Kalman filtering to suppress spurious signals in adaptive optics control

Poyneer, Lisa; Véran, Jean-Pierre

doi:10.1364/josaa.27.00a223

Cited by 40 publications

(31 citation statements)

References 22 publications

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“…(5), is computed recursively as an output of the Kalman filter based on the state-space model (19). Since the control criterion is defined on an infinite horizon, we restrict ourselves, without any performance degradation, to the steady-state time invariant version of the Kalman filter [34].…”

Section: Kalman Filter and Control Computationmentioning

confidence: 99%

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First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

Sivo¹,

Kulcsár²,

Conan³

et al. 2014

Opt. Express

105

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Adaptive optics provides real time correction of wavefront disturbances on ground based telescopes. Optimizing control and performance is a key issue for ever more demanding instruments on ever larger telescopes affected not only by atmospheric turbulence, but also by vibrations, windshake and tracking errors. Linear Quadratic Gaussian control achieves optimal correction when provided with a temporal model of the disturbance. We present in this paper the first on-sky results of a Kalman filter based LQG control with vibration mitigation on the CANARY instrument at the Nasmyth platform of the 4.2-m William Herschel Telescope. The results demonstrate a clear improvement of performance for full LQG compared with standard integrator control, and assess the additional improvement brought by vibration filtering with a tip-tilt model identified from on-sky data, thus validating the strategy retained on the instrument SPHERE at the VLT.

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Section: Kalman Filter and Control Computationmentioning

confidence: 99%

“…It has also been considered during preliminary studies on GPI using a Kalman filter with predictive Fourier-domain control [19]. LQG control has been demonstrated on-lab for WFAO systems [20].…”

Section: Introductionmentioning

confidence: 99%

First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

Sivo¹,

Kulcsár²,

Conan³

et al. 2014

Opt. Express

105

View full text Add to dashboard Cite

show abstract

“…However, benefits are extremely small because of bandwidth limit due to stability [4]. At present, most control algorithms are based on a linear quadratic Gaussian controller frame [5][6][7][8][9][10][11][12][13][14]. These techniques have been tested on laboratory level [5,6] and applied on some realistic systems in recent years [7,8].…”

Section: Introductionmentioning

confidence: 99%

Optical axis jitter rejection for double overlapped adaptive optics systems

Qinghong

Luo

2016

Opt Rev

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Optical axis jitters, or vibrations, which arise from wind shaking and structural oscillations of optical platforms, etc., cause a deleterious impact on the performance of adaptive optics systems. When conventional integrators are utilized to reject such high frequency and narrow-band disturbance, the benefits are quite small despite their acceptable capabilities to reject atmospheric turbulence. In our case, two suits of complete adaptive optics systems called double overlapped adaptive optics systems (DOAOS) are used to counteract both optical jitters and atmospheric turbulence. A novel algorithm aiming to remove vibrations is proposed by resorting to combine the Smith predictor and notch filer. With the help of loop shaping method, the algorithm will lead to an effective and stable controller, which makes the characteristics of error transfer function close to notch filters. On the basis of the spectral analysis of observed data, the peak frequency and bandwidth of vibrations can be identified in advance. Afterwards, the number of notch filters and their parameters will be determined using coordination descending method. The relationship between controller parameters and filtering features is discussed, and the robustness of the controller against varying parameters of the control object is investigated. Preliminary experiments are carried out to validate the proposed algorithms. The overall control performance of DOAOS is simulated. Results show that time delays are a limit of the performance, but the algorithm can be successfully implemented on our systems, which indicate that it has a great potential to reject jitters.

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“…For the linear slope prediction, the relatively larger computational complexity is difficult to overcome, and, for the artificial neural networks, it is easily plagued when running into local minima in the training error surface [12]. In recent years, a new kind of method based on a Kalman filter is widely used for atmospheric turbulence prediction [15,16]. However, no matter which predictor is used-adaptive linear predictor, predictor based on the artificial neural networks, or Kalman filter-all of them estimate the turbulence at a current sampling period or in several future sampling periods, according to several latest frames of aberrations.…”

Section: Introductionmentioning

confidence: 99%

Time delay compensation method for tip–tilt control in adaptive optics system

Wang

et al. 2015

Appl. Opt.

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The time delay engendered by wavefront sampling and data processing inevitability exists in almost all the wavefront sensor (WFS) based adaptive optics (AO) systems. Also, when WFS is used for tip-tilt aberration detection, the time delay significantly reduces the tip-tilt correction performance of the AO system. In this paper, we focus on researching time delay in a tip-tilt (TT) control system and introduce a predicted signal compensation method (PSCM) to compensate the time delay by modifying the WFS detected signals. Based on a precise model of a TT dynamic control system, the detection delay of TT corrections included in a WFS detected signal can be compensated. Experiments are conducted in the lab: the pure integrator (I), proportional and integral (PI) wavefront TT controllers, and these controllers with PSCM are compared to test the efficiency of the PSCM for TT corrections. For the PI controller, the rejection bandwidth increases from 52 to 62 Hz by using PCSM; meanwhile, the open-loop phase margin increases from 45 to 60 deg. In addition, astronomical observation results are also given based on the PI wavefront TT controller. The PSCM improves the Strehl ratio by a factor of 1.3. The new method is proven to improve the AO system closed-loop performance not only for increasing the closed-loop rejection bandwidth but also in favor of the error attenuation at low frequency. Furthermore, the method does not introduce more noise to the system.

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Kalman filtering to suppress spurious signals in adaptive optics control

Cited by 40 publications

References 22 publications

First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

Optical axis jitter rejection for double overlapped adaptive optics systems

Time delay compensation method for tip–tilt control in adaptive optics system

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