looking for a gps module with $GPZDA (date and time)

• looking for a gps module with $GPZDA (date and time)
  Posted by legacy on 02 Mar, 2019 22:03
• so I have recently bought an MP-954GPS module(1), which comes with a GPS module onboard, but it doesn't output any GPZDA packet. The GPZDA packet mainly shows time and date (year, month, and day).
  
  Does anyone know a GPS module known for providing the ZDA?
  
  Thanks 
  
  
  (1) manuals do not help because they do not not clearly report exactly WHAT is implemented.
• #1 Reply
  Posted by legacy on 02 Mar, 2019 22:19
• this article suggests that it might be possible to enable ZDA sentence 
• #2 Reply
  Posted by georges80 on 02 Mar, 2019 22:32
• I have a ublox 8 module. By default it does not output that sentence. But using the ublox u-center software I just went and enabled it. Checked the serial nmea stream and it DOES now get output.
  
  So, at the very least ublox 8 supports it. I'll see if the ublox 6 I also have can be set to output the sentence. Give me 10 - 20 mins to check.
  
  cheers,
  george.
  
• #3 Reply
  Posted by georges80 on 02 Mar, 2019 22:46
• ok, can enable the zda sentence on the ublox 6 as well.
  
  cheers,
  george.
• #4 Reply
  Posted by legacy on 03 Mar, 2019 12:13
• thanks 
• #5 Reply
  Posted by legacy on 03 Mar, 2019 12:20
• I wonder if also SiRF Star III GPS modules can enable the ZDA sentence 
  Cannot find any documentation about.
• #6 Reply
  Posted by Wiljan on 03 Mar, 2019 14:43
• If it's a SiRF Star III you should be able to send a cmd to tell the module what to send to you
  have a look here https://www.sparkfun.com/datasheets/GPS/NMEA%20Reference%20Manual-Rev2.1-Dec07.pdf
  on page 103 you can see that you can change the Query eg RMC does give you "Time, date, position, course and speed data"
  
  I did made Numitron clock long time ago using https://www.adafruit.com/product/746 GPS module and when you have the data you have  to calculate the current day and when to change summer/ winter time since there are no flag to indicate daylight saving
• #7 Reply
  Posted by gamblingfetus on 03 Mar, 2019 22:42
• Yes, the ADA746 supports GPZDA unofficially if you sweet talk it. I had to basically rewrite their library to use it for an automatically-setting GPS clock project.
• #8 Reply
  Posted by legacy on 04 Mar, 2019 13:22
• now the question is: will my Sirf-III miniPCI GPS work with ZDA, or will have to buy a new GPS (and a new miniPCI multi Uart card, since I need 3 Uart channels for other stuff)?
  
  It seems my GPS is not willing to enable the ZDA sentence 
  
  
• #9 Reply
  Posted by legacy on 04 Mar, 2019 13:35
• Quote from: gamblingfetus on 03 Mar, 2019 22:42

  automatically-setting GPS clock project.
  

  
  like in our sonoko project.
  
  

  Quote

  The rb532 board doesn't have an RTC chip, instead, it has been developed from the ground up a "software" clock that records the last time the board was shut down and restores it during startup. The GPS can be used to sync to date and time, but this works only if the GPS can track four satellites at least (minimal condition): a special software is being to be prepared for managing it.
  
  Anyway, this is useful on boards without a battery-backed RTC because it guarantees that the clock is always set to a value that is more recent than any filesystem timestamp, even during early boot and even if the clock is never set to a correct value.
  

  
  
  so it's a bit weird that a modern GPS doesn't provide the ZDA sentence by default 
• #10 Reply
  Posted by Wiljan on 04 Mar, 2019 18:53
• So to understand it correctly you do have the PCI card in a PC and then it turns up as 3 com port in the control-panel?
  2 of the port are "just" on the 2x 9pin D-sub and have noting to do with the GPS?
  and 1 are connected to the SiRF II module on board and this is the one giving you a 4800 GPS data?
  When you try to send data to the SiRF III module and described in the SiRF pdf I linked to doe you get any respond ? Can you change simple things like the rate where that data are send or other things?
  
  I would expect all SiFR III chipsset to respond likely but I can be wrong
• #11 Reply
  Posted by legacy on 04 Mar, 2019 20:07
• 
  
  System diagram about our Sonoko project; see the router (rb532) needs 4 serial lines, one of them is reserved for the onboard GPS, which is soldered to the miniPCI card.
  
  

  Quote from: Wiljan on 04 Mar, 2019 18:53

  So to understand it correctly you do have the PCI card in a PC and then it turns up as 3 com port in the control-panel?
  

  
  We are using a router, with a miniPCI multi uart cards.
  

  • /dev/ttyS0 is the router-built-in serial (it's the router's console, cannot be used)
  • /dev/ttyS1 is reserved for the miniPCI-built-in GPS
  • /dev/ttyS2 is reserved for talking with node0
  • /dev/ttyS3 is reserved for talking with node1
  • /dev/ttyS3 is reserved for talking with an engine that controls a display, an RFID reader and other stuff (not currently shown in the system diagram, still under development)

  
  

  Quote from: Wiljan on 04 Mar, 2019 18:53

  When you try to send data to the SiRF III module and described in the SiRF pdf I linked to do you get any response?
  

  
  Precisely. No response. Probably the command it's not supported, in fact, the pdf says "you can enable ZDA only if PPS is supported", and in our case ... there is no "PPS" signal.
  
  

  Quote from: Wiljan on 04 Mar, 2019 18:53

  Can you change simple things like the rate where that data are sent or other things?
  

  
  yes, we are using 1200bps instead of 4800bps: this was changed by issuing a command on the serial line, and the GPS accepted it.
  
  

  Quote from: Wiljan on 04 Mar, 2019 18:53

  I would expect all SiFR III chipset to respond likely but I can be wrong
  

  
  changing the baud rate was silent, without any feedback on the serial line: it just started talking at 1200bps.
• #12 Reply
  Posted by Wiljan on 04 Mar, 2019 21:49
• Is this the string you try to send?
  $PSRF103,00,08,00,01*2C
  
  mode 08 = ZDA
  I believe the chksum should be 2C