A Modified Tolles–Lawson Model Robust to the Errors of the Three-Axis Strapdown Magnetometer

Abstract

The estimating of the Tolles–Lawson model’s coefficients plays an important role in aeromagnetic compensation. The directional cosines, which are indispensable for estimating the coefficients, are usually measured by a three-axis strapdown magnetometer in a general aeromagnetic survey system. However, in some cases, the scalar magnetometer may have a much higher accuracy than the three-axis strapdown magnetometer. This imbalance of the measurement accuracy is then introduced into the Tolles–Lawson model and affects the estimation of the coefficients. In this letter, a modified Tolles–Lawson model is introduced to reduce the imbalance through substituting the error model of the three-axis strapdown magnetometer into the calculation of the directional cosines. The characteristics of the modified model are analyzed and the corresponding coefficient-estimating system is developed. Simulation results illustrate that the modified model is more robust to the larger errors of the three-axis strapdown magnetometer than the classical model.