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Conference on Digital Avionics systems (DASC)

作者： D.-J. Moelker Y. Bar-Ness Telecommunications and Traffic Control Systems Group Delft University of Technnology Netherlands Center for Communications and Signal Processing Research New Jersey Institute of Technology Newark NJ USA

Of the wide variety of array processors, which are available to GPS receiver designers for noise and RF interference suppression, few achieve good performance and possess well-defined signal preservation properties. We introduce a new optimal array processor for the reception of GPS signals in RF interference and noise, that maximises geometric positioning precision. Comparison with well-known and previously proposed array processors demonstrates a superior reduction of the positioning error from noise and interference residuals. In addition, we derive the processor for optimisation of precision in a single position co-ordinate, such as height, or time; the improvement of vertical precision could be a significant development for the use of GPS in aviation.

关键词： Global Positioning System Interference cancellation Phased arrays Electromagnetic interference RF signals Adaptive arrays Antenna arrays signal processing Noise reduction Traffic control

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Adaptive antenna arrays for interference cancellation in GPS and GLONASS receivers

Adaptive antenna arrays for interference cancellation in GPS...

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IEEE Symposium on Position Location and Navigation (PLANS)

作者： D.-J. Moelker E. van der Pol Y. Bar-Ness Center for Communications and Signal Processing Research New Jersey Institute of Technology Newark NJ USA Telecommunications and Traffic Control Systems Group Delft University of Technnology Delft Netherlands

This paper introduces the adaptive antenna array as a possible solution to interference to received GLONASS and GPS signals. Several possible array structures and processors are compared, resulting in a preferred array of 5 elements with a power-inversion processor. Special attention is paid to the array compatibility with the GPS and GLONASS receivers' tracking processes and to the situation where no interference is received. These considerations lead to specific array design choices. Without these choices, a GPS or GLONASS receiver would not be able to function satisfactorily.

关键词： Adaptive arrays Receiving antennas Interference cancellation Global Positioning System signal processing Satellite navigation systems Gratings Programmable control Adaptive control Weight control

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Adaptive multiuser detector for synchronous code division multiple access applications 13th

Adaptive multiuser detector for synchronous code division mu...

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13th International Zurich Seminar on Digital Communications, 1994

作者： Siveski, Zoran Bar-Ness, Yeheskel Chen, David W. Center for Communications and Signal Processing Electrical and Computer Engineering Department New Jersey Institute of Technology University Heights NewarkNJ07102 United States Delft University of Technology Faculty of Electrical Engineering Telecommunications and Traffic-Control Systems Group Delft Netherlands Center for Communications and Signal Processing Research NJIT NewarkNJ07102 United States

ISBN: (纸本)9783540578567

A two-stage multiuser detector for the code division multiple access environment employing a combination of a decorrelator and a nonlinear multiuser interference canceler is considered. The weights of the canceler are adaptively adjusted, thus rendering the knowledge of the received signal energies unnecessary. The probability of error is evaluated and compared to those of the decorrelator and a similar two-stage, fixed-weights scheme which requires an estimation of signal energies. © Springer-Verlag Berlin Heidelberg 1994.

关键词： Code division multiple access

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Error performance of the blind decision feedback equalizer using decorrelation

Error performance of the blind decision feedback equalizer u...

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MILCOM, Military Communications Conference

作者： R.E. Kamel Y. Bar-Ness Center for Communications and Signal Processing Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ USA Telecommunications & Traffic-Control Systems Group Delft University of Technnology Delft Netherlands

The decision feedback equalizer has the advantage of compensating for channel amplitude distortion without enhancing noise. Conventional decision feedback equalizers require a training sequence to help them adapt to unknown channel characteristics. Training sequences are not always appropriate. In such situations blind equalizers are more suitable. The blind decision feedback equalizer inherits from the conventional the advantage of not enhancing noise, while compensating for severe ISI. It is thus superior over the blind linear equalizer. On the other hand the blind decision feedback equalizer also suffers from error propagation. In this paper we study the transient behavior of the blind DFE. This is done by deriving an upper bound on the probability of error due to residual ISI and show that it vanishes for the noiseless case. We also determine lower and upper bounds on the probability of error for the additive white Gaussian noise case. The upper bound obtained is the same as that of Duttweiler, et al. (1974). Using a different approach from that of Duttweiler, et al., we derive a lower bound. This bound is tighter than tile "no ISI" lower bound.< >

关键词： Decision feedback equalizers Decorrelation Upper bound Blind equalizers Intersymbol interference Additive white noise Steady-state Convergence Gaussian noise AWGN

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ERROR PERFORMANCE OF SYNCHRONOUS MULTIUSER CODE-DIVISION MULTIPLE-ACCESS DETECTOR WITH MULTIDIMENSIONAL ADAPTIVE CANCELER

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EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 1994年第6期5卷 719-724页

作者： SIVESKI, Z BARNESS, Y CHEN, DW Center for Communications and Signal Processing Electrical and Computer Engineering Department New Jersey Institute of Technology University Heights Newark NJ 07102 - USA Was on sabbatical with Delft University of Technology Faculty of Electrical Engineering Telecommunications and Traffic-Control Systems Group Delft - The Netherlands.

A code division multiple access detector that employs a combination of a decorrelator and a multidimensional interference canceler is considered. The weights of the canceler are adaptively controlled using a steepest descent algorithm. The probability of error is evaluated and compared to those of the decorrelating detector and a similar, fixed-weights scheme that requires an estimation of received signal energies. It is shown that the proposed two-stage detector provides substantial improvement over the decorrelating detector, particularly in the presence of strong interfering signals. This is especially noticeable in the high bandwidth efficiency cases. It is also observed that in the presence of weak interferers, the proposed scheme performs better than its fixed-weights counterpart.

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Bootstrapped decorrelating algorithm for adaptive interference cancelation in synchronous CDMA communications systems

Bootstrapped decorrelating algorithm for adaptive interferen...

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IEEE International Symposium on Spread Spectrum Techniques and Applications

作者： Y. Bar-Ness Z. Siveski D.W. Chen Faculty of Electrical Engineering Telecommunications and Traffic-Control Systems Group Delft University of Technnology Delft Netherlands Center for Communications and Signal Processing Electrical and Computer Engineering Department New Jersey Institute of Technology Newark NJ USA

A code division multiple access detector that employs a combination of a correlation detector and a multiuser adaptive interference canceler was previously proposed by the authors. The weights of the canceler are adaptively controlled by the steepest descent algorithm using the minimum power criterion of the canceler outputs. It was shown that such a canceler substantially outperforms the decorrelating detector and has almost the same error probability as a canceler that uses reliable estimates of the received signal energies. In this paper, a different weight control criterion based on minimizing the correlation between the signals at the outputs of the canceler is used, and its performance is compared to that obtained with the minimum power criterion. It is shown that both cancelers have almost the same performance, particularly when SNR is modestly high. Although it is not shown in this paper, we believe that minimizing correlation rather than power outputs is a more suitable criterion when dealing with highly dispersive channels.< >

关键词： Decorrelation Interference cancellation Code division multiplexing Multiaccess communication Detectors signal processing algorithms Filters Impedance matching Communication system traffic Telecommunication traffic

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ASYNCHRONOUS TRANSFER MODE (ATM) OPERATION VIA SATELLITE - ISSUES, CHALLENGES AND RESOLUTIONS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 211-222页

作者： CHITRE, DM GOKHALE, DS HENDERSON, T LUNSFORD, JL MATHEWS, N COMSAT Laboratories 22300 Comsat Drive Clarksburg MD 20871 USA. Received his B.Sc. from the University of Bombay India an M.A. in mathematics from the University of Cambridge U.K. and a Ph.D. in physics from the University of Maryland. He is currently an Associate Executive Director of the Network Technology Division at COMSAT Laboratories. He has been involved in research and development activities in ISDN VSAT networks data communications and network systems and architectures. Prior to his current positions Dr. Chitre was a Principal Scientist in the Network Technology Division at COMSAT Laboratories. Dr. Chitre joined COMSAT Laboratories in 1980. He has made major contributions to the analysis and architecture of data communication ISDN and BISDN via satellite. Dr. Chitre directs and participates in the international and national standards activities in ISDN BISDN and data communication as they apply to satellite communication. He was Chairman of the Working Group on Protocols and Network Timing Function of the CCIR/CCITT Joint Ad Hoc Group on ISDN-Satellite Matters during 1990–1992. Currently he is the Chairman of the Working Group on New Technologies in the ITU Intersector Coordinating Group (ICG) on Satellite Matters. Dr. Chitre was a programme manager during 1990 and 1991 on a contract from INTELSAT on systems studies on satellite communications systems architectures for ISDN and broadband ISDN systems. Currently he is the technical manager of the DoD Contract on ATM via satellite demonstration and the programme manager for the INTELSAT contract on analysis and top-level specification of INTELSAT ISDN subnetworks and SDH compatible transport network. Department manager for ISDN/Data Communications in the Network Technology Division of COMSAT Laboratories. His responsibilities include managing the implementation of next generation telecommunication systems for fixed and mobile satellite systems. Current projects include the development of a high data rate gateway switch that provides for the

Key issues regarding the operation of the broadband integrated services digital network (BISDN) via satellite are presented herein. The specific issues, challenges, and their resolutions are detailed. In particular, the impact of error characteristics and propagation delay on the operation of BISDN via satellite is discussed. Solutions are presented for removing adverse effects and providing high-quality service to users of BISDN via satellite.

关键词： ATM BISDN

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Adaptive control of an alignment system with nonlinear plant characteristics 1

Adaptive control of an alignment system with nonlinear plant...

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1st IEEE Regional Conference on Aerospace control systems, AEROCS 1993

作者： Hill, D.A. Chand, S. Rockwell Intemational Autonetics Strategic Systems Division Systems Analysis and Mechanization Group AnaheimCA92803 United States Rockwell Intemational Science Center Control and Signal Processing Dept. Thousand OaksCA91360 United States

This paper presents Model Reference Adaptive control (MRAC) of a precision angular alignment system (small gimbaled mass) with nonlinear friction characteristics. Open loop frequency response tests yield a family of curves for different amplitude sweep generator inputs as seen in Fig. 1 giving the ratio of alignment angle output to amplifier input over frequency. These results are directly traced to nonlinear bearing friction. The goal of the control design is to regulate alignment errors to within 2 arcseconds of a given reference angle in the presence of variable friction parameters and torque disturbances. The adaptive controller is derived by considering a linearized 2nd order Plant, of relative degree 2, with variable parameters. The MRAC design is tested with nonlinear simulation using Boeing Computer Services EASY5TM. © 1993 IEEE.

关键词： Model reference adaptive control

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Robust controller design and mechaneza tion for precision platform alignment of the trident II Inertial Measurement Unit (IMU) 1

Robust controller design and mechaneza tion for precision pl...

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1st IEEE Regional Conference on Aerospace control systems, AEROCS 1993

作者： Hill, D.A. Strunk, J.R. Purslow, B.J. Bass, R.W. Rockwell International Autonetics Strategic Systems Division Systems Analysis Group AnaheimCA United States Rockwell International Autonetics Strategic Systems Division Electronics Design Group AnaheimCA United States Rockwell International Science Center Control and Signal Processing Dept. Thousand OaksCA United States

This paper presents robust controller design and mechanization for precision alignment of the ESGN platform IMU of the Trident II navigation system. The primary design and mechanization tool is Integrated systems Inc. software MATRIXx, utilizing the Robust control Module, and implementation using the AC-100 Rapid Prototyping System. In addition, alternative robust control algorithms are developed using both the Rockwell Science center developed Rho-Synthesis and The Mathworks Robust control Toolbox with MATLAB. The design requires precision platform alignment to the gyro inertial reference with tracking errors less than one arcsecond in the presence of torque disturbances and sensor noise. Performance and stability robustness are required in the design to counteract large parameter variations that may occur in the actuator or in the the gimbal bearing friction. Figure 1 shows the stable platform (innermost gimbal) with the additional outer gimbals required for alignment about all three stable platform fixed axes. At present the development is focused upon implementing the prototyping hardware and controller for a single platform axis. The control designs presented here are H and Hinf robust control algorithms for Single Input Single Output (SIS0) control about the platform +z axis. © 1993 IEEE.

关键词： Fixed platforms

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Adaptive control of an Alignment System with Nonlinear Plant Characteristics

Adaptive Control of an Alignment System with Nonlinear Plant...

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IEEE Regional Conference on Aerospace control systems

作者： D.A. Hill S. Chand Rockwell Intemational AUTONETICS Strategic Systems Division Systems Analysis and Mechanization Group Anaheim CA USA Control and Signal Processing Department Rockwell International Science Center Thousand Oaks CA USA

关键词： Adaptive control Friction Actuators Open loop systems Error correction Frequency response Limit-cycles DC motors Sensor phenomena and characterization Testing

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