Analysis of the visibility of GPS satellites in the urban environment using point cloud representation

Global Navigation Satellite System is a spatial data acquisition technique, mostly used in navigation and positioning. One of the main components of this technique is the satellite visibility, which refers to the connection between the satellite and the ground receiver. It is known that the GNSS positioning systems are not as performing in urban...

Potential of cost-efficient single frequency GNSS receivers for water vapor monitoring

Dual-frequency Global Navigation Satellite Systems (GNSSs) enable the estimation of Zenith Tropospheric Delay (ZTD) which can be converted to PrecipitableWater Vapor (PWV). The density of existing GNSS monitoring networks is insufficient to capture small-scale water vapor variations that are especially important for extreme weather...

Real-time multi-GNSS single-frequency precise point positioning

Precise Point Positioning (PPP) is a popular Global Positioning System (GPS) processing strategy, thanks to its high precision without requiring additional GPS infrastructure. Single-Frequency PPP (SF-PPP) takes this one step further by no longer relying on expensive dual-frequency GPS receivers, while maintaining a relatively high...

On User Algorithms for GNSS Precise Point Positioning

Precise Point Positioning (PPP) is a Global Navigation Satellite System (GNSS) processing method with the objective of providing high positioning accuracy without the need for a nearby base station or dense network of reference stations operated by the user. To reach this objective, PPP uses the very precise carrier phase measurements in...

Automatic registration of iPhone images to laser point clouds of urban structures using shape features

Fusion of 3D airborne laser (LIDAR) data and terrestrial optical imagery can be applied in 3D urban modeling and model up-dating. The most challenging aspect of the fusion procedure is registering the terrestrial optical images on the LIDAR point clouds. In this article, we propose an approach for registering these two different data from...