Accurate time measurement is essential to temporal analysis in sport. This study aimed to (a) develop a new method for time computation from surveyed trajectories using a high-end global navigation satellite system (GNSS), (b) validate its precision by comparing GNSS with photocells, and (c) examine whether gate-to-gate times can provide more detailed information about alpine skiing performance. The results demonstrated small mean time differences with no systematic bias, with a velocity dependent scatter of time differences, which diminished at higher velocities. Furthermore, the multiple gate-to-gate and lag times demonstrated that the GNSS enabled a more detailed analysis compared to photocells. The measurements using GNSS showed high validity and potential as a tool for more specific analysis of performance in skiing.