Airborne geophysical survey system

Abstract

An airborne ElectroMagnetic (EM) survey system wherein the system includes; first, a series of transmitter coils, which induce a primary (EM) field into the earth resulting in a secondary EM field being created in any sub-surface electrically conductive bodies; and second, a set of three orthogonal receiver coils which detect the secondary EM field. Multiple transmitter coils through which an electric current is pumped, form part of the structural, aluminum framework of a multi-rotor drone. The receiver sensor may be an EM induction sensor, comprised of multi-turn, copper windings, mounted inside an aerodynamic bird and separated by non-conductive sphalerite, which acts as an electrical insulator to limit self-induction and capacitance. Additionally a lighter-than-air balloon may be used to add vertical lift and increase a pendulum effect.

1 . A receiver system for use in an airborne geophysical survey system comprising an aircraft and a transmitting source supported on the aircraft so as to be arranged to generate a primary electromagnetic field; the receiver system comprising:
 at least one receiver coil arranged to be supported on the aircraft so as to be arranged to sense a ground response to the primary magnetic field generated by the transmitting source in a geophysical survey;   said at least one receiver coil comprising a plurality of windings of conductive wire supported about a common receiver axis of the receiver coil in which each winding is separated from other ones of the windings by a separation distance which is greater than a diameter of the conductive wire.   
     
     
         2 . The system according to  claim 1  wherein the receiver system further comprises a solid, non-conductive material spanning between the plurality of windings of said at least one receiver coil. 
     
     
         3 . The system according to  claim 2  wherein the solid, non-conductive material has a specific gravity of greater than 2. 
     
     
         4 . The system according to  claim 1  wherein the conducive wire of said at least one receiver coil comprises copper.