System and method for disambiguating the phase of a field received from a transmitter in an electromagnetic tracking system

An electromagnetic (“EM”) tracking system configured to disambiguate the phase of a field received from a wireless tracker, said system including:

• an EM tracker configured to transmit a tracking signal;
• one or more single-coil EM receivers configured to measure an EM field of said tracking signal, said single-coil EM receivers among an array of single-coil EM receivers;
• and
• tracker electronics configured to perform the following steps:
• determining a starting point of a phase of said tracking signal;
• locking onto said phase of said tracking signal based on said starting point;
• and
• determining a position and orientation of said single-coil EM tracker based on said EM field of said tracking signal.

A tracking apparatus for use in an electromagnetic (“EM”) tracking system, said tracking apparatus configured to lock on to a phase of a tracking signal transmitted by an EM tracker, said phase determined by one or more of the following steps:

• analyzing a carrier wave signal transmitted by said EM tracker to determine a time at which a desired phase of said carrier wave signal begins, said time also indicating a starting point of said phase of said tracking signal;
• receiving said phase of said tracking signal as transmitted by said EM tracker;
• and
• communicating said phase of said tracking signal to a transmitter configured to transmit said phase to said EM tracker, wherein said EM tracker is configured to receive said phase and transmit said tracking signal beginning at said phase.