Simulations using LEO-PNT systems: A Brief Survey.

As the whole space segment of satellites in low Earth orbits (LEO) grows, simulations of positioning, navigation, and timing (PNT) through LEO satellites are needed to understand the possible gains that the upcoming satellite missions can offer to global navigation satellite systems (GNSS). The simulations do not only help to forecast the optimal GNSS future advancements, but also guide us on how to implement the most optimized PNT missions. In the most recent years, several simulation tools have focused on broadcast orbit models, precise orbit determination of LEO satellites, signal structure designs, atmospheric models, constellation optimization strategies, satellite clock implementations, and positioning integration with distinct sensors. In this work, we overview most of the latest developments found in the literature to define the status and challenges of LEO-PNT system simulations.