Surveying device for improved target identification using atr difference image data

A retroreflective tape target to be surveyed by a geodetic surveying device, the retroreflective tape target comprising:

• an area where impinging light of a first wavelength range is retroreflected, and
• an element arranged within the retroreflective area, wherein the element:
• is transmissive to radiation of the first wavelength range, and
• is opaque to radiation of a second wavelength range, wherein the second wavelength range is at least partly in a visible wavelength range.

A geodetic surveying device, wherein the geodetic surveying device is configured for surveying retroreflective cooperative targets, the geodetic surveying device comprising:

• a base,
• a telescope, wherein the telescope is configured for carrying out a distance measurement by means of a laser beam emitted via a beam exit of the telescope,
• a support, wherein the support is attached to the base so as to be rotatable about a vertical axis of rotation and the telescope is attached to two opposing leg components of the support so as to be rotatable about a horizontal axis of rotation,
• a target recognition emitting unit, called ATR-illuminator, configured to emit a radiation beam in a beam divergence of 0.5° to 5°,
• a target recognition sensor, called ATR-sensor:
• defining a field-of-view corresponding to the beam divergence, called ATR-FOV, and
• having a position-sensitive area for receiving radiation of the radiation beam reflected at the retroreflective cooperative targets for generating ATR image data, wherein the received radiation appear as spots in the ATR image data,
• at least one angle encoder, or one angle encoder per axis, wherein the at least one angle encoder is configured to determine orientations of the telescope and/or the support and/or the ATR-illuminator relative to the base,
• a processing unit configured to determine angular data depending on spot positions in the image data,
• wherein the geodetic surveying device is configured for performing a retroreflecting target measurement mode in which the retroreflective cooperative target does not fit into the ATR-FOV, in which a series of ATR image data is generated, wherein with each of the ATR image data of the series of ATR image data a spatial analysis of illumination patterns is carried out, wherein based on the spatial analysis of illumination patterns and taken different orientations of the ATR-illuminator, i.e. angles determined by the at least one angle encoder in each of the different orientations of the ATR-illuminator, a reflection center of the retroreflective cooperative target is determined.