A system for obtaining air data, the system comprising: a fixed-wavelength laser device on a vehicle, the laser device configured to emit laser light pulses; a set of transmit optics configured to transmit the laser light pulses from the laser device into an external air volume adjacent to the vehicle; a set of receive optics configured to collect scattered portions of the laser light pulses from the external air volume; a whispering gallery mode, WGM, frequency discriminator configured to receive the scattered portions of the laser light pulses from the receive optics, the WGM frequency discriminator including a swept WGM resonator configured to output a selected portion of the laser light pulses at different optical signal frequencies via tuning the WGM resonator other than by an electro-optic effect, wherein the WGM resonator is controllable to have a variable resonant frequency; an optical detector configured to sample the selected portion of the laser light pulses from the WGM frequency discriminator, the optical detector configured to convert the sampled laser light pulses to one or more scalar values; and a processing unit operative to receive and record the one or more scalar values from the optical detector, the processing unit operative to execute instructions to perform a method comprising: (a) setting the WGM resonator to a single resonance frequency; (b) pulsing the laser device; (c) detecting range-resolved backscatter data, using the single resonance frequency; (d) storing the backscatter data; (e) repeating steps (a) to (d) for one or more different resonance frequencies; and (f) processing the stored backscatter data to obtain air data. a fixed-wavelength laser device on a vehicle, the laser device configured to emit laser light pulses; a set of transmit optics configured to transmit the laser light pulses from the laser device into an external air volume adjacent to the vehicle; a set of receive optics configured to collect scattered portions of the laser light pulses from the external air volume; a whispering gallery mode, WGM, frequency discriminator configured to receive the scattered portions of the laser light pulses from the receive optics, the WGM frequency discriminator including a swept WGM resonator configured to output a selected portion of the laser light pulses at different optical signal frequencies via tuning the WGM resonator other than by an electro-optic effect, wherein the WGM resonator is controllable to have a variable resonant frequency; an optical detector configured to sample the selected portion of the laser light pulses from the WGM frequency discriminator, the optical detector configured to convert the sampled laser light pulses to one or more scalar values; and a processing unit operative to receive and record the one or more scalar values from the optical detector, the processing unit operative to execute instructions to perform a method comprising: (a) setting the WGM resonator to a single resonance frequency; (b) pulsing the laser device; (c) detecting range-resolved backscatter data, using the single resonance frequency; (d) storing the backscatter data; (e) repeating steps (a) to (d) for one or more different resonance frequencies; and (f) processing the stored backscatter data to obtain air data. (a) setting the WGM resonator to a single resonance frequency; (b) pulsing the laser device; (c) detecting range-resolved backscatter data, using the single resonance frequency; (d) storing the backscatter data; (e) repeating steps (a) to (d) for one or more different resonance frequencies; and (f) processing the stored backscatter data to obtain air data.