Data Processing Of Frequency Domain Airborne Electromagnetic Survey

A systematic study on the data processing of frequency domain HDY402 Tri-frequency Airborne Electromagnetic System has been carried out, including the data pre-processing, data quality control, zero drift analysis, data leveling, anomaly auto-pick and recognition, color profile plan plotting, and application software development. The achievements made through the study are as following:Systematic computer data processing techniques and software for the HDY402 Tri-frequency AEM System are developed. Technique blank in automatic data leveling and anomaly auto-pick and recognition was filled. Systematic computer data processing of HDY402 AEM survey data was achieved, which is helpful to improve efficiency and quality of data processing.Airborne electromagnetic data pre-process and data quality control procedures were studies and improved. Wavelet coefficient threshold filter and moving average filter are employed to remove noise in the raw data. Airborne electromagnetic data are converted into alpha-beta domain to check their amplitude and phase error.A new automatic 2D data leveling technique are developed, which employed 2D moving average filter and could achieve data leveling automatically and quickly. Drift experiments were carried out and the experimental data was analyzed. The data leveling method will not make any information losing to the local anomalies and the algorithm is simple and fast. It could remove the"barrier-like"pattern error of AEM data caused by the zero drift and flight altitude effectively.Automatic anomaly pick and recognition method are developed for the first time. Using different parameters, different types of anomalies can be automatically picked up and recognized. The terrain correlative technique developed is helpful for identifying terrain effective anomalies. The technique of overburden anomalies recognition was also studied. Using electrical information derived from AEM data, the method supplied as many as possible analysis parameters for the following procedures of anomalies recognition.A colorful profile plan plotting technique was developed, with OLE Automatic technique and executed in the background with SURFER. It can plot gradation pseudo-transparency profile image of the AEM data very quickly. The quality of the profile image was satisfaction.Combining the techniques described above, practical data processing software was developed. It has been used in the data processing of the Tri-frequency AEM survey data. The results of the processed field data demonstrate the effectiveness and practicability of the techniques and software. Systematic data processing techniques of HDY402 AEM system have been established.