Research Of Sensors With Large Field Of View For Micro-Satellite

Attitude determination and control system (ADCS) is an important component of satellites. Its main function is to achieve a satellite’s attitude stable in a particular spacial coordinate system. Sun sensor and earth sensor which are general attitude sensors have been widely used in various aerospace fields. The sun sensor being studied in the lab can achieve large field of view and low power consumption, but has serious lens distortion thus unable to achieve high precision. Although Earth Sensor’s principle has been verified and each module algorithm is mature, but engineering hasn’t been realized.On this basis, studies sun sensor and earth sensor are studied respectively in this paper. Firstly hardware and code optimization on sun sensor.are performed. For lack of precision sun sensor status, this research studied the model of lens distortion, distortion calibration principles and methods, built a complete calibration platform, distorted fitting function and finally got a more accurate large field of sun sensor. As to panoramic infrared earth sensor, this research designed and implemented the earth sensor, including hardware and software. And on this basis a distortion calibration and accuracy testing were performed, and the results matching the design goals are achieved.The whole systems of sun sensor and earth both consist of three main blocks which are optical system, digital processing circuitry and software. The optical system is mainly composed of a large field of view of the lens in the front end, an image sensor and a rear end of the mounting structure. Fisheye lens and infrared panoramic annular lens are set as lens respectively for sun sensor and earth sensor. The lens imaging relations were studied to find out the method to improve the accuracy. Back-end image sensors have advanced high degree of flexibility and low power consumption. Digital processing circuits’design and component selection were done according to the principles of low-power consumption, and software was designed following the principles of reliability and ease. Each algorithm principle used and the specific steps is discussed, analyzed and verified by in this paper.Because of the distortion of the large field view lens, this research focuses on the calibration model and its distortion calibration methods. Ccombined with the characteristics of the lens as well as the existing laboratory environmental and equipment, a unique lens distortion calibration method was developed. The distortion of fisheye lens is much greater of the two kinds of lens, and therefore this research focuses more on fisheye calibration and gives out fitting function. Finally sun sensor gets accuracy of0.05°with power consumption200mW, and earth sensor accuracy of better than0.1°, the power consumption1.2W.