A Attitude Calculation Method Based on Sequential Correction of Earth's Gravity Field and Earth's Magnetic Field

Abstract

The present invention provides a kind of attitude calculation method based on the sequential correction of the earth's gravity field and the earth's magnetic field, and its steps include the following steps: (1) calculate the state transition matrix of the system model according to the angular rate collected by the gyroscope in the attitude system, and use The discretized quaternion differential equation updates the carrier attitude quaternion; (2) according to the carrier gravity acceleration collected by the accelerometer in the heading system, the attitude quaternion updated in step (1) is carried out by the principle of minimum mean square error Correction; (3) According to the carrier geomagnetic field vector collected by the magnetometer in the heading and attitude system, the attitude quaternion corrected in step (2) is corrected for the second time by the principle of minimum mean square error. The present invention uses geophysical field information to perform two sequential optimal estimates on the updated attitude quaternion. In this algorithm, it is not necessary to provide the system with a priori geomagnetic field information, but only with a priori gravity acceleration vector. The deficiencies in the application of the above-mentioned geomagnetic field are overcome.

Description

technical field [0001] The invention belongs to the technical field of positioning and navigation, and in particular relates to an attitude calculation method based on the sequential correction of the earth's gravity field and the earth's magnetic field. [0002] technical background [0003] Attitude and Heading Reference System (AHRS) integrates MEMS sensors (gyroscopes, accelerometers, magnetometers), which have the advantages of low cost, high integration, and small size. , but there are problems such as low accuracy of attitude calculation and large cumulative error caused by excessive output noise, zero drift cannot be completely eliminated, and angular rate output is easily disturbed. Therefore, under normal circumstances, it is necessary to use multiple sensors to achieve high-precision attitude calculation through information fusion algorithms. Compared with attitude calculation using Euler angles, quaternion is a very useful mathematical tool. Because of its few pa...

AI Technical Summary

Problems solved by technology

As an inherent physical feature of the earth, the geomagnetic field is more and more widely used in navigation, but the geomagnetic field is easily affected by surrounding buildings and steel structures. At different positions on the earth's surface, the geomagnetic field vector is different and unknown. The application of the geomagnetic field in navigation is greatly limited

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