capabilities of a one-dimensional array of sensors by using differential geometry

    Publication Year: 1994 , Page(s): 83 - 92
    Cited by:  Papers (18)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (580 KB)  

    The paper is concerned with the investigation of the detection and resolution capabilities inherent to the manifold of a linear (1-dimensional) array of omnidirectional sensors, not necessarily uniform. An initial discussion, associated with the shape of the manifold of a linear array, is presented by the application of differential geometry in complex space. The shape of the manifold, which for the case of linear arrays is a hyperhelix, can be fully characterised by its length and curvatures. In this paper it is shown that the array manifold may be locally approximated by a circular arc whose radius is the inverse of the manifold's first curvature. By using the above approximation, expressions for the thresholds of resolution and detection are derived as a function of the manifold length and first curvature even for sources of unequal powers. Two laws are established: the fourth-root law which is related to the resolution problem and the square-root law which is related to the detection problem. The overall conclusion is that the thresholds predicted via differential geometry concepts represent basic performance measures for assessing and comparing the performance of different linear array geometries irrespective of the algorithm used View full abstract»

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Aims & Scope

IEE Proceedings Radar, Sonar and Navigation covers the theory and practice of systems involving the processing of signals for radar, radio location, radio navigation and surveillance purposes.

Full Aims & Scope