Current borehole receivers only measure a single parameter of the magnetic field component, which does not meet the special requirements of controlled-source electromagnetic (CSEM) methods. This study proposes a borehole electromagnetic receiver that realizes synchronous acquisition of the vertical electric field component and three-axis orthogonal magnetic field components. Results of the experiments show that our system functioned adequately and that high-quality CSEM signals were obtained.

Based on existing ocean bottom E-field (OBE) receiver specifications, including low noise levels, low power consumption, and low time drift errors, we integrated two induction coils for the magnetic sensor and a three-axis omnidirectional geophone for the seismic sensor to assemble an ultra-short baseline (USBL) transponder as the position sensor, which improved position accuracy and operational efficiency while reducing field data acquisition costs.

High-power transmitters have been playing a significant role in deep electromagnetic exploration. However, a high-power transmitter needs high-voltage support, which is a potential risk for researchers. According to the actual situation of field exploration, we designed a wireless monitoring system. The system offers two advantages, the first of which is high security; the second advantage is simple operation.

To assess the performance of the developed EM receivers, this paper presents a multifunctional waveform generator with three waveforms: 1) a wideband, low-noise electromagnetic field signal to be used for magnetotelluric, audio-magnetotelluric, and long-period magnetotelluric studies; 2) a repeating frequency sweep square waveform for CSAMT and SIP studies; and 3) a “positive-zero–negative-zero” signal that contains primary and secondary fields for time-domain-induced polarization studies.