Research On Soft Compensation Of Full Tensor Magnetic Gradient Data By Rotor UAV

In recent years,breakthroughs have been made in the research and development of superconducting quantum interference device(SQUID)and superconducting full tensor magnetic gradiometer.The measurement of full tensor magnetic gradient(FTMG)has gradually become one of the leading techniques in aeromagnetic survey.Parts of ferromagnetic materials were used in the manufacture of the UAV's mobile platform and measuring system(pod).In the actual measurement process,due to the complex interference magnetic field generated by the platform itself,the signal-to-noise ratio of the FTMG data is reduced.Based on the research of the existing soft compensation method of aeromagnetic total field data,this paper constructs a soft compensation model of the FTMG data measured by the rotor UAV.The feasibility of the soft compensation method is verified by establishing the theoretical model to obtaining the simulation data.This paper summarizes the general theoretical basis involved in the construction of soft compensation model,and makes some research.The main contents are as follows:1.This paper summarizes the theoretical formula for the conversion between the three types of coordinate systems(geographic coordinate system,geocentric coordinate system and navigation coordinate system).Because the attitude of the UAV and the pods changed during the actual measurement operation.Therefore,the theoretical formula of the conversion of the three components and the full tensor between the ‘North-East-Down' navigation coordinate system(as the reference coordinate)and the pod coordinate system is summarized.In order to calculate the FTMG of the international geomagnetic reference field(IGRF),the conversion formula of the derivative of magnetic potential in the geocentric spherical coordinate system and the local ‘East-North-Up' Cartesian co-ordinate system is presented.2.The theoretical expression for calculating geomagnetic FTMG based on IGRF model is derived.This algorithm can provide the theoretical FTMG data on the learning flight path for solving soft compensation coefficients.At the same time,a test area is selected to verify the algorithm calculation results.3.The source of magnetic interference in the FTMG data were analyzed.The theoretical expressions of the soft compensation method for FTMG data are derived based on the experimental results of the magnetic field measurement of the rotor UAV.4.A coefficient of soft compensation solution process and a soft compensation model of FTMG data are constructed.Through the theoretical model simulation experiment,the feasibility and compensation effect of the soft compensation method for FTMG data by the rotor UAV.