On the Correction of the Positional Error Caused by the Coordinate Origin in Tolley-Lawson Model

The Tolley-Lawson (TL) model plays an important role in the aeromagnetic survey. The TLG model based on the TL model introduced the correction of the geomagnetic gradient in the real world and improved the precision of aeromagnetic compensation. The key to geomagnetic gradient compensation is to introduce the system's position information. However, in general, there is an offset between the origin of the coordinates of the magnetometer and the fuselage, which will lead to sensor position errors, especially during maneuvers. Correcting the positional error will eliminate the offset and increase the precision of the aeromagnetic survey. In this letter, the principle of the positional error is analyzed, and an improved model (TLG-C) aiming to correct the positional error is proposed. The positional error is modeled as a function of the attitude angle of the aircraft and the distance between the fuselage and the magnetometer. An improved aeromagnetic compensation algorithm is derived based on the TLG-C model. The results of 24 cases in actual calibration flights show that the proposed method can effectively enhance the improvement ratio.