Abstract Global navigation satellite systems (GNSSs) are the only global, free, comprehensive technology providing absolute and accurate positioning, navigation, and timing (PNT) services to users worldwide. These services have become an indispensable part of modern society, playing a critical role in many commercial, industrial, scientific, and safety-critical applications. Numerous applications, including mass marketing, professional, and other applications linked to critical infrastructure, heavily depend on GNSSs, with increased expectations for more reliability, accuracy, and availability. However, in specific scenarios, the number of visible satellites can be low, even when all GNSS constellations are used: this is the case, for example, in urban environments or mountain terrain, where the position accuracy can be poor or position estimation may not even be possible. In such cases, the integration of a GNSS with other positioning technologies, such as 5G, and the low Earth orbit (LEO)-PNT concept could improve results. Over the last years, LEO satellites have been put in orbit for several purposes such as telecommunication and Earth observation. Now, several private and institutional actors are considering the idea of designing and deploying LEO satellites for PNT services, by equipping these satellites with payloads able to transmit signals with a design that is interoperable with those already broadcasted by GNSS satellites. Therefore, the aim of this work is to assess the possible integration of GNSS (and 5G) with LEO-PNT positioning signals. Real-life GNSS and 5G data are used from a previous experiment, conducted in the fall of 2023 in northern Italy. LEO-PNT orbits are generated and provided by the European Space Agency. LEO visibility tables and pseudorange observations are simulated for a given location and date. The measurements are combined and processed in a tightly coupled extended Kalman filter, and results are generated for different configurations: 5G standalone, GNSS standalone, LEO-PNT standalone, LEO-PNT + 5G, and GNSS + LEO-PNT. Among these cases, the integrated GNSS + LEO-PNT solution provides the best results.
Alghisi et al. (Mon,) studied this question.