An Improved Magnetic Compensation Algorithm for Swing Noise

Magnetic compensation is an important means to suppress interference and improve signal-to-noise ratio in magnetic signal measurement. In the process of geomagnetic signal measurement, magnetic compensation plays a crucial role. At present, the commonly used method for magnetic compensation is the Tolles-Lawson (T-L) model, which can effectively correct magnetic measurement data. The T-L model is used to compensate for carrier attitude-related noise. In general, magnetic compensation systems, direction cosine is an indispensable parameter, usually measured by the fluxgate magnetometer. The T-L model assumes a rigid connection between the tail boom and the carrier. This ignores the swing noise generated by the tail boom swings, which leads to errors in the measured carrier attitude information and affects the magnetic compensation. Building upon the T-L model, this article analyzes the reasons behind swing noise affecting magnetic measurement data and derives the relationship between swing noise and magnetic compensation results. In this article, attitude sensors are used to obtain the relative angle offset between the carrier coordinate system and the sensor coordinate system. By combining the angle offset with the fluxgate magnetometer data, the calculation of direction cosine is corrected and an improved compensation method is proposed. The experiment shows that compared to the classic T-L model, this method improves the magnetic compensation quality by 20.3%–24.6%. This indicates that the method proposed in this article has a better magnetic compensation effect.