Gravity measuring method based on strapdown inertia/GPS combined auxiliary horizontal angular motion isolation

Abstract

The invention relates to a gravity measuring method based on strapdown inertia / GPS combined auxiliary horizontal angular motion isolation; the method comprises the following steps: in an actual measurement process, a double-shaft stabilized platform is arranged outside the IMU of a gravimeter so as to isolate the horizontal angular motion of a carrier, and a horizontal torquing amount is formed bynavigation resolving under dynamic conditions so as to control the platform to track the geography level; in the anaphase processing process of the gravity measuring data, the DGPS information is combined so as to complete Kalman filter estimation of residual horizontal errors, thus rotating the IMU specific force measured value to the geography coordinate system direction through postures. In the actual measurement process, the method uses the double-shaft inertia stabilized platform to control, thus keeping the IMU the be basically at the geography horizontal position; in the anaphase processing process of the actual measurement IMU data, the high precision difference GPS information is combined to complete the Kalman filter estimation of residual horizontal errors, thus realizing estimation and compensation of the gravity sensor element errors, and improving the dynamic environment adaptability and gravity measuring precision in the gravity measurement.

Description

technical field [0001] The invention belongs to the technical field of dynamic gravity measurement, in particular to a gravity measurement method based on strapdown inertial / GPS combined auxiliary horizontal angular motion isolation. Background technique [0002] In the process of dynamic gravity measurement, if the strapdown inertial information measurement unit (IMU) is directly connected to the carrier, the gravity sensor will always move with the carrier, especially the angular movement in the horizontal direction will amplify the gravity sensor and the horizontal direction. The influence of non-orthogonal error, scale factor error and other factors on the accuracy of gravity measurement. Therefore, a dual-axis platform is added to the periphery of the IMU to achieve inertial stabilization and real-time tracking of the geographic coordinate system through the IMU gyro and accelerometer information to ensure that the sensitive axis direction of the gravity sensor is alway...

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Problems solved by technology

[0003] However, in the above process, due to the calculation error of platform horizontal correction moment amount caused by the error of gyro and accelerometer components, the azimuth axis cannot isolate the angular motion of the carrier, the inertial stability error caused by the horizontal gyro coupling azimuth rotation, and the dynamic response error in the closed-loop control process There will still be a certain degree of deviation between the horizontal attitude of the IMU and the level of the geographic coordinate system, so that the gravity sensitive direction after orthogonalization cannot strictly coincide with the geographic vertical, resulting in the final gravity measurement error

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