Cannot get gpsd working on Pi3

[Bosse_B]

I posted the thread "USB GPS dongle BU-353 usage on RPi2" on the General discussion sub-forum when I started my quest for GPS on my Pi.
Now when I am having problems I post in Troubleshooting instead.

What has been done:
I switched to a new RPi3 and set it up with Raspbian Jessie (2016-02-26).
Then I tried the suggestions in the first thread to set up gpsd, but it failed in the end.
I have checked these items:
- GPS BU-353 is recognized by Raspbian as a Prolific serial port on ttyUSB0
- I can use stty to open ttyUSB0 and cat the data. NMEA sentences are listed so the GPS works OK.

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stty -F /dev/ttyUSB0 ispeed 4800
cat </dev/ttyUSB0
$GPGGA,205418.306,,,,,0,00,,,M,0.0,M,,0000*59
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,3,1,12,29,53,234,32,17,52,192,,02,44,122,,09,37,050,*71
$GPGSV,3,2,12,26,34,317,28,05,32,160,,31,15,280,,23,14,105,24*7E
...

- Then I installed gpsd and started it:

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sudo apt-get install gpsd gpsd-clients python-gps
sudo gpsd /dev/ttyUSB0 -F /var/run/gpsd.sock

According to instructions it should now be possible to see the NMEA data:

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cgps -s

But this shows only a blank panel of placeholders for the data and goes away with a timeout message

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xgps

This brings up a GUI window but it contains no data.
Then I checked if the system was listening to the gpsd TCP port 2947 (which is the default gpsd port):

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pi@rpi3-jessie:~ $ netstat -lnpt
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:2947          0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:139             0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:5901            0.0.0.0:*               LISTEN      650/Xtightvnc
tcp        0      0 0.0.0.0:6001            0.0.0.0:*               LISTEN      650/Xtightvnc
...

So it seems like gpsd is running and listening on the default port.
Still no data shows up.

Is there someone here who can help in debugging the connectivity issue here?
For instance, how does gpsd know the baudrate to use against ttyUSB0? I find no mention of such a setup in any page I have read...

Reference webpages:
http://blog.retep.org/2012/06/18/gettin ... pberry-pi/
http://www.catb.org/gpsd/installation.html

[Bosse_B]

Further to this I managed to find a list of gpsd commands so I could do this:
- First check that gpsd is not already running
- Then start it with the -N flag to make it display errors

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pi@rpi3-jessie:~ $ ps -e | grep gps
pi@rpi3-jessie:~ $ sudo gpsd /dev/ttyUSB0 -N
gpsd:ERROR: can't bind to IPv4 port gpsd, Address already in use
gpsd:ERROR: maybe gpsd is already running!
gpsd:ERROR: can't bind to IPv6 port gpsd, Address already in use
gpsd:ERROR: maybe gpsd is already running!

Notice that ps does not return any process holding the GPS port 2947 and yet the start command for gpsd (now using the -N debug flag) shows that this port is in fact occupied already!
So I went ahead and checked if there is some process holding that port:

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pi@rpi3-jessie:~ $ netstat -lnpt
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:2947          0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:139             0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:5901            0.0.0.0:*               LISTEN      650/Xtightvnc
tcp        0      0 0.0.0.0:6001            0.0.0.0:*               LISTEN      650/Xtightvnc
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:445             0.0.0.0:*               LISTEN      -
tcp6       0      0 ::1:2947                :::*                    LISTEN      -
tcp6       0      0 :::139                  :::*                    LISTEN      -
tcp6       0      0 :::22                   :::*                    LISTEN      -
tcp6       0      0 :::445                  :::*                    LISTEN      -

As you can see the port is open on both ipv4 and ipv6 for some strange reason. And to further muddy the waters I do not get a name for the process holding that port either...

I next ried to specifically tell cgps what port to use, but the result was the character screen with no data mentioned before plus now an error message at the bottom:

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cgps localhost:2947:/dev/ttyUSB0
lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqklqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqk
x    Time:       n/a                        xxPRN:   Elev:  Azim:  SNR:  Used: x
x    Latitude:   n/a                        xx                                 x
x    Longitude:  n/a                        xx                                 x
x    Altitude:   n/a                        xx                                 x
x    Speed:      n/a                        xx                                 x
x    Heading:    n/a                        xx                                 x
x    Climb:      n/a                        xx                                 x
x    Status:     NO FIX (0 secs)            xx                                 x
x    Longitude Err:   n/a                   xx                                 x
x    Latitude Err:    n/a                   xx                                 x
x    Altitude Err:    n/a                   xx                                 x
x    Course Err:      n/a                   xx                                 x
x    Speed Err:       n/a                   xx                                 x
x    Time offset:     n/a                   xx                                 x
x    Grid Square:     n/a                   xx                                 x
mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqjmqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj

r":3,"proto_minor":9}
{"class":"ERROR","message":"No such device as /dev/ttyUSB0"}

Notice the complaint about /dev/ttyUSB0!
This is definitely there, shown inside the /dev dir.
And gpsd is now running too:

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pi@rpi3-jessie:~ $ ps -e | grep gps
18369 ?        00:00:00 gpsd

Even after a reboot netstat shows something holding port 2947 open!
What is going on here, really?
Is it a Raspbian Jessie thing or some kind of firewalling or what?

[Bosse_B]

I finally got it all working by building from sources.
The apt-get version was really old and therefore not much to spent time on.
I have struggled a bit getting a build to work so I compiled a report available on my site.
Hope it may help someone doing the same as I did.

[Per_L]

Hi,

Had the same problem.

I think the problem is in how systemd is configured.

Try to change /lib/systemd/system/gpsd.socket
from

ListenStream=127.0.0.1:2947

which listens to localhost only
to

ListenStream=0.0.0.0:2947

which listens to "all" , and restart gpsd (or reboot).

Then netstat -lntp will show

tcp 0 0 0.0.0.0:2947 0.0.0.0:* LISTEN 1/init
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 412/sshd
tcp 0 0 127.0.0.1:6010 0.0.0.0:* LISTEN 596/0
tcp 0 0 127.0.0.1:6011 0.0.0.0:* LISTEN 632/1


Regards

Per Linderholm
Sweden

[beta-tester]

Hi,
...
Try to change /lib/systemd/system/gpsd.socket
from

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ListenStream=127.0.0.1:2947

which listens to localhost only
to

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ListenStream=0.0.0.0:2947

which listens to "all"
...
Regards
Per Linderholm
Sweden

thank you very much... very good hint
that issue caused a lot of headache to me...
now i have access to gps data from everywhere of my network.

do you know the replacement for ipv6?
only to have the same for IPv6 -> tcp6
i tired replacing

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ListenStream=[::1]:2947

with

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ListenStream=[::]:2947

but that will not work

[Bosse_B]

I have had a difficult time getting gpsd running on boot of my Raspbian Jessie system.
I have finally gotten it to work properly on startup by adding an entry into the bottom of /etc/rc.local:

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#Start the gpsd daemon
/etc/booted/startgpsd.sh
exit 0

And the startgpsd.sh script is here:

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#!/bin/sh -e
#Need to wait past boot so everything is done
date "+%Y-%m-%d %H:%M:%S" > /startgpsd.txt
sleep 2
echo "Starting GPSD" >> /startgpsd.txt
/usr/local/sbin/gpsd /dev/ttyUSB0 -G -n -F /var/run/gpsd.sock
date "+%Y-%m-%d %H:%M:%S" >> /startgpsd.txt
exit 0
p

and the logfile /startgpsd.txt reads:

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2016-03-26 10:24:20
Starting GPSD
2016-03-26 10:24:22

Now I can connect using the normal gpsd tools like
cgps -s

This was not possible before.

EDIT:
I updated the name of the script to run from rc.local to startgpsd.sh and also changed the logfile name correspondingly.

[beta-tester]

I have had a difficult time getting gpsd running on boot of my Raspbian Jessie system...

i got my working automatically on jessie by using the following settings in the /etc/default/gpsd file...

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# /etc/default/gpsd
START_DAEMON="true"
GPSD_OPTIONS="-n"
DEVICES="/dev/ttyAMA0"
USBAUTO="false"
GPSD_SOCKET="/var/run/gpsd.sock"

normally those settings should be configured by using dpkg-reconfigure gpsd...
but for unknown reason that command wasn't doing anything on my RPi. do i had to do the configuration by hand on the /etc/default/gpsd file.

i had an other issue, that the gpsd data wasn't recognized automatically by ntpd but that is a complete other story.

[drclong]

by Bosse_B » Tue Mar 08, 2016 2:13 pm
I finally got it all working by building from sources.
The apt-get version was really old and therefore not much to spent time on.
I have struggled a bit getting a build to work so I compiled a report available on my site.
Hope it may help someone doing the same as I did.
Bo Berglund
Sweden

Thank you for the help but I have run into a problem on your report where I can not install libxlt1-dev. Package is not available. Have tried updating and upgrading but no solution so far.

Any ideas?

[Bosse_B]

I don't know...
When I had the problem with libxslt back in March I asked in this forum thread and was directed towards the use of libxlt1-dev instead.
Then it worked and I have not looked at this since...

[beijota2]

Thank you for the help but I have run into a problem on your report where I can not install libxlt1-dev. Package is not available. Have tried updating and upgrading but no solution so far.

Any ideas?

I did a search for libxlt1-devcouple of searches and found a libxslt1-dev instead. I ran thru Bo's process and It worked for a while, but now i'm back to the same error message

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root@BBG1:~# gpsd -N -D3 -F /var/run/gpsd.sock
gpsd:INFO: launching (Version 3.16)
gpsd:ERROR: can't bind to IPv4 port gpsd, Address already in use
gpsd:ERROR: maybe gpsd is already running!
gpsd:ERROR: can't bind to IPv6 port gpsd, Address already in use
gpsd:ERROR: maybe gpsd is already running!
gpsd:INFO: command sockets creation failed, netlib errors -1, -1

Working my way thru the steps again to see if I can find the 'Magic' tweak.

[Bosse_B]

As indicated in the error message there may be another instance of gpsd running already.
You may want to check if there are other gpsd processes running and delete them if so.
If there is no other gpsd running then you should not have this problem.
This will show the running instances of gpsd:

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ps aux | grep gpsd
nobody    1225  1.0  0.2  11748  2160 ?        S<sl 08:51   0:02 /usr/local/sbin/gpsd /dev/ttyUSB0 -G -n -F /var/run/gpsd.sock

[delorian1986]

Hi there.
I am still using raspberry 2 but i just installed gpsd with the usual

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sudo apt-get install

and got the gps running by turning off the gpsd.socket using

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sudo systemctl stop gpsd.socket

and then

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 sudo systemctl disable gpsd.socket

.
I found this on adafruits homepage https://learn.adafruit.com/adafruit-ult ... i/use-gpsd over their own gps module and it worked for my USB dongle .
Hope this helps!
Best regards

[scorpion001]

There is a mistake in the blog your provided.
sudo apt-get install libxlt1-dev docbook-xsl xmlto asciidoc
libxlt1-dev should change to libxslt1-dev

[nullacht15]

i had an other issue, that the gpsd data wasn't recognized automatically by ntpd but that is a complete other story.

How did you solve this issue regarding ntpd?
my gpsd is running and cgps -s is giving me the right results but ntp is not working

/etc/default/gpsd

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START_DAEMON="true"
USBAUTO="true"
DEVICES="/dev/ttyUSB0"
GPSD_OPTIONS="-n"
GPSD_SOCKET="/var/run/gpsd.sock"

/etc/ntp.conf

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server 127.127.28.0
fudge 127.127.28.0 time1 +0.175 refid GPS stratum 3

ntpq -p:

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     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 SHM(0)          .GPS.            3 l    -   64    0    0.000    0.000   0.000

Any ideas?

[beta-tester]

i had an other issue, that the gpsd data wasn't recognized automatically by ntpd but that is a complete other story.

How did you solve this issue regarding ntpd?
my gpsd is running and cgps -s is giving me the right results but ntp is not working

/etc/default/gpsd

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START_DAEMON="true"
USBAUTO="true"
DEVICES="/dev/ttyUSB0"
GPSD_OPTIONS="-n"
GPSD_SOCKET="/var/run/gpsd.sock"

/etc/ntp.conf

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server 127.127.28.0
fudge 127.127.28.0 time1 +0.175 refid GPS stratum 3

ntpq -p:

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     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 SHM(0)          .GPS.            3 l    -   64    0    0.000    0.000   0.000

Any ideas?

i solved it by using the GPS NMEA data as the first ntp time source to get the date and time.
and used the GPS PPS signal for precise sync trigger ntp as second time source.
and force ntp to use the NMEA as preferred time source, otherwise ntp will not take that source in account, because it is relative inaccurate.

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# gpsd: GPS NMEA serial data reference
server 127.127.28.0  minpoll 4  maxpoll 4 prefer
fudge 127.127.28.0  refid NMEA  stratum 3  time1 0.510

and test, if ntp takes the GPS NMEA data into account, just after you did cgps -s once, then you have to "trigger" the gpsd at every start cycle like me.
see this thread: [FIXED]: RPi as high precise NTP Server with GPS/PPS dev

[nullacht15]

thank you, seems to work now

[manuyareshimi]

wow, am facing the same Bosse_B.

I had resolved this few months back.. And i turned on to some other work. .. Am kick myself.. i tried to make the best notes, but apparently missed it..

Now, i have to deliver something tomorrow.. and now this hits back.. Why is this so hard?? No one gets a PHD to solve this stupid errors.. .. Not sure if the open source world likes it this way. I wish this can be better..

gpsmon /dev/ttyUSB0
gpsmon:ERROR: device open failed: Device or resource busy - retrying read-only
gpsmon:ERROR: read-only device open failed: Device or resource busy
gpsmon: activation of device /dev/ttyUSB0 failed, errno=16 (Device or resource busy)


Can someone help.. or should i try to build from source.. (PS note - i still think that will be a long shot. )

[DougieLawson]

First thing to do is look at the output from a dmesg | grep tty command. Unplug your USB GPS, plug it back in and see what appears in dmesg. It may not be /dev/ttyUSB0.

You could see something like

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[   15.666363] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device
[   15.809199] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

which is my serial device appearing as /dev/ttyACM0 not /dev/ttyUSB0.

On another RPi the serial device appears as

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[    1.278005] 20201000.serial: ttyAMA0 at MMIO 0x20201000 (irq = 81, base_baud = 0) is a PL011 rev2
[   50.490693] usb 1-1.3.4: ch341-uart converter now attached to ttyUSB0

[B.Goode]

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gpsmon /dev/ttyUSB0
gpsmon:ERROR: device open failed: Device or resource busy - retrying read-only
gpsmon:ERROR: read-only device open failed: Device or resource busy
gpsmon: activation of device /dev/ttyUSB0 failed, errno=16 (Device or resource busy)

Why is /dev/ttyUSB0 (presumably your serial port connection to the host) busy?

This thread was originally about gpsd. Are you automatically starting gpsd? That might be claiming the serial port connection?

[manuyareshimi]

Firstly i want to thank DougieLawson and B.Goode for such a quick response. I had not expected that.

After further exploration, i think i found the problem. As am new to the linux world, it was hard for me to identify it quickly.

My GPS Receiver has gone BAD. Fortunately i had ordered another as a backup and that for sure came in handy.

How did i find out is as follows, And this may be a good way to test for others.
CREDIT - https://lifemeetscode.com/blog/2017/05/ ... -with-gps/

1. I uninstall all gpsd , using purge command.
2. After browsing, i found that when you attach usb linux has logs for the activity.. which is nice. tail -f /var/log/syslog and I found that when i was trying to connect my USB there used to be an error.. that led me to believe something was off with my machine or USB
2. Then followed the steps to trouble shoot with and my situation was exactly as described here - https://lifemeetscode.com/blog/2017/05/ ... -with-gps/
3. dmesg | grep tty - found that my GPS is still connected to USB0 and then tried - cat /dev/ttyUSB0 -> this led me to believe something was way off
4. Finally attached the new GPS and followed the steps, and yes now i get reading below.. Note the new one is connected to ttyACM0.

$GPGGA,180245.00,4740.72991,N,12201.77435,W,1,05,3.06,169.7,M,-18.6,M,,*6E

$GPGSA,A,3,02,29,05,20,25,,,,,,,,4.70,3.06,3.57*0C

$GPGSV,3,1,10,02,27,066,25,05,55,086,27,09,00,013,,12,15,168,20*75

$GPGSV,3,2,10,20,48,172,33,21,31,252,,25,43,195,32,26,19,318,27*78

$GPGSV,3,3,10,29,83,350,38,31,12,276,20*75

$GPGLL,4740.72991,N,12201.77435,W,180245.00,A,A*70


Now am getting back to reinstalling gpsd and figuring my work for the day. Thanks a lot guys.

[zorni]

Thank you everybody for this post!

I tried to get it running on Pi 3 B+.
I use Stretch 2018-06-27.

Error massage in debug mode:

something like

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ttyS0 already in use

I used this blog to install gpsd (thank you so much Bob Erglund!):http://blog.boberglund.com/Build_GPSD_from_sources.txt.

After first boot, rasbian makes a lot of updates.
To run gpsd don't forget to switch the serial interface on again (enable_uart=1). You can read this in many posts.
More important: You have to switch of the serial console! I did this in the raspberry-pi-configuration menu. This took me hours to find out...

Maybe this helps someone else.

regards
Stefan

[DougieLawson]

sudo apt install lsof
sudo lsof /dev/ttyS0

[DirkS]

I used this blog to install gpsd (thank you so much Bob Erglund!):http://blog.boberglund.com/Build_GPSD_from_sources.txt.

Or even Bo Berglund, aka Bosse_B on this forum

[beta-tester]

I tried to get it running on Pi 3 B+.
I use Stretch 2018-06-27.

Error massage in debug mode:

something like

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ttyS0 already in use

maybe my project "RPi-GPS-PPS-StratumOne" is also of interest to you.
it installs gpsd + chrony and should turn off bluetooth (the reason why serial port is busy) and enable serial port on GPIO header on RPi3, RPi3+ and RPi0w.

[warnergt]

I have a somewhat similar problem but (of course) different.
I'm using gpsd on a Pi 4 to talk to a Uputronics GPS hat which uses the serial port at /dev/ttyS0.
Under certain circumstances, it works fine.
If I have no USB devices connected to my Pi, I can start it up, run gpsd and everything is good.

But there is another case where it does not work.
If I connect an external LTE modem which uses two USB ports and start the Pi, gpsd does not communicate to my GPS hat.
Also, when the USB ports are in use, I find that gpsd is already running when I go to run it.

From the gpsd manpage at:
https://manpages.debian.org/buster/gpsd/gpsd.8.en.html
it says, "On Linux systems supporting udev, gpsd is normally started automatically when a USB plugin event fires (if it is not already running) and is handed the name of the newly active device. In that case no invocation is required at all."

I'm pretty sure this is a big clue to the problem.

If I kill the running gpsd and try to restart using the desired port:
sudo killall gpsd
sudo gpsd /dev/ttyS0 -F /var/run/gpsd.sock

it still doesn't work.

I did find a workaround. If I keep the modem unplugged, start up the PI, start gpsd and then plug in the modem USB connectors, it all works. But this is a kludge. How do I make this work without using a workaround?