Laser Doppler velocimeter-based initial alignment method of inertial navigation system during advancing

Abstract

The invention relates to a laser Doppler velocimeter-based initial alignment method of an inertial navigation system during advancing. The method comprises the following steps: under a geocentric inertial coordinate system and a local navigation coordinate system, establishing a process model and a measurement model of the alignment process of the strapdown inertial navigation system based on a speed measurement value, a specific force equation and attitude direction cosine matrix estimation of the laser Doppler velocimeter; constructing a state vector by taking an attitude error of inertial navigation equipment, zero offset drift of a gyroscope, zero offset drift of an accelerometer, and a mounting angle error and a scale coefficient error of a laser Doppler velocimeter as components, establishing a robust square root unscented quaternion estimator, and obtaining a predicted value of the state vector to carry out initial alignment between marches on the strapdown inertial navigation system. The process model and the measurement model of the method utilize the high-precision speed output of the laser Doppler velocimeter, and the error of the inertial measurement unit and the installation inclination angle and the scale coefficient of the laser Doppler velocimeter are considered in initial alignment, so that the attitude estimation precision can be improved.

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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