Patent ID: 6717410
Filing Date: 2004-04-06
Classification: E21B,G01V

Abstract:
A system for locating a horizontal bore below a ground surface, said system comprising:a transmitting source configured to radiate a magnetic field from said bore; a receiver remote from said transmitting source and having a plurality of coils disposed so that each said coil occupies a predetermined operative position with respect to a horizontal plane when said receiver is disposed in a first position with respect to said horizontal plane and so that at least one first said coil moves into said operative position of a second said coil when said receiver is rotated to a second position with respect to said horizontal plane; a processor; and a control circuit in communication with said coils to receive signals on said coils induced by said magnetic field and in communication with said processor to output said signals to said processor, wherein said control circuit is configured to detect said position of said receiver and to replace said signal of said second coil output by said control circuit to said processor with said signal of said first coil when said control circuit detects that said receiver is in said second position.