Fig. 1. Schematic diagram of LFM pulse sequence detection principle. (a) Schematic of LFM pulse sequence; (b) schematic of the original data reconstruction

Fig. 2. Schematic diagram of data processing algorithm flow

Fig. 3. Schematic of system structure

Fig. 4. Cross-correlation results under strain. (a) Frequency spectra of pulse sequence; (b) cross-correlation result of pulse sequence; (c) local RBS signal of chirped pulse; (d) cross-correlation result of LFM pulse

Fig. 5. Dynamic strain measurement coefficient calibration results. (a) Frequency sweep pulse sequence strain coefficient; (b) LFM pulse strain coefficient

Fig. 6. Reorganization matrix and demodulation results when large and small strains are applied. (a)(d) Frequency spectrum time distribution of frequency scanning sequence; (b)(e) LFM pulse RBS signal time and space distribution; (c)(f) strain demodulation results

Fig. 7. Measurement and demodulation results of amplitude modulated signals. (a) Frequency spectrum time distribution of frequency scanning sequence; (b) chirped pulse RBS signal time and space distribution; (c) strain demodulation results; (d) amplitude spectral density at the disturbance position

Fig. 8. Demodulation results of sinusoidal strain based on the cyclic calibration method. (a) Frequency spectrum time distribution of frequency scanning pulse sequence; (b) demodulation result

Fig. 9. Large amplitude triangle wave strain measurement result