Heterodyne detection through rain, snow, and turbid media: effective receiver size at optical through millimeter wavelengths
Abstract
An effective heterodyne receiver size for both a purely scattering channel and a real-world turbulent scatter channel is determined. Forward scattering reduces the effective heterodyne receiver area through spatial coherence degradation, and treatment of scattering as an attenuation phenomenon is demonstrated to be invalid in some cases, yielding an underestimation of the SNR. Dealing with scattering as attenuation is valid when the SNR is greater than 100, i.e., when the scattering angle is large. The SNR improves when the ratio of scattering particulate size to turbulence coherence diameter decreases. Arrays of small receivers are concluded to be more effective than large receivers for optically sampling the same area. The results are significant for optical sensing through fog, clouds, precipitation, and turbid media in general.
- Publication:
-
Applied Optics
- Pub Date:
- March 1983
- DOI:
- 10.1364/AO.22.000706
- Bibcode:
- 1983ApOpt..22..706K
- Keywords:
-
- Atmospheric Scattering;
- Microwave Scattering;
- Millimeter Waves;
- Optical Heterodyning;
- Rain;
- Snow;
- Atmospheric Optics;
- Forward Scattering;
- Microwave Attenuation;
- Radio Receivers;
- Signal Detection;
- Signal To Noise Ratios;
- Turbidity;
- Communications and Radar