A device for measuring soil moisture by GNSS direct reflection signal carrier interferometry

Abstract

The invention discloses a device for measuring soil moisture by GNSS direct reflection signal carrier interference. In this device, the dual-frequency right-handed circularly polarized antenna receives direct signals from N satellites in the navigation system; the navigation system includes GPS satellite navigation system and Beidou satellite navigation system; the dual-frequency left-handed circularly polarized antenna receives The reflected signal of the navigation system; the dual-mode navigation module generates positioning information; the four-channel RF front-end converts the direct signal and the reflected signal to obtain four digital intermediate frequency signals; the multi-channel direct / reverse collaborative processing module converts the four digital intermediate frequency signals according to the positioning information Perform interference processing to obtain the reflectivity amplitude and reflectivity phase; the soil moisture inversion module is used to perform inversion according to the reflectivity amplitude, reflectivity phase and location information to obtain the moisture of the soil to be measured. The invention is applied to a plurality of satellite signals with different elevation angles to obtain soil moisture, has high measurement accuracy and wide application range.

Description

technical field [0001] The invention relates to the field of soil moisture measurement, in particular to a device for measuring soil moisture by GNSS direct reflection signal carrier interferometry. Background technique [0002] The inversion of the physical parameters of the earth's surface using the reflected signals of the Global Navigation Satellite System (GNSS) is one of the new technologies in the field of remote sensing, which has the advantages of wide signal sources, low cost, and light detection equipment. This technology can detect surface physical parameters by receiving and processing GNSS reflection signals through spaceborne, airborne or shore-based special devices. [0003] As an important hydrological parameter, soil moisture has been one of the long-term concerns in the field of inland remote sensing. GNSS reflection signal technology obtains the reflectivity of the reflection surface by continuously receiving and processing the GNSS direct signal and the...

AI Technical Summary

Problems solved by technology

Another method is single-antenna interferometry, which uses the oscillation formed by the interference of the reflected signal to the direct signal to measure the amplitude and phase of the soil moisture reflectance, and inverts to obtain the soil moisture. The biggest disadvantage is that the time resolution is low, and only Capable of applying satellite signals at low elevation angles

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