Retrieval of Soil Moisture using NavIC Multipath Signal

Abstract

Navigation with Indian Constellation (NavIC) is a new entry in Global Navigation Satellite System (GNSS) systems available worldwide such as GPS, GLONASS, Galileo and BeiDou. Study of GNSS for various non-navigational applications is gaining importance day by day. One of the important non-navigational applications is the study of soil moisture with GNSS. NavIC is very much different from widely used and globally available GPS system. The analysis and development of the algorithms for soil moisture retrieval with NavIC Carrier to Noise (C/No) ratio for bare soil and vegetated land is an important aspect. Information of soil moisture is very beneficial for various applications such as groundwater estimation, management of agricultural, drought monitoring and prediction, weather forecasting and flood forecasting. The configuration of receiver set up was installed in the bare soil land and agriculture land for soil moisture study. An interference pattern is created at the receiver due to direct and ground reflected signal. Ground reflected signal is affected by the characteristic of soil, i.e., soil moisture, surface roughness and vegetation cover. The effect of dielectric on reflection of microwave signal is well known and well-studied. Soil dielectric constant is very much dependent on the moisture content in soil and varies from 3 to 50 as moisture changes. The dielectric constant of soil is approximately 3 whereas the dielectric constant of water is 80 therefore the soil water mixture changes it dielectric constant based on water content in soil. The change of moisture content in soil give rise to the change in dielectric constant which finally affect the reflected NavIC signal and this change is analyzed in multipath amplitude of received signal. newlineIn first phase, a methodology for in-situ soil moisture has been developed. The conventional method involves convection oven which takes 24 hours to determine ground truth soil moisture. Therefore, a microwave oven-based methodology has been developed which provides in