The use of navigation satellites signals for determination the characteristics of the soil and forest canopy

In this paper presents the measurements of the interference pattern of GNSS signals recorded on Right Hand Circular Polarization (RHCP) above the ploughed field, soil covered grass and under forest canopy. In addition, the theoretical models which links the interferometric pattern, recorded Global Navigation Satellite System (GNSS) reciever on RHCP, with the soil moisture and the attenuation of electromagnetic wave in forest canopy is presented. It is shown, that the interference pattern is recorded by GNSS receiver on the RHCP, weakly dependent on the moisture and surface roughness of the soil. At the same time retrieved value of soil moisture has an error of the order of the measured value. The weak dependence of the interference pattern, recorded by the GNSS receiver on the RHCP, from the properties of the underlying surface, for the first time have been used to measure the attenuation coefficient of the forest canopy.