Design of Micro Star Sensor

Micro-satellites, especially micro-nano satellites, have strict requirements on the quality and power consumption of star sensors. The micro-nano satellites launched in the early years had a mass of 25kg and a power consumption of only 10W, while the power consumption of most CCD star sensors is They are all higher than 10w and cannot be used. Therefore, while improving the accuracy of traditional star sensors, we will also focus on reducing the power consumption and quality of star sensors to meet the needs of micro-nano satellites.

The overall configuration of a star sensor can basically be divided into an integrated star sensor configuration and a split star sensor configuration.

Integrated star sensor configuration

The integrated star sensor has a compact structure, small size, and is easy to install and use; however, the signal processing, calculation and imaging parts are combined together, resulting in high power consumption, relatively large volume, and relatively high requirements for thermal control.

Split star sensor configuration

Split star sensors generally include an optical head and an electronic unit, which are connected through data transmission lines such as low-voltage differential signaling. One electronic processing unit can connect two or three optically sensitive heads simultaneously. The optically sensitive head is usually installed outside the cabin to facilitate sensitive starlight; at the same time, the optically sensitive head itself has low power consumption, which is also conducive to thermal control. The electronic processing unit is usually installed in the cabin, so the impact of temperature and space environment on the electronic processing unit will be greatly reduced. The picture shows the structure diagram of the optically sensitive head and electronic processing unit.

The integrated APSCMOS star sensor mainly includes a hood, lens and electronic system parts.

The quality of optical systems such as lenses is closely related to the focal length and aperture size of the system. The quality of systems with long focal lengths and large apertures must be improved.

The shading effect and extinction level of the hood directly determine its size and quality. The design of the hood is closely related to the lens design. The sensitivity magnitude of the APSCMOS star sensor is generally lower than that of CCD, and the extinction level of the hood can also be slightly reduced.

The miniaturized design of the hood is also a very important part of the star sensor design. Three parameters need to be considered in the design: the number of extinction times, the hood material and the light-absorbing paint.

Low power consumption design is an issue that must be considered in the design of APSCMOS star sensor. The overall design adopts a large field of view and low-magnitude design scheme. The number of satellite libraries is small, and the requirements for RAM capacity are reduced. In addition, the system adopts derating design and low-power electronic components to reduce overall power consumption.

Taking into account the technical indicators of the micro APSCMOS star sensor, the overall implementation plan of the star sensor will be developed around improving attitude measurement accuracy, improving real-time data processing, and reducing volume, mass and power consumption.