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Passive bistatic noise radar using DVB-T signals

IET RADAR SONAR AND NAVIGATION 2010年第3期4卷 403-411页

作者： Raout, J. Santori, A. Moreau, E. Res Ctr French AF MorphoAnal Signal Proc Lab F-13661 Salon De Provence France Univ Sud Toulon Var ISITV LSEET UMR CNRS 6017 F-83162 La Valette Du Var France

This study presents a new approach to passively detect targets using noise-like emitters of opportunity. This method combines the Wiener filtering to achieve clutter rejection and a proposed adaptation to noise-like signals of the amplitude and phase estimation (APES) method. This theoretical approach is confirmed by the detection of a helicopter by a bistatic radar using a digital video broadcasting terrestrial (DVB-T) transmitter.

关键词： amplitude estimation digital video broadcasting passive radar Wiener filters amplitude-phase estimation method Radar equipment, systems and applications helicopter detection signal detection phase estimation filtering methods in signal processing clutter rejection target detection noise-like emitters bistatic radar APES method television transmitters DVB-T signals Wiener filtering passive bistatic noise radar radar clutter radar detection theoretical approach digital video broadcasting terrestrial transmitter Radio and television transmitters Other topics in statistics

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Online estimation of distorted power system signal parameters

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IET GENERATION TRANSMISSION & DISTRIBUTION 2010年第6期4卷 746-755页

作者： Zadeh, R. Agha Ghosh, A. Ledwich, G. Zare, F. Queensland Univ Technol Brisbane Qld 4001 Australia

An algorithm based on the concept of Kalman filtering is proposed in this study for the estimation of power system signal attributes, like amplitude, frequency and phase angle. This technique can be used in protection relays, digital automatic voltage regulators (AVRs), distribution static compensators (DSTATCOMs), flexible AC transmission systems ( FACTS) and other power electronics applications. Furthermore, this algorithm is particularly suitable for the integration of distributed generation sources to power grids when fast and accurate detection of small variations of signal attributes are needed. Practical considerations such as the effect of noise, higher order harmonics and computational issues of the algorithm are considered and tested in the study. Several computer simulations are presented to highlight the usefulness of the proposed approach. Simulation results show that the proposed technique can simultaneously estimate the signal attributes, even if it is highly distorted due to the presence of non-linear loads and noise.

关键词： Power system protection digital automatic voltage regulators Kalman filtering online estimation Kalman filters distribution static compensators distorted power system signal parameters power grids power system protection static VAr compensators relay protection voltage regulators a.c. transmission power electronics filtering methods in signal processing protection relays flexible AC transmission systems

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Frequency-domain adaptive detectors for single-carrier frequency-domain equalisation in multiuser direct-sequence ultra-wideband systems based on structured channel estimation and direct adaptation

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IET COMMUNICATIONS 2010年第13期4卷 1636-1650页

作者： Li, S. de Lamare, R. C. Univ York Dept Elect Commun Res Grp York YO10 5DD N Yorkshire England

Here, the authors propose two adaptive detection schemes based on single-carrier frequency-domain equalisation (SC-FDE) for multiuser direct-sequence ultra-wideband systems, which are termed structured channel estimation (SCE) and direct adaptation (DA). Both schemes use the minimum mean square error (MMSE) linear detection strategy and employ a cyclic prefix. In the SCE scheme, adaptive channel estimation is performed in the frequency domain and the despreading is implemented in the time domain after the FDE. In this scheme, the MMSE detection requires the knowledge of the number of users and the noise variance. For this purpose, simple algorithms are proposed for estimating these parameters. In the DA scheme, the interference suppression task is fulfilled with only one adaptive filter in the frequency domain and a new signal expression is adopted to simplify the design of such a filter. Least mean squares, recursive least squares and conjugate gradient adaptive algorithms are then developed for both schemes. A complexity analysis compares the computational complexity of the proposed algorithms and schemes, and simulation results for the downlink illustrate their performance.

关键词： Electromagnetic compatibility and interference adaptive filters adaptive channel estimation least mean squares methods minimum mean square error linear detection strategy least mean squares algorithm ultra wideband communication frequency-domain adaptive detectors structured channel estimation multiuser direct-sequence ultra-wideband systems channel estimation direct adaptation adaptive filter gradient methods filtering methods in signal processing equalisers interference suppression task Interpolation and function approximation (numerical analysis) recursive least squares algorithm single-carrier frequency-domain equalisation computational complexity Radio links and equipment cyclic prefix conjugate gradient adaptive algorithms Communication channel equalisation and identification spread spectrum communication interference suppression

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Quantised H_∞ filtering for networked systems with random sensor packet losses

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IET CONTROL THEORY AND APPLICATIONS 2010年第8期4卷 1339-1352页

作者： Che, W. -W. Wang, J. -L. Yang, G. -H. Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore Northeastern Univ Coll Informat Sci & Engn Shenyang 110004 Peoples R China

This study is concerned with the quantised H-infinity filtering problem for discrete-time systems subject to limited communication capacity, which includes measurement quantisation and random sensor packet losses. By introducing an improved quantised random packet-loss model, the effects of the packet-loss rate and the upper bound of consecutive packet losses and the quantisation on the system performance are considered simultaneously. A quantised H-infinity filter design strategy with the minimised static quantiser range is designed to guarantee the error system exponentially mean-square stable and also achieve the prescribed H-infinity disturbance attenuation level. A numerical example is given to illustrate the effectiveness of the proposed filter design method.

关键词： H∞ control signal processing theory filtering theory mean-square stable Radio links and equipment sensor packet loss Stability in control theory packet-loss rate packet radio networks distributed control measurement quantisation H∞ disturbance attenuation mean square error methods Interpolation and function approximation (numerical analysis) filtering methods in signal processing Optimal control Discrete control systems discrete-time system quantised H∞ filtering discrete time systems asymptotic stability

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Huber-based unscented filtering and its application to vision-based relative navigation

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IET RADAR SONAR AND NAVIGATION 2010年第1期4卷 134-141页

作者： Wang, X. Cui, N. Guo, J. Harbin Inst Technol Harbin 150006 Peoples R China

A new algorithm called Huber-based unscented filtering (UF) is derived and applied to estimate the precise relative position, velocity and attitude of two unmanned aerial vehicles in the formation flight. The relative states are estimated using line-of-sight measurements between the vehicles along with acceleration and angular rate measurements of the follower. By making use of the Huber technique to modify the measurement update equations of standard UF, the new filtering could exhibit robustness with respect to deviations from the commonly assumed Gaussian error probability, for which the standard unscented filtering would exhibit severe degradation in estimation accuracy. Furthermore, contrast to standard extended Kalman filtering, more accurate estimation and faster convergence could be achieved from inaccurate initial conditions. During filter design, the global attitude parameterisation is given by a quaternion, whereas a generalised three-dimensional attitude representation is used to de. ne the local attitude error. A multiplicative quaternion-error approach is used to guarantee that quaternion normalisation is maintained in the filter. Simulation results are shown to compare the performance of the new filter with standard UF and standard extended Kalman filtering for non-Gaussian case.

关键词： acceleration measurements unmanned aerial vehicles Radionavigation and direction finding error statistics parameter estimation global attitude parameterisation Radar equipment, systems and applications vision-based relative navigation remotely operated vehicles angular rate measurements Kalman filtering filtering methods in signal processing Gaussian distribution Gaussian error probability Kalman filters multiplicative quaternion-error local attitude error three-dimensional attitude representation airborne radar line-of-sight measurements aircraft navigation Huber-based unscented filtering

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Fusion of panchromatic and multispectral images using temporal Fourier transform

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IET IMAGE processing 2010年第4期4卷 255-260页

作者： Mahyari, A. G. Yazdi, M. Shiraz Univ Fac Elect & Comp Engn Shiraz Iran

Image fusion techniques can be used to enhance the resolution of multispectral (MS) image, which is helpful for categorisation, recognition as well as other decision making processes. In this paper, a new class of image fusion algorithms is proposed that decomposes images into similar and non-similar information and fuses the corresponding non-similar one. It is based on temporal Fourier analysis. The details of panchromatic (PAN) image are fused with details of MS image by eliminating their similar information which is done by high-pass filtering of their temporal Fourier transform. The cut-off frequency of this filtering is obtained adaptively based on the input MS and PAN images. It results in minimum spectral and spatial distortion. The experimental results demonstrate the superior performance of the proposed method

关键词： image resolution PAN images cut-off frequency multispectral image resolution filtering methods in signal processing spectral analysis high pass filtering Computer vision and image processing techniques image recognition panchromatic images image fusion temporal Fourier transform Optical, image and video signal processing Integral transforms image classification decision making processes filtering theory Fourier transforms image fusion algorithm MS images

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Two-stage CIC-based decimator with improved characteristics

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IET signal processing 2010年第1期4卷 22-29页

作者： Jovanovic Dolecek, G. Mitra, S. K. Inst INAOE Dept Elect Puebla 72840 Mexico Univ So Calif Ming Hsieh Dept Elect Engn Los Angeles CA USA

A simple two-stage multiplierless cascaded-integrator-comb (CIC)-based decimator is presented. The first stage is a cascaded CIC filter whereas the second stage is a cascaded CIC filter and a second-order multiplierless compensator. The proposed decimator can be realised without filtering at high input rate by making use of the polyphase decomposition of the comb filter in the first stage. The proposed filter exhibits high aliasing attenuation and a low passband droop. The design parameters are the decimation factors, M-1 and M-2, numbers of cascaded CIC filters L and K, and parameter b of the compensator.

关键词： low passband droop two-stage multiplierless cascaded-integrator-comb based decimator comb filters cascaded CIC filter comb filter polyphase decomposition filtering methods in signal processing decimation factor second-order multiplierless compensator cascade networks low-pass filters two-stage CIC-based decimator high aliasing attenuation signal processing theory band-pass filters

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MMSE estimator for speech enhancement considering the constructive and destructive interference of noise

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IET signal processing 2010年第1期4卷 1-11页

作者： Hasan, T. Hasan, Md. K. United Int Univ Dept Elect & Elect Engn Dhaka Bangladesh

A new minimum mean square error (MMSE) estimator for discrete cosine transform (DCT) domain speech enhancement considering the two state possibilities of signal and noise DCT coefficients, the constructive and destructive interference, is proposed. Given proper identification of these events are possible, an optimum non-linear MMSE estimator can be derived considering the conditional events. Compared to the previously reported dual-gain multiplicative filters, the proposed estimator demonstrates superior theoretical and experimental performance with respect to mean square error (MSE) improvement and other objective quality measures.

关键词： Electromagnetic compatibility and interference Speech and audio signal processing filtering methods in signal processing Interpolation and function approximation (numerical analysis) Integral transforms in numerical analysis constructive noise interference Speech processing techniques dual-gain multiplicative filters discrete cosine transforms speech enhancement discrete cosine transform domain speech enhancement destructive noise interference filtering theory least mean squares methods minimum mean square error estimator optimum nonlinear MMSE estimator interference suppression

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Kalman filtering with state constraints: a survey of linear and nonlinear algorithms

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IET CONTROL THEORY AND APPLICATIONS 2010年第8期4卷 1303-1318页

作者： Simon, D. Cleveland State Univ Dept Elect & Comp Engn Cleveland OH 44115 USA

The Kalman filter is the minimum-variance state estimator for linear dynamic systems with Gaussian noise. Even if the noise is non-Gaussian, the Kalman filter is the best linear estimator. For nonlinear systems it is not possible, in general, to derive the optimal state estimator in closed form, but various modifications of the Kalman filter can be used to estimate the state. These modifications include the extended Kalman filter, the unscented Kalman filter, and the particle filter. Although the Kalman filter and its modifications are powerful tools for state estimation, we might have information about a system that the Kalman filter does not incorporate. For example, we may know that the states satisfy equality or inequality constraints. In this case we can modify the Kalman filter to exploit this additional information and get better filtering performance than the Kalman filter provides. This paper provides an overview of various ways to incorporate state constraints in the Kalman filter and its nonlinear modifications. If both the system and state constraints are linear, then all of these different approaches result in the same state estimate, which is the optimal constrained linear state estimate. If either the system or constraints are nonlinear, then constrained filtering is, in general, not optimal, and different approaches give different results.

关键词： signal processing theory extended Kalman filter optimal constrained linear state estimate constraint theory nonlinear algorithms Other topics in statistics linear dynamic systems state estimation minimum variance state estimator Gaussian noise state constraints Kalman filters filtering methods in signal processing optimal state estimator unscented Kalman filter

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Bandwidth selective filter for the pre-excision of narrowband interference in broadband beamformers

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IET COMMUNICATIONS 2010年第2期4卷 201-212页

作者： Tisdale, N. Kazmierski, T. J. Brooks, D. Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England ERA Technol Ltd Leatherhead KT22 7SA Surrey England

A novel frequency domain excision filter for use in front of broadband adaptive beamformer systems is presented. The proposed frequency domain excision filter uses image processing techniques to determine the excision threshold such that only narrowband interference is removed from the received signal. By preexcising the received signal of narrowband interference the adaptive beamformer only has to remove partialband or broadband interferers. This frees up degrees of freedom (DoF) in the adaptive beamformer in mixed interference environments allowing for a greater interference suppression capability. The proposed pre-excision system is simulated using a constrained space-time adaptive processor as well as a constrained suboptimal space-frequency adaptive processor. It is shown that when pre-excision is used in front of a beamformer the total number of interference sources that can be simultaneously rejected is increased as long as the beamformer's DoF are exceeded by narrowband interference.

关键词： array signal processing Electromagnetic compatibility and interference filtering methods in signal processing bandwidth selective filter frequency domain excision filter image processing space-time adaptive processing space-time adaptive processor excision threshold narrowband interference filtering theory broadband adaptive beamformers interference suppression

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