Research On Initial Alignment Method Of Inertial Guidance System Based On Trajectory Assistanc

Precision guided projectile is a kind of ammunition that not only has the characteristics of long strike distance and strong lethality,but also can achieve precise strike.It is an important symbol of modern high-tech information warfare.Guided projectiles often use inertial navigation/satellite/ballistic/geomagnetic combined navigation to obtain their movement information during flight.Initial alignment is a prerequisite for the normal operation of the inertial navigation system.The speed and accuracy of the initial alignment directly affect the follow-up The accuracy of the navigation results.This paper designs a fast air alignment algorithm based on matrix Kalman filter and ballistic model assistance,which verifies the feasibility and practicability of the algorithm from two aspects of simulation and experiment.First of all,this article derives the dual vector of the air alignment according to the velocity differential equation for the case of the shell flying in the air,draws on the traditional REQUEST algorithm and uses the K matrix to express the initial attitude of the carrier,and uses it as the estimation object of the matrix Kalman filter algorithm.,Using its characteristic of being a constant value in the alignment process to avoid the influence of the initial error,and to achieve the rapid alignment of the initial attitude angle.Secondly,considering that the projectile may face high overload and high speed rotation during the launch process and the special space structure inside the projectile,a miniature inertial guidance system based on rigid-flexible PCB circuit board is designed,and the inertia against high overload and high rotation is adopted.Chip,and designed auxiliary vertical welding structure to ensure the accuracy of orthogonal installation.Then,the device error of the designed inertial guidance system was calibrated carefully using the high-precision turntable,and the deterministic errors of the gyroscope and accelerometer including the bias error,the scale factor error and the non-orthogonal error were carried out.Detailed modeling,and calculating the parameters of the error model through the data obtained from the calibration experiment and applying the compensation model to the actual measurement output.After that,the Allan variance method was used to identify the random errors of the gyroscope and accelerometer,and then applied to the actual filtering estimation algorithm.Finally,the turntable is used to simulate the air flight environment of the artillery projectile,the accelerometer data is processed according to the high-precision attitude angle output by the turntable,and the inertial navigation data is collected by the host computer software,and the initial comparison of the inertial guidance system Quasi performance was verified.