Fig. 1. Frequency-modulated continuous wave interference ranging system

Fig. 2. Angular frequency relationship of frequency-modulated continuous wave interference signal under saw-tooth wave modulation

Fig. 3. Ideal signals under linear current modulation. (a) Linearly modulated current waveform; (b) angular frequency of ideal optical signal; (c) ideal interference beat signal

Fig. 4. Signals obtained by current node correction method. (a) Actual measured beat signal; (b) ideal beat signal; (c) current waveform before and after nonlinear correction

Fig. 5. Frequency-modulated continuous wave interference ranging system

Fig. 6. Linear saw-tooth current modulation waveform and beat signal. (a) Modulation waveform; (b) beat signal

Fig. 7. Nonlinearly corrected current modulation waveform and beat signal. (a) Modulation waveform; (b) beat signal

Fig. 8. Position distribution of minimum points of beat signals before and after correction

Fig. 9. Spectrograms of beat signals before and after correction. (a) Before correction; (b) after correction

Fig. 10. Measurement results of fixed target

Fig. 11. Linearity and repeatability measurement of ranging system