Underground full-space transient electromagnetic detecting instrument and detection method

The invention relates to an underground full-space transient electromagnetic detecting instrument and a detection method. A computer is connected with a receiving coil through a signal acquisition card and a signal conditioning circuit, a 12V battery is connected with the signal acquisition card through a discharge protection circuit, a transmitting logic and control module and an MCU, the discharge protection circuit is connected with the signal conditioning circuit through a low-voltage current limiting circuit and an optical coupler 8, an energy quick consuming circuit is connected with the transmitting logic and control module through a transmitting coil and the low-voltage current limiting circuit, and the computer is respectively connected with an E2PROM, the optical coupler and the signal conditioning circuit through MCU. Detection is performed by adopting a dipole-dipole mode, device size is decreased, and the detection accuracy is improved by adjusting a transmitting-receiving distance and an included angle of two coils and through multiple-time measurement. The accuracy of early phase signal acquired by the receiving coil is effectively improved, the signal to noise ratio of the received signals is effectively improved, and the problem that full-space transient electromagnetic detection data are inaccurate is solved.