| 摘要 |
A tracker unit for a measuring instrument and a method for operating a tracker unit are disclosed, to distinguish a specific target, such as at least one retroreflector, from other reflective objects in the vicinity of the measuring instrument. The tracker unit includes a plurality of photosensors and first and second optical radiation sources. Each photosensor adapted to generate at least one first set of signals during a period when the first optical radiation source is activated and the second optical radiation source is deactivated, and generate at least one second set of signals during a period when the second optical radiation source is activated and the first optical radiation source is deactivated. On basis of comparison between information extracted on basis of the first set of signals and the second set of signals, respectively, at least one specific target is distinguished from other reflective objects. |
