Optical system design of star sensor and stray light analysis

Asadnezhad, Mohammad; Eslamimajd, Abdollah; Hajghassem, Hassan

doi:10.1186/s41476-018-0078-8

Cited by 36 publications

(18 citation statements)

References 22 publications

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“…In the process of optical design, the diagonal field of view ( ω ) is usually employed to represent the field of view of the optical system. The relationship between the field of view and the focal length of the optical system is governed by Equation (3) [ 10 ]:

where ω and f are the half-field of view and the focal length of the optical system, respectively. H and V represent the overall length and width of the CCD pixel, respectively.…”

Section: Main Technical Parameters Of the Optical Systemmentioning

confidence: 99%

“…Optical systems of the star sensors have been extensively studied since the 1950s, of which most are designed with refraction and reflection structures [ 6 , 7 , 8 , 9 ]. The refractive optical systems are easy to realize high-quality large-field imaging, but they also have inherent defects such as a small aperture, a lot of optical lenses and it is difficult to correct their secondary spectrum [ 9 , 10 , 11 ]. The reflective optical systems have the advantages of a large system aperture, a small number of optical lenses and no chromatic aberration.…”

Section: Introductionmentioning

confidence: 99%

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Catadioptric Optical System Design of 15-Magnitude Star Sensor with Large Entrance Pupil Diameter

Bai

Zha

et al. 2020

Sensors

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The optical system is one of the core components for star sensors, whose imaging quality directly influences the performance of star sensors for star detection, thereby determining the attitude control accuracy of spacecrafts. Here, we report a new type of optical system with a catadioptric structure and a large entrance pupil diameter for a 15-magnitude star sensor. It consists of an improved Cassegrain system (R-C system), an aperture correction spherical lens group and a field of view correction spherical lens group. By embedding the secondary mirror of the R-C system into the output surface of the negative spherical lens of the aperture correction spherical lens group, the blocking of incident light is eliminated from the secondary mirror holder. After the structure optimization, the catadioptric optical system (COS) had a spectral range of 450 nm–950 nm, an entrance pupil diameter of 250 mm, a half-diagonal field of view of 1.4° and a focal length of 390 mm. By using theoretical calculations and experimental measurements, it was verified that the COS, with the ability to correct astigmatism, lateral color and distortion, can fulfill the detection of 15-magnitude dark stars.

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where ω and f are the half-field of view and the focal length of the optical system, respectively. H and V represent the overall length and width of the CCD pixel, respectively.…”

Section: Main Technical Parameters Of the Optical Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Catadioptric Optical System Design of 15-Magnitude Star Sensor with Large Entrance Pupil Diameter

Bai

Zha

et al. 2020

Sensors

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“…The star sensor used in the experiment is a Cypress STAR1000 CMOS image sensor, which employs a 1024 pixels × 1024 pixels image plane. The element size is 15 µm × 15 µm, as in [27]; this detector has higher responses to wavelengths ranging from 0.55 to 0.85 µm [34]. The focal length is 43.6 mm.…”

Section: Simulation Conditionsmentioning

confidence: 99%

Angular velocity estimation using characteristics of star trails obtained by star sensor for spacecraft

Ning

Chen

Huang

et al. 2020

Sci. China Inf. Sci.

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Many studies have been conducted about angular velocity estimation using star sensors, and fairly good performance is achieved when the spacecraft is working at low-dynamic environments. However, when the spacecraft rotates at a large angular velocity, the star image will become blurred, which makes it difficult to identify and recognize star centroids, which, in turn, reduces the accuracy of angular velocity estimation. Therefore, to solve the problem with angular velocity estimation in highly dynamic situations, this research studies a method of angular velocity estimation using blurred star images. The length and ending point coordinates of star trails obtained from these blurred star images are used for a series of processes, which includes the pre-processing of blurred star images, determination of starting and ending points, thinning and selection of star trails, and calculation of trail lengths. Simulations show that the effectiveness of the proposed method in highly dynamic situations and the angular velocity estimation errors in constant and sinusoidal variation are reduced by at least 66% and 62%, respectively, compared with those of the traditional method.

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“…In the case of the former, by investigating the novel mechanisms or identifying the optimal structures, the performance of the optical system can be improved. Indeed, many structural designs for small satellites have been studied [28][29][30]. Among them, Lee et al approximated the deflection of the primary mirror due to its own weight and presented an optical system based on an evaluation of optical tolerance [31].…”

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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Optical system design of star sensor and stray light analysis

Cited by 36 publications

References 22 publications

Catadioptric Optical System Design of 15-Magnitude Star Sensor with Large Entrance Pupil Diameter

Catadioptric Optical System Design of 15-Magnitude Star Sensor with Large Entrance Pupil Diameter

Angular velocity estimation using characteristics of star trails obtained by star sensor for spacecraft

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

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