In recent years, his research was mainly concentrated on solving PNT problems related to urban and low latitude region, such seamless navigation and low latitude ionospheric effects on GNSS. In urban PNT studies, he tries to solve some of key problems in urban environment, such as satellite signal shadowing, multipath. He has also been working on GNSS reflectometry for various applications, including deformation monitoring and pass radar applications.
GNSS technologies have been widely applied for various Positioning, Navigation, and Timing (PNT) applications. To achieve better PNT accuracy, various algorithms/models have been developed on to mitigate diversified errors in GNSS ranging measurements, such as ionospheric and tropospheric refractions, multipath, and site related motions. On the other hands, these corrections provide vital information of the media, which can be extracted from GNSS measurements, known as GNSS remote sensing. In this presentation, the general principles of GNSS remote sensing technologies will be reviewed. Particularly, how to use the GNSS reflected signals for deformation monitoring and passive radar will be analyzed in details. Furthermore, GNSS-R technologies can be extended to a wider class of applications using signal of opportunities with diversified radio signal sources