Article

A photodiode based miniature sun sensor

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Abstract

The solar vector is one of the most important parameters for attitude control of nanosatellites. This attitude control must be achieved without the sensors adding significantly to its size or mass. This paper presents a photodiode-based miniature sun sensor, which consists of two triangular pyramidal sensor unit structures, with each unit comprising three micro-silicon photodiodes. The two sensor units are installed on the diagonal of the nanosatellite to form a complete sun sensor capable of achieving a full-field range of solar vector measurements. In this paper, the mathematical model of the short-circuit currents of the silicon photodiodes as a function of the solar vector coordinates is deduced. A sensor sample was built and installed on a nanosatellite model, and the temperature compensation coefficient of the silicon photodiodes was obtained experimentally. The dynamic characteristic, linearity, hysteresis and repeatability of the component were measured. The sun sensor introduced in this paper can be placed on any satellite platform to allow a full range solar vector measurement, and this would result in an increase of only 1.86 g and 0.9 cm³ of the satellite's mass and volume, respectively.

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... Sun sensors, which can be formed by planar or non-planar sensor arrays, have a wide range of applications, such as the attitude control of satellites [1,2], assisted positioning for planetary rovers [3], ground-based navigation systems [4], and the efficiency improvement of solar power plants [5]. In the aerospace field, sun sensors formed by planar sensor arrays are primarily used to obtain high-accuracy solar orientation. ...
... Non-planar sun sensors determine solar orientation by the irradiance of the Sun passing through the planes of sensors, such as photodiodes, that are mounted on a non-planar array, such as the triangular pyramidal array shown in Figure 1b. These sun sensors are usually constructed by photodiodes mounted on different surfaces of spacecraft [1,2] or sometimes by the direct reuse of the spacecraft solar panels [9], which hardly generates an extra load for small aerospace equipment. However, due to its susceptibility to interference, these sun sensors are primarily used in spacecraft that do not require high-accuracy solar orientation determination or for the ground tracking of the Sun [5]. ...
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