Research Of Solution Of Airborne Gravity Anomaly Based On Kalman Filter

Based on aircraft carried,airborne gravimetry is a geophysics exploration way in which we can obtain the information of the gravity field of the earth at a high speed.China introduced the Russian GT-1A airborne gravity measurement system in 2007,but the modules containing GPS and airborne gravity solver were encapsulated.Over the years,taking GT-1A system as a platform,our research group studied the principle of airborne gravimetry and airborne gravity solver systematically,and obtained some preliminary results,but the difference of results to the software comes with GT-1A still existed.Based on the original research,this paper proposed the optimization for corresponding problems and added new features of innovation system noise adaptive Kalman filtering.(1)With different interpolation methods Kalman filter experiments was conducted.In the data preprocessing stage,for synchronization of data sets of different sampling frequency,in this study,based on the linear interpolation method,more interpolation methods(such as parabola,cubic spline)filtering experiments was carried out and found that when the sampling frequency was close to the sampling frequency of gravimeter,filter results of the higher order interpolation were better than results of the lower order interpolation.(2)The feasibility of low-frequency process was researched.Combining the low-pass filtering technique,distortion phenomenon was avoided successfully,which was also implemented in the program.Measured data processing results shown that Kalman filtering results after the low-frequency treatment were basically consistent with solution of GT-1A embedded software and the jump phenomenon was gone.(3)The problem of the height correction formula was improved and also the solution of processing of Penglai measured data.In the previous program,the results of data processing of Penglai flight always had a integral deviation of 9mGal to results of software of GT-1A.In this study,the reason was found it because of the misusing of height correction formulas,after improvement results turned out to be in good agreement with GT-1A.(4)Innovation system noise adaptive Kalman filtering was introduced.Since the measurement noise and system noise parameters of Kalman filter process can not be calculated for sure,generally,empirical value come from a lot of experiments was given.By model experiments of innovation system noise adaptive Kalman filtering,it was found that the purpose of noise reduction was got,even we did not know the exact system noise.Then the algorithm was applied to two measured airborne gravity data sets,results consistent with that of GT-1A were obtained.