摘要
Airborne geophysical data often suffer from corrugations or line level errors, which can be adjusted or removed by using level- ling procedure. Levelling is a critical step in airborne geophysical data processing and interpretation. Microlevelling routine can be ap- plied to removing the remaining line level after tie line leveling. Based on practical aeromagnetic data levelling, the authors deal in de- tail with the principle of microlevelling and key steps in microlevelling procedure. For the purpose of microlevelling data, a directional high pass filter perpendicular to the flight line direction is first employed to produce a decorrugation noise grid. The noise grid is then extracted as new channel flight data. Amplitude limiting and low pass filtering can be applied to the noise channel so as to remove the residual geological signal and leave only the component of line level drift, which is then subtracted from the original data to produce the final microlevelled data. This paper has also discussed some key technical problems in airborne geophysical data leveling, especially in microlevelling. The discussion in this paper may be useful in practical data processing.