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RefTek RT130 Timing Errors Affecting PASSCAL and FA Experiments

August 20, 2008

Updated: December 15, 2008. Program refj31fix released

Stations Affected: RT130 connected to a 130-GPS/01 with SiRF ublox Trimble module installed (aka SiRF-type)

Description of Problem: Starting on July 31st 2008 (julian day 213 2008) the SiRF-type started to shift in time by a second.  Since the 31st July 2008 the mysterious time shifts (back and forth) continue. At present SiRF has no explanation for these time shifts.

Identifying SiRF GPS:

  • Visually: The SiRF has no ring around the base of the connector attachment. If you see a white or orange ring the unit is NOT a SiRF.
  • Log Messages: If your RT130 is using a SiRF GPS, the following message will be in your logfiles or the RefTek RT130 raw SOH file on the CF card:


(Garmin-type GPS clocks produce the string “EXTERNAL CLOCK TYPE: NMEA - Garmin”)

Solution: Refj31fix: A python program that will find and correct time tears is released. Please follow the download link below which will direct you to the program, installation and use instructions.

Download refj31fix (New!)

Experiments with SiRF-type GPS Clocks

logpeek Example Illustrating the Problem

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