Fig. 1. Principle of dual frequency laser ranging

Fig. 2. Dual-frequency laser scanned-frequency ranging device

Fig. 3. Dual-frequency laser source

Fig. 4. Physical drawing of electro-optical modulator

Fig. 5. Diagram of signal source time base traceability

Fig. 6. GPS/BD clock

Fig. 7. Time base frequency

Fig. 8. (a) 20 MHz beat frequency test results; (b) 120 MHz beat frequency test results

Fig. 9. Ring ranging optical path

Fig. 10. Ranging device

Fig. 11. Signal demodulation

Fig. 12. Demodulated signal

Fig. 13. Demodulated signal fitting curve

Fig. 14. (a) Gaussian distribution of experimental results before correction; (b) Gaussian distribution of experimental results after correction