A Research On Software Compensation Technique For Airborne Geomagnetic Total Field Survey

Geomagnetic field is the interior of the earth’s natural magnetic phenomenon and contains abundant geophysical information. Its magnetic induction intensity and direction changes with the latitude and longitude, and has the characteristics of regional, low radiation and high precision. In recent years, as the country’s urgent needs in deep resource exploration and rapid development of inertial navigation system, algorithm, and magnetometer with the progress of science and technology,magnetic detection has played an important role in navigation and positioning,geological exploration and meteorological disaster forecasting.Aeromagnetic survey is the abbreviated form of aerial magnetic survey,measuring intensity and gradient of geomagnetic field in unknown area in accordance with the set line. Due to aeromagnetic survey is not subjected to the limitation of environmental factors such as jungle, valley, desert areas, it become the important means in getting geological information in recent years. As the form of metal material, the body of aircraft contains a large number of hard and soft iron material, generating aircraft interference magnetic field when flying. In order to ensure the accuracy of airborne magnetic data, aeromagnetic data must be compensated.Firstly, this paper studies the compensation principle of aeromagnetic survey,studying the formation of aircraft interference magnetic field based on formula TOLLES-LAWSON, analyzing and modeling aircraft interference magnetic field by MATLAB; then in simulation experiments, generating aircraft interference magnetic field by preset compensating coefficients and solving coefficients by traditional algorithm LS(least squares) estimation, concluding that the multi-collinearity has significant influence on compensating coefficients; meanwhile, research the forming reason of multi-collinearity, putting forward a solving method based on EIV(Errors-In- Variables); after that, introduce the principle and solving process of EIV, solving simulation signal by EIV and comparing the result of two algorithm; finally, use data collected by our research group in Beijing, In compensating flight, solvingcompensating coefficients by LS and EIV respectively, verify the superiority of EIV,in survey line flight, local geomagnetic total field is obtained by compensating coefficients and attitude angle, verifying the practicality of EIV, providing a new method for aeromagnetic compensation, improving the accuracy of aeromagnetic compensation and the development of aeromagnetic survey.