SwePub - sökning: L773:1557 9603 OR L773:0018 92...

Numrering	Referens	Omslagsbild	Hitta
1.	Aoki, E. H., et al. (författare) Labeling Uncertainty in Multitarget Tracking 2016 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1557-9603 .- 0018-9251. ; 52:3, s. 1006-1020 Tidskriftsartikel (refereegranskat)abstract In multitarget tracking, the problem of track labeling (assigning labels to tracks) is an ongoing research topic. The existing literature, however, lacks an appropriate measure of uncertainty related to the assigned labels that has a sound mathematical basis as well as clear practical meaning to the user. This is especially important in a situation where well separated targets move in close proximity with each other and thereafter separate again; in such a situation, it is well known that there will be confusion on target identities, also known as "mixed labeling." In this paper, we specify comprehensively the necessary assumptions for a Bayesian formulation of the multitarget tracking and labeling (MTTL) problem to be meaningful. We provide a mathematical characterization of the labeling uncertainties with clear physical interpretation. We also propose a novel labeling procedure that can be used in combination with any existing (unlabeled) MTT algorithm to obtain a Bayesian solution to the MTTL problem. One advantage of the resulting solution is that it readily provides the labeling uncertainty measures. Using the mixed labeling phenomenon in the presence of two targets as our test bed, we show with simulation results that an unlabeled multitarget sequential Monte Carlo (M-SMC) algorithm that employs sequential importance resampling (SIR) augmented with our labeling procedure performs much better than its "naive" extension, the labeled SIR M-SMC filter.
2.	Backén, Staffan, et al. (författare) RF replay system for narrowband GNSS if signals 2011 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 47:1, s. 586-595 Tidskriftsartikel (refereegranskat)abstract Although GNSS RF signal simulators have long possessed the capability to generate scenarios they are, for example, not yet able to model a realistic scenario with complex multipath. Software defined receivers bridge the gap between simulated and real data to the extent that they may offer a replay capability, where a data set is first recorded to disk and later can be processed several times. Unfortunately, the recorded data generally can not be used by other GNSS receivers, making receiver to receiver comparisons difficult and time consuming.This paper describes a system capable of replaying recorded IF data into any narrow bandwidth L1 GNSS receiver, including an evaluation of the difference (position, timing and SNR) between live and replayed data using a high sensitivity, consumer grade receiver. The performance of the replayed data set was found to match that of the live data.
3.	Biswas, Sinchan, 1988-, et al. (författare) Asymptotic Performance Analysis of Distributed Non-Bayesian Quickest Change Detection with Energy Harvesting Sensors 2022 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 58:4, s. 3697-3707 Tidskriftsartikel (refereegranskat)abstract This paper focuses on the distributed non-Bayesian quickest change detection of the probability distribution of a random process in a wireless senor network (WSN), where the distributions before and after the change point is assumed to be known. The individual sensors are capable of harvesting energy from their surroundings. Each sensor decides to sense the observation signal depending on the available energy at its disposal. Once, a sensor decides to sense, it takes a sample of the observation signal and computes the log-likelihood ratio (LLR) of the aforementioned two distributions, if enough energy is available in its battery for sensing and processing the sample. On the other hand, if enough energy is not available, the sensor decides to abstain from the sensing process during that time slot and waits until a future time slot when it accumulates enough energy to perform the sensing and processing. Once a sensor computes the LLR, it uses that information to calculate the Cumulative Sum (CUSUM) test statsistic to arrive at a local decision about the change point. When a change is detected, these decisions are then sent to the FC (provided the transmitting sensor has enough energy to transmit the decision to the fusion centre successfully), where they are collated to form a single decision about the detection of the change point based on some pre-decided fusion rule. In this work, using asymptotic results on the detection delay for CUSUM tests for a single sensor, we have derived asymptotic results for the expected detection delay (when the change occurs) for three common fusion rules, namely, OR, AND and $r$ out of $N$ rule respectively. These results are analyzed for the scenario when the average harvested energy ($\mathit{\bar{H}}$) at each sensor is greater than or equal to the amount of energy required for sensing ($E_{s}$). We show that in such cases, the standard existing asymptotic results for CUSUM test holds for the local decisions. Consequently, we have determined corresponding results for the detection delay for decisions taken at the FC with the three aforementioned fusion rules by using the theory of order statistics. Numerical results are provided to support the theoretical claims.
4.	Boström-Rost, Per, 1988-, et al. (författare) PMBM Filter With Partially Grid-Based Birth Model With Applications in Sensor Management 2022 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9251 .- 1557-9603 .- 2371-9877. ; 58:1, s. 530-540 Tidskriftsartikel (refereegranskat)abstract This article introduces a Poisson multi-Bernoulli mixture (PMBM) filter in which the intensities of target birth and undetected targets are grid-based. A simplified version of the Rao-Blackwellized point mass filter is used to predict the intensity of undetected targets and to initialize tracks of targets detected for the first time. The grid approximation can efficiently represents intensities with abrupt changes with relatively few grid points compared to the number of Gaussian components needed in conventional PMBM implementations. This is beneficial in scenarios where the sensors field of view is limited. The proposed method is illustrated in a sensor management setting, where trajectories of sensors with limited fields of view are controlled to search for and track the targets in a region of interest.
5.	Boström-Rost, Per, 1988-, et al. (författare) Sensor management for search and track using the Poisson multi-Bernoulli mixture filter 2021 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9251 .- 1557-9603. ; 57:5, s. 2771-2783 Tidskriftsartikel (refereegranskat)abstract A sensor management method for joint multi-target search and track problems is proposed, where a single user-defined parameter allows for a trade-off between the two objectives. The multi-target density is propagated using the Poisson multi-Bernoulli mixture filter, which eliminates the need for a separate handling of undiscovered targets and provides the theoretical foundation for a unified search and track method. Monte Carlo simulations of two scenarios are used to evaluate the performance of the proposed method.
6.	Carotenuto, Vincenzo, et al. (författare) Radar detection architecture based on interference covariance structure classification 2019 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 55:2, s. 607-618 Tidskriftsartikel (refereegranskat)
7.	Da Fontoura, A. A., et al. (författare) Timing Assurance of Avionic Reconfiguration Schemes using Formal Analysis 2020 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE. - 0018-9251 .- 1557-9603. ; 56:1, s. 95-106 Tidskriftsartikel (refereegranskat)abstract Reconfigurable avionics systems can tolerate faults by moving functionalities from failed components to another available system component. This paper proposes a distributed reconfigurable architecture for application migration from failed modules to working ones. The feasible system reconfiguration states are determined off-line to provide the expected configuration in foreseen situations. Model Checking is used to determine feasible configurations evaluating specific temporal properties. A case study is used to show the application of the presented approach as a proof of concept
8.	De Maio, Antonio, et al. (författare) Loading factor estimation under affine constraints on the covariance eigenvalues with application to radar target detection 2019 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 55:3, s. 1269-1283 Tidskriftsartikel (refereegranskat)
9.	Dokhanchi, S. H., et al. (författare) A mmWave Automotive Joint Radar-Communications System 2019 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 55:3, s. 1241-1260 Tidskriftsartikel (refereegranskat)
10.	Du, Lin, et al. (författare) Fully automatic computation of diagonal loading levels for robust adaptive beamforming 2010 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 46:1, s. 449-458 Tidskriftsartikel (refereegranskat)
11.	Garcia, Angel, 1984, et al. (författare) Poisson Multi-Bernoulli Mixture Filter: Direct Derivation and Implementation 2018 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 54:4, s. 1883-1901 Tidskriftsartikel (refereegranskat)abstract We provide a derivation of the Poisson multi-Bernoulli mixture (PMBM) filter for multitarget tracking with the standard point target measurements without using probability generating functionals or functional derivatives. We also establish the connection with the δ-generalized labeled multi-Bernoulli (δ -GLMB) filter, showing that a δ-GLMB density represents a multi-Bernoulli mixture with labeled targets so it can be seen as a special case of PMBM. In addition, we propose an implementation for linear/Gaussian dynamic and measurement models and how to efficiently obtain typical estimators in the literature from the PMBM. The PMBM filter is shown to outperform other filters in the literature in a challenging scenario.
12.	Garcia-Fernandez, Angel F., et al. (författare) Multiple Target Tracking Based on Sets of Trajectories 2020 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 56:3, s. 1685-1707 Tidskriftsartikel (refereegranskat)abstract We propose a solution of the multiple target tracking (MTT) problem based on sets of trajectories and the random finite set framework. A full Bayesian approach to TT should characterize the distribution of the trajectories given the measurements, as it contains all information about the trajectories. We attain this by considering multiobject density functions in which objects are trajectories. For the standard tracking models, we also describe a conjugate family of multitrajectory density functions.
13.	Granström, Karl, 1981-, et al. (författare) Extended Target Tracking Using a Gaussian-Mixture PHD Filter 2012 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 48:4, s. 3268-3286 Tidskriftsartikel (refereegranskat)abstract This paper presents a Gaussian-mixture implementation of the phd filter for tracking extended targets. The exact filter requires processing of all possible measurement set partitions, which is generally infeasible to implement. A method is proposed for limiting the number of considered partitions and possible alternatives are discussed. The implementation is used on simulated data and in experiments with real laser data, and the advantage of the filter is illustrated. Suitable remedies are given to handle spatially close targets and target occlusion.
14.	Granström, Karl, et al. (författare) New Prediction for Extended Targets With Random Matrices 2014 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 50:2, s. 1577-1589 Tidskriftsartikel (refereegranskat)abstract This paper presents a new prediction update for extended targets whose extensions are modeled as random matrices. The prediction is based on several minimizations of the Kullback-Leibler divergence (KL-div) and allows for a kinematic state dependent transformation of the target extension. The results show that the extension prediction is a significant improvement over the previous work carried out on the topic.
15.	Granström, Karl, 1981, et al. (författare) Poisson Multi-Bernoulli Mixture Conjugate Prior for Multiple Extended Target Filtering 2020 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 56:1, s. 208-225 Tidskriftsartikel (refereegranskat)abstract This paper presents a Poisson multi-Bernoulli mixture (PMBM) conjugate prior for multiple extended object filtering. A Poisson point process is used to describe the existence of yet undetected targets, while a multi-Bernoulli mixture describes the distribution of the targets that have been detected. The prediction and update equations are presented for the standard transition density and measurement likelihood. Both the prediction and the update preserve the PMBM form of the density, and in this sense, the PMBM density is a conjugate prior. However, the unknown data associations lead to an intractably large number of terms in the PMBM density, and approximations are necessary for tractability. A gamma Gaussian inverse Wishart implementation is presented, along with methods to handle the data association problem. A simulation study shows that the extended target PMBM filter performs well in comparison to the extended target \delta-generalized labelled multi-Bernoulli and LMB filters. An experiment with Lidar data illustrates the benefit of tracking both detected and undetected targets.
16.	Granström, Karl, 1981, et al. (författare) Systematic Approach to IMM Mixing for Unequal Dimension States 2015 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1557-9603 .- 0018-9251. ; 51:4, s. 2975-2986 Tidskriftsartikel (refereegranskat)abstract The interacting multiple model (IMM) estimator outperforms fixed model filters, e.g. the Kalman filter, in scenarios where the targets have periods of disparate behavior. Key to the good performance and low complexity is the mode mixing. Here we propose a systematic approach to mode mixing when the modes have states of different dimensions. The proposed approach is general and encompasses previously suggested solutions. Different mixing approaches are compared, and the proposed methodology is shown to perform very well.
17.	Guo, Xiaoxi, et al. (författare) Estimation in Wireless Sensor Networks With Security Constraints 2017 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9251 .- 1557-9603. ; 53:2, s. 544-561 Tidskriftsartikel (refereegranskat)abstract In this paper, we investigate the performance of distributed estimation schemes in a wireless sensor network in the presence of an eavesdropper. The sensors transmit observations to the fusion center (FC), which at the same time are overheard by the eavesdropper. Both the FC and the eavesdropper reconstruct a minimum mean-squared error estimate of the physical quantity observed. We address the problem of transmit power allocation for system performance optimization subject to a total average power constraint on the sensor(s), and a security/secrecy constraint on the eavesdropper. We mainly focus on two scenarios: 1) a single sensor with multiple transmit antennas and 2) multiple sensors with each sensor having a single transmit antenna. For each scenario, given perfect channel state information (CSI) of the FC and full or partial CSI of the eavesdropper, we derive the transmission policies for short-term and long-term cases. For the long-term power allocation case, when the sensor is equipped with multiple antennas, we can achieve zero information leakage in the full CSI case, and dramatically enhance the system performance by deploying the artificial noise technique for the partial CSI case. Asymptotic expressions are derived for the long-term distortion at the FC as the number of sensors or the number of antennas becomes large. In addition, we also consider multiple-sensor multiple-antenna scenario, and simulations show that given the same total number of transmitting antennas the multiple-antenna sensor network is superior to the performance of the multiple-sensor single-antenna network.
18.	Hammarstrand, Lars, 1979, et al. (författare) Adaptive Radar Sensor Model for Tracking Structured Extended Objects 2012 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 48:3, s. 1975 - 1995 Tidskriftsartikel (refereegranskat)abstract We propose a tracking framework jointly estimating the position of a single extended object and the set of radar reflectors that it contains. The reflectors are assumed to lie on a line structure, but the number of reflectors and their positions on the line are unknown. Additionally, we incorporate an accurate radar sensor model considering the resolution capabilities of the sensor. The evaluation of the framework on radar measurements shows promising results.
19.	Hammarstrand, Lars, 1979, et al. (författare) Extended Object Tracking using a Radar Resolution Model 2012 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 48:3, s. 2371 - 2386 Tidskriftsartikel (refereegranskat)abstract The work presented here concerns the problem of vehicle tracking when multiple radar reflection centers could be resolved on each vehicle. For this extended target tracking problem we propose a radar sensor model, capable of describing such measurements, incorporating sensor resolution. Furthermore, we introduce approximations to handle the inherently complex data association problem. The evaluation in terms of describing measured data and resulting tracking performance shows that the model effectively exploits the information in multiple vehicle detections.
20.	Huang, Huiping, 1991, et al. (författare) Low-Rank and Row-Sparse Decomposition for Joint DOA Estimation and Distorted Sensor Detection 2023 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 59:4, s. 4763-4773 Tidskriftsartikel (refereegranskat)abstract Distorted sensors could occur randomly and may lead to the breakdown of a sensor array system. In this article, we consider an array model within which a small number of sensors are distorted by unknown sensor gain and phase errors. With such an array model, the problem of joint direction-of-arrival (DOA) estimation and distorted sensor detection is formulated under the framework of low-rank and row-sparse decomposition. We derive an iteratively reweighted least squares (IRLS) algorithm to solve the resulting problem. The convergence property of the IRLS algorithm is analyzed by means of the monotonicity and boundedness of the objective function. Extensive simulations are conducted regarding parameter selection, convergence speed, computational complexity, and performances of DOA estimation as well as distorted sensor detection. Even though the IRLS algorithm is slightly worse than the alternating direction method of multipliers in detecting the distorted sensors, the results show that our approach outperforms several state-of-the-art techniques in terms of convergence speed, computational cost, and DOA estimation performance.
21.	Karlsson, Alexander, et al. (författare) Low-Angle Target Tracking in Sea Surface Multipath Using Convolutional Neural Networks 2023 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - New York, USA : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 59:5, s. 6813-6831 Tidskriftsartikel (refereegranskat)abstract Multipath interference while tracking sea-skimming targets can significantly distort the estimated height of the target. If accounted for however, this interference can be used to obtain more accurate estimates. In this study, we accomplish this with a convolutional neural network (CNN) used as a parameter estimator. The performance of this network is compared with maximum likelihood and least-squares methods. We found that the CNN performs well in comparison to these methods with only a fraction of the computations.
22.	Karlsson, Alexander, et al. (författare) Stepped Frequency Pulse Compression with Non-Coherent Radar using Deep Learning 2021 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. Tidskriftsartikel (refereegranskat)abstract A deep neural network (DNN) is used for achieving subpulse resolution in non-coherent stepped frequency waveform radar. The trade-off between high resolution and long range in radar systems is often addressed using pulse compression, allowing both long pulses and high resolution by increasing the pulse bandwidth. This typically requires a coherent radar. In this study we present a deep learning based solution for achieving subpulse resolution with a non-coherent radar. Our results for such a system are comparable to an equivalent coherent system for SNRs greater than 10 dB. All results are based on simulated data.
23.	Karlsson, Johan, et al. (författare) Fast Missing-Data IAA With Application to Notched Spectrum SAR 2014 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 50:2, s. 959-971 Tidskriftsartikel (refereegranskat)abstract Recently, the spectral estimation method known as the iterative adaptive approach (IAA) has been shown to provide higher resolution and lower sidelobes than comparable spectral estimation methods. The computational complexity is higher than methods such as the periodogram (matched filter method). Fast algorithms have been developed that considerably reduce the computational complexity of IAA by using Toeplitz and Vandermonde structures. For the missing-data case, several of these structures are lost, and existing fast algorithms are only efficient when the number of available samples is small. In this work, we consider the case in which the number of missing samples is small. This allows us to use low-rank completion to transform the problem to the structured problem. We compare the computational speed of the algorithm with the state of the art and demonstrate the utility in a frequency-notched synthetic aperture radar imaging problem.
24.	Klintberg, Jacob, 1994, et al. (författare) A Parametric Approach to Space-Time Adaptive Processing in Bistatic Radar Systems 2022 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 58:2, s. 1149-1160 Tidskriftsartikel (refereegranskat)abstract Space-time adaptive processing (STAP) is an important airborne radar technique used to improve target detection in environments of clutter and jammers. Effective STAP implementations are dependent on an accurate estimate of the space-time covariance matrix, which characterizes noise and interference in the radar signal. Inside-looking monostatic radar systems, the estimate based on secondary radar observations is rather straight forward as all the samples in secondary data can be argued to be from a single distribution, and the sample covariance can be used as an estimate of the space-time covariance matrix. However, in many other radar configurations, the vital underlying STAP training assumption that secondary data are identically distributed is violated, which implies that detection performance can be significantly degraded. This article develops a new method that can be used when secondary data do not share a common distribution due to geometry-induced range dependencies. This phenomenon is of particular concern in bistatic radar systems. We propose a model-based approach, where the distribution of noise and clutter for each range bin is parameterized by a set of scenario parameters. Using secondary data, the scenario parameters are estimated by maximizing the likelihood function. Based on the estimated scenario parameters, the STAP covariance estimate is formed for the cell under test. The presented method is compared with other state-of-the-art methods for bistatic radar STAP via numerical simulations. The simulations indicate that the presented method, with a proper initialization, yields an estimate of the STAP covariance matrix that significantly increases the signal-to-interference-plus-noise ratio compared to the other investigated methods.
25.	Klintberg, Jacob, 1994, et al. (författare) Scenario Tracking for Airborne Bistatic Radar Systems 2024 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; In Press Tidskriftsartikel (refereegranskat)abstract An effective space-time adaptive processing implementation provides an accurate estimate of the corresponding space-time covariance matrix of the distribution of the interference and the noise. Such an estimate is commonly calculated from secondary observations associated with the most recent coherent processing interval. In this paper, we derive the covariance matrix using a parametric model which depends on a few parameters describing the state of the radar scenario. With this formulation, it is sufficient to estimate the scenario parameters to obtain the covariance matrix estimate. The scenario parameters represents the position and velocities of the platforms comprising the airborne bistatic configuration. Moreover, the framework of radar scenarios enables information from previously considered coherent processing intervals to contribute to the covariance matrix estimate. Consequently, as the scenario parameters denotes motion characteristics of a platform, the scenario parameters can be tracked over time by assuming a motion model. Thus, the estimator of this paper uses a combination of the likelihood density of the most recent set of radar observations, together with a dynamical model which enables the propagation of the scenario parameters dynamics through time. Hence, the density of the likelihood and the prior density from the propagation of previous scenario parameter estimates through time is combined to calculate a maximum a posteriori estimate of the scenario parameters. In numerical simulations, the maximum a posteriori estimate is compared with the corresponding scenario parameter estimate considering only a maximum likelihood estimate. The numerical simulations indicates that the maximum a posteriori estimate obtains a scenario parameter estimate which is closer to the true scenario parameters. Moreover, the maximum a posteriori estimate is more robust towards a low number of secondary data comprising the likelihood density compared to the maximum likelihood estimate.
26.	Larsson, Erik G., et al. (författare) High-resolution SAR imaging with angular diversity 2001 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603 .- 2371-9877. ; 37:4, s. 1359-1372 Tidskriftsartikel (refereegranskat)abstract We propose to use the APES (amplitude and phase estimation) approach for the spectral estimation of gapped data and synthetic aperture radar (SAR) imaging with angular diversity. A relaxation-based algorithm, referred to as GAPES (Gapped-data APES), is proposed, which includes estimating the spectrum via APES and filling in the gaps via a least squares (LS) fitting. For SAR imaging with angular diversity data fusion, we perform one-dimensional (1-D) windowed fast Fourier transforms (FFTs) in range, use the GAPES algorithm to interpolate the gaps in the aperture for each range, apply 1-D inverse FFTs (IFFTs) and dewindow in range, and finally apply the two-dimensional (2-D) APES algorithm to the interpolated matrix to obtain the 2-D SAR image. Numerical results are presented to demonstrate the effectiveness of the proposed algorithm.
27.	Larsson, Erik G., et al. (författare) Spectral Analysis of Periodically Gapped Data 2003 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 39:3, s. 1089-1097 Tidskriftsartikel (refereegranskat)abstract We devise novel, interpolation-free, and computationally tractable extensions of the spectral analysis methods Capon and APES (amplitude and phase estimation) to periodically gapped data. Our methods are based on the observation that periodically gapped data usually have a structure that supports estimation of a relatively large number of covariance lags. The large signal-to-noise-ratio (SNR) behavior of the new algorithms is discussed, and numerical examples are provided to illustrate their performance.
28.	Li, Jian, et al. (författare) High resolution angle-Doppler imaging for MTI radar 2010 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 46:3, s. 1544-1556 Tidskriftsartikel (refereegranskat)
29.	Liang, Junli, et al. (författare) On designing the transmission and reception of multistatic continuous active sonar systems 2014 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 50:1, s. 285-299 Tidskriftsartikel (refereegranskat)
30.	Lu, Q., et al. (författare) Tracking Initially Unresolved Thrusting Objects Using an Optical Sensor 2018 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 54:2, s. 794-807 Tidskriftsartikel (refereegranskat)abstract This paper considers the problem of estimating the three-dimensional states of a salvo of thrusting/ballistic endo-atmospheric objects using two-dimensional (2-D) Cartesian measurements from the focal plane array (FPA) of a single fixed optical sensor. Since the initial separations in the FP are smaller than the resolution of the sensor, there are merged FP measurements, compounding the usual false-alarm and missed-detection uncertainty. We present a two-step methodology. First, we assume a Wiener process acceleration model for the motion of the images of the objects in the optical sensor's FPA. We model the merged measurements with increased variance, and thence employ a multi-Bernoulli (MB) filter using the 2-D measurements in the FPA. Second, using the set of associated measurements for each confirmed MB track, we formulate a parameter estimation problem, whose maximum likelihood solution can be obtained via numerical search and can be used for impact point prediction. Simulation results illustrate the performance of the proposed method.
31.	Manchester, Ian R, et al. (författare) Method for optical-flow-based precision missile guidance 2008 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - Piscataway : IEEE Press. - 0018-9251 .- 1557-9603. ; 44:3, s. 835-851 Tidskriftsartikel (refereegranskat)abstract A new precision guidance law is presented for three-dimensional intercepts against a moving target In contrast to previously published guidance laws, it does not require knowledge of the range to the target. This makes it appropriate for use on platforms which have an imaging device, such as a video camera, as a primary sensor. We prove that with idealized dynamic model, the guidance law results in zero miss distance, and a formula is given for impact angle error which tends to zero as does target speed, making this method particularly suitable against slow moving targets. Computer simulations are used to test the law with a more realistic model, with a video camera and optical-flow algorithm providing target information. It is shown to perform well compared with another law from the literature, despite requiring less information.
32.	Naghsh, Mohammad Mahdi, et al. (författare) Radar Code Design for Detection of Moving Targets 2014 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 50:4, s. 2762-2778 Tidskriftsartikel (refereegranskat)abstract In this paper, we study the problem of pulsed-radar transmit code design for detection of moving targets in the presence of signal-dependent clutter. For unknown target Doppler shift, the optimal detector does not lead to a closed-form expression. Therefore, we resort to average and worst case performance metrics of the optimal detector for code design. We propose several algorithms under two novel frameworks to solve highly nonconvex design problems. We also consider low peak-to-average-power ratio (PAR) code design.
33.	Nordlund, Per-Johan, 1971-, et al. (författare) Marginalized Particle Filter for Accurate and Reliable Terrain-Aided Navigation 2009 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 45:4, s. 1385-1399 Tidskriftsartikel (refereegranskat)abstract 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 [1]. The key idea with MPF is to estimate the nonlinear part using the particle filter and the part which is linear, conditionally upon the nonlinear part, is estimated using the Kalman filter. The extension lies in the possibility to deal with a third multi-modal 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 to the Cramer-Rao lower bound.
34.	Nordlund, Per-Johan, 1971-, et al. (författare) Probabilistic Noncooperative Near Mid-Air Collision Avoidance 2011 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 47:2, s. 1265-1276 Tidskriftsartikel (refereegranskat)abstract We propose a probabilistic method to compute the near mid-air collision risk as a function of predicted flight trajectory. The computations use state estimate and covariance from a target tracking filter based on angle-only sensors such as digital video cameras. The majority of existing work is focused on risk estimation at a certain time instant. Here we derive an expression for the integrated risk over the critical time horizon. This is possible using probability for level-crossing, and the expression applies to a three-dimensional piecewise straight flight trajectory. The Monte Carlo technique provides a method to compute the probability, but a huge number of simulations is needed to get sufficient reliability for the small risks that the applications require. Instead we propose a method which through sound geometric and numerical approximations yield a solution suitable for real-time implementations. The algorithm is applied to realistic angle-only tracking data, and shows promising results when compared to the Monte Carlo solution.
35.	Pettersson, Mats (författare) Detection of Moving Targets in Wideband SAR 2004 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE. - 0018-9251 .- 1557-9603. ; 40:3, s. 780-796 Tidskriftsartikel (refereegranskat)abstract A likelihood ratio is proposed for moving target detection in a wideband (WB) synthetic aperture radar (SAR) system. WB is defined here as any systems having a large fractional bandwidth, i.e., an ultra wide frequency band combined with a wide antenna beam. The developed method combines time-domain fast backprojection SAR processing methods with moving target detection using space-time processing. The proposed method reduces computational load when sets of relative speeds can be tested using the same clutter-suppressed subaperture beams. The proposed method is tested on narrowband radar data.
36.	Pettersson, Mats, et al. (författare) Performance of Moving Target Parameter Estimation Using SAR 2015 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 51:2, s. 1191-1202 Tidskriftsartikel (refereegranskat)abstract Synthetic aperture radar (SAR) gives not only the opportunity to image targets with high resolution but also to measure their position and velocity. Without acceleration (constant speed), the position and velocity both in range and azimuth can be estimated using a multichannel SAR system. This paper introduces a method to find the lower bound on variance of estimate of position and velocity for targets. The method is based on the assumptions needed for the Cramer-Rao lower bound (CRLB). The method works for both narrowband (NB) and ultrawideband (UWB) SAR systems. For demonstration, a monostatic single-channel UWB SAR system operating at low frequency is used. Thus, only lower bounds for estimate variance of azimuth, range, and relative speed are derived.
37.	Pinto, Juliano, 1990, et al. (författare) Deep Learning for Model-Based Multi-Object Tracking 2023 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1557-9603 .- 0018-9251. ; 59:6, s. 7363-7379 Tidskriftsartikel (refereegranskat)abstract Multi-object tracking (MOT) is the problem of tracking the state of an unknown and time-varying number of objects using noisy measurements, with important applications such as autonomous driving, tracking animal behavior, defense systems, and others. The MOT task can be divided into two settings, model-based or model-free, depending on whether accurate and tractable models of the environment are available. Model-based MOT has Bayes-optimal closed-form solutions which can achieve state-of-the-art (SOTA) performance. However, these methods require approximations in challenging scenarios to remain tractable, which impairs their performance. Deep learning (DL) methods offer a promising alternative, but existing DL models are almost exclusively designed for a model-free setting and are not easily translated to the model-based setting. This paper proposes a DL-based tracker specifically tailored to the model-based MOT setting and provides a thorough comparison to SOTA alternatives. We show that our DL-based tracker is able to match performance to the benchmarks in simple tracking tasks while outperforming the alternatives as the tasks become more challenging. These findings provide strong evidence of the applicability of DL also to the model-based setting, which we hope will foster further research in this direction.
38.	Saar de Moraes, Rodrigo, et al. (författare) Multi-UAV Based Crowd Monitoring System 2020 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9251 .- 1557-9603. ; 56:2, s. 1332-1345 Tidskriftsartikel (refereegranskat)abstract This article presents the development of a multi-unmanned aerial vehicle (UAV) based crowd monitoring system, demonstrating a system that uses UAVs to periodically monitor a group of moving walking individuals. Using auction paradigms to distribute targets among UAVs and genetic algorithms to calculate the best order to visit the targets, the system has shown capabilities to efficiently perform the surveillance, visiting all the targets during a surveillance period and minimizing the time between the visits made to each target. Moreover, the system showed robustness keeping the good performance under a variety of situations.
39.	Sanchez, Miguel A., et al. (författare) Implementing FFT-based Digital Channelized Receivers on FPGA Platforms 2008 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 44:4, s. 1567-1585 Tidskriftsartikel (refereegranskat)abstract This paper presents an in-depth study of the implementationand characterization of fast Fourier transform (FFT) pipelinedarchitectures suitable for broadband digital channelized receivers.When implementing the FFT algorithm on field-programmablegate array (FPGA) platforms, the primary goal is to maximizethroughput and minimize area. Feedback and feedforwardarchitectures have been analyzed regarding key designparameters: radix, bitwidth, number of points and stage scaling.Moreover, a simplification of the FFT algorithm, the monobitFFT, has been implemented in order to achieve faster real timeperformance in broadband digital receivers. The influence ofthe hardware implementation on the performance of digitalchannelized receivers has been analyzed in depth, revealinginteresting implementation trade-offs which should be taken intoaccount when designing this kind of signal processing systems onFPGA platforms.
40.	Schmidtbauer, Bengt (författare) High-accuracy sounding rocket attitude estimation using star sensor data 1978 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 14:6, s. 891-898 Tidskriftsartikel (refereegranskat)abstract A three-axis reconstitution scheme for spin stabilized sounding rockets is presented, using star transit pulse information from a single slit all solid state star sensor. The method, based on Kalman filtering and smoothing, gives accuracies in the arcminute range and has been successfully tested on four different missions in the Swedish sounding rocket program
41.	Shames, Iman, et al. (författare) Doppler Shift Target Localization 2013 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE Press. - 0018-9251 .- 1557-9603. ; 49:1, s. 266-276 Tidskriftsartikel (refereegranskat)abstract This paper outlines the problem of doppler-based target position and velocity estimation using a sensor network. The minimum number of doppler shift measurements at distinct generic sensor positions to have a finite number of solutions, and later, a unique solution for the unknown target position and velocity is stated analytically. Furthermore, we study the same problem where not only doppler shift measurements are collected, but also other types of measurements are available, e.g. bearing or distance to the target from each of the sensors. Later, we study the Cramer-Rao inequality associated with the doppler-shift measurements to a target in a sensor network, and use the Cramer-Rao bound to illustrate some results on optimal placements of the sensors when the goal is to estimate the velocity of the target. Some simulation results are presented in the end.
42.	Sjanic, Zoran, 1975-, et al. (författare) EM-SLAM with Inertial/Visual Applications 2017 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 53:1, s. 273-285 Tidskriftsartikel (refereegranskat)abstract The general Simultaneous Localisation and Mapping (SLAM) problem aims at estimating the state of a moving platform simultaneously with building a map of the local environment. There are essentially three classes of algorithms. EKF- SLAM and FastSLAM solve the problem on-line, while Nonlinear Least Squares (NLS) is a batch method. All of them scales badly with either the state dimension, the map dimension or the batch length. We investigate the EM algorithm for solving a generalized version of the NLS problem. This EM-SLAM algorithm solves two simpler problems iteratively, hence it scales much better with dimensions. The iterations switch between state estimation, where we propose an Extended Rauch-Tung-Striebel smoother, and map estimation, where a quasi-Newton method is suggested. The proposed method is evaluated in real experiments and also in simulations on a platform with a monocular camera attached to an inertial measurement unit. It is demonstrated to produce lower RMSE than with a standard Levenberg-Marquardt solver of NLS problem, at a computational cost that increases considerably slower.
43.	Sjanic, Zoran, 1975-, et al. (författare) Navigation and SAR focusing with Map Aiding 2015 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE Press. - 0018-9251 .- 1557-9603. ; 51:3, s. 1652-1663 Tidskriftsartikel (refereegranskat)abstract A method for fusing Synthetic Aperture Radar (SAR) images with opticalaerial images is presented. This is done in a navigation framework, where the absolute position and orientation of the flying platform, as computed from the inertial navigation system, is corrected based on the aerial image coordinates taken as ground truth. The method is suitable for new low-price SAR systems for small unmanned vehicles. The primary application is remote sensing, where the SAR image provides one further "colour" channel revealing reflectivity to radio waves. The method is based on first applying an edge detection algorithm to the images and then optimising the most important navigation states by matching the two binary images. To get a measure of the estimation uncertainty, we embed the optimisation in a least squares framework, where an explicit method to estimate the (relative) size of the errors is presented. The performance is demonstrated on real SAR and aerial images, leading to an error of only a few pixels.
44.	Sjanic, Zoran, et al. (författare) Simultaneous Navigation and Synthetic Aperture Radar Focusing 2015 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 51:2, s. 1253-1266 Tidskriftsartikel (refereegranskat)abstract Synthetic aperture radar (SAR) equipment is a radar imaging system that can be used to create high-resolution images of a scene by utilizing the movement of a flying platform. Knowledge of the platforms trajectory is essential to get good and focused images. An emerging application field is real-time SAR imaging using small and cheap platforms where estimation errors in navigation systems imply unfocused images. This contribution investigates a joint estimation of the trajectory and SAR image. Starting with a nominal trajectory, we successively improve the image by optimizing a focus measure and updating the trajectory accordingly. The method is illustrated using simulations using typical navigation performance of an unmanned aerial vehicle. One real data set is used to show feasibility, where the result indicates that, in particular, the azimuth position error is decreased as the image focus is iteratively improved.
45.	Sjögren, Tomas, et al. (författare) Moving Target Relative Speed Estimation and Refocusing in Synthetic Aperture Radar Images 2012 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : IEEE. - 0018-9251 .- 1557-9603. ; 48:3, s. 2426-2436 Tidskriftsartikel (refereegranskat)abstract In this paper, a method for moving target relative speed estimation and refocusing based on synthetic aperture radar (SAR) images is derived and tested in simulation and on real data with good results. Furthermore, an approach on how to combine the estimation method with the refocusing method is introduced. The estimation is based on a chirp estimator that operates in the SAR image and the refocusing of the moving target is performed locally using subimages. Focusing of the moving target is achieved in the frequency domain by phase compensation, and therefore makes it even possible to handle large range cell migration in the SAR subimages. The proposed approach is tested in a simulation and also on real ultrawideband (UWB) SAR data with very good results. The estimation method works especially well in connection with low frequency (LF) UWB SAR, where the clutter is well focused and the phase of the smeared moving target signal becomes less distorted. The main limitation of the approach is target accelerations where the distortion increases with the integration time.
46.	Stoica, P., et al. (författare) Improved sequential music 1995 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 31:4, s. 1230-1239 Tidskriftsartikel (refereegranskat)abstract MUSIC (multiple signal classification) is one of the most frequently considered methods for source location using sensor arrays. Among the location methods based on one-dimensional search, MUSIC has excellent performance. in fact, no other one-dimensional method that may outperform MUSIC (in large samples) was known to exist Our goal here is to introduce such a method, called improved sequential MUSIC (IES-MUSIC), which is shown to be strictly more accurate than MUSIC (in large samples). First, a class of sequential MUSIC estimates is introduced, which depend on a scalar-valued user parameter. MUSIC is shown to be a special case of estimate in that class, corresponding to a value of uro for the user parameter. Next, the optimal user parameter value, which minimizes the asymptotic variance of the estimation errors, is derived IES-MUSIC is the method based on that optimal choice of the user parameter. Simulation results which Lend support to the theoretical findings are included.
47.	Svensson, Daniel, 1979, et al. (författare) Multitarget Sensor Resolution Model and Joint Probabilistic Data Association 2012 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 1557-9603 .- 0018-9251. ; 48:4, s. 3418-3434 Tidskriftsartikel (refereegranskat)abstract In the design of target tracking algorithms, the aspect of sensor resolution is rarely considered. Instead, it is usually assumed that all targets are always resolved, and that the only uncertainties in the data association are which targets that are detected, and which measurement each detected target gave rise to. However, in situations where the targets are closely spaced in relation to the sensor resolution, this assumption is not valid, and may lead to degraded tracking performance due to an incorrect description of the data. We present a framework for handling sensor resolution effects for an arbitrary, but known, number of targets. We propose a complete multitarget sensor resolution model that can be incorporated into traditional Bayesian tracking filters. Further, the exact form of the posterior probability density function (pdf) is derived, and two alternative ways of approximating that exact posterior density with a joint probabilistic data association (JPDA) filter are proposed. Evaluations of the resulting filters on simulated radar data show significantly increased tracking performance compared with the JPDA filter without a resolution model.
48.	Torgrimsson, Jan, 1982, et al. (författare) Factorized Geometrical Autofocus for UWB UHF-band SAR with a GPS-supported Linear Track Model 2022 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - Piscataway : IEEE. - 1557-9603 .- 0018-9251. ; 58:4, s. 3147-3161 Tidskriftsartikel (refereegranskat)abstract This paper describes how to form a SAR image without proper motion quantities. That is within the scope of factorized geometrical autofocus (FGA). The FGA algorithm is a fast-factorized back-projection formulation with adjustable geometry parameters. Sub-apertures are tuned and merged pair by-pair (base-2) and step-by-step. With this technique, we can correct an erroneous geometry and form a focused image. The FGA algorithm has been applied on two data sets, acquired by the UWB CARABAS 3 system at UHF-band. The tracks are measured accurately by means of a DGPS. We however adopt and modify a geometry model. Equidistant linear tracks at fixed altitudes are assumed. These tracks are then regulated via a two-stage search strategy and a reverse processing procedure. As this is a first experiment at UHF-band, we provide GPS-based length values for the sub-apertures, to simplify the search. Multiple geometry solutions are tested for each sub-aperture pair, i.e. at each resolution level. Resulting FGA images are compared to reference images and verified to be focused. This indicates that it is feasible to form a focused image with wavelength resolution at UHF-band, i.e. with minimum support from a motion measurement system.
49.	Ulander, L.M.H., et al. (författare) Synthetic-aperture radar processing using fast factorized back-projection 2003 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - 0018-9251 .- 1557-9603. ; 39:3, s. 760-776 Tidskriftsartikel (refereegranskat)abstract Exact synthetic aperture radar (SAR) inversion for a linear aperture may be obtained using fast transform techniques. Alternatively, back-projection integration in time domain can also be used. This technique has the benefit of handling a general aperture geometry. In the past, however, back-projection has seldom been used due to heavy computational burden. We show that the back-projection integral can be recursively partitioned and an effective algorithm constructed based on aperture factorization. By representing images in local polar coordinates it is shown that the number of operations is drastically reduced and can be made to approach that of fast transform algorithms. The algorithm is applied to data from the airborne ultra-wideband CARABAS SAR and shown to give a reduction in processing time of two to three orders of magnitude.
50.	Veibäck, Clas, 1985-, et al. (författare) Learning Target Dynamics While Tracking Using Gaussian Processes 2020 Ingår i: IEEE Transactions on Aerospace and Electronic Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9251 .- 1557-9603. ; 56:4, s. 2591-2602 Tidskriftsartikel (refereegranskat)abstract Tracked targets often exhibit common behaviors due to influences from the surrounding environment, such as wind or obstacles, which are usually modeled as noise. Here, these influences are modeled using sparse Gaussian processes that are learned online together with the state inference using an extended Kalman filter. The method can also be applied to time-varying influences and identify simple dynamic systems. The method is evaluated with promising results in a simulation and a real-world application.

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Träfflista för sökning "L773:1557 9603 OR L773:0018 9251 "

Avgränsa träffmängd

År