Research On Key Technology Of Data Acquisition And Simulation For Aeromagnetic Detection

Aeromagnetic anomaly detection is a branch of the aeromagnetic detection which is a kind of based on aerial platform for magnetic measurement means. In geophysical studies address structure, mineral exploration, magnetic field mapping, it has a wide application. To make Aeromagnetic detection feasible, it is necessary to carry out the magnetic compensation, which aims to eliminate the interference caused by the attitude and course of the aircraft platform itself. During the course of magnetic compensation, if there is a significant fluctuation in the signal collected, it could be recognized as a magnetic anomaly. In this paper, we study how to collect data, how to deal with the data and trying to design a data acquisition system based on the PXI architecture. Finally, a set of hardware in the semiphysical simulation system is presented, which can be used to detect the availability and performance index of the data acquisition system, and this provides a reliable guarantee for the real aircraft magnetic anomaly detection. The main work and results of this paper include:First of all, it is necessary to measure the frequency as the electronic unit outputs the scalar magnetic field in the form of Larmor frequency. This paper summarizes the methods of frequency counts from the 1960 s to present and compares the advantages and disadvantages of them. To get a more accurate data, we combine the characteristics of the frequency of aeromagnetic data and present an improved method based on timestamp. Not only can it improve the accuracy of the data, it is also necessary in the PXI-based data acquisition system.Second, the methods of preprocessing the original data is proposed. The data collected by the data acquisition system contains all kinds of noise, and the signal frequency band which is meaningful for the final soft compensation algorithm is in the low frequency band. In order to eliminate the influence of noise and the influence of measurement errors as much as possible, the low pass filter and Kalman filter are studied in order to improve the accuracy of data preprocessing.Finally, based on PXI bus, by triggering synchronization, the final aeromagnetic data acquisition system is completely produced. To verify its ability, a semi-physical simulation is suggested. Based on this simulation, lots of experiments have been done and the result indicates the system is feasible. And through the user interface, aeromagnetic data can be described graphically.