GPS Rollover: Potential Data Logger Performance & Timing Issue

Late 2018 PASSCAL learned of a GPS week rollover event that can affect data logger performance and timing. PASSCAL has acquired a GNSS signal generator that can emulate GPS satellite signals. This satellite emulator allows us to test PASSCAL equipment that relies on GPS timing and to determine how equipment will handle the GPS rollover event. To date, we have determined that some models of GPS engines are affected by the rollover. How the rollover errors manifest is dependent on the data logger’s model and firmware version of the GPS engine.

If you have PASSCAL equipment that will be affected by rollover errors during your experiment, we should have contacted you to let you know what is required to avoid these errors. Requirements could include: replacing data loggers, replacing components associated to the data logger, firmware updates to station components or another action. If you currently have a PASSCAL experiment and have not heard from us, feel free to contact us to ensure your equipment is not affected.

If you own your own seismic equipment that utilizes GPS timing, we recommend you contact the manufacturer for information specific to your instrumentation’s handling of the GPS week rollover.