A Newton Iterative Method Based Estimation Method of Cannonball Attitude

Abstract

The invention discloses a method for estimating the attitude of a projectile based on the Newton iterative method. The method includes the following steps: (1) Calculate the inertial frame i of the carrier at time t according to the velocity and position of the projectile provided by the gyroscope and GPS b system is relative to the shell attitude matrix of the carrier system b, the navigation system n is relative to the navigation inertial system i n The shell attitude matrix (2) is calculated from the gyroscope and accelerometer measurements of i b department and i n The velocity of the projectile under the system v 1 (t) and v 2 (t); (3) define variable X=[q T u] T , and construct a nonlinear function F(X)=0; where, q is a 4-dimensional column vector representing i n tie to i b The changing quaternion of the system, u is the undetermined coefficient; (4) By seeking the first-order partial derivative and the second-order partial derivative of the function F(X), the Jacobian matrix and the Hessian matrix are obtained; (5) Using Newton's method to iteratively solve the quaternion The number q; according to the calculated attitude angle.

Description

technical field [0001] The invention belongs to the technical field of navigation, in particular to a method for estimating the attitude of a shell based on the Newton iteration method. Background technique [0002] A guided projectile is a low-cost, miniaturized precision-guided weapon that is installed on the basis of a traditional projectile with a guidance system and an aerodynamic device such as a driveable wing or tail compartment to improve the accuracy of the projectile's strike on the target. During the launch process of GPS / INS combined guided munitions from the platform, they usually suffer from severe conditions of high overload and high speed. In this high overload impact environment, the gyroscope, accelerometer and other on-board navigation system components cannot be powered on normally. All the equipment on the missile must be powered on after being out of the tube after experiencing this impact, and the initialization of the navigation system needs to be co...

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Problems solved by technology

[0003] However, the above method needs to introduce a geomagnetic sensor in actual use, which increases the cost, and the general integrated navigation estimation algorithm is not effective in a highly dynamic and complex environment

When using the angular velocity information measured by the gyro to estimate the roll angle, the measured value of the gyro is approximated as the angular velocity information of the carrier relative to the navigation system. Under high-speed flight, this approximation will bring a large calculation error, and even cannot meet the rough estimation requirements. Require

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