Method for calibrating accelerometer under unsupported state

Abstract

The invention discloses a method for calibrating an accelerometer under an unsupported state, which is applied to an inertial navigation system with the capacity of initially aligning with a static base attitude. The method comprises the following steps of: firstly, simplifying an error model, repeatedly changing the carrier position, and coarsely and finely aligning with each position by using the static base to acquire the attitude information; and calculating the three-axis component of an acceleration of gravity g projected under a carrier coordinate system according to the attitude information, and recording the measured value of the accelerometer at each position. The invention provides a 10-position calibrating scheme, which comprises the following steps of: acquiring zero offset to degenerate the error model into a linear model by identifying the zero offset through a nonlinear least square method according to the calculated value and measured value of the projected component; and mounting an error and scale factor coupled matrix by identifying through a linear least square method. Therefore, the key parameters of the accelerometer are calibrated. The method has the advantages of capacities of realizing unsupported calibration of the accelerometer and effectively estimating the key parameters of the accelerometer with time-varying performance, along with simple process and high speed.

Description

technical field [0001] The invention belongs to the technical field of inertial navigation, and in particular relates to a method for calibrating an accelerometer in an unsupported state. Background technique [0002] Effective calibration of accelerometers can solve the problem of time-varying performance parameters, which is very necessary to improve measurement accuracy. The traditional calibration method requires complete system-level calibration of unknown parameters with the help of calibration equipment such as turntables and centrifuges. The calibration accuracy is high, but the operation is complicated, the calibration cycle is long, and the real-time performance is poor; Under the concept of accelerometer calibration, it is required to break away from the laboratory conditions, and only use the inertial device itself to achieve calibration at the use site. Due to the limitations of on-site calibration conditions, usually only the parameters that have the most serio...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the above-mentioned problems that the installation error and scale factor error of the accelerometer cannot be marked or identified, and the accuracy of the identification result is low, the present invention proposes a calibration method for the accelerometer in the unsupported state. Before performing the calibration process, it is first necessary to consider the acceleration The most serious error parameter affecting the performance of the accelerometer, the simplified error model of the three-axis accelerometer is

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