Polarization remote sensing can be used to obtain polarization data for a given target. It can be acquire not only radiation data, as also measured by conventional remote sensing, but also to quantify the polarization of the target according to its intrinsic characteristics. Polarization remote sensing allows for more accurate quantification of ground objects. The polarization pattern of the whole sky, neutral point concept, separation of ground-gas parameters, and multi-angle observation of atmospheric particles underpin atmospheric polarization remote sensing. Polarization remote sensing measurements of a target surface provide relatively reliable polarization information, which is indispensable in modern optical remote sensing. Bionic polarization-based autonomous navigation, advanced space-based polarization detection, and global change research based on the Earth polarization phenomenon are new application areas of polarization remote sensing.

The scattering phase function and the degree of linear polarization for small crystals oriented randomly in space have been computed using the geometric ray tracing theory and assuming that the crystals are homogeneous and isotropic. Calculations have been carried out for the main crystal geometries. Detection of halos from crystals other than hexagonal water ice is briefly discussed. The crystal size and shape parameters have also been averaged over some simple distributions in order to examine general light scattering properties of sharp-edged particles. A scalar physical optics correction has been developed for the geometric optics phase functions. Results can be applied to light scattering from regoliths and planetary rings, and possibly also to atmospheric halos. Retroreflecting crystals in the regolith would cause an opposition spike, a phenomenon observed for many bright satellites.