System and method for controlled-source electromagnetic exploration based on staggered frequency excitation of crossed sources

A method for controlled-source electromagnetic exploration based on staggered frequency excitation of crossed sources, comprising the following steps:

• constructing a staggered frequency signal pair, wherein the staggered frequency signal pair comprises two sets of high-order pseudo-random signals having effective exploration frequencies not overlapping with each other and each of the two sets of the high-order pseudo-random signals is capable of covering at least a complete frequency range, and the exploration frequencies of the staggered frequency signal pair are capable of being increased or decreased by an equal multiple;
• at a signal transmitting terminal, providing a set of crossed sources each configured to transmit simultaneously a set of high-order pseudo-random signals in the staggered frequency signal pair;
• wherein the set of the crossed sources comprises two controlled-sources arranged at a same position, the two controlled-sources are perpendicular to each other and coincide at a central point, and
• at a signal receiving terminal, providing two sets of mutually orthogonal electrodes, configured to simultaneously receive the two sets of the high-order pseudo-random signals, distinguish polarization modes based on components of the frequencies of the two sets of the high-order pseudo-random signals, and extract corresponding polarization mode data, wherein the two sets of mutually orthogonal electrodes are perpendicular to each other and coincide at the central point, and each electrode of the two sets of mutually orthogonal electrodes has a same distance from the central point;
• a transmission time and an observation time for the two sets of the high-order pseudo-random signals are both at least an integral multiple of a minimal common period;
• each signal received by the receiving terminal contains the exploration frequencies of the two sets of the high-order pseudo-random signals, and received data in two polarization directions corresponding to each set of the high-order pseudo-random signals is obtained.