Cannot Establish GPS Connection Sixfab Base Hat + Telit LE910C1

[a.lancioni]

I cannot acquire a connection with the GPS using the telit LE910C1-EU module.
Following the instructions on the tutorial(Read GNSS/GPS Data with Sixfab Shield/HAT) the GPS cannot acquire the signal.

Also, I would need to use the GPS data from Python and if I try to run the gps.py file present in the tutorial(Sixfab_RPi_3G-4G-LTE_Base_HAT/GPS.py at master · sixfab/Sixfab_RPi_3G-4G-LTE_Base_HAT · GitHub) I get the error: [Errno 16] could not open port / dev / ttyUSB1: [Errno 16] Device or resource busy: ‘/ dev / ttyUSB1’

I have no more ideas.
Is there anyone who could help me?
Thanks

[ensar]

Hi @a.lancioni ,

The gps.py script is prepared for Quectel modules. For Telit module, please follow from here.

If none of the troubleshooting steps at the end of the tutorial solve your problem, Telit prepared A-GPS Application Note will help.

[a.lancioni]

Followed the tutorial for Telit you posted(Read GNSS/GPS Data with Sixfab Shield/HAT) and also the Application Note.
Trying to do this:

I get no GPS signal as you can see

Next issue is I need to get GPS data from Python but I am unable to access the GPS USB port from Python due to the “port busy” error.

[ensar]

There may be some reasons:

• Poor antenna performance.
• Environment

Please pay attention to that the GPS antenna should be placed in an open-sky environment. How long did you test it? It can take some time to get a fix.

[a.lancioni]

I tested the antenna for about 4 hours near the window. Non GPS signal.
Now I leave it on place for all the day, I hope the GPS signal will be fixed.

Also, I don’t find any tutorials to access GPS data from python which is what I really need!

[davidbonn]

The antenna included with the kit works poorly indoors. Where “poorly” can mean anything from not working at all to working just barely well enough to test your code. I’d really consider a better antenna (which costs under $10), since it is much cheaper than your time.

If you are inside a metal or concrete building you can’t expect good GPS performance, no matter what antenna you are using. Metal roofs or roofs with lots of solar panels on them are also going to make it very difficult to get good GPS results.

I’m not 100 percent sure, but I’ve noticed that if you are using cellular data that GPS fixes can take longer, sometimes much longer. I think that is related to the antenna and likely will be fixed by a separate and better antenna.

Depending on what you are doing, you can do fine getting GPS fixes by using the AT$GPSACP commands and parsing the results. For me, that has proven simpler than monitoring a separate serial channel and parsing the NMEA sentences there.

[a.lancioni]

After about 5 hours I finally have a GPS signal(not stable)
Getting GPS data:

Lost GPS signal after about 2 minutes

Now, how can I access this data from Python?
Using PySerial and accessing the USB port I get the “Device or resource is busy”.

[a.lancioni]

Anyone can help me to use sixfab gps module from python?

[davidbonn]

On this thread I posted sample python code that accesses GPS data from the Telit LE910xx.

You’ll need to install cu and the pexpect python package to get it to work.

[a.lancioni]

Hi David, could you post me the AT commands you use to start up the GPS reciver?
Using the telit guide(Read GNSS/GPS Data with Sixfab Shield/HAT) I have this results:
$GPGSV,3,1,09,21,57,125,25,01,77,092,03,69,310,04,37,195,166
$GPGSV,3,2,09,06,08,07,175,09,05,210,10,168
$GPGSV,3,3,09,14,168
$GPVTG,T,M,N,K,N2C
$GPGSA,A,1,32
$GPGGA,0,66
$GPRMC,V,N,V29
$GPGLL,V,N64

It seems GPGSA, GPGGA, GPRMC, GPGLL get no data and your python code cannot get the position due to a Timeout Error.

Am I doing something wrong?
Thanks

[a.lancioni]

After about 3 hours I get this data from cu command:

Trying to run the python code I get this error:

It seems the GPGSA is not full, why?

Thanks

[davidbonn]

You need to use /dev/ttyUSB2 or /dev/ttyUSB3 with that program. Those are the ports that accept AT commands. /dev/ttyUSB1 had straight-up GPS sentences that I don’t parse.

The commands that are sent are:

AT
AT$GPSP?
AT$GPSP=1
AT$GPSACP (and repeat until we get a good fix)
AT$GPSP=0