AIRBORNE ELECTROMAGNETIC SURVEY SYSTEM WITH MULTIPLE TRANSMITTER ARRANGEMENTS

摘要

An objective is achieved by an airborne electromagnetic survey system configured for geophysical prospecting (2) of an underground formation (3), which airborne electromagnetic survey system comprises a transmitter arrangement Tx (10), comprising at least one current source (15) connected to at least one transmitter coil arrangement (24 covering an area A for generating a magnetic moment (5) for building up a primary electromagnetic field (11) inducing a secondary electromagnetic field (12) in the underground formation (3) and a switch arrangement comprising at least one switch inserted in between the at least one current source (15) and the at least one transmitter coil arrangement (24). The switch arrangement (20) is configured to connect (30) the at least one current source (15) with the at least one transmitter coil arrangement (24) to build up a connecting secondary electromagnetic field (38), which connect (30) is at a connection time (32) at a connection voltage (34) at a connection current (36). The switch arrangement (20) is furthermore arranged to disconnect (40) the at least one current source (15) from the at least one transmitter coil arrangement (20) to build up a disconnecting secondary electromagnetic field (48); which disconnect (40) is at a disconnection time (42) at a disconnection voltage (44) at a disconnection current (46). The connecting secondary electromagnetic field (38) and disconnecting secondary electromagnetic field (48) provide a combined secondary electromagnetic field (50). The airborne geophysical prospecting system further comprises a receiver arrangement Rx comprising at least one receiver coil configured to receive the combined connecting and disconnecting secondary electromagnetic fields (50). The airborne electromagnetic survey system comprises multiple transmitter arrangements Tx (101,..., 10N) generating a total secondary electromagnetic field (55) comprising a sum of individual combined secondary electromagnetic fields (501,..., 50N).