| The star sensor,as a high-precision pose measuring equipment and dark target detector,is sensitive to stray light and tends to be affected by the stray light existed in its working environment.In the actual working environment,besides the direct stray light that comes in the entrance pupil of star sensor directly coming from the close-range stars such as sun,the structural stray light due to mechanical structure of aircraft itself or surrounding aircraft is also an important source of stray light in star sensor.The near Space Hypersonic Vehicle usually works in the near space of the atmosphere.In order to avoid the effects of aerodynamic heat on the measuring equipment and to keep the aerodynamic shape,the star sensor is usually installed in the interior of the aircraft and executes Star identification through the porthole.In the ground simulation test,it is found that the porthole structure introduces additional stray light,as a result,the Star sensor fails to work properly.In this paper,we simulate the phenomenon,analyze its causes and study its means of inhibition.The simulation test results show that this part of the stray light mainly comes from the porthole glass,specifically speaking,from the glass’ s inward scattering sunlight which should be scattered out of the lens hood.So the stray light suppression scheme is proposed to reduce the scattering rate of the side window glass and improve the absorption rate of the inner wall of the hood.For large aircraft such as space stations,the structure itself may become the source of structure-caused stray light,and the resulting stray light may also affect the normal work of the star sensor mounted on the aircraft itself or surrounding aircraft.The methods of simulation and reappearance are used to study this kind of stray light.The results of the simulation can be used to evaluate the effective working distance and effectiveness of the Star SensorWhen space station and Tracking vehicle work in different relative motion stages.The results show that the stray light generated on the surface of the space station has no influence on the star sensor when the tracking aircraft works on the stages of Accompany-flying and around-flying Flying-around,but in the stage of rendezvous and docking(RVD),Stray light effects are presented at some locations(e.g.20 meters).This paper starts from the demand of actual problem and is combined with specific project item.Then this paper puts forward the analyzing method for the stray light caused by these two structures,Porthole structure and Large space station’s structure,studies the main factors and presents the solutions.The analyzing method can also be generalized to some other similar structures and provides a set of useful methods for similar problems. |
