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Astroberry GPS with Adafruit GPS breakout board

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I have been trying to get above gps board up and running, following these instructions:

learn.adafruit.com/adafruit-ultimate-gps...aspberry-pi?view=all

Looks I am not receiving any meaningful data, the NMEA sentences coming in on gpsmon contain zero’s but no positional data, but time only. Needless to say, „no fix“.

I wonder whether someone more experienced could tell from the screenshot whether this has to do with poor configuration or just signals being too weak?

N.B. I also applied recommendations from Radek in another thread on gps.

Thanks inadvance! Helge
6 years 1 month ago #23289
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First, confirm that serial connection works - try connecting to gps with any terminal emulator e.g. minicom, screen etc. (remember to stop gpsd before testing to free the serial line). If you get NMEA stream of data you're ok, if not, something's wrong with serial communication - check baud rate, double check that rx is connected to tx and tx is connected to rx, check power... Second, if it connects ok, run gpsmon or cgps and make sure your gps device has free access to sky - test it outside. Cold fix takes some time, be patient. If it does not get fix after 5 minutes outside, there's some major malfunction.
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6 years 1 month ago #23292

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First I run sudo killall gpsd.

I checked the connection with sudo cat /dev/ttyS0 and received a datastream in NMEA format, but mostly zero values, please see also previously attached screenshot (see bottom row of top left window). Does it mean that the serial connection works?

When starting up minicom, I am not getting a lot of information, except it says port/dev/tty8 - not sure why tty8. But no datastream or anything else.

Which command is needed to check baud rate? The wiring is fine, checked again.
6 years 1 month ago #23295

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Serial device seems to work.
You need to set port for minicom by running
minicom -D /dev/ttyS0 -b 9600

If you have miniterm.py available on your system you can run:
miniterm.py /dev/ttyS0 9600

... and observe the output - you should get raw NMEA data over serial.

If not... well double check that your gpsd user is in dialout group by running
id gpsd

You can find gpsd config in /etc/default/gpsd
Last edit: 6 years 1 month ago by Radek Kaczorek.
6 years 1 month ago #23298

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Thanks a lot! With the minicom command, I am receiving a NMEA datastrea („raw“).

„id gpsd“ gives: uid=123(gpsd) gid =20 (dialout) groups = 20 (dialout), 5(tty)

Not sure if this is expected?

I also entered the following command, but probably it did not make a lot of sense and the result was confusing me:

gpsd -N -D3 /var/run/gpsd.sock following which I received error messages that can‘t bind to IPv4 and 6, suggesting that „maybe gpsd is already running“

Can I discard this kind of result?

If - as you say - the serial device is working, maybe I need to connect to an external antenna - I was relying on the antenna that is placed on the board.
6 years 1 month ago #23315

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If you see raw NMEA data, your gps device is ok. gpsd access rights are also ok (gpsd is a member of dialout group so it can access /dev/ttyS0)
This means your gpsd should receive gps data stream (double check config options in /etc/default/gpsd). I think it's all about getting fix. The module should work with the internal antenna... if you have external antenna, give it a try.
6 years 1 month ago #23317

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I Just installed this myself with little difficulty.
To the file /etc/default/gpsd add the line
# Devices gpsd should collect to at boot time.
DEVICES="/dev/ttyS0"
 
# Other options you want to pass to gpsd
GPSD_OPTIONS="-b -n"

Also for system clock synchronization to the file /etc/ntp.conf
add to the end
# GPS Serial data Reference
server 127.127.28.0 minpoll 4 maxpoll 4
fudge  127.127.28.0 time1 0.0 refid GPS
#GPS PPS reference
server 127.127.28.1 minpoll 4 maxpoll 4 prefer
fudge  127.127.28.1 refid PPS
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Last edit: 6 years 1 month ago by Andrew.
6 years 1 month ago #23364

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You miss the leading / in DEVICES - it should be:
DEVICES="/dev/ttyS0"
Last edit: 6 years 1 month ago by Radek Kaczorek.
6 years 1 month ago #23378

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Thank you. Fixed my post.
6 years 1 month ago #23406

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Great, now it is working. Not sure what made the difference, I tried again back home, updated /etc/default/gpsd by adding „-b“. I did not touch the ntp.conf file.

Either it is the different position, the „-b“ or just luck. Anyway appreciate the support received!

Helge
6 years 1 month ago #23408

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Hello!

An old threat, but its exactly the point

I use a fresh installed astroberry image.
then I edit the file /etc/default/gpsd and add the following: DEVICES="/dev/ttyUSB0"
(the orginal was DEVICES="/dev/ttyS0", but this is not working)
After that I connect the Adafruit GPS at USB and reboot.

The GPS is detected and the System asks me to use the GPS as time source. I agree, but nothing happens with the system-time.

In Ekos in the GPSD area, Main Control the correct coordinates and time are displayed
At Options the Time Source is set to GPS.

Any idear ?

CS
Reiner
4 years 2 months ago #48154

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I've always had to go through with setting up NTP to get the system to use the GPS as a time source, and GPSD required a few options on startup. Alternatively you can try Chrony instead of NTP.
gpsd.gitlab.io/gpsd/gpsd-time-service-howto.html
4 years 2 months ago #48175

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