The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
K.b. Letaief - One of the best experts on this subject based on the ideXlab platform.
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A quasi-Orthogonal Group space-time architecture to achieve a better diversity-multiplexing tradeoff
IEEE Transactions on Wireless Communications, 2007Co-Authors: S. Sfar, K.b. LetaiefAbstract:Most existing MIMO (multiput-input multiput-output) schemes optimize only either the diversity gain or the multiplexing gain. To obtain a good tradeoff between these two, the quasi-Orthogonal Group space-time (QoGST) architecture is proposed, wherein the transmit stream is subGrouped but encoded via an inter-Group space-time block encoder, with Group interference suppression at the receiver. This paper also considers another combined space-time coding and layered space-time architecture, which we refer to as Group layered space-time (GLST), where space-time block coding is employed within each Group. Under the assumption of Rayleigh fading and a prior perfect channel state information at the receiver, a performance analysis will demonstrate that both QoGST and GLST can achieve a good diversity-multiplexing tradeoff. QoGST is even superior to GLST. Simulation results will validate our analysis and further show that compared to the existent layered space-time block code (LSTBC) scheme, both QoGST and GLST can achieve a significant performance gain.
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A quasi-Orthogonal Group space-time architecture for higher diversity gains
IEEE Global Telecommunications Conference 2004. GLOBECOM '04., 2004Co-Authors: S. Sfar, K.b. LetaiefAbstract:Multiple-input multiple-output (MIMO) systems can provide two kinds of gain: diversity gain and multiplexing gain. Most existing MIMO schemes, including space-time coding and layered space-time, aim at maximizing either of them. Therefore, it is desirable to design a scheme to get a better tradeoff between the multiplexing gain and diversity gain. In this paper, a novel quasi-Orthogonal Group space-time (QOGST) architecture is proposed. In QOGST, the transmit stream is divided into several Groups and all the Groups are encoded via an inter-Group space-time block encoder. Group interference suppression is adopted at the receiver. Performance is evaluated in terms of symmetric energy and it is shown that compared to the Group layered space-time (GLST) architecture, the proposed QOGST can achieve a higher symmetric energy and a better diversity-multiplexing tradeoff. Simulation results validate our analysis and show that QOGST can achieve at least 3 dB gain over GLST at a FER of 10/sup -3/, for instance.
Robert Mahony - One of the best experts on this subject based on the ideXlab platform.
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A second order minimum-energy filter on the special Orthogonal Group
2012 American Control Conference (ACC), 2012Co-Authors: Mohammad Zamani, Jochen Trumpf, Robert MahonyAbstract:This work documents a case study in the application of Mortensen's nonlinear filtering approach to invariant systems on general Lie Groups. In this paper, we consider the special Orthogonal Group SO(3) of all rotation matrices. We identify the exact form of the kinematics of the minimum-energy (optimal) observer on SO(3) and note that it depends on the Hessian of the value function of the associated optimal control problem. We derive a second order approximation of the dynamics of the Hessian by neglecting third order terms in the expansion of the dynamics. This yields a Riccati equation that together with the optimal observer equation form a second order minimum-energy filter on SO(3). The proposed filter is compared to the multiplicative extended Kalman filter (MEKF), arguably the industry standard for attitude estimation, by means of simulations. Our studies indicate superior transient and asymptotic tracking performance of the proposed filter as compared to the MEKF.
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Attitude tracking of rigid bodies on the special Orthogonal Group with bounded partial state feedback
Proceedings of the 48h IEEE Conference on Decision and Control (CDC) held jointly with 2009 28th Chinese Control Conference, 2009Co-Authors: Sylvain Bertrand, Tarek Hamel, Hélène Piet-lahanier, Robert MahonyAbstract:A solution to the attitude tracking problem of rigid bodies with kinematic representation directly on the special Orthogonal Group SO(3) of rotation matrices is proposed. A dynamic partial state feedback controller is designed to address the case where no angular velocity measurements are available. In addition, the gains in the control design can be tuned in advance to ensure that the torque inputs satisfy arbitrary saturation bounds. Stability conditions are provided based on Lyapunov function analysis and Barbalat's lemma. Simulation results are presented to illustrate the performance of the proposed control scheme.
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Nonlinear Complementary Filters on the Special Orthogonal Group
IEEE Transactions on Automatic Control, 2008Co-Authors: Robert Mahony, Tarek Hamel, Jean-michel PflimlinAbstract:This paper considers the problem of obtaining good attitude estimates from measurements obtained from typical low cost inertial measurement units. The outputs of such systems are characterized by high noise levels and time varying additive biases. We formulate the filtering problem as deterministic observer kinematics posed directly on the special Orthogonal Group SO (3) driven by reconstructed attitude and angular velocity measurements. Lyapunov analysis results for the proposed observers are derived that ensure almost global stability of the observer error. The approach taken leads to an observer that we term the direct complementary filter. By exploiting the geometry of the special Orthogonal Group a related observer, termed the passive complementary filter, is derived that decouples the gyro measurements from the reconstructed attitude in the observer inputs. Both the direct and passive filters can be extended to estimate gyro bias online. The passive filter is further developed to provide a formulation in terms of the measurement error that avoids any algebraic reconstruction of the attitude. This leads to an observer on SO(3), termed the explicit complementary filter, that requires only accelerometer and gyro outputs; is suitable for implementation on embedded hardware; and provides good attitude estimates as well as estimating the gyro biases online. The performance of the observers are demonstrated with a set of experiments performed on a robotic test-bed and a radio controlled unmanned aerial vehicle.
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Complementary filter design on the special Orthogonal Group SO(3)
Proceedings of the 44th IEEE Conference on Decision and Control, 2005Co-Authors: Robert Mahony, Tarek Hamel, Jean-michel PflimlinAbstract:This paper considers the problem of obtaining high quality attitude extraction and gyros bias estimation from typical low cost intertial measurement units for applications in control of unmanned aerial vehiccles. Two different non-linear complementary filters are proposed: Direct complementary filter and Passive non-linear complementary filter. Both filters evolve explicity on the special Orthogonal Group SO(3) and can be expressed in quaternion form for easy implementation. An extension to the passive ocmplementary filter is proposed to provide adaptive gyro bias estimation.
Kenneth Mcisaac - One of the best experts on this subject based on the ideXlab platform.
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guaranteed performance of nonlinear attitude filters on the special Orthogonal Group so 3
IEEE Access, 2019Co-Authors: Hashim A Hashim, Lyndon J Brown, Kenneth McisaacAbstract:This paper proposes two novel nonlinear attitude filters evolved directly on the Special Orthogonal Group SO(3) able to ensure prescribed measures of transient and steady-state performance. The tracking performance of the normalized Euclidean distance of attitude error is trapped to initially start within a large set and converge systematically and asymptotically to the origin from almost any initial condition. The convergence rate is guaranteed to be less than the prescribed value and the steady-state error does not exceed a predefined small value. The first filter uses a set of vectorial measurements with the need for attitude reconstruction. The second filter instead uses only a rate gyroscope measurement and two or more vectorial measurements. These filters provide good attitude estimates with superior convergence properties and can be applied to measurements obtained from low cost inertial measurement units (IMUs). Simulation results illustrate the robustness and effectiveness of the proposed attitude filters with guaranteed performance considering high level of uncertainty in angular velocity along with body-frame vector measurements. Keywords: Attitude, estimate, estimator, observer, filter, nonlinear deterministic attitude filter, special Orthogonal Group, Euler angles, angle-axis, Rodrigues vector, mapping, parameterization, prescribed performance, representation, robust, Multiplicative Extended Kalman Filter, KF, EKF, MEKF, asymptotic stability, almost global asymptotic, noise, rotational matrix, identity, origin, orientation, body frame, inertial frame, rigid body, three dimensional, 3D, space, micro electromechanical systems, sensor, MEMS, roll, pitch, yaw, UAVs, QUAV, SVD, fixed, moving, vehicles, robot, robotic system, spacecraft, submarine, underwater vehicle, passive complementary filter, explicit complementary filter, autonomous, comparative study, SO(3).
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Nonlinear Stochastic Attitude Filters on the Special Orthogonal Group 3: Ito and Stratonovich
IEEE Transactions on Systems Man and Cybernetics: Systems, 2019Co-Authors: Hashim A Hashim, Lyndon J Brown, Kenneth McisaacAbstract:This paper formulates the attitude filtering problem as a nonlinear stochastic filter problem evolved directly on the Special Orthogonal Group 3 (SO(3)). One of the traditional potential functions for nonlinear deterministic complimentary filters is studied and examined against angular velocity measurements corrupted with noise. This paper demonstrates that the careful selection of the attitude potential function allows to attenuate the noise associated with the angular velocity measurements and results into superior convergence properties of estimator and correction factor. The problem is formulated as a stochastic problem through mapping SO(3) to Rodriguez vector parameterization. Two nonlinear stochastic complimentary filters are developed on SO(3). The first stochastic filter is driven in the sense of Ito and the second one considers Stratonovich. The two proposed filters guarantee that errors in the Rodriguez vector and estimates are semi-globally uniformly ultimately bounded in mean square. Simulation results are presented to illustrate the effectiveness of the proposed filters considering high level of uncertainties in angular velocity as well as body-frame vector measurements.
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Guaranteed Performance of Nonlinear Attitude Filters on the Special Orthogonal Group SO(3)
IEEE Access, 2019Co-Authors: Hashim A Hashim, Lyndon J Brown, Kenneth McisaacAbstract:This paper proposes two novel nonlinear attitude filters evolved directly on the special Orthogonal Group $\mathbb {SO}\left ({3}\right)$ , able to ensure prescribed measures of transient and steady-state performance. The tracking performance of the normalized Euclidean distance of attitude error is trapped to initially start within a large set and converge systematically and asymptotically to the origin from almost any initial condition. The convergence rate is guaranteed to be less than the prescribed value, and the steady-state error does not exceed a predefined small value. The first filter uses a set of vectorial measurements with the need for attitude reconstruction. The second filter does not require attitude reconstruction and instead uses only a rate gyroscope measurement and two or more vectorial measurements. These filters provide good attitude estimates with superior convergence properties and can be applied to measurements obtained from low-cost inertial measurement units. The simulation results illustrate the robustness and effectiveness of the proposed attitude filters with guaranteed performance considering high level of uncertainty in angular velocity along with body-frame vector measurements.
S. Sfar - One of the best experts on this subject based on the ideXlab platform.
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A quasi-Orthogonal Group space-time architecture to achieve a better diversity-multiplexing tradeoff
IEEE Transactions on Wireless Communications, 2007Co-Authors: S. Sfar, K.b. LetaiefAbstract:Most existing MIMO (multiput-input multiput-output) schemes optimize only either the diversity gain or the multiplexing gain. To obtain a good tradeoff between these two, the quasi-Orthogonal Group space-time (QoGST) architecture is proposed, wherein the transmit stream is subGrouped but encoded via an inter-Group space-time block encoder, with Group interference suppression at the receiver. This paper also considers another combined space-time coding and layered space-time architecture, which we refer to as Group layered space-time (GLST), where space-time block coding is employed within each Group. Under the assumption of Rayleigh fading and a prior perfect channel state information at the receiver, a performance analysis will demonstrate that both QoGST and GLST can achieve a good diversity-multiplexing tradeoff. QoGST is even superior to GLST. Simulation results will validate our analysis and further show that compared to the existent layered space-time block code (LSTBC) scheme, both QoGST and GLST can achieve a significant performance gain.
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A quasi-Orthogonal Group space-time architecture for higher diversity gains
IEEE Global Telecommunications Conference 2004. GLOBECOM '04., 2004Co-Authors: S. Sfar, K.b. LetaiefAbstract:Multiple-input multiple-output (MIMO) systems can provide two kinds of gain: diversity gain and multiplexing gain. Most existing MIMO schemes, including space-time coding and layered space-time, aim at maximizing either of them. Therefore, it is desirable to design a scheme to get a better tradeoff between the multiplexing gain and diversity gain. In this paper, a novel quasi-Orthogonal Group space-time (QOGST) architecture is proposed. In QOGST, the transmit stream is divided into several Groups and all the Groups are encoded via an inter-Group space-time block encoder. Group interference suppression is adopted at the receiver. Performance is evaluated in terms of symmetric energy and it is shown that compared to the Group layered space-time (GLST) architecture, the proposed QOGST can achieve a higher symmetric energy and a better diversity-multiplexing tradeoff. Simulation results validate our analysis and show that QOGST can achieve at least 3 dB gain over GLST at a FER of 10/sup -3/, for instance.
Jean-michel Pflimlin - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear Complementary Filters on the Special Orthogonal Group
IEEE Transactions on Automatic Control, 2008Co-Authors: Robert Mahony, Tarek Hamel, Jean-michel PflimlinAbstract:This paper considers the problem of obtaining good attitude estimates from measurements obtained from typical low cost inertial measurement units. The outputs of such systems are characterized by high noise levels and time varying additive biases. We formulate the filtering problem as deterministic observer kinematics posed directly on the special Orthogonal Group SO (3) driven by reconstructed attitude and angular velocity measurements. Lyapunov analysis results for the proposed observers are derived that ensure almost global stability of the observer error. The approach taken leads to an observer that we term the direct complementary filter. By exploiting the geometry of the special Orthogonal Group a related observer, termed the passive complementary filter, is derived that decouples the gyro measurements from the reconstructed attitude in the observer inputs. Both the direct and passive filters can be extended to estimate gyro bias online. The passive filter is further developed to provide a formulation in terms of the measurement error that avoids any algebraic reconstruction of the attitude. This leads to an observer on SO(3), termed the explicit complementary filter, that requires only accelerometer and gyro outputs; is suitable for implementation on embedded hardware; and provides good attitude estimates as well as estimating the gyro biases online. The performance of the observers are demonstrated with a set of experiments performed on a robotic test-bed and a radio controlled unmanned aerial vehicle.
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Complementary filter design on the special Orthogonal Group SO(3)
Proceedings of the 44th IEEE Conference on Decision and Control, 2005Co-Authors: Robert Mahony, Tarek Hamel, Jean-michel PflimlinAbstract:This paper considers the problem of obtaining high quality attitude extraction and gyros bias estimation from typical low cost intertial measurement units for applications in control of unmanned aerial vehiccles. Two different non-linear complementary filters are proposed: Direct complementary filter and Passive non-linear complementary filter. Both filters evolve explicity on the special Orthogonal Group SO(3) and can be expressed in quaternion form for easy implementation. An extension to the passive ocmplementary filter is proposed to provide adaptive gyro bias estimation.
