Optical testing of star sensor (I): Defocus spot measuring technique for ground-based test

Kawano, Hiroyuki; Shimoji, Haruhiko; Yoshikawa, Shoji; Miyatake, Katsumasa; Hama, Kazumori; Nakamura, Shuji

doi:10.1007/s10043-008-0016-x

Cited by 13 publications

(5 citation statements)

References 7 publications

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“…The star tracker optical system is usually aligned in a defocused position so that the size of the star image is 3 × 3 to 5 × 5 pixels to improve the star location measurement accuracy [23]. Hence, the star tracker needs rotate 3 × FOV/N pixel to 5 × FOV/N pixel perpendicular to the boresight to ensure that a star completely enters the FOV, where N pixel is pixel resolution of the image sensor.…”

Section: ) Star Pair Listmentioning

confidence: 99%

Improved Grid Algorithm Based on Star Pair Pattern and Two-dimensional Angular Distances for Full-Sky Star Identification

Wei

Wang

et al. 2020

IEEE Access

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Section: ) Star Pair Listmentioning

confidence: 99%

Improved Grid Algorithm Based on Star Pair Pattern and Two-dimensional Angular Distances for Full-Sky Star Identification

Wei

Wang

et al. 2020

IEEE Access

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“…To improve the pattern quality, we must inspect the spot array in the maskless lithography system. The profile measurement of an optical spot in a spot array has been required in various optical systems such as wavefront sensors [8][9][10], star sensors [11,12], and point spread function (PSF) measurement systems [13][14][15]. The profile measurement methods can be classified into two categories [16].…”

Section: Introductionmentioning

confidence: 99%

Measuring two-dimensional profiles of beam spots in a high-density spot array for a maskless lithography system

Kang

Hahn

2014

Appl. Opt.

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We measure two-dimensional (2D) profiles of beam spots in a high-density spot array for a maskless lithography system. Since the size of each spot is comparable to that of a pixel in a charge-coupled device (CCD), we detect image frame data, which are the distribution of the intensity of the spot overlapped on the active area of the pixel in the CCD, by scanning with a nano-stage. Using the image frame data of the scanning CCD we determine reconstructed images of the beam spot array. We calculate the 2D profile of each spot by taking the deconvolution of the reconstructed image of the spot with the active area of the CCD pixel. We theoretically analyze the uncertainty in the measurement of profiles in terms of spot size for the variation of the scanning step of the nano-stage and determine the step size to achieve uncertainty of less than 100 nm. We experimentally demonstrate the measurement of profiles of an 11×11 spot array for the proof of concept. Also, we analyze various parameters of the spot array, such as ellipticity, rotation of the spot profile, spot size, intensity distribution, and position.

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“…To achieve high geometric accuracy of the remote sensing images, it is necessary to increase the focus on the star sensor. According to the calculations, when the angle between the optical axis of the satellite remote sensor and the star sensor randomly changes by an angle of several tens of angular seconds, the resulting positioning error is approximately a hundred meters [2][3][4]. Many researchers in China have analyzed the geometric accuracy of satellite images.…”

Section: Introductionmentioning

confidence: 99%

Method and Implementation of Improving the Pointing Accuracy of an Optical Remote Sensor Using a Star Sensor

Liu¹,

He²,

Fengwei³

et al. 2019

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Based on the analysis of the pointing accuracy of the optical sensor in a star sensor, this paper introduces the geometric accuracy of the star sensor as an external orientation element that affects the optical remote sensing image and analyzes the characteristics of the installation method of the star sensor in different optical remote sensors. The key factors affecting the pointing accuracy of the star sensor are considered, and the geometrical accuracy of the image is improved by analyzing the installation method of the star sensor, the star sensor bracket design, and the star sensor thermal control component. Achievable measures are made, and the pointing stability of the star sensor is verified through a ground test and by measuring the temperature fluctuations of the orbiting sensor. Through ground testing and on-orbit testing, the star sensor bracket has a temperature fluctuation of <1 ℃ in one photography cycle, and the star sensor's attitude error around the axis is less than 5", so the uncontrolled geometric positioning accuracy of the image product can be obtained as 11.4 m (rms).

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Optical testing of star sensor (I): Defocus spot measuring technique for ground-based test

Cited by 13 publications

References 7 publications

Improved Grid Algorithm Based on Star Pair Pattern and Two-dimensional Angular Distances for Full-Sky Star Identification

Improved Grid Algorithm Based on Star Pair Pattern and Two-dimensional Angular Distances for Full-Sky Star Identification

Measuring two-dimensional profiles of beam spots in a high-density spot array for a maskless lithography system

Method and Implementation of Improving the Pointing Accuracy of an Optical Remote Sensor Using a Star Sensor

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