3R intersection target positioning in real time based on distance

The positioning error based on angle, angle-distance or single station positioning increases with the distance increasing. 3R target positioning based on distance can obtain the high precision measurements in long distance. Here we give the 3R model for the intersection positioning, provide the two necessary conditions for getting the optimum intersection point. The experimental results show that the intersection precision based on angle is over 2m and will degrade greatly with the increasing of distance while the one based on 3R model will improve and the error decrease gradually. That the precision of the distance measurement is about 1m means the 3R model is better than the angle positioning, which can compensate the drawbacks of the angle positioning at short distance.