Design And Verification On Sun Sensor Threshold Centroid Algorithm

With the dramatical development of spacecraft, the positioning technology isinviting more and more attention in the aerospace fie ld. Sun sensor, as an importantpart of the spacecraft attitude determination subsystem, has been widely used in thefie ld of spacecraft. Sun sensor is mainly divided into analog sun sensor and digitalsun sensor. As the rapid development of technology, the spacecraft volume becomessmaller and smaller, thus sun sensor volume is very huge when comparing to othersmall size spacecrafts. Therefore, studying of digital sun sensor is very crucial.Digital sun sensor could be used by mask with a pinho les to collect solar ray tosun sensor interior, and get sun image on the focal plane. The facular quantity in thissun image is equal to the pinhole number on the mask. By calculating the averagedistance of spot centroid location to above two boards, and sun sensor thresholdcentroid algorithm can get the incident angle of solar rays, then determinethe location of the spacecraft relative to the sun.To determine the algorithm used, the first analys is of the traditional sun sensorcentroid algorithm can be seen that this method of calculation is relatively large,resulting in calculation speed will drop. By analyzing the principle of traditionalcentroid algorithm, this method can be improved to sun sensor threshold centroidalgorithm, so to ensure accuracy at the same time reduce the amount of calculationand optimization of the algorithm. Among them, the division and more complicatedcalculation can be calculated by the CORDIC algorithm.By using the C programming language, the algorithm thought can be realizedout and go to test, and compared with standard values for the correctness andaccuracy of the software implementation. Algorithm hardware realization by theVerilog HDL hardware programming language, and test design through simulationresults to judge the correctness of the hardware design. Finally, put the hardwaredesign to logic synthesize, to determine whether the design can be the linecorresponding to the circuit.