Development Of Environment Parameter Compensation System For High-Precision Laser Measurement For Field Baseline

As an important length standard of outdoor surveying and mapping instruments,the field baseline has an important significance in large-scale engineering construction,precision engineering safety detection and other aspects.Therefore,the research on the field baseline measurement method and the improvement of the measurement accuracy of baseline value are the hot topics of the relevant research institutions at home and abroad.However,the outdoor environment is not controllable,and the environmental factors span a large amount of change,which will affect the measurement accuracy of the baseline.Generally,high-precision rangefinders,white light interferometry and baseline measurement methods are affected by environmental conditions.In order to improve the accuracy of baseline measurement,a set of high real-time environmental parameter compensation system is built on the basis of the standard baseline field of Changping experimental base of China Academy of metrology.The specific research contents are as follows:1.A parallel design scheme is proposed to solve the problem of real-time acquisition of environmental parameter compensation system.By analyzing the operation mechanism of the original environmental parameter compensation system,it is found that the data transmission mode is the main reason for the low acquisition rate of the system.Therefore,the system introduces a number of data transmission equipment,uses the parallel mode to group all sensors,and designs the corresponding software acquisition module for each group,and simultaneously collects the sensor data of each group in parallel,so as to reduce the cycle of 95 sensors’ cyclic acquisition to less than 7 s.2.Further analysis of the error caused by the delay of each environmental parameter when the acquisition period is 7 s,the environmental parameter data along the baseline under two typical weather conditions,sunny and cloudy,are respectively selected in this paper.By means of data statistics,the delay error of each environmental parameter of the improved acquisition platform is quantified,and the refractive index correction error introduced by the delay error value is calculated.3.Aiming at the problem that baseline measurement results can not be effectively evaluated,an algorithm for baseline measurement data evaluation is proposed.The algorithm is used to draw the relative change map of baseline measurement value and the fluctuation map of environmental parameters respectively.Through envelope matching,the effective evaluation of baseline measurement data is realized and the reliability of baseline measurement results is improved.4.In order to apply the research results of field baseline high-precision laser measurement method to other baseline measurements,a portable field baseline high-precision laser measurement system is developed,and the corresponding automatic measurement software is developed.The system uses wireless transmission technology and serial communication technology to obtain the environmental parameters along the optical path and real-time compensate the ranging value,and the feasibility of the portable field baseline high-precision laser measurement system is verified by experiments.