Influence of atmospheric aerosol single backscattering on waveform of target-reflected signal in incoherent frequency-modulation continuous-wave short-distance laser detection

Abstract

The atmospheric aerosol scattering is considered as a major distortion mechanism in laser detection. Its influence on the targetreflected signal in incoherent frequency-modulation continuous-wave (FMCW) short-distance laser detection, which has not yet been well addressed, has been theoretically and experimentally studied in this paper. Assuming intensity of one-particle backscattering as an interference signal, the expression of this interference signal is calculated based on the model of one-particle backscattering and the Mie theory. Only single scattering is considered when optical thickness of the particle group is low. Broadenings of the hybrid signal formed with the particle group backscattering signal and the target-reflected signal are emulated, combining the model of particle group backscattering with the particle distribution function. The broadening time caused by the particle group is far less than the minimum response time of the photodiode. Experimental results confirm that the output voltage of the hybrid signal is identical to the output voltage of the target-reflected signal, except for attenuation in amplitude. Therefore, the incoherent FMCW short-distance laser detection shows a good capability of antiaerosol interference, which is very important for signal processing and target identification. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).