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Aerospace and Electronic Systems, IEEE Transactions on

Issue 3  Part 1 • Date Jul 2000

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  • Admittance space stability analysis of power electronic systems

    Publication Year: 2000 , Page(s): 965 - 973
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB)  

    Power electronics based power distribution systems (PEDSs) are becoming increasingly common, particularly in marine and aerospace applications. Stability analysis of this class of systems is crucial due to the potential for negative impedance instability. Existing techniques of stability analysis introduce artificial conservativeness, are sensitive to component grouping, and at the same time do not explicitly address uncertainties and variations in operating point. A new stability criterion, which reduces artificial conservativeness and is also insensitive to component grouping is described. In addition, a means of readily establishing design specifications from an arbitrary stability criterion which specifically includes a provision to incorporate uncertainty, parameter variation, and nonlinearities is set forth. The method is presented in the context of a hardware test system and is experimentally validated. View full abstract»

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  • Line-of-sight pointing accuracy improvements through analytic boresighting

    Publication Year: 2000 , Page(s): 974 - 982
    Cited by:  Papers (88)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

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  • Transfer circuit for measuring individual battery voltages in series packs

    Publication Year: 2000 , Page(s): 933 - 940
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

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  • 1999 Pioneer Award

    Publication Year: 2000 , Page(s): 1013 - 1015
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    Freely Available from IEEE
  • Source tracking with a gradient-based eigenstructure algorithm

    Publication Year: 2000 , Page(s): 859 - 868
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    A new gradient-based eigenstructure algorithm to locate and track the azimuth and elevation angles of unknown sources in a 3-dimensional environment is proposed and investigated. Starting from initial estimates of the source locations from, say, a coarse search of the multiple signal classification (MUSIC) spectrum, the algorithm obtains better estimates and tracks sources in a repetitive cyclical manner. To refine a particular source location estimate: (1) a preprocessor is designed to remove the effects of the other sources; (2) the eigenvector for the largest eigenvalue of the covariance matrix after preprocessing is found and its difference from the ideal value is determined; and finally (3) a gradient calculation is used to obtain an estimate for the difference of the assumed source location from the actual position. The advantages of using the proposed technique rather than performing a thorough MUSIC search in the 2-dimensional spectrum are: (1) the implementation complexity can be reduced considerably, and (2) the algorithm is well suited to be employed for continuous adaptive filtering purposes in a tracking scenario View full abstract»

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  • Scalar-based direct algorithm mapping FPLD implementation of a Kalman filter

    Publication Year: 2000 , Page(s): 879 - 888
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB)  

    A methodology of the scalar-based direct algorithm mapping (SBDAM) is defined and presented. The methodology uses direct mapping of the arithmetic expressions on to a field-programmable logic device (FPLD). A Kalman filter used in multiple target tracking (MTT) applications has been implemented in FPLD via SBDAM and via the other matrix-based systolic algorithm engineering (MBSAE) approach. The comparison between SBDAM and MBSAE drawn from this example is given in terms of various performance measures such as speed of the resulting circuit, required space (resource) requirements, ease of development, and others View full abstract»

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  • Polarimetric classification of scattering centers using M-ary Bayesian decision rules

    Publication Year: 2000 , Page(s): 738 - 749
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB)  

    A Bayes-optimal decision rule is presented for detection and classification of scattering centers in clutter. Scattering centers are modeled as one of M canonical reflectors with unknown amplitude, phase and orientation angle; clutter is modeled as a spherically invariant random vector. A choice of costs in the Bayes risk is shown to yield a two-stage classification rule. The first stage is a Neyman-Pearson detector which rejects clutter, whereas the second stage classifies the detection in one of the M target classes. The resulting decision rule yields computationally simple implementation, intuitive geometric interpretation, and posterior estimation of decision uncertainty. Performance of the proposed classifier is illustrated on imagery from an airborne UHF-hand radar View full abstract»

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  • Communications capacity analysis for multiple-beam processing satellites

    Publication Year: 2000 , Page(s): 941 - 947
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    This paper analytically compares the communications capacity of various satellite payload architectures against a fixed quality of service (QoS) metric which is connection blocking probability. The effectiveness of the payload architectures is dependent on the payload switching technique, multiple access scheme, and the number of satellite antenna beams utilized. The payloads considered are an on-board circuit switch and an on-board asynchronous transfer mode (ATM) switch. It is shown that a demand assigned multiple access scheme (DAMA) with an on-board ATM switch provides the best performance in terms of communications payload resource utilization. It is also shown that DAMA with a circuit-switched payload provides efficient performance if the number of satellite beams employed is small. Finally, it is shown that the degree of DAMA resource sharing allowed in the system strongly influences resource utilization performance. The sensitivity of these results to key system parameters is determined and further work in this area is proposed View full abstract»

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  • Doppler tracker for a spaceborne ScanSAR system

    Publication Year: 2000 , Page(s): 907 - 924
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB)  

    This paper presents a methodology for tracking the Doppler parameters in long swaths of ScanSAR signals. The approach is entirely developed around the physical model of the Doppler effect, parameterized in terms of the spacecraft attitude angles. A new, combined algorithm is designed to estimate yaw and pitch and resolve the PRF (pulse repetition frequency) ambiguity using all available, current, and past, return samples. It is shown that the variance of the Doppler centroid (DC) estimates can be brought down to the low single-digit Hz level with computationally simple estimation algorithms View full abstract»

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  • Multiple model bootstrap filter for maneuvering target tracking

    Publication Year: 2000 , Page(s): 1006 - 1012
    Cited by:  Papers (56)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB)  

    The extension of the bootstrap filter to the multiple model target tracking problem is considered. Bayesian bootstrap filtering is a very powerful technique since it represents samples by random samples and is therefore not restricted to linear, Gaussian systems, making it ideal for the multiple model problem where very complex densities can be generated View full abstract»

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  • Fusion of reduced-rank TMA estimates

    Publication Year: 2000 , Page(s): 750 - 759
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    The problem of bearings-only target motion analysis (TMA) in incompletely observable situations is considered. Both target and observer trajectories are rectilinear uniform motions (RUMs). A specific method is first established for the estimation of such reduced-rank TMA (RR-TMA). Then, the statistical fusion of two (or more) RR-TMA estimates into a complete observable TMA is established. Remarkably, this second stage is analytical. Finally the fusion algorithm is shown to be efficient for a reasonable domain of measurement errors. Applications are listed among radar and sonar tracking problems. They are specially encountered in large-scale multiplatform situations where combinatorial testing of multiple hypotheses is a big issue, or in long-term integration of moving targets where the dimension reduction of the search-grid is critical View full abstract»

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  • Multisensor tracking of a maneuvering target in clutter using IMMPDA fixed-lag smoothing

    Publication Year: 2000 , Page(s): 983 - 991
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    We present a suboptimal fixed-lag smoothing algorithm for tracking a highly maneuvering target in a cluttered environment using multiple sensors. The fixed-lag smoothing algorithm is developed by applying the basic interacting multiple model (IMM) approach and the probabilistic data association (PDA) technique to a state-augmented system. In the past this approach had been restricted to Markovian switching systems with no uncertainty regarding the origin of the measurements (i.e., no clutter). The algorithm is illustrated via a highly maneuvering target tracking simulation example where two sensors, a radar and an infrared sensor, are used and are assumed to operate in a cluttered environment. Compared with an existing IMMPDA filtering algorithm, the proposed smoothing algorithm achieves significant improvement in the accuracy of track estimation by introducing a small time lag between the instants of estimation and latest measurements whereas the computational load increases linearly with lag. However, the tracking delay may lead to undesired effects on control loops in certain applications View full abstract»

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  • Determination of cross regulation in multioutput resonant converters

    Publication Year: 2000 , Page(s): 760 - 772
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB)  

    This paper presents the analysis and the technique of determining the cross regulation characteristics in multioutput resonant converters. The steady state cross regulation characteristics are derived using the state-plane technique, illustrated by the example of a two-output clamped series resonant converter (SRC) operating in the discontinuous conduction mode below resonance. The cross regulation characteristics in conjunction with the control curves can be used to determine the converter operation for optimum performance. The theoretical prediction of converter operation and cross regulation characteristics in a two-output power supply is verified experimentally. This technique can be applied to most converters with more than two outputs View full abstract»

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  • Classical equivalent circuit parameters for a double-layer capacitor

    Publication Year: 2000 , Page(s): 829 - 836
    Cited by:  Papers (39)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (732 KB)  

    As an emerging technology in the area of energy storage, the double-layer capacitor is a promising device for certain niche applications. The double-layer capacitor is a low voltage device exhibiting an extremely high capacitance value in comparison with other capacitor technologies of a similar physical size. Capacitors with values in excess of 1500 F are now available. In slow discharge applications on the order of a few seconds, the classical equivalent circuit for a double-layer capacitor, composed of a capacitance (C), an equivalent parallel resistance (EPR), and an equivalent series resistance (ESR), can adequately describe capacitor performance. The focus of this work is the determination of these parameters for four different capacitors from discharge data using standard laboratory equipment such as an oscilloscope. Capacitance values are calculated using a change in stored energy approach which allows determination of an initial capacitance, a discharge capacitance, and variations in capacitance with voltage. The sensitivity of ESR and capacitance to charge rate and initial charge voltage is also reported View full abstract»

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  • Analysis and implementation of a three-level PWM rectifier/inverter

    Publication Year: 2000 , Page(s): 948 - 956
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB)  

    A three-level pulse width modulation (PWM) technique for ac/dc/ac converter is proposed. Single-phase three-level rectifier based on double boost configuration with power factor correction is used in the input side. Three-phase three-level voltage source inverter based on diode clamped scheme is employed in order to reduce the harmonic content of the inverter output voltages. In the rectifier side, the hysteresis current controller is used to track the line current command in phase with the mains voltage. A capacitor voltage compensator is adopted to balance the neutral point voltage in order to maintain good quality voltage waveforms on the output of the inverter. In the inverter side, three-level PWM based on sine-triangular comparison is used to reduce the voltage harmonics. The major advantage of the adopted three-level scheme is that the blocking voltage of each power switch is clamping to half of dc-link voltage. The proposed control scheme is verified by the software simulation and experimental results based on a laboratory prototype View full abstract»

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  • Robust algorithm for real-time route planning

    Publication Year: 2000 , Page(s): 869 - 878
    Cited by:  Papers (36)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1324 KB)  

    Route planning for intelligent guidance and navigation systems is an extremely complex problem with both military and commercial applications. Standard route planning algorithms usually generate a minimum cost route based on a predetermined cost function. Unfortunately, such a solution may not represent a desirable route for various mission scenarios. We present a novel route planning approach to generate mission-adaptable routes in an accurate and efficient manner. The routes are computed in real-time and are able to take into account various mission constraints including: minimum route leg length, maximum turning angle, route distance constraint, and fixed approach vector to goal position View full abstract»

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  • Robust optimal solution to the attitude/force control problem

    Publication Year: 2000 , Page(s): 784 - 792
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    Many spacecraft have an orbit control subsystem (OCS) which applies forces in order to maintain the orbital parameters within certain bounds. On the other hand, the attitude control subsystem (ACS) applies torques so that the spacecraft keeps its desired orientation. We explore the interaction of an orbital control maneuver with the attitude of a spacecraft. We propose to use the thrusters that provide the force for the orbit control as actuators to control the attitude as well. We obtain the conditions on the thruster configuration which guarantee that any perturbation torque can be compensated while performing the orbit control maneuver. We prove that the minimum number of thrusters which solve this problem is 4. Furthermore, we prove that the same problem can be solved with a minimum of 6 thrusters if a single failure in any thruster is accepted. We compute a robustness index which measures the maximum allowable uncertainty in the thruster configuration while still solving the problem stated previously. In the case of 4 thrusters with bounded thrusts, we solve the problem of maximizing the resulting force in a certain direction View full abstract»

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  • Mixed coordinate tracking of generalized maneuvering targets using acceleration and jerk models

    Publication Year: 2000 , Page(s): 992 - 1000
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (580 KB)  

    In a recent paper the authors introduced an all-Cartesian formulation of a jerk model for tracking highly maneuvering targets. Here a more complex but realistic case is considered, where target motion modeling and tracking are carried out in the 3-D Cartesian frame using measurements obtained in a spherical system. The transformation of the measurements into the Cartesian system results in nonlinear measurement equations. We solve the problem using an extended Kalman filter (EKF) approach, and also treat the earlier acceleration model similarly for comparison of results View full abstract»

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  • Detectability models for multiple access low-probability-of-intercept networks

    Publication Year: 2000 , Page(s): 848 - 858
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB)  

    Increased demands for communications in the tactical battlefield have driven the development of multiple access low-probability-of-intercept (LPI) networks. Most detectability studies of LPI networks focus on the individual links of the network, in which the intercept and detectability calculations are conducted for a single network transmitter. We assume here that the interceptor does not attempt to distinguish one emitter from another, but rather focuses on the operational status of the network so that LPI network performance quality metrics can be established View full abstract»

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  • Modified GLRT signal detection algorithm

    Publication Year: 2000 , Page(s): 810 - 818
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (680 KB)  

    The problem of signal detection in unknown Gaussian interference utilizing an adaptive array is considered here. Two modified generalized likelihood ratio test (GLRT) detectors are suggested that improve on the performance of Kelly's GLRT when the interference has low-rank property and the sample support for estimating the array covariance matrix is limited. Under these adverse conditions, the sample covariance matrix might be ill conditioned. This problem may be overcome either by diagonal loading of the covariance matrix or rank reduction of the data. The two modified GLRT detectors are referred to as loaded GLRT (L-GLRT) and reduced-rank GLRT (RR-GLRT), respectively. Expressions are developed for the probabilities of false alarm and detection. The advantage of the proposed detectors is illustrated by numerical examples View full abstract»

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  • Adaptive CFAR processor for nonhomogeneous environments

    Publication Year: 2000 , Page(s): 889 - 897
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (764 KB)  

    A new constant false alarm rate (CFAR) processor is presented, that exhibits a noticeable detection performance in the presence of interfering targets, as well as an excellent false alarm rate (FAR) regulation at the clutter power transition regions. The presented CFAR processor, which is designed to work on the logarithmic amplified video signals, can also easily adapt itself to new environmental conditions. Furthermore, in the steady state, its performance does not depend on the background noise power. Simulation results show the obvious preference of the presented processor to the conventional GOCA-LOG/CFAR, regarding FAR regulation at the clutter power transition regions. Noncoherent integration of radar pulses is considered in the analyses View full abstract»

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  • Small field-of-view star identification using Bayesian decision theory

    Publication Year: 2000 , Page(s): 773 - 783
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1056 KB)  

    We describe a simple autonomous star identification algorithm which is effective using a narrow field of view (FOV) (2 deg), making the use of a science camera for star identification feasible. This work extends that of Padgett and Kreutz-Delgado (1997) by setting decision thresholds using Bayesian decision theory. Our simulations show that when positional accuracy of imaged stars is 0.5 pixel (standard deviation) and the apparent brightness deviates by 0.8 unit stellar magnitude, the algorithm correctly identifies 96.0% of the sensor orientations, with less than a 0.3% rate of false positives View full abstract»

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  • Intelligent CFAR processor based on data variability

    Publication Year: 2000 , Page(s): 837 - 847
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB)  

    An intelligent constant false alarm rate (CFAR) processor to perform adaptive threshold target detection is presented. It employs a composite approach based on the well-known cell averaging CFAR (CA-CFAR), smallest of CFAR (SO-CFAR), and greatest of CFAR (GO-CFAR) processors. Data in the reference window is used to compute a second-order statistic called the variability index (VI) and the ratio of the means of the leading and lagging windows. Based on these statistics, the VI-CFAR dynamically tailors the background estimation algorithm. The VI-CFAR processor provides low loss CFAR performance in a homogeneous environment and also performs robustly in nonhomogeneous environments including multiple targets and extended clutter edges View full abstract»

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  • Study of system instability in solar-array-based power systems

    Publication Year: 2000 , Page(s): 957 - 964
    Cited by:  Papers (11)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    A study of power system stability, based on analytical modeling, is presented for application to a current-mode dc-dc converter power system with a solar array input and a line-filter interface. A fundamental analytical background is provided for use in analyses of systems of similar architecture. With this architecture, there is a potential for two sources of instability: (1) the relatively high-Q resonant tank formed by the input filter inductance (L) and the array capacitance (C) combined with excessive array voltage regulation loop-gain; and (2) positive feedback due to in-phase response produced by the current-mode converter at low frequencies. Such a low-frequency instability is dependent upon the magnitude of the array current, the array impedance, and the array voltage regulation loop-gain View full abstract»

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  • Application of continuous wavelet transform for study of voltage flicker-generated signals

    Publication Year: 2000 , Page(s): 925 - 932
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    An application of continuous wavelet transform (CWT) for the analysis of voltage flicker-generated signals is proposed. With the time-frequency localization characteristics embedded in wavelets, the time and frequency information of a waveform can be integrally presented, thereby enhancing the monitoring of voltage flicker-generated signals at different time intervals. The Morlet wavelet has been selected as the basis function for the CWT in the proposed method. The merit of the method lies in that the signal component at any frequency of interest can be more easily monitored than by discrete wavelet transform (DWT). The high frequency required in the voltage flicker study can be also comfortably accomplished. This approach has been applied to investigate various simulated voltage flicker-generated signals, and inspect the data recorded from the actual are furnace operation. Test results help solidify the practicality and advantages of the proposed method for the applications View full abstract»

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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