Accuracy-Power Trade-Offs in GNSS-Based Positioning for Frugal Floating Devices

This paper quantifies the accuracy versus power trade-off in ultra low-power GNSS tags for marine tracking. Field tests (more than 22000 fixes) on land and in a coastal lagoon reveal that receiver metadata (fix quality and 2D/3D status) outperform EHPE as predictors of true error. Building on these insights, we propose an embedded fix selection algorithm that stops acquisition once spatial stability and quality thresholds are met. For field deployment conditions, the method cuts energy use by about 40 percent while keeping median error within 5 m of the best available fix, extending tag autonomy from 9 to 15 days without hardware changes.