Inertial Navigation System Initial Alignment Method on the Go Based on Laser Doppler Velocimeter

Abstract

The present application relates to an initial alignment method of an inertial navigation system based on a laser Doppler velocimeter. The method includes: in the earth-centered inertial coordinate system and the local navigation coordinate system, based on the speed measurement value of the laser Doppler velocimeter, the specific force equation and the estimation of the cosine matrix of the attitude direction, the alignment process of the strapdown inertial navigation system is established. Process models and measurement models. Construct the state vector with the attitude error of the inertial navigation equipment, the gyroscope zero offset drift, the accelerometer zero offset drift, and the installation angle error and scale coefficient error of the laser Doppler velocimeter as components, and establish a robust square root unscented quaternion estimation device, and get the predicted value of the state vector to carry out the initial alignment of the strapdown inertial navigation system during travel. The process model and measurement model of the above method utilizes the high-precision velocity output of the laser Doppler velocimeter, considers the inertial measurement unit error in the initial alignment, and the installation inclination and scale coefficient of the laser Doppler velocimeter, which can improve the attitude estimation precision.

Description

technical field [0001] The present application relates to the technical field of integrated navigation, in particular to a laser Doppler velocimeter-based initial alignment method for an inertial navigation system during travel. Background technique [0002] In the whole navigation process, the level of initial alignment accuracy is directly related to the performance of inertial navigation. The existing alignment methods include transfer alignment, static base alignment, and on-the-fly alignment. Transfer alignment requires high-precision inertial navigation as a reference, which is generally used for large ships or some special applications. Static base alignment is a commonly used alignment method for high-precision inertial navigation, which requires the carrier to remain stationary during the alignment process. This makes the alignment of the static base have high precision, but limits the mobility of the carrier and cannot be carried out as needed. On-the-fly alignm...

AI Technical Summary

Problems solved by technology

[0003] At this stage, it is most common to use GPS to provide accurate speed and position information for initial alignment during travel, but the use of GPS has the following disadvantages: (1) The GPS signal is unstable, the GPS receiver has poor anti-interference ability, and the GPS signal is easily damaged by tall buildings. (2) GPS is the second-generation satellite navigation system developed by the United States. It is a non-autonomous system and is highly uncontrollable.

Although my country's Beidou satellite navigation system has been networked, it is also non-autonomous

In addition, the odometer can also provide speed and mileage information for the vehicle. The initial alignment between the journeys assisted by the odometer has the characteristics of being completely autonomous, so it is widely used, because the measurement result of the odometer is related to the wheel circumference of the vehicle, and The circumference of the wheel is affected by the temperature, pressure and wear of the wheel, so the measurement accuracy is low. In addition, the slipping and jumping of the wheel will also cause large deviations in the measurement results of the odometer

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