The Testing Technology Research Of Semi-airborne Transient Electromagnetic Receiver

With the wide application of transient electromagnetic method in geological exploration, the requirement of transient electromagnetic instrument has also increasingly higher demand.It's necessary to test every property index of the instruments after they are been developed successfully.The test results will directly affect the debugging of the system.Semi-airborne Transient Electromagnetic signals are similar to e exponential decay signals,so an input of e exponential decay signals during testing has a better test effect. Although the signals produced by the arbitrary waveform generator on the market can produce e index signal,it is difficult to change the signal parameters,and atmospheric noise, coil motor noise and other Semi-airborne Transient Electromagnetic noise signal cannot be simulated. Therefore, this paper designed a kind of special test equipment for the Semi-airborne Transient Electromagnetic receiver.It not only can produce a transient electromagnetic signal and all kinds of noise signal, but also the theory of signal through the comparative analysis and collect signal receiver.It achieve the purpose of testing receiver.The dissertation is based on the project “half airborne transient electromagnetic exploration technology research based on UAV”(project number:201311037) which is supported by public welfare project of Ministry of Land and Resources of China. First, this paper introduces the research background of the transient electromagnetic method and the current research status of transient electromagnetic receiver testing technology. Secondly, this paper analyzes theoretically the principle of transient electromagnetic signal, the characteristics of the transient electromagnetic response and field test of the transient electromagnetic signal, established the simulation model of transient electromagnetic signal.It analysed the main noise affecting Semi-airborne Transient Electromagnetic signals(such as atmospheric noise, Coil motion noise,unmanned aerial vehicles noise, etc.) and their characteristics.It sets up the corresponding matlab simulation model and laid a theoretical foundation for the development of the special signal source transient electromagnetic. Again, this paper introduces the principle of DDS and puts forward the system design scheme based on SOPC and in detail elaborated the system of digital to analog conversion module and power module design. Then,a test software is designed by using the graphical programming language—LabVIEW.It not only can set the parameters and display waveform, but also can have a analysis and contrast between the theory of signals and actual collection signals.It can be used to test receiver's signal acquisition performance. Finally, a test for the signal generator is been carried out.Then a joint test is been carried out with using the signal generator.It can evaluate the performance of the receiver through the experimental data.These data can provide a valuable experience for the test and calibration of Semiairborne Transient Electromagnetic receiver.Through these researches that is beneficial to reduce the cost of testing experiment of transient electromagnetic receiver and it is of great significance to improve the receiver's performance index.