Support infrastructures based on high altitude platforms for navigation satellite systems

In this article the use of an augmentation system based on high altitude platforms (HAPs) for supporting global navigation satellite systems is discussed. In fact, HAP-based systems are being studied and designed for several communication applications, but they can also be considered added value infrastructure if integrated with navigation systems, providing aiding services based on terrestrial stations or geostationary satellites. The article investigates the results of a feasibility study for the design of a stratospheric pseudo-satellite to provide additional ranging signal to improve the accuracy and availability of the overall navigation system, and an effective integrity service, strengthening the reliability of the positioning procedures. The work here presented discusses issues that have arisen in the design, and provides simulation performance of the proposed architecture.