Micro satellites,especially micro nano satellites,have strict requirements for the weight and power consumption of star trackers,and most CCD star trackers abroad have power consumption above this level,which is basically unusable.While improving the accuracy of traditional star trackers,the focus will also be on reducing the power consumption,quality,and other aspects of star trackers to meet the needs of micro and nano satellites.
In the world,the overall configuration of star trackers can be basically divided into integrated star trackers and split star trackers.
1.Integrated star tracker configuration
Compact structure,small size,easy to install and use,but the signal processing,computing and imaging parts are combined together,high power consumption,and the volume will be larger.The internal structure from top to bottom is the hood,the lens,the image sensing part,the signal processing part,etc.
2.Split type star tracker configuration
The split star tracker generally includes an optical sensitive head and an electronic processing unit,and a brain processing unit can be connected to two or three optical sensitive heads at the same time.The optical sensitive head is usually installed outside the cabin to facilitate the sensitivity of starlight.
At the same time,the optical 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 that the impact of factors such as temperature and space environment on the electronic processing unit will be greatly reduced.
The integrated APS CMOS star tracker mainly consists of a hood,a lens and an electronics system.The quality of lens and other optical systems is closely related to the focal length and aperture size of the system,and the quality of the system with long focal length and large aperture must be improved.The shading effect and extinction level of the mask directly determine its size and quality,and the design of the mask is closely related to the design of the lens.
Low power design is a necessary consideration in the design of APSCMOS star sensors.In order to meet the needs of aerospace technology development,it is best to use anti fuse products for FPGAs,which have a one-time internal burning and do not require external configuration of random access memory(RAM),and have relatively low power consumption.
The star tracker adopts a low-power APSCMOS photodetector,with a power consumption of less than 300mW when operating at full speed;In the overall design,a large field of view and low magnitude design scheme were adopted,with a small number of star libraries and reduced requirements for RAM capacity.
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TY-Space Technology (Beijing) Ltd. is professional focusing on advanced attitude optical sensors, especially Star Trackers for space industry.
