Timing performance of various GPS receivers

11 inexpensive, commercially available GPS-recivers have been bought and the timing performance of them has been studied since autumn 1998. The one PPS (pulse per second) output of each receiver has been compared to Cs-clock of National T&F Laboratory (VTT Automation) every 10 minutes over several months. As a rule, GPS receivers were in 3D-mode. After short settling time 10 receivers out of 11 the PPSs of the receivers were within +- 200 ns of the national time. Short term noise of PPSs varied from 30 ns to 150 ns (SD). The results show that timing performances of the receivers were as a rule in specifications.