Abstract: A laser tracker system for measuring six degrees of freedom may include a main optics assembly structured to emit a first laser beam, a pattern projector assembly structured to emit a second laser beam shaped into a two-dimensional pattern, and a target. The target may include a retroreflector and a position sensor assembly. A center of symmetry of the retroreflector may be provided on a different plane than a plane of the position sensor assembly. A method of measuring orientation of a target may include illuminating the target with a laser beam comprising a two-dimensional pattern, recording a position of the two-dimensional pattern on a position sensor assembly to create a measured signature value of the two-dimensional pattern, and calculating an orientation of the target based on the measured signature value.

Abstract: Methods and apparatus for performing heap management in programmable recording instruments used to record process data; and protecting the integrity of data structures stored in non-volatile memory included such instruments should a power failure or power shut down occur while heap management operations are in progress. Furthermore, according to the invention, methods and apparatus are provided for (a) validating the integrity of the aforementioned data structures quickly on power up of the recording instrument; (b) finishing certain predetermined processes that were in progress when a power failure occurred, at the time when the recording instrument is powered back up; (c) locating any memory allocated to a user prior to a power failure or shut down; and (d) assuring the user, whenever power is restored to the system, that only pointers to previously allocated data blocks containing valid data are provided in response to users requests for such pointers.