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Methods _parse_gpgll, _parse_gpvtg added to Adafruit GPS class
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@tomas-fryza
tomas-fryza committed Feb 24, 2025
1 parent 0431fa3 commit 9e02951
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120 changes: 92 additions & 28 deletions examples/11-gps/adafruit_gps.py
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,11 @@
GPS parsing module. Can parse simple NMEA data sentences from serial GPS
modules to read latitude, longitude, and more.
* Author(s): Tony DiCola, Alexandre Marquet.
* Author(s): Tony DiCola, Alexandre Marque
https://github.com/alexmrqt/Adafruit_CircuitPython_GPS
Tomas Fryza:
2025-02-25: Added _parse_gpgll, _parse_gpvtg
2025-02-25: Small modifs
Implementation Notes
--------------------
Expand All @@ -42,8 +46,6 @@
https://github.com/micropython/micropython
"""
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/alexmrqt/Adafruit_CircuitPython_GPS.git"

# Internal helper parsing functions.
# These handle input that might be none or null and return none instead of
Expand Down Expand Up @@ -87,8 +89,8 @@ def __init__(self, uart):
self.horizontal_dilution = None
self.altitude_m = None
self.height_geoid = None
self.velocity_knots = None
self.speed_knots = None
# self.velocity_knots = None
self.speed = None
self.track_angle_deg = None

def update(self):
Expand All @@ -97,16 +99,21 @@ def update(self):
nothing new was received.
"""
# Grab a sentence and check its data type to call the appropriate
# parsing function.
# parsing function
sentence = self._parse_sentence()
if sentence is None:
return False
data_type, args = sentence
data_type = data_type.upper()

if data_type == b'GPGGA': # GGA, 3d location fix
self._parse_gpgga(args)
elif data_type == b'GPRMC': # RMC, minimum location info
self._parse_gprmc(args)
elif data_type == b'GPGLL': # GLL, geographic position
self._parse_gpgll(args)
elif data_type == b'GPVTG': # VTG, track and ground speed
self._parse_gpvtg(args)
return True

def send_command(self, command, add_checksum=True):
Expand All @@ -133,6 +140,7 @@ def has_fix(self):
def _parse_sentence(self):
# Parse any NMEA sentence that is available.
sentence = self._uart.readline()
# print(sentence)
if sentence is None or sentence == b'' or len(sentence) < 1:
return None
sentence = sentence.strip()
Expand All @@ -157,11 +165,12 @@ def _parse_sentence(self):

def _parse_gpgga(self, args):
# Parse the arguments (everything after data type) for NMEA GPGGA
# 3D location fix sentence.
# 3D location fix sentence
data = args.split(b',')
if data is None or len(data) != 14:
return # Unexpected number of params.
# Parse fix time.
return # Unexpected number of params

# Parse fix time
time_utc = int(_parse_float(data[0]))
if time_utc is not None:
hours = time_utc // 10000
Expand All @@ -174,7 +183,8 @@ def _parse_gpgga(self, args):
self.timestamp_utc[2], hours, mins, secs, 0, 0)
else:
self.timestamp_utc = (0, 0, 0, hours, mins, secs, 0, 0)
# Parse latitude and longitude.

# Parse latitude and longitude
self.latitude = _parse_degrees(data[1])
if self.latitude is not None and \
data[2] is not None and data[2].lower() == b's':
Expand All @@ -183,7 +193,8 @@ def _parse_gpgga(self, args):
if self.longitude is not None and \
data[4] is not None and data[4].lower() == b'w':
self.longitude *= -1.0
# Parse out fix quality and other simple numeric values.

# Parse out fix quality and other simple numeric values
self.fix_quality = _parse_int(data[5])
self.satellites = _parse_int(data[6])
self.horizontal_dilution = _parse_float(data[7])
Expand All @@ -192,29 +203,32 @@ def _parse_gpgga(self, args):

def _parse_gprmc(self, args):
# Parse the arguments (everything after data type) for NMEA GPRMC
# minimum location fix sentence.
# minimum location fix sentence
data = args.split(b',')
if data is None or len(data) < 11 or data[0] is None:
return # Unexpected number of params.
# Parse fix time.
return # Unexpected number of params

# Parse fix time
time_utc = int(_parse_float(data[0]))
if time_utc is not None:
hours = time_utc // 10000
mins = (time_utc // 100) % 100
secs = time_utc % 100
# Set or update time to a friendly python time struct.
# Set or update time to a friendly python time struct
if self.timestamp_utc is not None:
self.timestamp_utc = (
self.timestamp_utc[0], self.timestamp_utc[1],
self.timestamp_utc[2], hours, mins, secs, 0, 0)
else:
self.timestamp_utc = (0, 0, 0, hours, mins, secs, 0, 0)
# Parse status (active/fixed or void).

# Parse status (active/fixed or void)
status = data[1]
self.fix_quality = 0
if status is not None and status.lower() == b'a':
self.fix_quality = 1
# Parse latitude and longitude.

# Parse latitude and longitude
self.latitude = _parse_degrees(data[2])
if self.latitude is not None and \
data[3] is not None and data[3].lower() == b's':
Expand All @@ -223,24 +237,74 @@ def _parse_gprmc(self, args):
if self.longitude is not None and \
data[5] is not None and data[5].lower() == b'w':
self.longitude *= -1.0
# Parse out speed and other simple numeric values.
self.speed_knots = _parse_float(data[6])

# Parse out speed and other simple numeric values
self.speed = _parse_float(data[6]) * 1.852 # kilometers per hour = knots × 1.852
self.track_angle_deg = _parse_float(data[7])
# Parse date.

# Parse date
if data[8] is not None and len(data[8]) == 6:
day = int(data[8][0:2])
month = int(data[8][2:4])
year = 2000 + int(data[8][4:6]) # Y2k bug, 2 digit date assumption.
# This is a problem with the NMEA
# spec and not this code.
if self.timestamp_utc is not None:
# Replace the timestamp with an updated one.
# Replace the timestamp with an updated one
self.timestamp_utc = (year, month, day,
self.timestamp_utc[3],
self.timestamp_utc[4],
self.timestamp_utc[5],
0,
0)
self.timestamp_utc[3],
self.timestamp_utc[4],
self.timestamp_utc[5],
0,
0)
else:
# Time hasn't been set so create it.
self.timestamp_utc = (year, month, day, 0, 0, 0, 0, 0)
# Time hasn't been set so create it
self.timestamp_utc = (year, month, day, 0, 0, 0, 0, 0)

def _parse_gpgll(self, args):
# Parse the arguments (everything after data type) for NMEA GPGLL
# geographic position
data = args.split(b',')
if data is None or len(data) < 6 or data[0] is None:
return # Unexpected number of params

# Parse latitude and longitude
self.latitude = _parse_degrees(data[0])
if self.latitude is not None and \
data[1] is not None and data[1].lower() == b's':
self.latitude *= -1.0
self.longitude = _parse_degrees(data[2])
if self.longitude is not None and \
data[3] is not None and data[3].lower() == b'w':
self.longitude *= -1.0

# Parse fix time
time_utc = int(_parse_float(data[4]))
if time_utc is not None:
hours = time_utc // 10000
mins = (time_utc // 100) % 100
secs = time_utc % 100
# Set or update time to a friendly python time struct
if self.timestamp_utc is not None:
self.timestamp_utc = (
self.timestamp_utc[0], self.timestamp_utc[1],
self.timestamp_utc[2], hours, mins, secs, 0, 0)
else:
self.timestamp_utc = (0, 0, 0, hours, mins, secs, 0, 0)

# Parse status (active/fixed or void)
status = data[5]
self.fix_quality = 0
if status is not None and status.lower() == b'a':
self.fix_quality = 1

def _parse_gpvtg(self, args):
# Parse the arguments (everything after data type) for NMEA GPVTG
# track made good and ground speed
data = args.split(b',')
if data is None or len(data) < 8 or data[0] is None:
return # Unexpected number of params

# Parse out speed and other simple numeric values
self.track_angle_deg = _parse_float(data[0])
self.speed = _parse_float(data[6]) # kilometers/hour
118 changes: 0 additions & 118 deletions examples/11-gps/main.py
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