MicroPython library for quectel L76 glnss gps on pycom pytrack

2020-03-25 add new methods for quering the chip

• get_dt_release: get the software version of the chip
• get_chip_version: get the hardware version of the chip
• better handling of messages send by the chip

2020-03-20

• added fix for newer chips with longer messages (Kudos to askpatrickw for finding the issue)
• RMC -> added NavigationaalStatus
• GSA -> added GNSSSystemID
• GSV -> added SignalID
• new messages are added to newer versions of the chip (V4.10 and later). this should fix this.

2019-06-10 new version L76GLNSV5

https://github.com/andrethemac/L76GLNSV5

this is a rewrite, the messages are now read and parsed in a separed thread.

2019-06-08

• added new features
• enterStandBy: put gps off, needs powercycle to restart
• hotStart: restart the GPS with last found data in non volitale ram
• warmStart: restart the GPS with last known data not in ram
• coldStart: as powercycle
• fullColdStart: forget everything and start al over, takes long to get fix (same as powercycle)
• setPeriodicMode: Mode 2 preserves the most energy
• setAlwaysOn: same as setPeriodicMode(0), keeps the gps awake

improved fix speed

improved nmea message handling

example using the pycom pytrack and wipy3 or lopy4

this example uses the machine.deepsleep to put the wipy/lopy to sleep, but the pytrack board keeps powered. The L76 gps doesn't looses its rtc clock or the satelites in view, resulting in a very quick fix. powering down the pytrack means you need to look anew for satelites, this takes a long time. the Periodic StandBy mode seems to be the most enery efficient. (more test needs to be done) Don't use the pytrack sleep, if you want quick fixes. The pytrack sleep powers the whole board down.

pytrack has a parameter to keep the gps powered during deepsleep of the pytrack module py.go_to_sleep(gps=True)

from pytrack import Pytrack
from L76GNSV4 import L76GNSS
import machine, time
import pycom

print("up")
py = Pytrack()
L76 = L76GNSS(pytrack=py)
L76.setAlwaysOn()

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

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

L76.get_fix(debug=False)
pycom.heartbeat(0)
if L76.fixed():
    pycom.rgbled(0x000f00)
else:
    pycom.rgbled(0x0f0000)
print("coordinates")
# 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=False))
print(L76.getUTCDateTime(debug=True))

# example using the periodicmode of the gps
print("put gps in low power for 40 seconds after 20 seconds")
L76.setPeriodicMode(2,20000,40000,60000,60000)
print("wait 15 seconds")
for x in range(15,0,-1):
    pycom.rgbled(0x000f00+x)
    time.sleep(1)
print("put lopy to deepsleep for 1 minute ")
print("the gps schould be awake before the lopy")
machine.deepsleep(60000)

# example using the deepsleep mode of the pytrack
machine.idle()
py.setup_sleep(60) # sleep 1 minute
py.go_to_sleep(gps=True)