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Aerospace and Electronic Systems, IEEE Transactions on

Issue 4 • Date July 1979

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Displaying Results 1 - 25 of 28
  • Table of contents

    Publication Year: 1979 , Page(s): c1
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  • IEEE Aerospace and Electronic Systems Society

    Publication Year: 1979 , Page(s): c2 - 591a
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  • From the Editors

    Publication Year: 1979 , Page(s): 465
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  • Packet Radio Monitoring Via Repeater-On-Packets

    Publication Year: 1979 , Page(s): 466 - 473
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    The packet radio network (PRNET) is a store-and-forward packet switching system consisting of switching nodes which share a single radio communication channel. Recent studies have shown that PRNETs can easily be saturated and become unstable unless efficient routing and flow control algorithms are used. To enable point-to-point packet transportation, network stations assign a code (label) to each repeater; the process of assigning such labels is referred to as "network initialization." The initialization procedure assumes that the network topology is now known a priori and is changing with time. Thus the initialization procedure involves mapping of network topology, determining network structure (labels for repeaters), and transmitting labels to the repeaters. Although many authors have developed analytical models to study channel access schemes, no one has yet addressed the initialization issue. We present a Markov chain model which enables one to obtain in close form the optimal rates at which repeaters and station must transmit repeater-on-packets (ROPs) and label packets (LLPs) to minimize the network initialization time in a one-hop network, finite buffer station. Our most important result is that the network initialization time is relatively insensitive to the station transmission rate, but the repeater transmission rate must be carefully chosen to achieve rapid initialization. View full abstract»

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  • Probability Densities and Characteristic Functions for Fluctuating Targets

    Publication Year: 1979 , Page(s): 474 - 480
    Cited by:  Papers (1)
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    Probability density functions and characteristic functions for the projected area of a tumbling target object are derived together with the densities and characteristic functions for the corresponding signal-plus-noise voltage output of an infrared sensor. Several cases are considered in which the signal pulse arrival time is either known or unknown, a matched filter or a suboptimum filter is used; the signal pulse shape is either Gaussian or is unspecified; and the target orientation angles are either uniformly or nonuniformly distributed. View full abstract»

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  • Integrating Voice and Data on Circuit-Switched Networks

    Publication Year: 1979 , Page(s): 481 - 493
    Cited by:  Papers (2)
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    Integrating voice and data traffic on a common network using circuit switching is considered. A reasonable design methodology was employed to probe a variety of economic issues. Among these were the cost benefits of voice digitization, the effect of data terminal user behavior, and the overhead of network signaling. View full abstract»

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  • Modeling and Performance Evaluation of Nonlinear Satellite Links-A Volterra Series Approach

    Publication Year: 1979 , Page(s): 494 - 507
    Cited by:  Papers (104)
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    An analytical solution to the problem of modeling bandpass nonlinear channels and evaluating the performance of digital communication systems operating on them is presented. A method based on a Volterra series representation of the overall channel is first proposed, which allows one to extend to nonlinearities with memory the well-known concepts of complex envelope of bandpass signals and low-pass equivalent of bandpass linear systems. The general results previously mentioned are then applied to digital satellite communication systems operating over nonlinear channels. The effect of a nonlinear amplifier located in the satellite is considered, in combination with that of transmitting and receiving filters located in the Earth stations. In addition, both uplink and downlink noise are taken into account. Basic advantages of this approach are the generality it offers to the analysis and the fact that it allows accurate evaluation of the error probability in a short computer time. View full abstract»

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  • Automated Tracking for Aircraft Surveillance Radar Systems

    Publication Year: 1979 , Page(s): 508 - 517
    Cited by:  Papers (4)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3430 KB)  

    An improved moving target detector (MTD) (a digital signal processor) has been designed, constructed, and tested which successfully rejects all forms of radar clutter while providing reliable detection of all aircraft within the coverage of the radar. The MTD is being tested on both terminal and enroute surveillance radars for the FAA. This processor has been integrated with automatic tracking algorithms to give complete rejection of ground clutter, heavy precipitation, and angels (birds). View full abstract»

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  • Small Signal Compensation of Magnetic Fields Resulting from Aircraft Maneuvers

    Publication Year: 1979 , Page(s): 518 - 525
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1583 KB)  

    Tolles and Lawson identified three permanent, five induced, and eight eddy-current fields as sources of magnetic interference associated with airframe maneuvers. Small signal approximations are used here to separate the eddy-current terms and thus decouple the sixteen equations into two sets of eight equations. It was found that a singularity exists in the small signal equations for the permanent and induced terms. This causes an ambiguity amoung three of the coefficients which can be resolved mathematically by resorting to large maneuvers. Flight test data exhibit a large amount of magnetic hysteresis and the magnetic anomality detector (MAD) equipped aircraft will not remain compensated from one flight to the next. This complicates the problem of resolving the dip angle ambiguity. Furthermore, significant differences exist in the compensation terms as determined from manual pilot maneuvers and the terms when the maneuvers are performed by the automatic pilot. This has been attributed to differences in altitude stability and the frequency content of the maneuvers. It was found that both optimal frequency filtering and altitude compensation can be used to improve the figure of merit (FOM) resulting from pilot maneuvers. View full abstract»

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  • Detectability of Spread-Spectrum Signals

    Publication Year: 1979 , Page(s): 526 - 537
    Cited by:  Papers (47)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2191 KB)  

    Methods of detecting spread-sprectrum signals without knowledge of the pseudorandom code used to generate the signal are described. Exact and approximate methods of calculating relationships among detection probability, false alarm rate, and signal-to-noise ratio are given for radiometers and for channelized pulse-detection systems. The detection performance of the radiometer is compared graphically with that of pulse-detection systems, for two different kinds of pulse detection decision rules. Detection performance as a function of certain signal parameters is shown to be very different for a pulse-detection system than for a radiometer, and this difference in behavior provides a basis for selecting signal parameters that minimize the probability of detection. The reasoning that underlies the selection process is explained, and the process is outlined for each of several signal parameters. View full abstract»

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  • Adaptive Clutter Filtering Using Autogressive Spectral Estimation

    Publication Year: 1979 , Page(s): 538 - 546
    Cited by:  Papers (15)  |  Patents (2)
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    A new adaptive filter to reject clutter is derived using autoregressive spectral analysis techniques. The adaptive filter performs open. Ioop processing, resulting in a shorter transient response, and is therefore suitable for radar waveforms containing only a small number of samples. A number of examples including application to ballistic missile defense are presented to demonstrate the performance capabilities of the new adaptive filter. View full abstract»

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  • Range Correlation Guidance for Cruise Missiles

    Publication Year: 1979 , Page(s): 547 - 554
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1700 KB)  

    A dual-mode position updating system for extended long-range cruise missiles is presented. During either extremely high-or low-altitude cruise missile flight, this system can periodically establish the actual position of the cruise missile by comparing prestored reference data with radar-return data obtained from an onboard conventional radar operated in either a range-only or an altimeter mode. The general features of this position updating system and details of the range-only concept are presented. This includes a discription of the radar system, the data processor, the prestored reference data, and the system performance characteristics. View full abstract»

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  • Multiradar Tracking System Using Radial Velocity Measurements

    Publication Year: 1979 , Page(s): 555 - 563
    Cited by:  Papers (5)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1530 KB)  

    Multiradar tracking using both position and radial velocity measurements is discussed. The measurement of two or more different radial velocity components allows the calculation of rectangular velocity components. The measurement noise of the velocity components is filtered using a Kalman filter in the same way as the Cartesian position components. Before the conversion of velocity components from radial to Cartesian coordinates, the radial velocities are aligned on a time scale to account for the time shift of the radar measurements. In order to compare multiradar tracking system performance with and without radial velocity, some simulation tests have been performed for typical paths. The simulation results show a significant improvement when radial velocity is used for tracking. View full abstract»

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  • The GYROLITE: Is it Unstable?

    Publication Year: 1979 , Page(s): 565 - 567
    Cited by:  Papers (1)
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    A new derivation of the GYROLITE stability criterion is presented. It is confirmed that, for the satellite to have a stable attitude, the spinning part must have a favorable inertia ratio. View full abstract»

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  • On Increasing Usable MTI Filter Bandwidth by Removing Linear-Phase Constraint

    Publication Year: 1979 , Page(s): 567 - 570
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    It has been shown in the literature that the linear-phase constraint of finite-duration impulse-response (FIR) digital filters can, under certain circumstances, be effectively traded either for a better filter amplitude response or a reduction in the number of filter coeficients. It is shown that such a tradeoff can be exploited for moving target indicator (MTI) radar signal processors to increase the usable bandwidth for target detection. Although it is demonstrated that the increase is significant for narrowband (ground) clutter, it is negligible for wideband (weather) clutter. View full abstract»

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  • Performance Analysis of Adaptive Processors via Diffusion Model Approximations and the Fokker-Planck Equation

    Publication Year: 1979 , Page(s): 570 - 571
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    Some results on adaptive array processors and adaptive filters that have been obtainsd by the use of diffusion model approximations and the Fokker-Planck equation are described. View full abstract»

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  • Performance of Likelihood Ratio Processors

    Publication Year: 1979 , Page(s): 571 - 573
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    Summarized by its ROC curve, the performance of a Bayes optimal detector is a function of two joint a priori probability density functions on the uncertain parameters involved. An investigation is made to determine at what point in the generation of an ROC curve for a given pair of priors sufficient information is retained for the calculation of a new ROC based on a different pair of priors. View full abstract»

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  • Trimmed Generalized Sign and Modified Median Detectors for Multiple Target Situations

    Publication Year: 1979 , Page(s): 573 - 575
    Cited by:  Papers (1)
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    The trimmed generalized sign (TGS) nonparametric detector is introduced. The TGS and the modified median detector (MMD) are considered in situations when more than one target is present. Their performance is obtained through Monte Carlo simulations and compared with that of the generalized sign (GS) detector when detecting nonfluctuating signal in Gaussian noise. View full abstract»

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  • Maximizing the Utility of Two Existing Radionavigation Systems

    Publication Year: 1979 , Page(s): 575 - 576
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    First Page of the Article
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  • Reference Loop Phase Shift in an N-Element Adaptive Array

    Publication Year: 1979 , Page(s): 576 - 582
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (839 KB)  

    Adaptive arrays based on the LMS algorithm require the generation of a reference signal which is usually derived from the array output. A particular problem associated with this technique is that of a phase shift in the reference signal loop. The effects of this phase shift on the performance of an N-element adaptive array are discussed. It is shown that a reference loop phase shift causes the array weights to cycle, thereby frequency translating the signals at the output. The weight-cycling frequency is related to various system parameters of an N-element array. In particular, it is observed that the cycling frequency increases as the number of antennas (N) increases. View full abstract»

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  • Corrections to "A Family of Air Traffic Control Radars"

    Publication Year: 1979 , Page(s): 582
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  • Corrections to "Ambiguity Resolution for Satellite Doppler Positioning Systems"

    Publication Year: 1979 , Page(s): 582
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  • Harry Rowe Mimno Award for 1979

    Publication Year: 1979 , Page(s): 583
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  • H. R. McNaught Personal Reminiscences of Harry Rowe Mimno

    Publication Year: 1979 , Page(s): 584 - 587
    Cited by:  Papers (1)
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    First Page of the Article
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  • Call for Pioneer Award Nominations

    Publication Year: 1979 , Page(s): 588
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Aims & Scope

IEEE Transactions on Aerospace and Electronic Systems focuses on the equipment, procedures, and techniques applicable to the organization, installation, and operation of functional systems designed to meet the high performance requirements of earth and space systems.

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Meet Our Editors

Editor-in-Chief
Lance Kaplan
Army Research Laboratory