Modelling Of The Structural Error And The Precision Design Of The Gravity Gradient Instrument

Aimed at carry out high-precision gravitational gradient instrument,the GGI(gravitational gradient instrument)is regarded as the research object in this paper,which focuses on several aspects of error analysis and precision design.The details of the relevant theoretical research are as following:Based on the physical meaning of gravity gradient,the measurement principle of gravity gradient instrument is analyzed by Newton’s law.As a result of the characteristic of uniaxial rotation modulation technology,the precision limit of the single measurement element is broken.The measurement model of gravity gradient sensor is established by mathematical modeling method.By the further analysis of the relative motion of the inertial system and the non-inertial system,the measurement model of the sensor is optimized.Establish the error models of the accelerometer installation,after taking the error term as the input of the measurement model,and analyzing the influences on the output.Based on the propagation law of the structural error term in the measurement model,the error function is established and the limit error of the installation precision is deduced by the error distribution method.The design of the accuracy of the installation of the accelerometer makes the control of the structural error reach achievement.The precision design of the gravity gradient instrument in this paper is focused on the shaft and the hole which considered as taking the first place in the whole structure of the sensor.In order to completed a set of suitable design for the sensor,the theoretical design and the experience design are both used as the method,meanwhile,the functional requirements,the economic requirements and the manufacturing requirements are taken as the basic principle.The design work consist of the design and calculation of the size and fit of the shaft and the hole,the calculation of the bearing capacity,the safety test,the failure situation analysis,and the overall optimization design of the fit of the GGI.