A Study On Practical Methods For Aeromagnetic Data Leveling

As a main method of airborne geophysical exploration, aeromagnetic surveyis widely used in various fields of geology. It is very important to improve dataquality for whole exploration process. This thesis has discussed preprocessingof aeromagnetic survey, and proposed some new methods of data preprocess.The main work are as follows:Depending on the difference of processed data types, the past levelingmethods could categorized into two kinds: discrete data, gridded data. Theaccuracy is higher based on processing discrete data, but the efficiency is low.The speed is more quickly based on processing gridded data, but it can be easyto damage the data.According to the phenomenon that error changes in a step-rate caused by thedisagreement of flight level, this thesis proposed a method named steps tend toeliminate the error steps.According to the feature that direct filter could easy to damage the qualityof data, this thesis proposed a method to correct data based on trend-surfaceanalysis. After the trend-surface analysis, then eliminate the errors by low passfilters. This method could effectively reduce the influence caused by filters, andit is easy to recognize errors form.When join different precision of aeromagnetic data, the edge area had a lotof disorganized information. To solve this problem, this thesis proposed amethod based on least square to fitting.In need of identify mixed data, this thesis put forward the method based ontriangulation to track each points. This method is useful to separate data orremove low precision points. The efficiency could be greatly improved ifmanually select processing area.All the methods above have integrated into a software. The software has good visual interface. And the data could displayed in the shape of contours.Besides, the software increased functions included automatic test based ontemplate and gridded data real-time editing. It is conveniently to operate.