A Horizontal Damping Method for Marine Strapdown Inertial Navigation System Based on LMS Algorithm

Abstract

The invention provides a marine strapdown inertial navigation system horizontal-damping method based on an LMS (Least mean square) algorithm. The method is characterized in comprising the following steps that: S1: a marine strapdown inertial navigation system carries out real-time solving to collected a horizontal attitude angle and a course angle; S2: through a Schuler oscillation estimation algorithm based on the LMS algorithm, the Schuler oscillation component of the horizontal attitude angle is estimated; S3: the estimated Schuler oscillation component of the horizontal attitude angle is subjected to closed loop feedback to the marine strapdown inertial navigation system; and S4: marine strapdown inertial navigation system information is output in real time. By use of the method, the Schuler periodic oscillation component of the horizontal attitude angle is estimated by the LMS algorithm, then, the estimated result is used for carrying out feedback correction on the strapdown inertial navigation system, so that the horizontal damping of the inertial navigation system is realized, external information does not need to be imported, and therefore, the system has the advantages ofbeing small in calculated amount and good in damping effect.

Description

technical field [0001] The invention relates to the field of navigation, in particular to a horizontal damping method for a marine strapdown inertial navigation system based on an LMS algorithm. Background technique [0002] The strapdown inertial navigation system is an autonomous navigation system. Most carriers work in an undamped state that is not disturbed by acceleration. For aircraft, missiles and other systems with high acceleration and speed and short use time, The accumulation of errors is not serious; but for ships that have been used for a long time and whose acceleration is not too large, there will be three kinds of periodic oscillation errors, namely Schuler periodic oscillation, Foucault periodic oscillation and Earth periodic oscillation, and with the The accumulation of time, the error is divergent. [0003] At present, scholars are trying to find an effective algorithm to suppress the Schuler oscillation error. The integrated navigation system of inertia...

AI Technical Summary

Problems solved by technology

The integrated navigation system of inertial navigation system and GPS can eliminate divergent oscillatory errors, but GPS is susceptible to interference and cannot be used underwater. Therefore, when the position information cannot be obtained, the Schuler oscillation can only be suppressed by speed information.

[0004] The traditional external horizontal damping network provides speed information by Doppler, and each damping parameter is obtained by trial and error, which can eliminate the Schuler oscillation error very well, but overshoot error will occur when the damping is switched, and the greater the external reference speed error , the greater the resulting overshoot

Therefore, He Qianen et al. proposed that in the literature "Design of Horizontal Damping Network of Inertial Navigation System Based on Complementary Filtering", the constant-velocity network with excellent high-frequency characteristics and the phase-lag-advanced network with excellent low-frequency characteristics are complementary matched, and both are obtained. The damping network with excellent high and low frequency characteristics, the difference between the speed information provided by the log and the speed information calculated by the inertial navigation is used to suppress the Schuler oscillation through the damping network, but this method is applied to the digital filter when it is implemented, and the discretized period will be Affects the effect and stability of damping, and the selection of parameters is more sensitive, resulting in certain limitations

Subsequently, Liu Fei et al. proposed "A Strapdown Inertial Navigation System Horizontal Damping Algorithm Based on Kalman Filtering Technology". Based on modern control theory, they proposed a horizontal damping algorithm for inertial navigation / Doppler based on Kalman filtering technology. The Mann filter algorithm is very sensitive to the selection of the initial value and the covariance of the process noise. In practical applications, it is impossible to obtain accurate accelerometer error and gyro drift.

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