Research On Strapdown Inertial Navigation Algorithm Based On High-order Polynomial Iteration

Strapdown inertial navigation algorithm is a classic and core topic of strapdown inertial navigation technology.To design high-precision strapdown inertial navigation algorithm is the key to improve the precision of strapdown inertial navigation system in the case of existing accuracy of inertial instruments.The accuracy of classical strapdown inertial navigation algorithms is limited and the calculation error of navigation parameters is relatively large when the carrier is under high dynamic environment.To settle this problem,a high-precision strapdown inertial navigation algorithm suitable for different dynamic environments is designed after the differential equation of navigation parameters is solved iteratively based on the polynomial motion model of angular rate and specific force.The research contents mainly include:Firstly,it is introduced that the related basic concepts of strapdown inertial navigation,and the specific contents and functions of strapdown inertial navigation algorithm are described.According to the differential equations of navigation parameters,the whole framework of strapdown inertial navigation algorithm is established,which provides basis for the design of strapdown inertial navigation algorithm.Secondly,the classical attitude updating algorithms are derived under the polynomial angular motion and coning motion and the accuracy and characteristics of each algorithm are summarized.The accuracy of each attitude updating algorithm is vertified by simulation and the simulation results demonstrate that calculating high-order noncommntativity error correction terms can effectively improve the accuracy of attitude when strapdown inertial navigation system is under high dynamic environment.Thirdly,for the accuracy of the polynomial of angular rate,the numerical relationship between the coefficients of the polynomial of angular rate in coning motion is introduced as an additional constraint and then a polynomial of angular rate in time up to N or(N(10)1)is derived according to N angular increments provided by gyros.The polynomial of angular rate is also offered for N(28)4 6.In view of the accuracy of attitude,the quaternion reconstruction and its optimized algorithm based on the high-order polynomial iteration is designed according to the high-order polynomial of angular rate and polynomial iteration technology.The convergence and computation cost of the algorithm are analyzed in detail,and the accuracy of the new algorithm is verified by simulation experiments.At last,for the selection of reference coordinate used in the design of strapdown inertial navigation algorithm,the scheme of solving the navigation parmeters in the earth coordinate is selected according to the mechanical arrangement characteristics of the inertial navigation system.In view of the accuracy of navigation parameters,on the basis of quaternion reconstruction and optimized algorithm based on high-order polynomial iteration,a strapdown inertial navigation algorithm based on high-order polynomial iteration is designed.The high-order polynomial of angular rate and the polynomial of specific force are applied to solve the differential equation of inertial navigation in the earth coordinate and the navigation parameters are solved iteratively.The simulation results show that the strapdown inertial navigation algorithm based on high-order polynomial iteration can solve the navigation parameters of the carrier with high accuracy.