Research On Attitude Determination Method Based On Three-axis Magnetometer Cross Array

Magnetic navigation in Marine geophysical navigation takes advantage of the Earth’s inherent magnetic field measurement for navigation and has great advantages over other auxiliary navigation techniques,which effectively ensures the concealment of underwater weapons.The pose determination method based on the magnetic field gradient tensor measurement can eliminate the influence of the interfering magnetic field by extracting the gradient information of the magnetic field,and can also solve the problem that a single magnetometer cannot determine the attitude independently,providing an autonomous and concealed way for the pose determination of the underwater carrier.This thesis studies the theoretical and experimental algorithm based on the triaxial magnetometer.It derives the theory of nonlinear equation algorithm on the quaternion,and verifies the feasibility and influence of error on this algorithm.We derive an algorithm for matrix orthogonal diagonalization based on the magnetic gradient tensor,which finds the relationship between the attitude matrix and the one corresponding to the tensor under different coordinate systems,and then solves the orthogonal matrix composed by the eigenvectors corresponding to the tensor.The simulation results of the two algorithms are compared,yielding the conclusion that the former algorithm has high anti-interference solution accuracy,the latter algorithm has clear calculation steps and small computation.The error theory analysis of the second algorithm leads to the specific expression of the attitude angle.The simulation and calculation results verify the correctness of the error analytics and the relationship between the different noise levels and the fixed pose.This thesis introduces the operation and the processing of the attitude angle,the problem of the compensation of the magnetic gradient tensor of the arm effect.Experimentally specific operational steps are presented and data obtained from rotating measurements around three axes.The data obtained with the measurement is processed as necessary to calculate the attitude angles.To obtain the more ideal solution results,the solution results within the two angular intervals with the most distributions are selected.Finally,the rod arm effect problem is introduced and the compensation for the magnetic tensor independent component caused by rod arm effect is derived and the expression is simulated verified.