Trouble getting a fix with LE910

5 thoughts on “Trouble getting a fix with LE910

  1. Hi,

    I am trying to get a simple, one-shot GPS-only fix with my xE910 modules. So far, I’ve been successful with GE910-GNSS, with only AT$GPSP=1 and AT$GPSNMUN=2,1,0,0,0,0,0. This works very nicely: I get the desired URCs at 1Hz and I just have to wait until I feel the DOP is small enough. Then turn off the GPS module, and I’m fine.

    I then tried the same code on an LE910-EUG module, but things did not go as smoothly. The commands are accepted, but $GPSNMUN doesn’t initiate the URC stream I expect. I have tried $GPSNMUNEX with various settings, with no success. Obviously, AT$GPSACP doesn’t return a fix – so it seems the module is not trying to acquire a position.

    I have found an application note for the HE910 module, but the commands seem to differ slightly and this didn’t work either.

    Did I miss something? I’m pretty sure there is a small gotcha somewhere.

    Many thanks in advance,

    Thibault

    1. Please post firmware version, check if AT$GPSP is indeed 1, and try the online mode with AT$GPSNMUN=3,….

      1. AT$GPSNUM mode 1 and 2 output the unsolicited messages in the dedicated NMEA port, mode 3 outputs in the normal AT command serial port.

        1. Please post firmware version, check if AT$GPSP is indeed 1, and try the online mode with AT$GPSNMUN=3,….

          Thanks for the quick reply.

          FW version (AT+CGMR): 17.01.522

          AT$GPSP is 1 and I have tried AT$GPSNMUN=3,…. This actually worked (whereas it quite didn’t on GE910-GNSS, though I have not investigated that in depth) and I now get the URC stream I was expecting.

          AT$GPSNUM mode 1 and 2 output the unsolicited messages in the dedicated NMEA port, mode 3 outputs in the normal AT command serial port.

          That was the trap! This is actually not documented as the AT command guide (r14), p. 419, states:

          Set command permits to activate an Unsolicited streaming of GPS data (in NMEA
          format) through the standard GSM serial port and defines which NMEA sentences
          will be available Parameters:

          For $GPSNMUNEX p. 422 the story is different:

          Set command permits to activate an Unsolicited streaming of GNSS(or
          GLONASS) data (in NMEA extended format) through the NMEA port and
          defines which NMEA extended sentences will be available

          I have certainly overlooked the “NMEA port” part of $gpsnmunex, but to my credit this term is never defined – neither in the AT command guide, nor the hardware user guide (r6). I’m pretty much left to guessing this is some sort of logical channel; and that maybe it can be rerouted to some actual interface (UART, USB, …).

          I would be glad if you could point me to some resources/documentation to understand what are NMEA ports and how we use them. It would also be nice if you could forward this issue to the people in charge of the documentation.

          Thanks

          1. If you are only using RS232 that is what we have now, the NMEA USB/COM dedicated port is created by the drivers in Win, Linux and can be used. I signaled this inconsistency and the doc inaccuracies to the people in charge and we should have an opinion soon.