Space luminous environment adaptability of missile-borne star sensor

Zhao, Shenghui; Wang, Hong-Tao; Wang, Yu; Cai-yan, JI

doi:10.1007/s11771-012-1426-2

Cited by 3 publications

(2 citation statements)

References 13 publications

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“…The irradiance of the Earth's moon when it's full is 1.4 mW/m 2 . 21) The function of the baffle is to prevent stray light from bright objects (i.e., Sun, Earth and Earth's moon) outside the FOV from directly reaching the lens surface and to reduce the intensity of stray light so that the star tracker can identify the stars effectively. A single-stage, diffused cylindrical baffle with straight vanes has been designed for the APST.…”

Section: Baffle Designmentioning

confidence: 99%

Development of the Arcsecond Pico Star Tracker (APST)

Muruganandan

Park

Lee

et al. 2017

Trans. Japan Soc. Aero. S Sci.

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The second-generation star tracker estimates pointing knowledge of a satellite without a-priori knowledge. But star trackers are larger in size, heavier, power hungry and expensive for nanosatellite missions. The Arcsecond Pico Star Tracker (APST) is designed based on the limitations of nanosatellites and estimated to provide pointing knowledge in an arcsecond. The APST will be used on the SNUSAT-2, Earth-observing nanosatellite. This paper describes the requirements of APST, trade-off for the selection of image sensor, optics, and baffle design. In addition, a survey of algorithms for star trackers and a comparison of the specifications of APST with other Pico star trackers are detailed. The field of view (FOV) estimation shows that 17°and 22°are suitable for APST and this reduces stray light problems. To achieve the 100% sky coverage, the FOV of 17°and 22°should able to detect the 5.85 and 5.35 visual magnitude of stars, respectively. It is validated by estimating the signal to noise ratio of APST and night sky test results. The maximum earth stray light angle is estimated to be 68°and a miniaturized baffle is designed with the exclusion angle of 27°.

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Section: Baffle Designmentioning

confidence: 99%

Development of the Arcsecond Pico Star Tracker (APST)

Muruganandan

Park

Lee

et al. 2017

Trans. Japan Soc. Aero. S Sci.

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“…The maximum irradiance from the sun is 918.1 W/m 2 and the Earth reflects 35% of the Sun's light, which is known as albedo.The maximum irradiance from the Earth is 321.3 W/m 2 . The irradiance of the Earth's moon when it's full is 1.4 mW/m 2[32]. The function of the baffle is to prevent stray light from bright objects (i.e., Sun, E a r t h and Earth's moon) outside the FOV from directly reaching the lens surface and to reduce the intensity of stray light so that the star tracker can identify the stars effectively.…”

mentioning

confidence: 99%

Star Selection algorithm for Arcsecond Pico Star Tracker

Muruganandan

Park

Lee

et al. 2018

2018 AIAA Aerospace Sciences Meeting

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The star tracker estimates pointing knowledge of a satellite in arcsecond accuracy in three axes without apriori knowledge. But star trackers are larger in size, heavier, power hungry and expensive for nanosatellite missions. The Arcsecond Pico Star Tracker (APST) is designed based on the limitations of nanosatellites and estimated to provide pointing knowledge in arcsecond. The APST is developed using fully COTS components because it's affordable, and less development time. A theoretical model is developed to estimate the performance of the COTS components (image sensor, lens, and baffle) used in the APST. Using this model, it's possible to validate if the components meet the requirements of the star tracker. But COTS component decreases the overall performance due to the errors in image sensor noise, lens distortion, and aberration etc. In APST, the lens distortion and inaccurate centroiding are the dominant error sources. The radial lens distortion causes an error in angular distance measurement, which leads misidentifying or identification of stars and high processing time. This leads to functional failure of APST. To overcome this, the relative star selection method is iv developed which selects the stars based on the angular distance information. Based on the fact that star pair with low angular distance has minimum measurement error, the relative star selection selects the four stars with low measurement error. It's compared with conventional bright star selection method, whereas stars are selected based on brightness. The relative selection algorithm is tested with 75-star constellation in star simulator and it has delivered 100% success rate and accuracy of 71 arcseconds in boresight. Whereas the conventional bright star selection delivered low success rate of 28% because the star pairs are not selected based on angular distance separation. Hence the relative star selection algorithm is efficient for APST.

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