Research On High-Precision Initial Alignment Of Strapdown Inertial And Integrated Navigation System

Strapdown Inertial Navigation is an important airborne navigation system, and is of wide application both in military and civil domain. In this paper, as a key technology, initial alignment of Strapdown Inertial Navigation System (SINS) is researched, so that information of both inertial sensors and other airborne navigation system can be fully used to improve the initial attitude accuracy of SINS and its navigation positional performance as well.Firstly, high-accuracy initial alignment of SINS on stationary base is researched. Navigation algorithm and error models are deep studied, and the structure design is improved so that a newly initial alignment based on rotating base is proposed. The alignment method is proved to be with high observable degree through observable degree analysis based on spectral condition number. Then, the wholly digital simulation is done, and contrast analysis to normal alignment methods shows that its accuracy and real-time performance is of great superiority in rotating SINS.Secondly, in-flight fast alignment of integrated navigation system is deeply researched, in order to improve attitude accuracy of Inertial/Satellite integrated Navigation System on the condition of high speed and complex motivation. A fast alignment technical of Inertial/GNSS integrated navigation system is proposed, and the corresponding simulation platform is built, to prove its validity. Further, information elimination based on ARIMA Filter and improved Genetic-Newton alignment method is studied to improve the signal-to-noise and attitude-resolving real-time performance. The semi-physical simulation with real tested data indicates that, the fast alignment method can be realized on the normal flight condition, and is characterized with fast-resolving, high-accuracy and good practicality, so it is of great importance in air start and fault restart of integrated navigation system on the condition of high-speed and complex-motivation.Thirdly,"specific force integration / angular velocity"matched transfer alignment method is studied according to precision guided weapons and aiming pod system. The difference of specific force integration and angular velocity between master navigation system and slave navigation system is set to be observed quantity, and misalignment errors of slave navigation system are estimated and compensated. Moreover, transfer alignment digital simulation platform is developed, and impaction of sensor precision to alignment performance is proved. To meet the alignment demands of airborne electrical system like aiming pod system, the transfer alignment performance on the conditions of low-speed flight, takeoff and climbing is tested, and the results show that both the alignment precision and real-time performance meet the corresponding-condition target, and is of prominent application value. Finally,a set of semi-physical simulation platform for transfer alignment is built successfully, the important algorithms discussed above are applied in the simulation platform. The experiments prove that the system hardware is reliable, and the algorithms are effective. The experiment results show that the algorithms adapt well to the DSP micro-navigation computer and the simulation platform has good reliability. Furthermore, this paper analyzes the influence of information time delay on performance of transfer alignment process, also proposes and verifies the methods of compensation.The research work in this paper has important military significance and engineering value.