Patent ID: 8724118

Claim:
A position-referenced mobile system comprising: a mobile apparatus including: a transport mechanism for moving the mobile apparatus along or substantially along a plane of motion; a rotatable position detection assembly including: a laser; a first photo detector; and a second photo detector; and at least one encoder for monitoring an amount of rotation of the position detection assembly; wherein the first photo detector is disposed within a first hollow tube, and the second photo detectors disposed within a second hollow tube and wherein the first hollow tube, the second hollow tube and the laser are parallel to or substantially parallel to each other; a controller for interpreting signals provided by the first photo detector and the second photo detector; and a position referencing structure including: a reflective linear reference member; a first reflective cylindrical surface disposed at a first end of the linear reference member; and a second reflective cylindrical surface disposed at a second end of the linear reference member.