Jin S., Cardellach E., Xie F. GNSS Remote Sensing. Theory, Methods and Applications

Springer, 2014. — 286 p.The Global Navigation Satellite System (GNSS) has provided an unprecedented high accuracy, flexibility and tremendous contribution to navigation, positioning, timing and scientific questions related to precise positioning on Earth’s surface, since Global Positioning System (GPS) became fully operational in 1994. Since GNSS is characterized as a highly precise, continuous, all-weather and near-realtime microwave (L-band) technique, additional more applications and potentials of GNSS are being explored by scientists and engineers. When the GNSS signal propagates through the Earth’s atmosphere, it is delayed by the atmospheric refractivity. GNSS radio occultation together with ground GNSS have been used to produce accurate, all-weather, global refractive index, pressure, density profiles in the troposphere, temperature with up to the lower stratosphere (35–40 km), and the ionospheric total electron content (TEC) as well as electron density profiles, to improve weather analysis and forecasting, monitor climate change, and monitor ionospheric events. Therefore, GNSS has great potentials in atmospheric sounding, meteorology, climatology and space weather.
In addition, surface multi-path is one of main error sources for GNSS navigation and positioning. It has recently been recognized, however, that the special kind of GPS multi-path delay reflected from the Earth’s surface, could be used to sense the Earth’s surface environments. A recent interesting result on fluctuations in near surface soil moisture has been successfully retrieved from the ground GNSS multipath, fairly matching soil moisture fluctuations in soil measured with conventional sensors. In addition, the space-borne GNSS received delay of the GNSS reflected signal with respect to the rough surface could provide information on the differential paths between direct and reflected signals. Together with information on the receiver antenna position and the medium, the delay measurements associated with the properties of the reflecting surface can be used to produce the surface roughness parameters and to determine surface characteristics. The Bistatic radar using L-band signals transmitted by GNSS can be as an ocean altimeter and scatterometer. A number of experiments and missions using GNSS reflected signals from the ocean and land surface have been tested and applied, such as determining ocean surface height, wind speed and wind direction of ocean surface, soil moisture, snow and ice thickness.
Therefore, the refracted, reflected and scattered GNSS signals can image the Earth’s surface environments as a new, highly precise, continuous, all-weather and near-real-time remote sensing tool, which is expected to revolutionize various atmospheric sounding, ocean remote sensing and land/hydrology mapping, especially for various Earth’s surfaces and the atmosphere. With the development of the next generation of multi-frequency and multi-system GNSS constellations, including the US’s modernized GPS-IIF and planned GPS-III, Russia’s restored GLONASS, and the coming European Union’s GALILEO system and China’s Beidou/COMPASS system as well as a number of Space Based Augmentation Systems, such as Japan’s Quasi-Zenith Satellite System (QZSS) and India’s Regional Navigation Satellite Systems (IRNSS), more applications and opportunities will be exploited and realized using new onboard GNSS receivers on future space-borne GNSS reflectometry and refractometry missions in the near future.GNSS Theory and Delays.
Introduction to GNSS.
GNSS Atmospheric and Multipath Delays.
GNSS Atmospheric Sensing and Applications.
Ground GNSS Atmospheric Sensing.
Ground GNSS Ionosphere Sounding.
Theory of GNSS Radio Occultation.
Atmospheric Sensing Using GNSS RO.
Ionospheric Sounding Using GNSS-RO.
GNSS Reflectometry and Remote Sensing.
Theory of GNSS Reflectometry.
Ocean Remote Sensing Using GNSS-R.
Hydrology and Vegetation Remote Sensing.
Cryospheric Sensing Using GNSS-R.
Summary and Future Chances.