Research On SINS/CNS Integrated Navigation Technique Of Aerospace Vehicle

Aerospace Vehicles (ASV) put forward higher demands for the autonomy and accuracy oflong-endurance navigation which single navigation system cannot achieved. Integrating of INS andCNS could give full play to their strengths and compose high-precision navigation system which hasstrong autonomy and anti-interference ability. To propose celestial navigation attitude determination,positioning and INS/CNS integrated navigation algorithm, integrated navigation technology based onastronomical observation information for ASV s was studied.Considering the characteristic of ASV of long endurance, this paper firstly studied the ASVpositioning algorithm based on altitude difference method and analyzed the error of this algorithmfocusing on navigation star selection. During the error analysis, the affection of two star selectionmethod, static star selection and dynamic star selection according to azimuth, on positioning effectwas compared. The simulation proves the effectiveness of this positioning and star selection method.To develop the precision of attitude determination, this paper studied on the error of attitudedetermination algorithm based on star sensor. A error analysis method focus on TRAID algorithm waspresented and the attitude error affected by the star geometric distribution was analyzed. Also, due tothe need of attitude determination in the geographic coordinate, the attitude conversion from theinertia coordinate to the geographic coordinate was studied and the factor influencing the attitudedetermination error was analyzed in the geographic coordinate. The theoretical analysis and thesimulation prove the effectiveness of the error analysis method.In order to further improve the celestial positioning accuracy, the navigation theme based ondirectly sensing the horizon to achieve celestial analytical positioning and integrated filtering isproposed. In the theme a inertia benchmark is built by star sensor and gyro, then celestial positioningbased on infrared horizon sensor is calculated, and at last the INS/CNS integrated filtering isimplemented. The simulation results show that this method can not only fix the gyro output error, butalso fix the error of position, velocity and attitude so that the performance of the whole navigationsystem was improved.To meet the demand of precise and independent attitude measurement of ASV, attitudeCNS/SINS integrated algorithm, considering non-liner attitude measurement and the coupling ofattitude and position error in the geographic coordinate, was put forward, considering that aerospaceflight has the characteristics of non-liner and star sensors can put out precise attitude information in the inertia coordinate. By using different method of information fusion, the attitude precision waseffectively improved.At last, an ASV CNS/SINS integrated navigation system based on Matlab/STK was designed andcompleted. The system is able to simulate and generated parameters such as the aerospace vehicleflight path, inertial measurement unit output, astronomical observations, to provide an platform toverify the CNS/SINS integrated algorith.