Hi List Like many of you I also use a Navman Jupiter TU30 in a GPSDO. Besides the 10 kHz used for the PLL I also have a display showing time. But since a couple of years, Jan 15?, the time sometimes jumps -1 s and and then later returns by jumping +1 s Please see an example of the latter below: PC-time Diff. GPS-time Diff ... 011606.005 0.992 011604 1 011607.013 1.008 011605 1 011608.005 0.992 011607 2 <--- The issue 011609.013 1.008 011608 1 011610.004 0.991 011609 1 ... I don't experience the same with a ublox GPS. I don't think I saw this more than two years ago and wonder if the GPS satellites send some correction data that the rather old TU30 misinterpret? Any clues? Thanks in advance Bo

 Björn

Hi Bo, Are you getting data in binary format [1] or NMEA? The NMEA mode for some Jupiter receivers are known to behave badly in NMEA-mode. The delay would go from 1:ish to 2:ish seconds depending on signal processing load. -- Björn [1] Navman/Jupiter/Conexant/Zodiac/Rockwell binary... http://aprs.gids.nl/gpskit/documents/rockwell/iospec_w708.pdf > Hi List > > Like many of you I also use a Navman Jupiter TU30 in a GPSDO. Besides the > 10 kHz used for the PLL I also have a display showing time. But since a > couple of years, Jan 15?, the time sometimes jumps -1 s and and then later > returns by jumping +1 s Please see an example of the latter below: > > PC-time Diff. GPS-time Diff > ... > 011606.005 0.992 011604 1 > 011607.013 1.008 011605 1 > 011608.005 0.992 011607 2 <--- The issue > 011609.013 1.008 011608 1 > 011610.004 0.991 011609 1 > ... > > I don't experience the same with a ublox GPS. I don't think I saw this > more than two years ago and wonder if the GPS satellites send some > correction data that the rather old TU30 misinterpret? > > Any clues? > > Thanks in advance > Bo > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Hi Welcome to the ever growing list of people with buggy GPS modules. One thing that makes this stuff tough to track down is the firmware. A lot of these parts went out with various revs of the standard firmware. Some of them went out with specific customized versions of the firmware. Since most of the trouble looks like code errors, mine (with version 6.5.4.3.2.1a2) may be fine and yours (with version 6.5.4.3.2.1a2a) may be horrid. While it is tempting to find “new” firmware and blast away, that may not be the best approach. Some of these modules went through minor hardware changes over the years. The stuff with custom firmware often pukes in odd ways when standard firmware is loaded. Getting back to the “original” firmware in your part after re-flashing is rarely possible …. Bob > On Apr 4, 2017, at 5:27 AM, Bo Hansen <timenuts@rudius.net> wrote: > > Hi List > > Like many of you I also use a Navman Jupiter TU30 in a GPSDO. Besides the 10 kHz used for the PLL I also have a display showing time. But since a couple of years, Jan 15?, the time sometimes jumps -1 s and and then later returns by jumping +1 s Please see an example of the latter below: > > PC-time Diff. GPS-time Diff > ... > 011606.005 0.992 011604 1 > 011607.013 1.008 011605 1 > 011608.005 0.992 011607 2 <--- The issue > 011609.013 1.008 011608 1 > 011610.004 0.991 011609 1 > ... > > I don't experience the same with a ublox GPS. I don't think I saw this more than two years ago and wonder if the GPS satellites send some correction data that the rather old TU30 misinterpret? > > Any clues? > > Thanks in advance > Bo > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.