Research Of Digital Sun Sensor Based On The Panoramic Annular Lens

Sun sensor, as an important attitude determination sensor, has been widely used in attitude determination system of micro-satellites and other aircrafts. Digital sun sensor is a part of sun sensor and it has the advantage of high precision and good anti-jamming ability. The principle of general sun sensor is based on the pinhole imaging, which is realized by pinhole on the MEMS mask. However, restricted by the size of image area and measure accuracy, the field of sun sensor is only about±60°. When the angle of sun is out of the field, the sun sensor cannot work properly.According to these deficiencies, a design method of digital sun sensor which is suitable for the micro-satellite is presented in this paper. The optical system of the sensor is composed of panoramic annular lens, which is developed by Zhejiang University. The sun sensor has a large field of 120°×180°. Besides, the sensor uses the CMOS image sensor as the light detector and it can reduce the power consumption of the system. While considering the measure precision and complexity, this paper presents a simple and flexible design method, which can reduce power consumption and volume of the system.Based on the panoramic annular lens, this paper analyzes the principle of sun sensor and also compares the difference between the general sun sensor and this design. This paper gives the detail design scheme of the sun sensor, including the design of the optical system, the selection of devices and the hardware design. Then this paper introduces the design of the digital processing unit, this unit is composed of FPGA and micro-controller. After the primary design, a sensor model and the parameter solution of the model is presented by this paper. Besides, in order to finish the test and calibration of the sun sensor, this paper introduces the design of the auto test and calibration platform. At last, we give the test result and analyze the error source. The result of testing indicates that the sun senor can meet the requirement of attitude determination system which is needed by micro-satellite.