Pytrack GPS API

[bmarkus]

From the GPS only longitude and latitude is available via the API. For production use many other data is required, like

• altitude
• date/time
• HDOP
• speed
• direction
• number of satellites visible /used for fix
• ...

Please add these to the API. Also, it would be good to make raw NMEA sentences available for user space with user filtering to select which sentences must be passed (callback?).

[stefan85e]

This post is deleted!

[andrethemac]

@stefan85e I'm up to 5 minutes now (timeout=300)
when your outside you'll get a fix a lot faster

[stefan85e]

@andrethemac Okay thanks... what time are you using!?

[andrethemac]

@stefan85e yes.
maybe of interest. I have 2 pytrack board and testing them side by side I found out that 1 takes way longer to get a fix, almost double as long.
So you need to tweak the timeout parameter to get the best results for your module.
best regards

[stefan85e]

@andrethemac Like this?

[andrethemac]

some tweaks to my library https://github.com/andrethemac/L76GLNSV4
methods returning multiple values now return them as a dict;

[andrethemac]

@stefan85e Hi Stefan
sorry for the delay. you better put the the two firsts lines following the while(true): before. you don't need to init the library every run . I'll guess it's generating the error's.
the commands stop when the timeout runs out (default aflter 180 seconds). you can change that if needed.
The timeout occurs if the gps itself can't get a fix because it can't see (enough) sattelites.
best regards

[stefan85e]

@andrethemac

(I dont get any nr due to I done get a signal from the GPS, I have to go outside to get it)

When I do this the program keeps running:

#print(L76.gps_message('GSV'))
print(L76.gps_message('GGA'))

And when I doing this then this happens:

print(L76.gps_message('GSV'))

print(L76.gps_message('GGA'))

[stefan85e]

This post is deleted!

[stefan85e]

@andrethemac

The program stop after 180 sec and if I do this:

#print(L76.coordinates(debug=True)) it will not do anything :)

[andrethemac]

@andrethemac published a new version of the Library to github
https://github.com/andrethemac/L76GLNSV4

If you find some errors or have a request, please ask.
best regards

[andrethemac]

@stefan85e The timeout is to prevent the library to wait for ever. 180 seconds (3 minutes) is (for me) most of the time enough to get a fixed location. (that is after a cold start)
the GGA sentences contains the number of messages seen by the GPS, In the dict that GGA returns, this is the "NumberOfSV' fied.
with this you get this number -> L76.gps_message('GGA')['NumberOfSV']
In your screenshot the line that prints the number of satellites has scrolled out of view
but if you make this line the last you get the number:
print(L76.gps_message('GGA')['NumberOfSV'])
or remove the 'debug=True) from the coordinates line (the debug spews out a lot of information)
I'm still working on the library to make it faster
best regards

[stefan85e]

@andrethemac

Got this

I see that you have a 180 timeout in the code:

-> L76GNSV4 - So how do I know how many sattelites i have then :) just so I look at right nr :)

´´´´
def init(self, pytrack=None, sda='P22', scl='P21', timeout=180,debug=False):
´´´´

[andrethemac]

@stefan85e An example on how to get the number of satelites with my library

from pytrack import Pytrack
from L76GNSV4 import L76GNSS

py = Pytrack()
L76 = L76GNSS(pytrack=py)

print("test L76")
# returns the info about sattelites in view at this moment
# even without the gps being fixed
print(L76.gps_message('GSV'))

# returns the number of sattelites in view at this moment
# even without the gps being fixed
print(L76.gps_message('GGA')['NumberOfSV'])

# returns the coordinates
# with debug true you see the messages parsed by the 
# library until you get a the gps is fixed
print(L76.coordinates(debug=True))
#L76.getUTCDateTime(debug=True)
#L76._read_message(debug=True)

[Neuromystix]

@stefan85e If you are using my code (and just my code, not the one from @andrethemac), when you call gps_data = l76.coordinates1() it will return a list gps_data with latitude at first position (gps_data[0]), longitude at second (gps_data[1]), and so on till the sixth position where you get the number of satellites (gps_data[5]). So, number_of_satellites = gps_data[5].

[stefan85e]

@neuromystix said in Pytrack GPS API:

num_satellites

Does this work:

return(lat_d, lon_d, gps_time, gps_altitude, valid, num_satellites)

I want num_satellites...

[stefan85e]

@andrethemac
(2018, 4, 17, 11, 29, 12, 564887, None)(None(53.33632, 12.53262)
(None, None) Got when I add this:

gps_data = l76.coordinates1()
n_sat = gps_data[5]

Did also try to use this lib:
https://github.com/andrethemac/L76GLNSV4

[Neuromystix]

@stefan85e Hello,

You have to do something like this inside your code, and you'll get the number of satellites used for fix:

...
gps_data = l76.coordinates1()
n_sat = gps_data[5]
...

Or you can use the @andrethemac library which will get you all the data ;)

[stefan85e]

@neuromystix said in Pytrack GPS API:

For use it just call l76.coordinates1() which will return (lat, long, time(not formatted), altitude (M), valid fix (true ou false), number of satellites).
L76GNSS.py
So what did you do to get the nimber of satellites? We are trying this and we cant get it to work.