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IEEE Transactions on Aerospace and Electronic Systems

Issue 1 • Jan. 1990

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Displaying Results 1 - 17 of 17
  • Comments, with reply, on "A new look at nonseparable synthetic aperture radar processing" by A. Di Cenzo

    Publication Year: 1990, Page(s):195 - 197
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (222 KB)

    The commenters point out that the idea using a two-dimensional digital correlation technique to perform synthetic-aperture-radar (SAR) processing, presented as new in the above-titled paper (see ibid., vol.24, p.218-23, May 1988), was described by them as early as 1978 and has since been described by other authors. They discuss some of these earlier studies. The author replies that he was unaware ... View full abstract»

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  • A model for target detection with over-the-horizon radar

    Publication Year: 1990, Page(s):68 - 83
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1048 KB)

    The effects of including Faraday rotation and multipath on the probability of detecting low-flying, distant, fluctuating and nonfluctuating targets immersed in Rayleigh noise plus clutter are studied. The effect of ionospheric fluctuations is also considered. It is found that both multipath and Faraday rotation strongly influence the detection statistics, with the effect being greatest for linearl... View full abstract»

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  • Moving target imaging algorithm for SAR data

    Publication Year: 1990, Page(s):57 - 67
    Cited by:  Papers (113)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (724 KB)

    A digital processing algorithm for fine-resolution imaging of synthetic aperture radar (SAR) moving targets is described. The targets may have any translational and rotational motion components relative to the data collection platform. The algorithm requires the presence of up to three prominent points in the image of the target; the signals from these points provide estimates of the unknown targe... View full abstract»

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  • Convergence properties of Gram-Schmidt and SMI adaptive algorithms

    Publication Year: 1990, Page(s):44 - 56
    Cited by:  Papers (38)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    The open-loop Gram-Schmidt (GS) canceler is shown to be numerically identical to the sampled matrix inversion (SMI) algorithm in the transient state if infinite numerical accuracy is assumed. Two forms of the GS canceler are discussed and analyzed: concurrent and nonconcurrent processing. Results for concurrent and nonconcurrent SMI cancelers have been obtained in the past by I.S. Reed, J.D. Malle... View full abstract»

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  • On-orbit calibration of satellite antenna-pointing errors

    Publication Year: 1990, Page(s):88 - 112
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1232 KB)

    A pragmatic approach is presented to the on-orbit calibration of the spaceborne gimbaled parabolic reflector antennas to enhance their pointing and tracking accuracies in the presence of unknown structural deformations and other errors. The technique described is based on the second-order extended Kalman filter. Except for some knowledge of Kalman filtering, the work is self-contained and tutorial... View full abstract»

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  • A novel multistage estimation of signal parameters

    Publication Year: 1990, Page(s):181 - 194
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1020 KB)

    A multistage estimation scheme is presented for estimating the parameters of a received carrier signal possibly phase-modulated by unknown data and experiencing very high Doppler, Doppler rate, etc. Such a situation arises, for example, in the case of the Global Positioning Systems (GPS). In the proposed scheme, the first-stage estimator operates as a coarse estimator of the frequency and its deri... View full abstract»

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  • Maximum likelihood azimuth estimation applied to SSR/IFF systems

    Publication Year: 1990, Page(s):27 - 43
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1068 KB)

    A conventional (nonmonopulse) secondary surveillance radar (SSR) is significantly cheaper than a monopulse SSR but exhibits much greater azimuthal error, especially when some of the replies are missing. Estimation techniques and their performance are discussed with special reference to SSR applications, and a novel estimator for conventional SSR is described. The proposed technique is a close appr... View full abstract»

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  • Reducing geometric dilution of precision using ridge regression

    Publication Year: 1990, Page(s):154 - 168
    Cited by:  Papers (12)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1084 KB)

    A signal processing technique is proposed for improving position-fix navigation system accuracy performance when the geometry of the navigation landmarks (e.g. sensors) are nearly collinear. In the navigation literature, the accuracy degradation associated with a nearly collinear measure geometry is termed the geometric dilution of precision (GDOP). Its presence causes not only the variance of the... View full abstract»

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  • A performance analysis of DS-CDMA and SCPC VSAT networks

    Publication Year: 1990, Page(s):12 - 21
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    Spread-spectrum and single-channel-per-carrier (SCPC) transmission techniques work well in very small aperture terminal (VSAT) networks for multiple-access purposes while allowing the Earth station antennas to remain small. Direct-sequence code-division multiple-access (DS-CDMA) is the simplest spread-spectrum technique to use in a VSAT network since a frequency synthesizer is not required for eac... View full abstract»

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  • Ensembling clocks of Global Positioning System

    Publication Year: 1990, Page(s):84 - 87
    Cited by:  Papers (4)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    The Global Positioning System (GPS) is a satellite navigation system capable of providing 15-m position accuracy. Its system time reference is currently one of the monitor station clocks. Using a simple two-clock example, it is shown analytically that improved reference time stability and overall state estimation accuracy can be achieved by constructing GPS time as an ensemble of all system clocks... View full abstract»

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  • Analysis of some modified ordered statistic CFAR: OSGO and OSSO CFAR

    Publication Year: 1990, Page(s):197 - 202
    Cited by:  Papers (39)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    It is necessary for automatic detection radars to be adaptive to variations in background clutter in order to maintain a constant false alarm rate (CFAR). A CFAR based on an ordered statistic technique (OS CFAR) has some advantages over the cell-averaging technique (CA CFAR), especially in clutter edges or multiple target environments; unfortunately the large processing time required by this techn... View full abstract»

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  • Improved multi-target tracking in clutter by PDA smoothing

    Publication Year: 1990, Page(s):113 - 121
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (660 KB)

    An algorithm is presented for the recursive tracking of multiple targets in cluttered environment by making use of the joint probabilistic data association fixed-lag smoothing (JPDAS) techniques. It is shown that a significant improvement in the accuracy of track estimation of both nonmaneuvering and maneuvering targets may be achieved by introducing a time lag of one or two sampling periods betwe... View full abstract»

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  • Digital accumulators in phase and frequency tracking loops

    Publication Year: 1990, Page(s):169 - 180
    Cited by:  Papers (5)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (812 KB)

    Results on the effects of digital accumulators in phase and frequency tracking loops are presented. Digital accumulators or summers are used extensively in digital signal processing to perform averaging or to reduce processing rates to acceptable levels. For tracking the Doppler of high-dynamic targets at low carrier-to-noise ratios, it is shown through simulation and experiment that digital accum... View full abstract»

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  • Model-based segmentation of FLIR images

    Publication Year: 1990, Page(s):2 - 11
    Cited by:  Papers (30)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (792 KB)

    The use of gray-scale intensities together with the edge information present in a forward-looking infrared (FLIR) image to obtain a precise and accurate segmentation of a target is presented. A model of FLIR images based on gray-scale and edge information is incorporated in a gradient relaxation technique which explicitly maximizes a criterion function based on the inconsistency and ambiguity of c... View full abstract»

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  • False alarm control using Doppler estimation

    Publication Year: 1990, Page(s):146 - 153
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB)

    A technique which uses maximum-likelihood estimates (MLEs) of target Doppler and target amplitude is developed for rejecting clutter residues. Multiple estimates are made and consistency checks are applied to the estimates. Simulation results indicate that for large clutter-to-noise ratios (C/N⩾55 dB) the probability of false alarm from clutter residues is reduced from 1.0 to... View full abstract»

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  • Effect of bias on bearing-only target location

    Publication Year: 1990, Page(s):22 - 26
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The influence of angle measurement bias on passive target location estimation is investigated. First the conditions for target observability are found and generalized to the non-zero-mean measurement noise case. Then the Cramer-Rao lower bound on the estimation error is derived. Numerical examples are included, illustrating the target location uncertainty in the presence of measurement bias View full abstract»

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  • Nonlinear target enhancement for the hostile nuclear environment

    Publication Year: 1990, Page(s):122 - 145
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1748 KB)

    A necessary requirement of a strategic defence system is the detection of incoming nuclear warheads in an environment that may include nuclear detonations of undetected or missed target warheads. A computer model which simulates incoming warheads as distant endoatmospheric targets is described. A model of the electromagnetic noise expected in the nuclear environment is developed. Predicted atmosph... View full abstract»

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Aims & Scope

IEEE Transactions on Aerospace and Electronic Systems focuses on the organization, design, development, integration, and operation of complex systems for space, air, ocean, or ground environment.  These systems include, but are not limited to, navigation, avionics, spacecraft, aerospace power, radar, sonar, telemetry, defense, transportation, automated testing, and command and control. 

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Lance Kaplan
Army Research Laboratory