Research On The Technology Of Fiber Optic Gyro SINS/BeiDou Gravimetry

Compared to the influence of terrain,smaller measurement range and the slow speed of the traditional ground relative and absolute gravimetry,the strapdown inertial marine airborne gravimetry has a broad range of amplitude measurement,and the speed of measurement is fast,more economy and low cost,and in recent years has been a hot research field in gravimetry.At the same time with the development of fiber optic gyro,and high precision accelerometer,as well as the mature application of SINS algorithm,in addition to the regional navigation function of BeiDou navigation system is well,so the SINS and Beidou become an important part of fiber optic gyro SINS/Bei Dou system gravimetry.This paper establishes strapdown marine airborne gravimetry model besed on classic strapdown inertial navigation equations,and analyzes the measurement technology in strapdown inertial navigation marine airborne gravimetry in detail.At first,this paper introduces commonly coordinate in gravimetry,and then deduces gravimetry model expression in detail.Based on the model expressions,introduces the measurement parameters of SINS and Beidou system,according to the gravimetry precision,analyzes the accuracy requirements of fiber optic gyro SINS and BeiDou system,finally introduces the application of nonlinear tracking differentiator in gravimetry in the processing of lever-arm.Then,firstly analyzes the observation results of static position of BeiDou systembased on the measurement parameters of BeiDou system.At the same time this paper introduces the carrier-phase measurements,and analyzes the calculation method of vector velocity and acceleration based on the BeiDou system carrier-phase measurements in detail,as well as the calculation method of velocity and acceleration of the BeiDou system's GEO satellites and MEO/IGSO satellites according to the ephemeris information.At the same time,introduces the calculation expression in carrier-phase difference in single user receiver and satellite single differential measurements of velocity and acceleration.Secondly,analyzes the SINS error,established the SINS error model and the Beidou system error model because of the fiber optic gyro SINS error accumulated along with the elapse of time.And design the SINS/Beidou system position,speed integrated of kalman filter and pseudorange,pseudorange rate integrated of Kalman filter model.By estimating parameters' error of SINS integrated filter and feedback correction to SINS navigation parameters calculation,to improvethe measurement accuracy of SINS.In addition to,introduces the commonly FIR filter because of the marine airborne gravity measurement data usually contains a large number of high frequency noise.Finally,this paper designs the simulator of flying trajectory as a result of without real dynamic measurement data of the fiber optic gyro SINS and Beidou system carrier-phase.According to the simulation of flight trajectory,establishs the simulation of SINS/Beidou system position,velocity integrated filter.The filter results show that navigation position,velocity error decrease obviously after integrated navigation,and compared to pure inertial navigation error,the error after correction of filter feedback reduce remarkable.At the same time based on gravity measurement model,according to the simulation results,calculation results show that can obtain a certain accuracy of gravity measurement according to the method.Besides,the simulation analysis of the input signal are a unit step,velocity signal and sine signal,the output results of nonlinear tracking differentiator tracking show that the designed nonlinear tracking differentiator tracking effect is good,in the process of tracking without overshoot and the tracking error is very small.