Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2022, Vol. 19, No. 4, pp. 328-334
Three-dimensional reflecting objects in the problem of modeling a lidar signal from a scattering layer
G.P. Arumov
1 , A.V. Bukharin
1 , V.S. Makarov
1 1 Space Research Institute RAS, Moscow, Russia
Accepted: 15.08.2022
DOI: 10.21046/2070-7401-2022-19-4-328-334
Three-dimensional reflecting objects are considered for modeling the backscatter and extinction coefficients. Sphere, truncated cone and spherical segment can be selected as such objects. For these figures, the relationship between the base coefficients can be modeled through the ratio of the radius of curvature of the front surface of the specified figure to the radius of the scattering section. The ideal probing scheme in which the optical axes of the receiving and transmitting channels are parallel or coincide, and the angular dimensions of the fields of view are equal to the angular dimensions of the probing beam is optimal in the problem of backscattering signal calibration. For ideal schemes, one can use perforated screens that increase the field of view and the angular size of the beam by a given value. Such screens make it possible to determine the field of view, the angular size of the beam, and also to simulate the dependence of the geometric form-factor of the receiving and transmitting channels on the distance. However, this does not allow measurement of the backscatter coefficient. It is proposed to use reflective spheres to calibrate the backscatter signal. This is due to the known angular pattern of radiation reflected by the sphere. The intensity of this radiation is comparable to the intensity of the backscatter signal from the atmosphere, in contrast to the signals reflected by scattering screens. An expression is obtained for the coupling coefficient between the return signal from the scattering layer and the backscattering coefficient.
Keywords: backscattering coefficient, extinction coefficient, truncated cone, spherical segment, equivalent cross section, conducting sphere, perforated screen, scattering layer, geometric form-factor, lidar
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