Fig. 1. Atmospheric temperature detection principle based on two-stage FPI and multi-mode laser. (a) Separation of Mie signals by FPI-1; (b) Temperature measurement using FPI-2 transmission and reflection signals

Fig. 2. Optical path of temperature lidar receiving system based on two-stage FPI and multi-mode laser

Fig. 3. Mie-signal transmittance and Rayleigh-signal transmittance at different atmospheric temperatures of three receiving channels of two-stage FPI in the relative frequency range of (a) −6-+6 GHz; (b) −100-+100 MHz

Fig. 4. Temperature measurement deviation due to matching error and locking error for different backscatter ratios

Fig. 5. FPI-1 transmittance curve obtained by cavity length scanning with different matching errors

Fig. 6. Curve of FPI-1 transmittance peak changing with matching error

Fig. 7. Profile of simulated atmospheric parameters with altitude. (a) Backscatter coefficients of atmospheric molecules and aerosols; (b) Backscatter ratio

Fig. 8. Simulation profile of temperature measurement deviation varying with altitude due to matching and locking errors

Fig. 9. Simulation profile of parameter measurement error due to signal noise varying with altitude. (a) Temperature; (b) Backscatter ratio