Fig. 1. Transceiver split laser five-degree of freedom measurement structure

Fig. 2. Optical path of straightness measurement unit

Fig. 3. Installation diagram of beam angle drift measurement optical path

Fig. 4. Optical path of telescopic objective

Fig. 5. Schematic diagram of beam angle drift measurement

Fig. 6. Schematic diagram of angular crosstalk error

Fig. 7. QD measurement model based on Gaussian beam

Fig. 8. Relationship of the spot position and its relative position on QD （x-direction）

Fig. 9. Straightness calibration system at fixed distance

Fig. 10. Schematic diagram of calibration interval division under long distance

Fig. 11. Schematic diagram of QD measurement zero offset under long distance

Fig. 12. Schematic diagram of QD measurement zero offset correction

Fig. 13. Measurement device of five-degree of freedom

Fig. 14. Calibration experiment at fixed distance

Fig. 15. Calibration results at fixed distances

Fig. 16. Calibration effect test results

Fig. 17. QD measurement zero deviation correction experiment

Fig. 18. Simulation experiment of angular crosstalk error

Fig. 19. Test results of angle crosstalk error compensation

Fig. 20. Straightness measurement stability test results