Control of fast steering mirror for accurate beam positioning in FSO communication system

Lahari, Sreerama Amrutha; Raj, A. Arockia Bazil; Soumya, S.

doi:10.1109/icscan53069.2021.9526537

Cited by 10 publications

(8 citation statements)

References 21 publications

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“…In the formula, ∂y(k) ∂u(k) represents the Jacobian information, as shown in Equation (21). η represents the learning rate, and it satisfies 0 < η < 1.…”

Section: Nonlinear Active Disturbance Rejection Controller Based On R...mentioning

confidence: 99%

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A Dual-FSM GI LiDAR Imaging Control Method Based on Two-Dimensional Flexible Turntable Composite Axis Tracking

Cao,

Xie,

Wang

et al. 2024

Remote Sensing

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In this study, a tracking and pointing control system with a dual-FSM (fast steering mirror) two-dimensional flexible turntable composite axis is proposed. It is applied to the target-tracking accuracy control in a GI LiDAR (ghost imaging LiDAR) system. Ghost imaging is a multi-measurement imaging method; the dual-FSM GI LiDAR tracking and pointing imaging control system proposed in this study mainly solves the problems of the high-resolution remote sensing imaging of high-speed moving targets and various nonlinear disturbances when this technology is transformed into practical applications. Addressing the detrimental effects of nonlinear disturbances originating from internal flexible mechanisms and assorted external environmental factors on motion control’s velocity, stability, and tracking accuracy, a nonlinear active disturbance rejection control (NLADRC) method based on artificial neural networks is advanced. Additionally, to overcome the limitations imposed by receiving aperture constraints in GI LiDAR systems, a novel optical path design for the dual-FSM GI LiDAR tracking and imaging system is put forth. The implementation of the described methodologies culminated in the development of a dual-FSM GI LiDAR tracking and imaging system, which, upon thorough experimental validation, demonstrated significant improvements. Notably, it achieved an improvement in the coarse tracking accuracy from 193.29 μrad (3σ) to 87.21 μrad (3σ) and enhanced the tracking accuracy from 10.1 μrad (σ) to 1.5 μrad (σ) under specified operational parameters. Furthermore, the method notably diminished the overshoot during the target capture process from 28.85% to 12.8%, concurrently facilitating clear recognition of the target contour. This research contributes significantly to the advancement of GI LiDAR technology for practical application, showcasing the potential of the proposed control and design strategies in enhancing system performance in the face of complex disturbances.

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“…In the formula, ∂y(k) ∂u(k) represents the Jacobian information, as shown in Equation (21). η represents the learning rate, and it satisfies 0 < η < 1.…”

Section: Nonlinear Active Disturbance Rejection Controller Based On R...mentioning

confidence: 99%

“…The composite axis tracking system is the main mechanism to ensure stable beam pointing and tracking [19][20][21][22][23]. Long-range and high-speed target capture, as well as stable imaging, are all achieved by pointing and tracking (PAT) systems.…”

Section: Introductionmentioning

confidence: 99%

A Dual-FSM GI LiDAR Imaging Control Method Based on Two-Dimensional Flexible Turntable Composite Axis Tracking

Cao,

Xie,

Wang

et al. 2024

Remote Sensing

View full text Add to dashboard Cite

show abstract

“…Because FSO communication requires a line of sight (LOS) between FSO terminals, the pointing, acquisition, and tracking (PAT) system is essential for FSO communication [ 15 ]. To maintain uninterrupted LOS, various methods were proposed using a quadrant photodiode (QPD), modulated retro-reflector (MRR), fast steering mirror (FSM), and hybrid of QPD and FSM [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. MRR-based PAT systems, represented by retroreflector free space optics, were mounted on UAVs for 560 m FSO communication, but they exhibited a limited performance in terms of transmission speed (Mbps) and simplex communication [ 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

“…Full-duplex communication, which is essential for FSO network scalability and Gbps communication diversification, requires TRx’s on both the FSO terminals [ 9 , 10 , 11 , 12 , 13 , 14 ]. The FSM-based PAT system increases the control complexity and requires additional integrated modules for precision control [ 19 , 20 , 21 ]. Hybrid methods exhibit a good and stable performance.…”

Section: Introductionmentioning

confidence: 99%

Tracking Efficiency Improvement According to Incident Beam Size in QPD-Based PAT System for Common Path-Based Full-Duplex FSO Terminals

Park

Yeo

Heo

et al. 2022

Sensors

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Free space optical (FSO) communication can support various unmanned aerial vehicles’ (UAVs) applications that require large capacity data transmission. In order to perform FSO communication between two terminals, it is essential to employ a pointing, acquisition, and tracking (PAT) system with an efficient and optimal performance. We report on the development of a common optical-path-based FSO communication system, tailored for applications in UAVs. The proposed system is equipped with a quadrant photodiode (QPD)-based PAT system without an additional beacon beam subsystem. The presented approach reduced the structural complexity and improved the tracking efficiency for the same size, weight, and power (SWaP). To achieve a robust FSO link in a dynamic UAV environment, the observability and controllability were obtained based on the linearized control according to the incident beam size on the QPD, which was verified by optical simulation and experiments. As a result, the QPD-based PAT system for implementing FSO links demonstrated an up to 4.25 times faster tracking performance. Moreover, the FSO link experimentally confirmed the 1.25 Gbps full-duplex error-free communication at a 50 m distance.

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“…It is widely used to suppress beam jitter with large values. The FSM's output accuracy determines the control accuracy of the beam dithering system [12][13][14][15]. However, when the FSM rotates in response to two free degrees, there will be mechanical coupling, that is, the response of one degree of freedom will cause the response of the other free degree.…”

Section: Introductionmentioning

confidence: 99%

A Tracking Imaging Control Method for Dual-FSM 3D GISC LiDAR

Qian

et al. 2022

Remote Sensing

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In this paper, a tracking and pointing control system with dual-FSM (fast steering mirror) composite axis is proposed. It is applied to the target-tracking accuracy control in a 3D GISC LiDAR (three-dimensional ghost imaging LiDAR via sparsity constraint) system. The tracking and pointing imaging control system of the dual-FSM 3D GISC LiDAR proposed in this paper is a staring imaging method with multiple measurements, which mainly solves the problem of high-resolution remote-sensing imaging of high-speed moving targets when the technology is transformed into practical applications. In the research of this control system, firstly, we propose a method that combines motion decoupling and sensor decoupling to solve the mechanical coupling problem caused by the noncoaxial sensor installation of the FSM. Secondly, we suppress the inherent mechanical resonance of the FSM in the control system. Thirdly, we propose the optical path design of a dual-FSM 3D GISC LiDAR tracking imaging system to solve the problem of receiving aperture constraint. Finally, after sufficient experimental verification, our method is shown to successfully reduce the coupling from 7% to 0.6%, and the precision tracking bandwidth reaches 300 Hz. Moreover, when the distance between the GISC system and the target is 2.74 km and the target flight speed is 7 m/s, the tracking accuracy of the system is improved from 15.7 μrad (σ) to 2.2 μrad (σ), and at the same time, the system recognizes the target contour clearly. Our research is valuable to put the GISC technology into practical applications.

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Control of fast steering mirror for accurate beam positioning in FSO communication system

Cited by 10 publications

References 21 publications

A Dual-FSM GI LiDAR Imaging Control Method Based on Two-Dimensional Flexible Turntable Composite Axis Tracking

A Dual-FSM GI LiDAR Imaging Control Method Based on Two-Dimensional Flexible Turntable Composite Axis Tracking

Tracking Efficiency Improvement According to Incident Beam Size in QPD-Based PAT System for Common Path-Based Full-Duplex FSO Terminals

A Tracking Imaging Control Method for Dual-FSM 3D GISC LiDAR

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