The Study On Transverse Output Characteristic Of Accelerometer And The Affect On Inertial Unit

AccelerometerisonenecessarymeasurecomponentsofINS(inertialnavigationsystem),the precision of which has a direct bearing on the INS. The transverse sensitivity is the mostimportant parameter that can affect the precision of accelerometer, but because of the tetherof the property of sensitive materials and the process technique, the transverse sensitivityalwayscan'tbeeliminatecompletely.Thus,so-calledtransverseoutputerroremerges.This dissertation first analyzes the mechanisms of transverse sensitivity in piezoelectric,piezoresistive and capacitive accelerometer. Both the rolling experiment is made forsimulating gravity field and the transverse sensitivity ratio experiment is made by usingcentrifuge. The experiment results indicate that the transverse sensitivity ratio is related withthe direction of transverse acceleration, and independent of the amount of transverseacceleration. In the plane whose normal is the principal axis direction of accelerometer, thetransverse sensitivity ratio is distributed with the shape of"8". Based on the existing formulafor the transverse output of accelerometer, this dissertation established a compensation modelfortransverseoutputerror,andverifiedthevalidityofthemodelthroughtheexperiment.This dissertation established the static navigational equations of GFIMU (gyros freeinertial measurement unit) which taking transverse output into account. When the transversesensitivityis zero, these equations are classical static navigational equations of GFIMU. Thisdissertation composed two inertial measurement units, which are"nine accelerometers"and"twelve accelerometers"respectively, with the accelerometers of same parameters. Under thesame navigation parameters, this dissertation conducts simulating experiment by usingMATLAB. In this simulating experiment, a series of transverse sensitivity coefficient aregiventotheaccelerometer.The result of simulatingindicates that,becauseofthe existenceof transverse output of GFIMU, the error is coming with resolution of vectors. Besides that thelarger the transverse sensitivity is the larger the error is.