Granted Patent
Utility
US 6,525,539 · App. 09/808,976
Apparatus and method for locating subsurface objects in conductive soils by measurements of magnetic fields by induced currents with an array of multiple receivers
Inventors:
Ralf Birken, Thorkild Hansen
Patented Case
View Patent ↗
Granted: Feb 25, 2003
Filed: Mar 15, 2001
Inventors
Ralf Birken
Thorkild Hansen
Assignee (at issue)
Witten Technologies Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.