04829250 is referenced by 53 patents and cites 8 patents.

A system for determining the relative orientation in three dimensions between a fixed frame of reference and an unconstrained object. Mutual coupling between three orthogonally disposed transmitting coils driven by a multifrequency source and three orthogonal receiving coils produce sets of analog voltages which are sampled; digitized and processed using a fast fourier transform device to yield directional components for determining the pitch and yaw angles about a line-of-sight axis. By using a multi-frequency source to drive the transmitting coils and by deriving coordinate component measurements to at least two discrete frequencies, errors in the results due to eddy currents in surrounding conductive structures can be compensated for.

Title
Magnetic direction finding device with improved accuracy
Application Number
7/154230
Publication Number
4829250
Application Date
February 10, 1988
Publication Date
May 9, 1989
Inventor
Donald J Rotier
St. Paul
MN, US
Agent
Frederick W Niebuhr
Thomas J Nikolai
Orrin M Haugen
Assignee
Honeywell
MN, US
IPC
G01S 3/02
G01B 7/14
View Original Source