GNSS RO utilizes the various navigation satellite systems as signal sources for atmospheric remote sensing. The frequency stability of the signals emitted by GNSS satellites is tied to the stability of the atomic frequency standards (AFS) they carry onboard and is thus critical to the quality of the atmospheric profiles derived from the occultation measurements. Because of the variety of AFS us...

Unmanned Aerial Vehicle (UAV) technology is now commonplace in many defence and civilian environments. However, the high cost of owning and operating a sophisticated UAV has slowed their adoption in many commercial markets. Universities and research groups are actively experimenting with UAVs to further develop the technology, particularly for automated flying operations. The two main UAV platf...

Nowadays, GNSS-Reflectometry (GNSS-R) can be a new promising remote sensing tool in the ocean, snow/ice and land surfaces, e.g., vegetation biomass monitoring. Although GNSS-R provides a potentially special L-band multi-angular and multi-polarization measurement, the theoretical vegetation scattering properties and mechanisms for GNSS-R are not understood clearly. In this paper, the GNSS-R vege...

Global Navigation Satellite System (GNSS) signals, such as those from United States Global Positioning System (GPS), Europe’s Galileo, and Russia’s Global Navigation Satellite System (GLONASS), typically have extremely low received signal strengths at the Earth’s surface and are therefore susceptible to a range of interference signals. Such interference examples include, but not limited to, int...

The number of satellites visible to a Global Navigation Satellite System (GNSS) receiver is important for high accuracy surveys. To aid with this, there are software packages capable of predicting GNSS visibility at any location of the globe at any time of day. These prediction packages operate by using regularly updated almanacs containing positional data for all navigation satellites; however...

The Global Navigation Satellite Systems (GNSS) transmit L-band signals (see the Reference [1]). The GNSS receivers, as its main objective, measure the time elapsed from the transmission to the reception of L Band signals to infer the distance transmitter-receiver and to derive the three coordinates and time status of the receiver. The same signals could be recorded after its reflection on the E...