Six-freedom Displacement Measurement Based on Forward and Backward Laser Beam Paths

A displacement survey method that can be used in fields such as tunnel engineering, huge dam engineering and so on is introduced. According to this method, a series of measuring stations are set along a fold line, and a number of bi-direction laser beams and 2-D displacement sensors are used to realize the line and angle displacement measurements to obtain the distortion information of each point. The calculation formulas are given, and the errors are analyzed. This method can also be used in other distortion-measurement fields such as building, bridge and mountain distortion measurements.