gps_test.py

# Simple GPS module demonstration.
# Will wait for a fix and print a message every second with the current location
# and other details.
import time
import board
#import busio

import adafruit_gps

# Create a serial connection for the GPS connection using default speed and
# a slightly higher timeout (GPS modules typically update once a second).
# These are the defaults you should use for the GPS FeatherWing.
# For other boards set RX = GPS module TX, and TX = GPS module RX pins.
#uart = busio.UART(board.TX, board.RX, baudrate=9600, timeout=10)

# for a computer, use the pyserial library for uart access
import serial
uart = serial.Serial("/dev/serial0", baudrate=9600, timeout=10)

# If using I2C, we'll create an I2C interface to talk to using default pins
#i2c = busio.I2C(board.SCL, board.SDA)

# Create a GPS module instance.
gps = adafruit_gps.GPS(uart, debug=False)     # Use UART/pyserial
#gps = adafruit_gps.GPS_GtopI2C(i2c, debug=False)  # Use I2C interface

# Initialize the GPS module by changing what data it sends and at what rate.
# These are NMEA extensions for PMTK_314_SET_NMEA_OUTPUT and
# PMTK_220_SET_NMEA_UPDATERATE but you can send anything from here to adjust
# the GPS module behavior:
#   https://cdn-shop.adafruit.com/datasheets/PMTK_A11.pdf

# Turn on the basic GGA and RMC info (what you typically want)
gps.send_command(b'PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0')
# Turn on just minimum info (RMC only, location):
#gps.send_command(b'PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0')
# Turn off everything:
#gps.send_command(b'PMTK314,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0')
# Tuen on everything (not all of it is parsed!)
#gps.send_command(b'PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0')

# Set update rate to once a second (1hz) which is what you typically want.
gps.send_command(b'PMTK220,1000')
# Or decrease to once every two seconds by doubling the millisecond value.
# Be sure to also increase your UART timeout above!
#gps.send_command(b'PMTK220,2000')
# You can also speed up the rate, but don't go too fast or else you can lose
# data during parsing.  This would be twice a second (2hz, 500ms delay):
#gps.send_command(b'PMTK220,500')

# Main loop runs forever printing the location, etc. every second.
last_print = time.monotonic()
while True:
    # Make sure to call gps.update() every loop iteration and at least twice
    # as fast as data comes from the GPS unit (usually every second).
    # This returns a bool that's true if it parsed new data (you can ignore it
    # though if you don't care and instead look at the has_fix property).
    gps.update()
    # Every second print out current location details if there's a fix.
    current = time.monotonic()
    if current - last_print >= 1.0:
        last_print = current
        if not gps.has_fix:
            # Try again if we don't have a fix yet.
            print('Waiting for fix...')
            continue
        # We have a fix! (gps.has_fix is true)
        # Print out details about the fix like location, date, etc.
        print('=' * 40)  # Print a separator line.
        print('Fix timestamp: {}/{}/{} {:02}:{:02}:{:02}'.format(
            gps.timestamp_utc.tm_mon,   # Grab parts of the time from the
            gps.timestamp_utc.tm_mday,  # struct_time object that holds
            gps.timestamp_utc.tm_year,  # the fix time.  Note you might
            gps.timestamp_utc.tm_hour,  # not get all data like year, day,
            gps.timestamp_utc.tm_min,   # month!
            gps.timestamp_utc.tm_sec))
        print('Latitude: {0:.6f} degrees'.format(gps.latitude))
        print('Longitude: {0:.6f} degrees'.format(gps.longitude))
        print('Fix quality: {}'.format(gps.fix_quality))
        # Some attributes beyond latitude, longitude and timestamp are optional
        # and might not be present.  Check if they're None before trying to use!
        if gps.satellites is not None:
            print('# satellites: {}'.format(gps.satellites))
        if gps.altitude_m is not None:
            print('Altitude: {} meters'.format(gps.altitude_m))
        if gps.speed_knots is not None:
            print('Speed: {} knots'.format(gps.speed_knots))
        if gps.track_angle_deg is not None:
            print('Track angle: {} degrees'.format(gps.track_angle_deg))
        if gps.horizontal_dilution is not None:
            print('Horizontal dilution: {}'.format(gps.horizontal_dilution))
        if gps.height_geoid is not None:
            print('Height geo ID: {} meters'.format(gps.height_geoid))