[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [gpsd-users] Set up for time sync and separate serial port use

From: Pittman, Randall
Subject: Re: [gpsd-users] Set up for time sync and separate serial port use
Date: Fri, 10 Mar 2017 20:34:39 +0000

Also, I apologize for the dumb questions that I could probably answer 
empirically. I'm flying blind at the moment--I cannot access the GPS hardware 
again until next Tuesday, and need to get up and running by Wednesday!

Randall Pittman
Faculty Research Assistant | School of Civil and Construction Engineering | 
Oregon State University
Location: 006 Covell Hall | Mailing: 101 Kearney Hall | Corvallis, OR 97331-2132
Office: 541-737-2102 | Mobile: 541-286-7896

-----Original Message-----
From: gpsd-users [mailto:address@hidden On Behalf Of Gary E. Miller
Sent: Friday, March 10, 2017 10:04 AM
To: address@hidden
Subject: Re: [gpsd-users] Set up for time sync and separate serial port use

Yo Randall!

On Thu, 9 Mar 2017 18:04:18 +0000
"Pittman, Randall" <address@hidden> wrote:

> I have a python app that connects to my GPS Compass (Hemisphere Vector 
> V103), sets it up to send certain messages, and then records the 
> messages as they come in and parses them with the pynmea2 library.

You might consider adding that functionality to gpsd.

> However, I'd also like to sync the system clock (CentOS 7) with the 
> 1PPS signal from the GPS. Here is how I'm considering doing this, but 
> I have no idea if it will work:

Have you read the gpsd howtos?  Like the time service howto?

> serial connection      38400 baud, GPZDA @ 20Hz, PASHR @ 20 Hz, GPGGA
> @ 20 Hz, GPROT @ 5 Hz from V103 with 1PPS
> __   on DCD line
>   \                                   ________
>   |                                  /
>   |==================================|  USB-to-serial adapter >>
>   |    \\                            \________ Used by Python app
> __/     \\
>          \\
>           \\
>            \\                          __
>             \\  Tap RX line,          /
>              \\ Split off DCD line    |
>               \=======================|  Serial port (ttyS0) >>
>                                       |    used by gpsd for time sync
>                                       \__
> Will this work?

The problem is there is no way for gpsd to talk to the GPS.  gpsd will 
configure the GPS as it needs to be.

> What NMEA messages does gpsd need to work for time-sync? GPZDA only? 
> My setup is currently outputting GPZDA at 20Hz

The minimal set of NMEA messages required is not a single unique set.
There are many ways to get the minimum.  You will need the sats used (maybe 
GPGSV and or GPGSA) and PVT data (maybe GPRMC).

> I guess an alternate approach could be to set up the message sending 
> in my app and then is there any easy way to record all the message 
> data with gpsd?

gpspipe -r

> Oregon State University Location

Stop by if you get to Bend.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin

reply via email to

[Prev in Thread] Current Thread [Next in Thread]