Quantifying the effects of transmitter-receiver geometry variations on the capabilities of airborne electromagnetic survey systems to detect targets of high conductance

The objectives of this thesis are to determine how the transmitter and the receiver move with respect to one another for various fixed-wing airborne EM systems; demonstrate why movement between the transmitter and the receiver compromises a system's ability to detect highly conductive targets; and estimate how accurately the transmitter-receiver geometry must be measured in order to detect a vertical target of high conductance for four configurations of airborne electromagnetic systems (GEOTEM, GEOTEM+, HeliGEOTEM and a Generic Concentric configuration). These objectives are achieved by analyzing the effect of the individual x, y, and z transmitter and receiver offsets, the transmitter attitude (roll, pitch, and yaw), and transmitter loop deformation.; The level of accuracy required for each geometric variation between the transmitter and the receiver is dependent on: the type, shape, orientation and depth of the target, as well as the configuration of the exploration system. For this analysis, the GEOTEM system is most sensitive to variations in the loop deformation followed by pitch, x-distance, z-distance, roll and y-distance. GEOTEM+ is similar to the GEOTEM system but is more sensitive to variations in pitch than loop deformation. The HeliGEOTEM system is most sensitive to variations in the pitch followed by loop deformation and z-distance then x-distance, roll and y-distance. The Generic Concentric system is most sensitive to loop deformation, z-distance, x- and y-distance, and roll and pitch. Of all the systems analyzed, the GEOTEM+ system has the lowest accuracy requirement followed by GEOTEM, HeltGEOTEM and the Generic Concentric. The Generic Concentric system requires an extremely high degree of accuracy for each variable. (Abstract shortened by UMI.)...