Thermal refocusing method for spaceborne high-resolution optical imagers

Selimoglu, Ozgur; Ekinci, Mustafa; Karcı, Özgür

doi:10.1364/ao.55.004109

Cited by 5 publications

(2 citation statements)

References 13 publications

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“…Despite these efforts, both cooling and heating actions could consume lots of energy to operate. To decrease working temperatures of the thermally-driven refocusing mechanisms, Selımoglu et al presented a novel mechanism that produces 30 µm of De-space, with respect to 10 • C variation in temperature [33]. Here, they reduced energy consumption, but the stroke was relatively small, compared to the size of the secondary mirror (Diameter: 144 mm).…”

Section: Introductionmentioning

confidence: 99%

A Single Motor-Driven Focusing Mechanism with Flexure Hinges for Small Satellite Optical Systems

Jung

Lee

et al. 2020

Applied Sciences

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For earth observation, the optical systems in small satellites are crucial to obtain high- resolution images. However, the alignment between a primary and a secondary mirror in an optical system can be disturbed due to the harsh environments inside vehicles or space (i.e., vibrations, shock loading during launch, dramatic temperature changes, or high vacuum pressure in space). To compensate for such undesired deformations, a focusing mechanism should be embedded into the optical system. In this paper, we propose a novel Single Motor-Driven Focusing mechanism with Flexure Hinges (SMFH), allowing the Flexure Hinge (FlexHe) to displace in the longitudinal direction. The presented FlexHe incorporates radial zig-zag-patterned slits to achieve flexibility, and preloading of the hinge structures to reduce the resulting hysteresis. To investigate an optimal configuration of FlexHe, a numerical simulation is performed by means of ANSYS 19.2. The variation of Modulation Transfer Function (MTF), corresponding to an image resolution, is evaluated by using an optics simulation program (CODE-V). The experimental setups are built by exploiting the fabricated SMFH and five LVDT (Linear Variable Differential Transformer) sensors with a high resolution of 0.031 µm. As a result, hysteresis can be reduced up to 6.52% with a pre-stretched length of 3 µm. The proposed SMFH allows not only the De-space to displace up to 23.93 µm, but also the De-center and the Tilt to achieve the desired displacements of 5.20 µm and 88.45 µrad, respectively. Conclusively, the SMFH shows promising characteristics to embed a feedback control, due to its high resolution (up to 0.1 µm) for De-space with the MTF of 37%.

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Section: Introductionmentioning

confidence: 99%

A Single Motor-Driven Focusing Mechanism with Flexure Hinges for Small Satellite Optical Systems

Jung

Lee

et al. 2020

Applied Sciences

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“…In order to obtain high-resolution images, the thermal control technique has been widely used in spaceborne remote sensors for the past few years. This technology is already widely used in space engineering [6,7,8,9]. The present thermal control research on aerial optoelectronic sensors usually adopts experience acquired in space engineering.…”

Section: Introductionmentioning

confidence: 99%

Impact of Thermal Control Measures on the Imaging Quality of an Aerial Optoelectronic Sensor

Liu

Zou

Jia

et al. 2019

Sensors

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The image resolution is the most important performance parameter for an aerial optoelectronic sensor. Existing thermal control methods cannot eliminate the sensor’s temperature gradient, making the image resolution difficult to further improve. This article analyzes the different impacts of temperature changes on the imaging resolution and proposes modifications. Firstly, the sensor was subjected to thermo-optical simulation by means of finite element analysis, and the different impacts of temperature changes on the imaging quality were analyzed. According to the simulation results, an active thermal control method is suggested to enhance the temperature uniformity of the sensor. Considering the impacts of active and passive thermal control measures, thermal optical analysis was carried out to predict the performance of the sensor. The results of the analysis show that the imaging quality of the sensor has been significantly improved. The experimental results show that the image resolution of the optoelectronic sensor improved from 47 to 59 lp/mm, which demonstrates that the sensor can produce a high image quality in a low-temperature environment.

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Stability metering method for high-resolution space telescope with large F-number based on combination optimization

Wang

Zhang

Yang

et al. 2023

Optik

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Thermal refocusing method for spaceborne high-resolution optical imagers

Cited by 5 publications

References 13 publications

A Single Motor-Driven Focusing Mechanism with Flexure Hinges for Small Satellite Optical Systems

A Single Motor-Driven Focusing Mechanism with Flexure Hinges for Small Satellite Optical Systems

Impact of Thermal Control Measures on the Imaging Quality of an Aerial Optoelectronic Sensor

Stability metering method for high-resolution space telescope with large F-number based on combination optimization

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