Patent ID: 8860809
Filing Date: 2014-10-14
Classification: G01C

Abstract:
1. A tracker unit for a measuring instrument including an instrument body, the tracker unit configured to distinguish at least one specific target comprising at least one retroreflector from other targets and other reflective objects in a vicinity of the measuring instrument, the tracker unit comprising: a plurality of photosensors, each of the plurality of photosensors configured to generate a signal corresponding to intensity of reflected optical radiation impinging on a corresponding one of the plurality of photosensors; a first optical radiation source and at least one second optical radiation source, each of the first optical radiation source and the at least one second optical radiation source being arranged in the instrument body and configured to emit optical radiation when activated, the first optical radiation source being coaxially arranged in relation to at least some of the plurality of photosensors and the at least one second optical radiation source being eccentrically arranged in relation to the first optical radiation source; a control module configured to, a signal processing module configured to,