(Beijing Engineering Research Center of Precision Measurement Technology and Instruments, Beijing University of Technology, Beijing 100124, China)


Abstract: Aiming at the problem of wavelength change caused by the change of refractive index of air in laser tracer measurement system, the air refractive index method suitable for laser tracer measurement system was studied. An air refractive index compensation system based on empirical formula was proposed. The hardware circuit of the compensation system was used to collect environmental parameters, and the data was transmitted through the UART protocol. Air refractive index compensation software for laser tracking measurement system was developed to measure and compensate the refractive index of air. The Michelson interferometer was used to measure the refractive index of the air and the measurement results of the system were compared. The uncertainty analysis of the system was carried out. The results show that the air refractive index compensation system can realize the realtime measurement, display and compensation of the air refractive index. It overcomes the shortcomings of complex structure and complicated to operate by using the air refractometer directly, and the twocolor interference method need to rebuild the optical path, and is more suitable to solve the problem of air refractive index compensation for the laser tracer measurement system.
Key words: compensation of air refractive index; laser tracer measurement system（LTMS）; hardware design