| 摘要 |
<p>A tracker unit for a measuring instrument and a method for operating a tracker unit are disclosed. The tracker unit is adapted to distinguish at least one specific target comprising at least one retroreflector from other targets and/or other reflective objects in the vicinity of the measuring instrument. The tracker unit comprises a plurality of photosensors. Each photosensor is adapted to generate a signal corresponding to intensity of reflected optical radiation impinging on the photosensor. The tracker unit comprises a first and at least one second optical radiation source. Each of the first and second optical radiation sources is arranged in the instrument body and configured to emit optical radiation when activated. The first optical radiation source is coaxially arranged in relation to at least some photosensors in the plurality of photosensors and the second at least one optical radiation source is eccentrically arranged in relation to first optical radiation source. The plurality of photosensors is caused to generate at least one first set of signals during a period when the first optical radiation source is activated and the at least one second optical radiation source is deactivated, and generate at least one second set of signals during a period when the at least one 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 targets and/or other reflective objects in the vicinity of the measuring instrument.</p> |
