I finally got back to working on the HP58534A GPS Timing Antenna. Because it uses RS-422 instead of RS-232 I had put it off after initially scoping it.
I got an RS422/RS232 to Ethernet converter on ebay to connect it and finally got it working. The output is NMEA with additional Private $PFEC sentences (Furuno Electric Company). I also finally found the manual for it at: http://www.symmetricom.com/media/files/support/productmanual/097-58534-01-iss-1.pdf It seems to work fine once you configure it properly (see Below). I use visualGpsEX to watch its behavior in Survey Mode. Initially visualGpsEX showed all the satellites but did not see any of them as active. This was because by default the 58534 was not sending the $GPGSA message which indicates which Satellites the GPS is locked to for fixes. By sending the sentence: $PFEC,GPint,GSA01<CR><LF> the unit started sending the GSA sentences every second along with the other sentences. The unit does have a Fixed Position Mode in addition to the default Survey Mode which can be enabled. For it to work in Fixed Position you need to send the Lat/Long and Alt of the Fixed Position with the $GPGGA sentence for Lon/Lat and the $PFEC,GPset,H000254.0 for the Altitude. The you can enable the Fixed Observation point with the $PFEC,GPset,Z2 sentence. You may want to enable the Time RAIM Option also with the $PFEC,GPrss,1,100,1 sentence for more reliable results. You also want to enable the $PFEC,GPrmm sentence since it reports the error in the next 1PPS Pulse in nanoseconds between -85ns to +85ns which can be used to correct the normal saw tooth behavior of GPS units. In Fixed Mode you might want to turn off some of the other sentences since it no longer takes fixes and always report the lon/lat/alt that was set. Once the Unit is in Fixed Observation Point Mode, it stops taking fixes and requires at least one good Satellite to keep the 1PPS Accurate. Additional Notes: 1. The unit only outputs NMEA and not TSIP. 2. The unit uses super capacitors to backup its RAM. If the unit is powered down for more than a few hours it loses and default settings and its almanac, which means a restart will take longer and all settings revert to the defaults. You should probably send all your set up commands every time you use it. 3. The unit only supports 9600 BAUD and can not be changed. 4. For various reasons the unit is limited to sending 480 characters per second and if you have too many sentences enable which exceed this limit, the unit will not function properly. 5. The RS422 supports a cable length of up to 500 Ft. The commands suggested to put the unit in Fixed Observation Point mode and set the appropriate Sentence output are as follows: $PFEC,GPint,GGA01,GSA01,GSV03,VTG00,tps01,rrm01<CR><LF> $PFEC,GPset,Z2,H000254.1<CR><LF> $GPGGA,3444.4700,N,7221.2000,E<CR><LF> $PFEC,GPrss,1,100,1<CR><LF> I Hope this is helpful. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
