System and method for aligning a robot device in a data storage library

In a data storage library having a plurality of cells for use in housing media cartridges, each media cartridge having a location in the library, the library further having a moveable robot for use in retrieving the cartridges from the cells, a system for aligning the robot with a cell, the system comprising:

• a target in the library, the target having a first target portion in a first plane, and a second target portion in a second plane different than the first plane, the first target portion having a first section with a first reflectivity and a second section with a second reflectivity, the second target portion having a third section with a third reflectivity;
• a source on the robot for directing a beam toward the target;
• an actuator for use in scanning the beam source over the first, second and third sections of the first and second target portions, wherein the beam reflects off the sections as a reflected beam;
• a sensor on the robot for sensing the reflected beam and generating a signal representing the intensity of the reflected beam;
• and
• a controller for receiving the signal from the sensor, determining a location of the target in the library relative to the robot based on changes in the intensity of the reflected beam, and generating a control signal for use in aligning the robot with the media cartridge based on a known relationship between the target location determined and the location of the media cartridge.