Method and apparatus for position and orientation measurement using a magnetic field and retransmission

DETAILED DESCRIPTION The present invention ovecomes the deficiencies and shortcomings of the prior art as espoused hereinabove by providing three exemplary embodiments.
In a first embodiment of the present invention, a system is provided which includes three coils deployed as a three-axis antenna and utilized for both transmitting and receiving of magnetic fields between approximately 10 and 100 kilohertz.
A retransmitter is provided as attached to an object the position and orientation of which are to be determined.
The transmitter consists of three passive resonant circuits whose coils are attached together as a three-axis antenna.
In the operation of the system, a magnetic field is transmitted from the three transmitter/receiver coils sequentially using three different frequencies.
These three frequencies correspond to the respective resonant frequencies of the three passive resonant circuits attached to the object.
Each respective passive resonant circuit retransmits its respective magnetic field and, from these received sequential magnetic fields, the position and orientation of the object may be determined.
A second embodiment of the present invention is similar to the above-described first embodiment thereof.
The main difference therebetween lies in the fact that the second embodiment uses a separate transmitter for the respective magnetic fields and the coils utilized in the first embodiment as transmitter/receivers, in this embodiment, merely comprise receivers.
The transmitter sequentially transmits the three frequencies which are retransmitted by the retransmitters and received by the receiver coils.
From the received magnetic fields, the position and orientation of the object may be determined.
In a third embodiment of the present invention, the system includes a transmitter coil, one retransmitter attached to the object the position and orientation of which are to be determined, and nine receiver coils which are deployed as three three-axis antennas.
In the operation of this embodiment, the transmitter coil transmits a magnetic field at a predetermined frequency corresponding to the resonant frequency of the resonance circuit in the retransmitter