Mixing Real and Simulated Observables to Assess the Performance of Hybrid GNSS/LEO-PNT Precise Positioning

In this work, a methodology and tool supporting both fully simulated and hybrid scenarios is presented. In the hybrid-scenario configuration, the combination of real GNSS observables collected during test campaigns in the field and simulated LEOPNT observables are processed. This allows to perform tests representative of real-life scenarios to compare current GNSS-only performance and future GNSS/LEO-PNT expected performance. Initial results with this methodology show how different error components for a large LEO constellation (for 304 satellites) on the model affect the convergence time on the user receiver. They show that the geometry of the simulated urban environments (as an azimuth-elevation mapping on the observations) can affect the design of the LEO-PNT constellation (trying full constellations of 304 and 312 satellites). Finally, the results with the hybrid-simulation mixing both actual GNSS observations and simulated LEOPNT observations are shown demonstrating the capability of the methodology. Currently, improvements on the error models are underway expecting to have more realistic simulations for the LEO-PNT components in the future; more receivers, urban scenarios and constellation types are being added, along with new figures of merit to capture better the user needs.