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Aerospace and Electronic Systems, IEEE Transactions on

Issue 4 • Date July 1976

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Displaying Results 1 - 23 of 23
  • Table of contents

    Publication Year: 1976 , Page(s): c1
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  • IEEE Aerospace and Electronic Systems Society

    Publication Year: 1976 , Page(s): c2 - 528a
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  • From the Editors

    Publication Year: 1976 , Page(s): 433
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  • On the Design of Suboptimal Controllers for Minimal Time Feedback Regulators

    Publication Year: 1976 , Page(s): 434 - 438
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1773 KB)  

    A method for designing suboptimal minimal time controllers for linear, time-invariant regulator systems is presented. An economical closed-loop controller is obtained by using Lyapunov surfaces, corresponding to a quadratic Lyapunov function, as a continuous approximation for isochronal surfaces. Systems employing this controller are obtained by minimization, with respect to parameters of the quadratic Lyapunov function, of the worst case upper bound on the arrival time of an arbitrary initial state at the origin. View full abstract»

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  • Perspectives for Strategic Analysis in Advancing Ocean Technology

    Publication Year: 1976 , Page(s): 439 - 443
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    There is a growing need for the scientist, engineer, and administrator to better understand the kinds of overall, across-the-board planning problems involved in the development of off-shore coastal areas. A recommended approach is to use systems analysis techniques. Principles will be set forth on maintaining and improving the quality of the ocean environment, with considerations of cost in so doing. Each proponent of an aspect of ocean technology usually believes that his field must be greatly enlarged in the near future. Along with these advances there is the likelihood of unnecessary social costs emanating from undesirable modifications of the environment. In making the analysis, an early step is to identify specific needs and appropriate roles. A next step is to lay out alternatives for achieving objectives both within a given organization and external to it. The alternatives may be appraised through their costs and benefits. But how do you make choices between goals when resources are limited? How can we gather the data, accomplish the evaluation, and do the planning that will make rational choices possible? This paper elucidates the problems involved in these kinds of questions and suggests methodology that might lead toward solutions. View full abstract»

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  • High Power Radar Implementation of Coherent Waveforms

    Publication Year: 1976 , Page(s): 444 - 450
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2473 KB)  

    The radar use of coherent burst waveforms to obtain clutter suppression is summarized and problems arising from the high power implementation of such waveforms are discussed. These problems arise from the nonlinear nature of the typical high power radar transmitter and result in loss of subpulse-to-subpulse amplitude and phase accuracies, causing clutter suppression degradation. adaptive control loop used to measure transmission errors and provide continuous updating to minimize such errors is proposed. Residual transmission errors resulting via use of the control loop are calculated and shown to have an insignificant effect upon the clutter suppression properties of the coherent waveform. Experimental verification of control loop performance is presented. View full abstract»

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  • Limiter Intermodulation Improvement Due to Selective Carrier Spacing

    Publication Year: 1976 , Page(s): 451 - 458
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2537 KB)  

    In many space communications applications, the intermodulation between carriers, due to limiting in a common amplifier, reduces the overall signal-to-noise ratio of the signal received at the ground station. By selectively spacing the carriers, one is often able to avoid the strong or low-order intermodulation. The question arises how much improvement is gained in carrier-to-interference ratio and signal-to-interference ratio by selectively spacing carriers such that low-order cross products are avoided or their impact is effectively reduced. The following analysis investigates interference improvement due to selective carrier spacing for several spacing sequences relative to equal carrier spacing. It is shown that the intermodulation noise reduction depends on the carrier packing density of the selected spacing sequence. The carrier-to-intermodulation noise ratio increases with the number of participating carriers, while the bandwidth efficiency decreases. The signal-to-intermodulation noise ratio improves not only because of the improved carrier-to-intermodulation noise ratio, but also because the remaining interference components have spectra with larger frequency spreading. View full abstract»

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  • A Functionally Redundant Altimeter

    Publication Year: 1976 , Page(s): 459 - 463
    Cited by:  Papers (2)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1710 KB)  

    A scheme to provide redundant sensor data in an automatic control system using the principle of functional redundancy is described. Normally there are three redundant radar altimeters used in the terminal phase of automatic landing of jet transport airplanes. This scheme replaces one of these altimeters with a data processing scheme based on a Kalman filter. The filter is driven by altitude rate and acceleration signals from the air data computer and vertical accelerometer. A special initialization technique employs the two altimeter signals. The feasibility of this scheme is indicated by tests in which data obtained from these several sensors during flight tests are used to drive the functionally redundant altimeter. View full abstract»

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  • Energy Management for Fuel Conservation in Transport Aircraft

    Publication Year: 1976 , Page(s): 464 - 471
    Cited by:  Papers (2)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2611 KB)  

    Optimal control techniques have been applied to the problem of conserving fuel in C-141A aircraft. Numberical results form the basis for designing an on-board energy management system, which can automatically command fuel-optimal climb, cruise, and descent flight paths for a majority of this aircraft's missions. View full abstract»

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  • The closed-form solution of true proportional navigation

    Publication Year: 1976 , Page(s): 472 - 482
    Cited by:  Papers (38)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2208 KB)  

    The closed-form solution of the equations of motion of an ideal missile pursuing a nonmaneuvering target according to the true propotional navigation law is obtained. An analysis of the solution is performed, and the conditions necessary for the missile to reach the target are determined. View full abstract»

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  • Dynamics of Wind Generators on Electric Utility Networks

    Publication Year: 1976 , Page(s): 483 - 493
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2628 KB)  

    Dynamic interaction of wind-turbine-driven generators on electric utility networks was studied by computer simulation. Nonlinear representations of wind-turbine and various drive train elements and Park equation representations of synchronous and induction generators were implemented. An infinite capacity network was assumed. Time history responses for various system configurations were computed using as the input function severe wind gust data added to cyclical torque variations occurring at turbine blade frequency. Results indicated that severe transient mechanical and electrical stresses can be induced for certain system configurations. Best results were obtained by interposing rate or damped compliant couplings between the wind turbine and a synchronous generator. The induction generator did not appear to require such means. Blade pitch control (or equivalent) was required to limit output above rated wind velocities for wind turbines configured to produce maximum mum specific power. The blade pitch control loop must exhibit high performance to limit transient overshoots. An aerodynamically limited turbine driving an induction generator exhibited good response without the need for blade pitch control, but at the cost of increased turbine rotor diameter. Further work is indicated, taking into account wind-turbine aeroelastic effects, finite capacity networks, and other factors. View full abstract»

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  • On the Perfomance of Air Traffic Control Radar Beacon System

    Publication Year: 1976 , Page(s): 494 - 502
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2800 KB)  

    The sidelobe suppression and improved sidelobe suppression mode performance of terminal and enroute air traffic control radar beacon systems using the existing antenna and a typical improved antenna in the presence of perfectly dielectric flat ground are investigated theoretically. Necessary analytical expressions for various quantities characterizing the system performance have been derived. A general purpose computer program has been developed for the computation and tabulation of these quantities as functions of the elevation angle of the observation point and for different combinations of heights of the directional and omnidirectional antennas of the beacon. Although the discussions given here apply to some specific antenna configurations, the theoretical method developed has more general application in evaluating quantitatively the performance of the beacon system in a given situation. View full abstract»

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  • Signal to Noise Ratio Improvement by Frequency Division in the Presence of Bandpass Noise

    Publication Year: 1976 , Page(s): 503 - 505
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    The performance of a wide band frequency divider in the presence of additive Gaussian noise is presented. It is shown that the same theoretical signal to noise ratio improvement is attainable in this case as in the case where the spurious signal is a sine wave. View full abstract»

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  • Limiting Performance of Generalized Sign Test Detector

    Publication Year: 1976 , Page(s): 505 - 509
    Cited by:  Papers (1)
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    The limiting performance of the generalized sign test detector as the number M of target returns becomes infinite has been derived by Hansen and Olsen [1]. Simple expressions are derived herein for the limiting performance for finite M as K, the number of noise samples in the reference set, becomes infinite. Curves are presented which indicate how this limiting performance is approached as K is increased for both constant target returns and fluctuating target returns. View full abstract»

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  • A Note on the Application of the Basic Kinematical Law

    Publication Year: 1976 , Page(s): 509
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    A set of guidelines is presented for correctly deriving the motion equations for a space vehicle by using the basic law of kinematics. View full abstract»

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  • Compensators for Bandpass Nonlinearities in Satellite Communications

    Publication Year: 1976 , Page(s): 509 - 514
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB)  

    The characteristics of optimum compensators for bandpass non-linearities are described. A predistortion compensator to reduce the nonlinear phase and envelope distortion at the output of a traveling-wave tube (TWT) is developed, and a possible implementation as a simple network of power law devices in cascade with the input to the TWT is given. The overall compensated characteristic of the TWT approximates that of a piecewise linear limiter with a small phase shift. A computer simulation shows that the compensated system yields 0.3 to 0.5-dB improvement in performance of a 2-phase coherent phase shift keying (CPSK) system over the uncompensated system. View full abstract»

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  • Stability of 2-Degree-of-Freedom Gyro in a Spinning Vehicle

    Publication Year: 1976 , Page(s): 514 - 517
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    Using the Lyapunov approach, the conditions are presented for the stability of the spin axis of a 2-degree-of-freedom gyro which is mounted in a spinning vehicle. View full abstract»

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  • Error Probability in Binary Digital Communication in the Presence of an Interfering Signal

    Publication Year: 1976 , Page(s): 517 - 519
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (463 KB)  

    The presence of an interferring signal i(t) in a binary coherent symmetric channel is investigated. The probability of error is maximum when i(t) is antipodal to the transmitted signal, so(t) or s1 (t). The error probability is derived in the presence of a delayed interfering signal - so (t - r), where r is the time delay. An example of phase shift keying signals is given. View full abstract»

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  • Performance Degradation of MTI Circuits Due to Amplitude Limiting

    Publication Year: 1976 , Page(s): 519 - 522
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    The loss in output signal-to-noise ratio (SNR) due to amplitude limiting is obtained for a radar circuit consisting of a bandpass limiter, coherent demodulator, matched filter, and moving-target-indicator (MTI) filter. The circuit is used in scanning MTI radars. The tandem connection of the limiter and coherent demodulator is a model for the saturation of the intermediate-frequency (IF) demodulator of an MTI radar. Results on special functions are used to obtain simple formulas for the loss in output SNR relative to a linear IF demodulator when the input SNR is less than -15 dB and the number of hits per 3-dB beamwidth exceeds 15. View full abstract»

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  • Defending a Moving Target Against Missile or Torpedo Attack

    Publication Year: 1976 , Page(s): 522 - 526
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (935 KB)  

    Problems involving kinematics of a counterweapon intercepting an attacking missile are well known. However, when the attacker's target, the counterweapon's launch platform, is moving, the problem generally becomes amenable only to trajectory simulation. Such may be the case in defense against torpedo attack against a ship and other situations involving the use of antimissile missiles. This paper derives the kinematic relations among the three bodies (missile, target, and counterweapon) in closed form under the asymptotic approximation of constant-bearing trajectories (collision courses). It is shown that the defending target, even if moving, can still determine the optimum course for its counterweapon when range and speed of the attacking vehicle are unknown. A simple relation is derived for the ratio between the attacker-target range (and time to impact) at counterweapon launch and the range at interception of the attacker by the counterweapon. Normalized curves are presented for some representative cases of defense by a counterweapon of known speed against a torpedo or missile attack on a moving target. The equations are shown to reduce to the familiar form for a stationary target. View full abstract»

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  • Correction to "Strapdown Matrix Orthogonalization: The Dual Iterative Algorithm"

    Publication Year: 1976 , Page(s): 526
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  • 1976 Pioneer Award

    Publication Year: 1976 , Page(s): 527
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  • Information for authors

    Publication Year: 1976 , Page(s): 528
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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