Method to Improve the Detection Accuracy of Quadrant Detector Based on Neural Network

Wang, Xuan; Su, Xiuqin; Liu, Guizhong; Han, Jiuqiang; Zhu, Wenxin; Liu, Zengxin

doi:10.1109/lpt.2021.3116240

Cited by 10 publications

(9 citation statements)

References 15 publications

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“…As can be seen from Figure 3 b, APD and QPD are mounted on a three-axis stage having a 10 µm resolution for a precise optical alignment. The QPD with an active diameter of 2 mm consists of a 2 × 2 array of p-i-n photodiodes arranged counterclockwise in the Q 1 , Q 2 , Q 3 , and Q 4 order, as shown in Figure 3 c. The position information can be extracted by monitoring the signal from QPD by using the following equations [ 29 , 30 , 31 , 32 , 33 , 34 , 35 ]:

where

, and

are the output voltage values of the four photodiodes Q 1 , Q 2 , Q 3 , and Q 4 , respectively. V is the total voltage produced by the four photodiodes.…”

Section: Methodsmentioning

confidence: 99%

“…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%

“…The realization of a precise PAT system, which enables Gbps full-duplex transmission and maintains LOS, is more challenging in dynamic UAV environments. The high resolution and fast response speed of the QPD-based PAT system emerged as an interesting solution [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. In addition, based on the incident beam size and incident beam position on the QPD, tracking efficiency was increased without additional components (i.e., FSM, deformable mirror, etc.).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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where

, and

are the output voltage values of the four photodiodes Q 1 , Q 2 , Q 3 , and Q 4 , respectively. V is the total voltage produced by the four photodiodes.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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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show abstract

“…After FFT operation, the amplitude value are A A j , A B j , A C j , A D j . xj and ŷj represent the offset of the center position of the target spot measured by the j-th laser light relative to the center of the QD on the x-axis and y-axis, which can be obtained according to the addition and subtraction algorithm theory [24]: (16) xj and ŷj are the relative position information of the spot center solved by Equation ( 16) under the ideal situation without introducing noise. In the position detection system, the x-axis and the y-axis are independent and symmetrical.…”

Section: Working Principle Of Multi-beam Position Detectionmentioning

confidence: 99%

Research on Quadrant Detector Multi-Spot Position Detection Based on Orthogonal Frequency Division Multiplexing

Ye,

Yu,

Lin

et al. 2023

Applied Sciences

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Free space optical communication is developing towards laser communication networking. A novel method of quadrant detector (QD) multi-spot position detection based on orthogonal frequency division multiplexing (OFDM) is proposed for multi-spot laser communication systems. The mathematical model is constructed, and the Monte Carlo method is used to validate it. The position calculation of three beams incident on QD is simulated. The influence of key parameters on the accuracy of position detection is analyzed when the spots are at the same position and a different position. The results show that when the SNR of the system is 31.74 dB, the radius of the Gauss spot is 2 mm, the number of FFT (fast Fourier transform) points is 1024, and the center of the multi-spot is at the same position of the detector target; the accuracy of signal position detection calculated by the equation is 1.433 μm, and the simulation results are 1.351 μm, 1.354 μm, and 1.389 μm, respectively. When the center position of the multi-spot is at different positions of the detector target, the detection accuracy calculated by the formula is 1.438 μm, 1.433 μm, and 1.434 μm, respectively, and the simulation results are 1.419 μm, 1.387 μm, and 1.346 μm, respectively. The experimental results verify the effectiveness of the proposed multi-target simultaneous detection method. This article proposes a new multi-spot position detection method which can not only achieve one-to-multiple node laser communication but also improve the accuracy of point position detection.

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“…While electrical and electromechanical techniques provide the highest beam-steering precision (nrad resolution), mechanical systems are typically required to ensure a wideenough field-of-view, together with µrad steering resolution, which might be sufficient for most short and medium-reach (<10 km) FSO applications [44]. To that end, gimbal-based systems have been widely exploited in the literature, either operating with standalone optical beam alignment control [44] or with an auxiliary O/E mechanism, such as a quadrant detector [45], spatial light modulator [17] or near-infrared camera [46]. In these systems, the digital control algorithm plays a key role in finding and keeping the optimum alignment between transmitter and receiver.…”

mentioning

confidence: 99%

Coherent Free-Space Optical Communications: Opportunities and Challenges

Guiomar

Fernandes

Nascimento

et al. 2022

J. Lightwave Technol.

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The ever-increasing data rate demand for wireless systems is pushing the physical limits of standalone radiofrequency communications, thus fostering the blooming of novel high-capacity optical wireless solutions. This imminent penetration of optical communication technologies into the wireless domain opens up a set of novel opportunities for the development of a new generation of wireless systems providing unprecedented capacity. Unlocking the full potential of free-space optics (FSO) transmission can only be achieved through a seamless convergence between the optical fiber and optical wireless domains. This will allow taking advantage of the staggering progress that has been made on fiber-based communications during the last decades, namely leveraging on the latest generation of Terabit-capable coherent optical transceivers. On the other hand, the development of these high-capacity optical wireless systems still faces a set of critical challenges, namely regarding the impact of atmospheric turbulence and pointing errors. In this work, we provide an in-depth experimental analysis of the main potentialities and criticalities associated with the development of ultra-highcapacity FSO communications, ultimately leading to the longterm (48-hours) demonstration of a coherent FSO transmission system delivering more than 800 Gbps over ∼42 m link length, in an outdoor deployment exposed to time-varying turbulence and meteorological conditions.

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Method to Improve the Detection Accuracy of Quadrant Detector Based on Neural Network

Cited by 10 publications

References 15 publications

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

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

Research on Quadrant Detector Multi-Spot Position Detection Based on Orthogonal Frequency Division Multiplexing

Coherent Free-Space Optical Communications: Opportunities and Challenges

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