A Latitude-Free Initial Alignment Method Under a Rocking Pedestal Based on Gradient Descent Optimization

Abstract

The invention discloses a latitude-free initial alignment method under a rocking base based on gradient descent optimization. Firstly, the non-latitude alignment of the rocking base is regarded as the problem of Wahba attitude determination to suppress device noise interference, and the objective function is established based on the gravity acceleration vector in the earth system; then the exact solution of the objective function is obtained by using the gradient descent optimization method. Inertial frame conversion quaternion estimation is realized under the condition of inertial system conversion; finally, the attitude quaternion is determined under the condition of only using the accelerometer and gyro information of the strapdown attitude system itself, so as to realize the latitude-free initial alignment under the swing base. The invention can solve the problem that the initial alignment cannot be completed when the lower latitude of the swing base is unknown, thereby ensuring the application range of the strapdown attitude system.

Description

technical field [0001] The invention relates to the field of initial alignment of a strapdown inertial navigation system, in particular to a latitude-free initial alignment method under a rocking base based on gradient descent optimization. Background technique [0002] The strapdown attitude system uses gyroscopes and accelerometers to measure the angular velocity and linear acceleration information of the carrier. After solving, it can continuously and real-time output the horizontal attitude and heading information of the carrier. It has the advantages of small size, fast start-up, strong autonomy and high accuracy of attitude measurement. , is widely used as the attitude benchmark of combat units such as combat vehicles, ships, and various weapon platforms. The initial alignment technology is the key technology of the strapdown attitude system, and its alignment speed and alignment accuracy will directly determine the start-up response time and attitude measurement accur...

AI Technical Summary

Problems solved by technology

[0005] However, the traditional swing base alignment methods, including the two-vector-based inertial frame analytical alignment method and the multi-vector optimization-based inertial frame alignment method, require the use of external sensors such as GPS and beacon transducers for initial alignment. The device acquires local latitude information, which will reduce the autonomy and safety of the strapdown attitude system

For the initial alignment of the rocking base under the conditions of GPS signal lock-out and rejection on the water surface and the inability to receive positioning signals underwater, the traditional initial alignment method of the rocking base will not be able to complete the alignment task, which greatly limits the rapid The scope of application of the joint attitude system

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