Station-transfer measurement accuracy improvement of laser tracker based on photogrammetry

•We propose a method of photogrammetry assists measurement of laser tracker.•We propose a graphic correction method for correcting the coordinates.•The distance and direction constraints of common points are built.•Improving station-transfer measurement accuracy of laser tracker. Laser tracker has been used in a diverse range of applications due to its high accuracy and efficient, specifically as measuring the coordinates of points or scanning shape of objects. In real applications, we often need to measure common points on multi-stations by using this technology if objects are large scale. To ensure every common point within the range of laser tracker, common points are usually placed far from the laser tracker. However, the long distance between common points and laser tracker will decrease the accuracy of the result. In this research, we proposed a new method where photogrammetry and laser tracker are integrally used to measure common points to reduce measurement error. With the help of photogrammetry, we first constructed the geometric constraints of common points. Then, by using graphic correction method, the coordinates of common points on laser tracker will be corrected. Both of the theoretical and experimental study results indicated the great success of improving the measurement accuracy of laser tracker. We consider that this method we reported can highly increase the accuracy of measurement on laser tracker station-transfer.