SEMI-RIGID AIRBORNE ELECTROMAGNETIC TRANSMITTER ANTENNA SYSTEM

摘要

An apparatus for airborne electromagnetic surveying is provided, comprising a central hub defining an equatorial plane, a transmitter loop, and radials connecting the hub to the transmitter loop. The loop generally lies in a plane during flight, and comprises loop sections, some of which are connected with flexible joints allowing the loop to flex out of the plane during lift-offs and landings. A loop section comprises current conducting elements connected to current conducting elements of adjacent loop sections forming a transmitter loop circuit. A radial connects to the hub at a point that is substantially offset from the transmitter loop plane, thereby contributing to the stability of the transmitter loop connection point in an up-down direction relative to the hub. Additionally, a loop section comprising rigid conductive elements retained in a spaced-apart relationship by a frame member is also provided.

主权项

1. An apparatus for airborne electromagnetic surveying, the apparatus comprising:
a rigid central hub having a vertical extent and defining an equatorial plane; a transmitter loop disposed around the rigid central hub; a plurality of radials connecting the rigid central hub and the transmitter loop, a distal end of each radial being connected to the transmitter loop at a transmitter loop connection point and a proximal end of each radial being connected to the hub at a hub connection point; the transmitter loop comprising: a plurality of substantially rigid loop sections connected in an end-to-end manner with joints, wherein a plurality of the joints are flexible joints and the loop sections are disposed to lie in a transmitter loop plane during flight and may flex out of the transmitter loop plane at the flexible joints during lift-offs and landings, wherein, each loop section comprises one or more current conducting elements electrically connected to current conducting elements in an adjacent loop section to collectively form a transmitter loop circuit into which current may be driven by a transmitter, and wherein the proximal end of at least one radial connects to a hub connection point that is substantially offset from the transmitter loop plane along the vertical extent of the rigid central hub, whereby the offsetting contributes to the stability of the transmitter loop connection point in an up-down direction relative to the equatorial plane of the hub, and wherein the transmitter loop plane and the equatorial plane of the hub are substantially parallel during flight.