Off-line fusion method for redundant measurement signals of gravity gradient sensor of rotary accelerometer

Abstract

The invention relates to an off-line fusion method for redundant measurement signals of a gravity gradient sensor of a rotary accelerometer. The method comprises the steps: calculating Fourier transform of two groups of measurement signals through an offline processing method; comparing the phase angle difference of the two signals at the same frequency with a preset threshold value, if the phaseangle difference is smaller than the threshold value, reserving the signal at the frequency point, and if the phase angle difference is larger than the threshold value, abandoning the signal at the frequency point; and finally, obtaining a final output result of the gravity gradient sensor measurement signal through inverse Fourier transform. Compared with conventional smooth filtering, the methodhas the advantages that the rejection ratio of irrelevant noise can be effectively increased, and the requirement for high-precision gravity gradient measurement is met; and according to the method,under the condition that the original precision of the gravity gradient measurement signals is low, the fusion method can be matched with the noise conditions of the two groups of measurement signalsin a threshold value adjusting mode so as to obtain the optimal gravity gradient signal.

Description

technical field [0001] The invention belongs to the technical field of measurement signal processing of a gravity gradient sensor of a rotational accelerometer, and in particular relates to an off-line fusion method for redundant measurement signals of a gravity gradient sensor of a rotational accelerometer. Background technique [0002] Rotational accelerometer-type gravity gradiometer is an instrument for continuous measurement of micro-gravity gradient changes on the earth's surface. like figure 1 As shown, the gravity gradient measurement component as the core sensor is based on the accelerometer position differential measurement principle, and modulates the gravity gradient tensor component to the double frequency of the system rotation frequency by mechanical rotation. The accelerometer output and the gravity gradient tensor The relationship between the components can be expressed as: [0003] (a 1 +a 3 )-(a 2 +a 4 )=2R(Γ xx -Γ yy )sin2ωt+4RΓ xy cos2ωt (1) ...

AI Technical Summary

Problems solved by technology

Through data comparison, it is considered that a large amount of noise in the two sets of gravity gradient measurement signals is irrelevant, and the traditional average fusion method has a low suppression ratio for uncorrelated noise. Therefore, it is necessary to establish an effective signal extraction method. The irrelevant noise in the signal is filtered out to improve the measurement accuracy of the gravity gradient signal

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