Research And Realization Of The High Precision Coordinate Measurement Technique Using Laser Tracker

Large Scale Spatial Coordinate Measuring System is an important research content of industry metrology and precise engineering survey. With the development of laser interferometric ranging and laser tracker, measurement accuracy and working volume of spatial coordinate is raising remarkably, and it accelerated the development of industry metrology and precise engineering survey. Furthermore, Integrated measurement of Multi-type instrument is pressing requirement to complicated measurement task, so new measurement theory and method is important to improving spatial coordinate measuring accuracy and building higher precision coordinate reference datum. So many worldwide research institutions dedicate to continuous research on laser tracker.Based on the research of laser tracker measurement characteristic, The project has got support both from National Science Foundation of China with project number 41101446 and spaceflight precise metrology project, This paper brings into focus the spatial coordinate precise measuring technology with laser tracker.At present, according to positioning principle, the spatial coordinate precise measuring technology can be divided into three types: angle intersection, space-polar and spatial spur traverse, This paper build the new spatial coordinate measurement system info of space linear forward intersection with laser tracker, based on horizontal trilateration network adjustment, adjustment of spatial weighted rank defect free-network with laser interferometric distance is deducted. The addition constraint matrix is set up to solving 3D trilateration network without angle datum, so each center point coordinate of laser tracker station can be solved. Furthermore, quasi-stable adjustment and addition system parameter and constraints parameter adjustment are also used to solve the spatial network to improving the positional accuracy of station and orientation point.With accurate weight matrix model, Three-dimensional side-angle network adjustment of six-freedom degree is also adopted to getting translation and rotation parameters of laser tracker station and orientation point positioning, and this adjustment model can solve leveling and tilting state of laser tracker. Based on these station parameters, each laser tracker station can get point position in unified coordinate system with space-polar positioning principle.The generalized USMN adjustment model is build up to compensating the shortage of classical USMN adjustment model in existence. With the generalized USMN adjustment model, The interferometric distance replaces scale bar of theodolite angle intersection system to solving integrated measurement network without station aiming angle and scale-bar angle, and translation and rotation parameters of laser tracker station and theodolite station are all solved, the variance of interferometric ranging and scale-bar length is eliminated, and solving accuracy didn’t reduce with several redundant observation but measuring efficiency increase.Based on position and orientation solving of multi-station of laser tracker, this paper studies space linear forward intersection and builds up positioning PDOP model of 3D trilateration network and space linear forward intersection. Furthermore, the space isoline map of PDOP is emulated and the relationship of PDOP and volume is also studied to optimizing positioning accuracy.At last, the coordinate accuracy of single laser tracker space-polar system can be calibrated with higher accuracy coordinate value of 3D trilateration network, this method is also called self-calibration.