Distributed wide field electromagnetic method based on high-order 2n sequence pseudo random signal
(1. Geotechnical and Structural Engineering Research Center, Shandong University, Ji’nan 250061, China;
2. Institute of Urban Underground Space and Energy Studies, The Chinese University of HongKong, Shenzhen 518172, China;
3. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
4. Shandong Coal Geological Planning and Exploration Research Institute, Ji’nan 250109, China)
2. Institute of Urban Underground Space and Energy Studies, The Chinese University of HongKong, Shenzhen 518172, China;
3. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
4. Shandong Coal Geological Planning and Exploration Research Institute, Ji’nan 250109, China)
Abstract: To make three-dimensional electromagnetic exploration achievable, the distributed wide field electro- magnetic method (WFEM) based on the high-order 2n sequence pseudo-random signal is proposed and realized. In this method, only one set of high-order pseudo-random waveforms, which contains all target frequencies, is needed. Based on high-order sequence pseudo-random signal construction algorithm, the waveform can be customized according to different exploration tasks. And the receivers are independent with each other and dynamically adjust the acquisition parameters according to different requirements. A field test in the deep iron ore of Qihe-Yucheng showed that the distributed WFEM based on high-order pseudo-random signal realizes the high-efficiency acquisition of massive electromagnetic data in quite a short time. Compared with traditional controlled-source electromagnetic methods, the distributed WFEM is much more efficient. Distributed WFEM can be applied to the large scale and high-resolution exploration for deep resources and minerals.
Key words: distributed wide field electromagnetic method (WFEM); high-order pseudo-random signal; multi- frequency; massive data