A system for determining a location of an instrument within an anatomy is provided. The system can include a first instrument, which can define at least one lumen. The system can further include a second instrument, which can be received through the at least one lumen. The system can include at least...http://www.google.com/patents/US20090264739?utm_source=gb-gplus-sharePatent US20090264739 - Determining a position of a member within a sheath
