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Aerospace and Electronic Systems, IEEE Transactions on

Issue 4 • Date Oct. 2009

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Displaying Results 1 - 25 of 38
  • IEEE Transactions on Aerospace and Electronic Systems - Table of contents

    Publication Year: 2009 , Page(s): C1
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  • IEEE Aerospace and Electronic Systems Society

    Publication Year: 2009 , Page(s): C2
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  • From the Editors

    Publication Year: 2009 , Page(s): 1249
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  • Analysis of Stepped-Frequency Pulse Train Design

    Publication Year: 2009 , Page(s): 1251 - 1261
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3264 KB) |  | HTML iconHTML  

    For uniform frequency stepped pulse trains, there can be undesirable peaks of the autocorrelation function, known as "grating lobes." In this paper we address this issue, using an approach which allows us to suppress grating lobes in the case of appropriately chosen stepped-frequency waveforms, i.e., sequences of narrowband pulses that span the desired bandwidth. We introduce a multiparametric generalization of a stepped-frequency train, and by exploiting a factorization of the autocorrelation function, will be able to effect a useful tradeoff between competing properties of the factors by careful choices of relevant parameters. We provide a detailed description of the method applied to a representative data set. View full abstract»

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  • Sigma Overbounding using a Position Domain Method for the Local Area Augmentaion of GPS

    Publication Year: 2009 , Page(s): 1262 - 1274
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1844 KB) |  | HTML iconHTML  

    The local area augmentation system (LAAS) is a differential GPS navigation system being developed to support aircraft precision approach and landing navigation with guaranteed integrity and availability. While the system promises to support Category I operations, significant technical challenges are encountered in supporting Category II and III operations. The primary concern has been the need to guarantee compliance with stringent requirements for navigation availability. This paper describes how a position domain method (PDM) may be used to improve system availability by reducing the inflation factor for standard deviations of pseudo-range correction errors. Used in combination with the current range domain method (RDM), a 30% reduction in the inflation factor is achieved with the same safety standard. LAAS prototype testing verifies the utility of the PDM to enhance Category II/III user availability. View full abstract»

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  • Multisensor Track Management for Targets with Fluctuating SNR

    Publication Year: 2009 , Page(s): 1275 - 1292
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2579 KB) |  | HTML iconHTML  

    In active sonar tracking applications, targets frequently undergo fading in which the target's detection probability can shift suddenly between high and low values. This characteristic is a function of the undersea environment. Using a multisensor active sonar problem, we examine the performance of track management (confirmation and termination) routines where target detections are based on an underlying hidden Markov model (HMM) with high and low detection states. Rule-based track confirmation tests are compared including M/N rules and rules that differentiate the measurements by receiver source (M/N from at least C sensors), each of which is suboptimal compared with a fixed-length likelihood ratio test. We show that significant performance improvements (to near-optimal) can be obtained using a composite track confirmation test that combines two or three such rules in a logical OR operation. Track termination tests are next compared, and it is shown that a Bayesian sequential test (the Shiryaev test) yields dramatic performance improvements over a K/N track termination rule and the Page test. The model-based results are validated using simulations of a multisensor tracking scenario. The results of this paper are informed by a multisensor sonar application. However, targets may fade in and out of view in other modalities as well, due to aspect-dependent radar cross-section or occlusion. As such, our suggestions for improved HMM-modulated SNR track initiation and termination apply to multisensor radar target tracking as well. View full abstract»

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  • Distributed Linear Parameter Estimation over Wireless Sensor Networks

    Publication Year: 2009 , Page(s): 1293 - 1306
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1244 KB) |  | HTML iconHTML  

    In this paper, we consider distributed linear least squares (LLS) and Bayesian minimum mean square error (BMMSE) parameter estimation over sensor networks. In particular, we propose distributed iterative algorithms that asymptotically converge to the centralized solutions. These algorithms are first studied for the case of unclustered (flat architecture) sensor networks; in this venue, we provide necessary and sufficient conditions for the distributed algorithm to converge. Subsequently, we extend our analysis to clustered sensor networks with pulsed inter-cluster updates. In this latter scenario, inter-cluster communications occur every ß time steps (with ß > 1) and the corresponding updates are held until the next update instant. Depending on sensor locations and the employed network topology construction algorithm, it may be the case that inter-cluster communications require higher transmitter power support than intracluster communications. For energy-constrained sensor networks, it will therefore be beneficial-from a power efficiency (or alternately, network lifetime) point of view-to limit the extent of inter-cluster communication, without significantly deteriorating the convergence properties of the distributed estimation algorithm. We anticipate that a pulsed inter-cluster update scheme will also be useful for applications such as ground or airborne sensor networks, where low probability of detection and interception is essential. Our analysis provides sufficient conditions under which such distributed estimation algorithms, operating on a pulsed inter-cluster update scheme, converge. Simulation results illustrating the dependence of the convergence rate of the algorithm on the hold interval ß conclude the paper. View full abstract»

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  • Wave Front Sensor for Solar Concentrator Control (October 2007)

    Publication Year: 2009 , Page(s): 1307 - 1319
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2547 KB) |  | HTML iconHTML  

    This article is the culmination of research directed into finding a system to control the position of the focal spot of paraboloid concentrators for use in terrestrial and space solar concentration applications. After a brief introduction into the area of study, the article describes how a normal Shack-Hartmann wave front sensor is modified for use in detecting and tracking the focal spot. The paper details the analysis and development of the algorithms used in locating the focal spot on a thruster absorber utilizing a correlation method and an area centroid method. The article concludes with a paragraph on suitable future work. View full abstract»

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  • Channeling Partitioning Policies for Multi-Class Traffic in LEO-MSS

    Publication Year: 2009 , Page(s): 1320 - 1334
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2987 KB) |  | HTML iconHTML  

    This paper studies channel partitioning policies and channel resource prioritization techniques for handovers, which efficiently support multi-class traffic in low Earth orbit mobile satellite systems (LEO-MSS). Analytical methods are developed for evaluating the performance of complete partitioning (CP) and complete sharing (CS) with and without fixed channel reservation (FCR) for multi-class traffic in LEO-MSS. Furthermore, a novel threshold call admission (TCA) scheme which achieves better channel utilization and fair channel access is introduced and analyzed. View full abstract»

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  • Distributed Detection for Macrodiversity Enhanced Cellular Communication Systems

    Publication Year: 2009 , Page(s): 1335 - 1349
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2233 KB) |  | HTML iconHTML  

    This paper considers the design of soft decision distributed detection schemes for achieving macrodiversity in uplink cellular communication systems with and without channel knowledge at the fusion center. Distributed detection macrodiversity (DDM) techniques are proposed where the quatizer thresholds of local detectors at base stations (radio access points) are optimized using a numerical global optimization algorithm called adaptive simulated annealing (ASA). The performance of such DDM schemes is studied for systems with and without channel coding, where the base stations employ multiple receive antennas over quasi-static Rayleigh fading channels. It is shown that properly designed quantizers for the local detectors, with a few resolution bits can make the performance very close to optimal macrodiversity that requires a much larger bandwidth from the connection links to the fusion center. View full abstract»

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  • Design of a Solar Power Management System for an Experimental UAV

    Publication Year: 2009 , Page(s): 1350 - 1360
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3013 KB) |  | HTML iconHTML  

    The design of a solar power management system (SPMS) for an experimental unmanned aerial vehicle (UAV) is summarized. The system will provide power required for the on-board electronic systems on the UAV. The power management system mainly consists of the maximum power point tracking (MPPT), the battery management, and the power conversion stages. The MPPT stage attempts to obtain the maximum power available from the solar cell panels. The battery management stage monitors and controls the charge and discharge processes of the Li-ion polymer battery modules. The last stage is for power conversion that consists of dc/dc synchronous buck converters to generate +5 V and +12 V powers for the on-board computers and other electronic circuitries. View full abstract»

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  • Source Bearing and Steering-Vector Estimation using Partially Calibrated Arrays

    Publication Year: 2009 , Page(s): 1361 - 1372
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1956 KB) |  | HTML iconHTML  

    The problem of source direction-of-arrival (DOA) estimation using a sensor array is addressed, where some of the sensors are perfectly calibrated, while others are uncalibrated. An algorithm is proposed for estimating the source directions in addition to the estimation of unknown array parameters such as sensor gains and phases, as a way of performing array self-calibration. The cost function is an extension of the maximum likelihood (ML) criteria that were originally developed for DOA estimation with a perfectly calibrated array. A particle swarm optimization (PSO) algorithm is used to explore the high-dimensional problem space and find the global minimum of the cost function. The design of the PSO is a combination of the problem-independent kernel and some newly introduced problem-specific features such as search space mapping, particle velocity control, and particle position clipping. This architecture plus properly selected parameters make the PSO highly flexible and reusable, while being sufficiently specific and effective in the current application. Simulation results demonstrate that the proposed technique may produce more accurate estimates of the source bearings and unknown array parameters in a cheaper way as compared with other popular methods, with the root-mean-squared error (RMSE) approaching and asymptotically attaining the Cramer Rao bound (CRB) even in unfavorable conditions. View full abstract»

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  • Helicopter Classification with a High Resolution LFMCW Radar

    Publication Year: 2009 , Page(s): 1373 - 1384
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2400 KB) |  | HTML iconHTML  

    Helicopter classification using a high resolution linear frequency modulated continuous wave (LFMCW) radar is addressed. A blade echo modelling for this radar system is derived, taking into account that the stop-and-go assumption is not longer applicable. The standard classification schemes based on the L/N-quotient and the evenness of the number of blades are easily reproduced in this high resolution context, although two main advantages are added: a high pulse repetition frequency (PRF) to acquire the Doppler bandwidth is no longer necessary, and the time for which we receive returned signal from the target may be maximized. On the other hand, a characteristic critical classification problem, for which the standard approaches do not properly work, is presented. Two classification schemes are proposed for this situation, the first one based on coherent matched masks and the second one based on incoherent masks where a robustness parameter has also been defined. Identification probabilities as a function of the signal-to-noise ratio (SNR) are obtained in order to characterize the performance of both techniques. Real data validate both the derived model and the proposed classification algorithms. View full abstract»

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  • Marginalized Particle Filter for Accurate and Reliable Terrain-Aided Navigation

    Publication Year: 2009 , Page(s): 1385 - 1399
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1721 KB) |  | HTML iconHTML  

    This paper details an approach to the integration of INS (inertial navigation system) and TAP (terrain-aided positioning). The solution is characterized by a joint design of INS and TAP, meaning that the highly nonlinear TAP is not designed separately but jointly with the INS using one and the same filter. The applied filter extends the theory of the MPF (marginalized particle filter) given by. The key idea with MPF is to estimate the nonlinear part using the particle filter (PF), and the part which is linear, conditional upon the nonlinear part, is estimated using the Kalman filter. The extension lies in the possibility to deal with a third multimodal part, where the discrete mode variable is also estimated jointly with the linear and nonlinear parts. Conditionally upon the mode and the nonlinear part, the resulting subsystem is linear and estimated using the Kalman filter. Given the nonlinear motion equations which the INS uses to compute navigation data, the INS equations must be linearized for the MPF to work. A set of linearized equations is derived and the linearization errors are shown to be insignificant with respect to the final result. Simulations are performed and the result indicates near-optimal accuracy when compared with the Cramer-Rao lower bound. View full abstract»

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  • Efficient and Enhanced Multi-Target Tracking with Doppler Measurements

    Publication Year: 2009 , Page(s): 1400 - 1417
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3189 KB) |  | HTML iconHTML  

    In many radar and sonar tracking systems, the target state typically includes target position and velocity components that are estimated from a time sequence of target position and Doppler measurements. The use of measured Doppler information directly in the target trajectory estimation leads to a nonlinear filter implementation such as the extended Kalman filter (EKF), particle filter etc. We investigate a method for including Doppler measurements as part of the data association process and then assess the benefits of this approach. It is well understood that data association performance can dominate the total performance of a tracker that is designed to track targets in the presence of clutter. In this case, the Doppler component of the measurements may be used in combination with the target position measurement as an additional discriminant of measurement origin. We have developed a simple but efficient Doppler data association (DDA) method which utilises both position and Doppler measurements for single and multi-target tracking. If the Doppler measurements are not used in trajectory state estimation, then the nonlinear filters for the incorporation of Doppler measurements are not required, however a significant improvement in tracking performance is still observed. The proposed DDA method is demonstrated using both the linear multi-target integrated probabilistic data association algorithm (LMIPDA) and the linear multi-target integrated track splitting algorithm (LMITS) in an active sonar underwater multi-target tracking scenario. View full abstract»

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  • Characterization of the Effects of CW and Pulse CW Interference on the GPS Signal Quality

    Publication Year: 2009 , Page(s): 1418 - 1431
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3232 KB) |  | HTML iconHTML  

    In the Global Positioning System (GPS), code division multiple access (CDMA) signals are used. Because of the spectral characteristics of the CDMA signal, each particular type of interference (signals to be rejected) has a different effect on the quality of the received GPS satellite signals. In this paper, the effects of three types of interference are studied on the carrier-to-noise ratio (C/No) of the received GPS signal as an indicator of the quality of that signal; continuous wave (CW), pulse CW, and swept CW. For CW interference, it is analytically shown that the C/No of the signal can be calculated using a closed formula after the correlator in the receiver. This result is supported by calculating the C/No using the I and Q data from a software GPS receiver. For pulsed CW, a similar analysis is performed to characterize the effect of parameters such as pulse repetition period (PRP) and also duty cycle on the received signal quality. It is specifically shown that for equal interference power levels, in the cases where the PRP is far less than the pseudorandom noise code period, the signal degradation increases with increasing the duty cycle whereas it doesn't change when the two periods are equal or the PRP is far bigger than the code period. View full abstract»

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  • Multiscan Multitarget Tracking in Clutter with Integrated Track Splitting Filter

    Publication Year: 2009 , Page(s): 1432 - 1447
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (607 KB) |  | HTML iconHTML  

    A fully automatic tracking algorithm must be able to deal with an unknown number of targets, unknown target initiation and termination times, false measurements and possibly time-varying target trajectory behaviour. The approach presented in this paper follows the previously published integrated track splitting (ITS) framework which integrates a recursive calculation of the probability of target existence with multiscan trajectory estimation. This paper combines this framework with two multitarget tracking techniques. The first technique, joint multitarget tracking, enumerates and evaluates all feasible global measurement to track assignments resulting in a conditionally optimal but potentially computationally expensive technique. The second technique, linear multitarget (LM), achieves multitarget functionality by modulating clutter measurement density. LM is a suboptimal, but computationally very efficient technique. A simulation study is presented to show the effectiveness of this approach in the presence of nonuniform clutter when tracking targets in an environment where the targets perform violent manoeuvres. View full abstract»

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  • Distributed Fault Detection with Correlated Decision Fusion

    Publication Year: 2009 , Page(s): 1448 - 1465
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2743 KB) |  | HTML iconHTML  

    Quick and accurate fault detection is critical to the operation of modern dynamic systems. In this paper, the fault detection problem when using multiple sensors is investigated. At each time step, local sensors transmit binary data to the fusion center, where decision fusion is performed to detect the potential occurrence of a fault. Since the sensors observe a common dynamic process, their measurements, and thus the local decisions, are correlated. Under a likelihood-ratio-based local decision rule constraint, we propose efficient suboptimal system designs involving local sensor rules and fusion rule that include the correlation consideration. Two correlation models are proposed to approximate the complicated correlation between sensor measurements for general systems. Experimental results show that the designs with correlation consideration outperform the design under the independence assumption significantly when the correlation between sensor measurements is strong. View full abstract»

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  • Structural Analysis Approach for the Generation of Structured Residuals for Aircraft FDI

    Publication Year: 2009 , Page(s): 1466 - 1482
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2507 KB) |  | HTML iconHTML  

    A systematic methodology is described for calculating structured residuals with high fault diagnostic capabilities for detecting sensor and actuators failures. The effort addresses implementation issues for real-time applications such as residual computation complexity and sensitivity to measurement noise. These specific requirements have been rigorously introduced through a cost function measuring the quality of the residual signal. A structural analysis approach of the nonlinear model of the system in conjunction with the unknown variables elimination method is used to derive subsets of residual equations. An algorithm is proposed for selecting the residual equations with maximum "failure isolability" and minimum cost, according to the selected performance criteria. The methodology has been applied to the design of a real-time residual generator for a nonlinear model of a remotely controlled semi-scale YF-22 research aircraft. View full abstract»

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  • Dual Airborne Laser Scanners Aided Inertial for Improved Autonomous Navigation

    Publication Year: 2009 , Page(s): 1483 - 1498
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4697 KB) |  | HTML iconHTML  

    A dead-reckoning terrain referenced navigation (TRN) system is presented that uses two airborne laser scanners (ALS) to aid an inertial navigation system (INS). The system uses aircraft autonomous sensors and is capable of performing the dual functions of mapping and navigation simultaneously. The proposed system can potentially serve as a backup to the Global Positioning System (GPS), increase the robustness of GPS or it can be used to coast for extended periods of time. Although the system has elements of a conventional TRN system, it does not require a terrain database since its in-flight mapping capability generates the terrain data for navigation. Hence, the system can be used in both non-GPS as well as unknown terrain environments. It is shown that the navigation system is dead-reckoning in nature since errors accumulate over time, unless the system can be reset periodically by the availability of geo-referenced terrain data or a position estimate from another navaid. Results of the algorithm using a combination of flight trajectory data and synthesized ALS data are presented. View full abstract»

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  • A Statistical Inference Technique for GPS Interference Detection

    Publication Year: 2009 , Page(s): 1499 - 1511
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1829 KB) |  | HTML iconHTML  

    Narrowband interference can severely degrade the performance of GPS receivers. Detecting the interference and then characterizing it can lead to its removal. Knowledge that can be useful is the location of the source or direction of arrival of the interference (spatial-directional characteristics) and/or the time specification, frequency, and power of the interference (temporal-spectral characteristics). This work focuses on the second type. In previous work power spectral density fluctuation detection technique has been introduced [1], and statistical inference has been used to detect narrowband CW interference in the GPS signal band after being captured by the RF front end. In this technique, an assessment window of data is first divided into blocks and then analyzed to obtain the statistical parameters of the signal without interference. Then presence of interference is tested by comparing these parameters as a null hypothesis with the parameters extracted from a later window. The effect of the assessment window size on the level of confidence of this test has been already analyzed also in [1]. In this paper, using properties of the fast Fourier transform (FFT) and the effects of the number of FFT points on the test statistic mean and variance, we show that an appropriate data block size (for a specific window size) can be selected to achieve an optimum solution to detect "minimum power detectable interference." The algorithm to find the optimal solution is introduced. The theoretical result is supported by real experiments. Finally this algorithm is employed to detect a real GPS interference signal generated by a TV transmitter in Sydney, Australia. View full abstract»

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  • HRR Automatic Target Recognition from Superresolution Scattering Center Features

    Publication Year: 2009 , Page(s): 1512 - 1524
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1523 KB) |  | HTML iconHTML  

    The work presented here introduces a procedure for the automatic recognition of ground-based targets from high range resolution (HRR) profile sequences that may be obtained from a synthetic aperture radar (SAR) platform. The procedure incorporates an adaptive target mask and uses a superresolution algorithm to identify the cross-range positions of target scattering centers. These are used to generate a pseudoimage of the target whose low-order discrete cosine transform coefficients form the recognizer feature vector. Within the recognizer, the states of a hidden Markov model (HMM) are used to represent the target orientation and a Gaussian mixture model is used for the feature vector distribution. In a closed-set identification experiment, the misclassification rate for ten MSTAR targets was 2.8%. Also presented are results from open-set experiments and investigates the effect on recognizer performance of variations in feature vector dimension, azimuth aperture, and target variants. View full abstract»

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  • Message Passing for Hybrid Bayesian Networks: Representation, Propagation, and Integration

    Publication Year: 2009 , Page(s): 1525 - 1537
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1904 KB) |  | HTML iconHTML  

    The traditional message passing algorithm was originally developed by Pearl in the 1980s for computing exact inference solutions for discrete polytree Bayesian networks (BN). When a loop is present in the network, propagating messages are not exact, but the loopy algorithm usually converges and provides good approximate solutions. However, in general hybrid BNs, the message representation and manipulation for arbitrary continuous variable and message propagation between different types of variables are still open problems. The novelty of the work presented here is to propose a framework to compute, propagate, and integrate the messages for hybrid models. First, we combine unscented transformation and Pearl's message passing algorithm to deal with the arbitrary functional relationships between continuous variables in the network. For the general hybrid model, we partition the network into separate parts by introducing the concept of interface node. We then apply different algorithms for each subnetwork. Finally we integrate the information through the channel of interface nodes and then estimate the posterior distributions for all hidden variables. The numerical experiments show that the algorithm works well for nonlinear hybrid BNs. View full abstract»

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  • Generalized Theory of Code Tracking with an Early-Late Discriminator Part I: Lower Bound and Coherent Processing

    Publication Year: 2009 , Page(s): 1538 - 1556
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (358 KB) |  | HTML iconHTML  

    Code tracking is an important attribute of receivers for Global Positioning System (GPS) and other global navigation satellite systems (GNSS). This paper and its sequel provide analytical expressions for performance of code-tracking loops using early-late discriminators, under small-error conditions. Expressions are provided for output signal-to-noise-plus-interference ratio (SNIR) and code-tracking error for arbitrary signal spectra, and Gaussian noise and interference having arbitrary spectral shapes. This first paper addresses coherent early-late processing (ELP) for given receiver precorrelation bandwidth and given early-late spacing, also providing a tight lower bound on code-tracking error independent of discriminator design. Theoretical expressions are derived, showing that code-tracking accuracy depends on more than merely signal-to-noise ratio and early-late spacing - the shape of signal and interference spectra are important, as is the receiver precorrelation bandwidth. View full abstract»

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  • Generalized Theory of Code Tracking with an Early-Late Discriminator Part II: Noncoherent Processing and Numerical Results

    Publication Year: 2009 , Page(s): 1557 - 1564
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2366 KB) |  | HTML iconHTML  

    Code tracking is an important attribute of receivers for Global Positioning System (GPS) and other global navigation satellite systems (GNSS). This paper and its antecedent provide analytical expressions for performance of code-tracking loops using early-late discriminators, under small-error conditions. Expressions are provided for output signal-to-noise-plus-interference ratio (SNIR) and code-tracking error, for arbitrary signal spectra, and Gaussian noise and interference having arbitrary spectral shapes. This second paper addresses noncoherent early-late processing (NELP) for given receiver precorrelation bandwidth and given early-late spacing, comparing the results to results for coherent early-late processing (CELP) and to a lower bound (LB) on code-tracking error. Theoretical expressions are derived and compared, and numerical results are provided to examine the effect of different modulation designs and interference conditions. 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