Raspberry Pi Pico: NEO-6M GPS Module – Get Location and Time (MicroPython)

Learn how to interface the NEO-6M GPS module with the Raspberry Pi Pico to get GPS data: latitude, longitude, altitude, date, and time. We’ll show you how to connect the module to the Pico and establish a serial communication to get sensor data. We’ll program the Raspberry Pi Pico board using MicroPython firmware.

New to the Raspberry Pi Pico? Check out our eBook: Learn Raspberry Pi Pico with MicroPython.

Table of Contents

Throughout this guide, we’ll cover the following topics:

• Introducing the NEO-6M GPS Module
• Wiring the NEO-6M GPS Module to the Raspberry Pi Pico
• Getting Raw GPS Data – Testing the NEO-6M GPS Module with the Raspberry Pi Pico (MicroPython)
• Uploading the micropyGPS Module
• Raspberry Pi Pico with NEO-6M: Getting GPS Data with MicroPython

Prerequisites – MicroPython Firmware

To follow this tutorial you need MicroPython firmware installed in your Raspberry Pi Pico board. You also need an IDE to write and upload the code to your board.

The recommended MicroPython IDE for the Raspberry Pi Pico is Thonny IDE. Follow the next tutorial to learn how to install Thonny IDE, flash MicroPython firmware, and upload code to the board.

• Programming Raspberry Pi Pico using MicroPython

Introducing the NEO-6M GPS Module

The NEO-6M GPS module is a GPS receiver compatible with most microcontroller boards. It can get data about location, speed, altitude, and time.

It comes with a small backup battery, external EEPROM, and an LED signal indicator. This LED will start blinking when it gets a position fix.

Usually, these modules come with a GPS ceramic antenna.

But, you can change it to any other compatible antenna that might suit your project better. For example, I like to use the one at the right in the picture below because it is waterproof, and the antenna comes with a long cable which allows for more flexibility.

The NEO-6M GPS Module communicates with a microcontroller using serial communication protocol.

This module works with standard NMEA sentences. NMEA stands for National Marine Electronics Association, and in the world of GPS, it is a standard data format supported by GPS manufacturers.

NEO-6M GPS Module Features

In summary:

• This module has an external antenna and built-in EEPROM.
• Interface: RS232 TTL
• Power supply: 3V to 5V
• Default baudrate: 9600 bps
• Works with standard NMEA sentences

Where to buy?

You can get the NEO-6M GPS module for a price between $5 to $20. We recommend checking the NEO-6M GPS module page on Maker Advisor to compare the prices in different stores and find the best one.

You can use the preceding links or go directly to MakerAdvisor.com/tools to find all the parts for your projects at the best price!

Wiring the NEO-6M GPS Module to the Raspberry Pi Pico

To get data from the NEO-6M GPS module, we need to establish a serial communication. The Raspberry Pi Pico has the following options for UART pins:

UART Interface	TX GPIOs	RX GPIOs
UART0	GPIO0, GPIO12, GPIO16	GPIO1, GPIO13, GPIO17
UART1	GPIO4, GPIO8	GPIO5, GPIO9

We’ll use UART 1 and GPIO 4 (TX) and GPIO 5 (RX).

NEO-6M GPS Module	Raspberry Pi Pico
VCC	3V3
RX	TX (GPIO 4) (Pin 6)
TX	RX (GPIO 5) (Pin 7)
GND	GND

Related article: Raspberry Pi Pico and Pico W Pinout Guide: GPIOs Explained

Getting Raw GPS Data – Testing the NEO-6M GPS Module with the Raspberry Pi Pico (MicroPython)

To get raw GPS data you just need to start a serial communication with the GPS module and read the available data.

The following code establishes a serial communication with the GPS module and reads the available data.

# Rui Santos & Sara Santos - Random Nerd Tutorials
# Complete project details at https://RandomNerdTutorials.com/raspberry-pi-pico-neo-6m-micropython/

import machine
from time import sleep

# Define the UART pins and create a UART object
gps_serial = machine.UART(1, baudrate=9600, tx=4, rx=5)

while True:
    if gps_serial.any():
        line = gps_serial.readline()  # Read a complete line from the UART
        if line:
            line = line.decode('utf-8')
            print(line.strip())
    sleep(0.5)

View raw code

Testing the Code

After establishing a connection with the board using Thonny IDE, run the previous code.

Make sure the antenna is connected and that the module or antenna is placed outside or next to a window so that it can get data from the satellites.

The module’s blue LED will start blinking when it finds a position fix—this might take a few minutes on the first run.

The shell will display NMEA sentences with GPS data.

Each line you get in the serial monitor is an NMEA sentence.

NMEA stands for National Marine Electronics Association, and in the world of GPS, it is a standard data format supported by GPS manufacturers.

NMEA Sentences

NMEA sentences start with the $ character, and each data field is separated by a comma.

$GPRMC,110827.00,A,4107.32485,N,00831.79799,W,0.888,30.44,180724,,,A*4B
$GPVTG,30.44,T,,M,0.888,N,1.644,K,A*01
$GPGGA,110827.00,41XX.32485,N,00831.79799,W,1,07,0.99,123.1,M,50.1,M,,*48
$GPGSA,A,3,03,32,22,08,04,14,17,,,,,,2.25,0.99,2.02*0A
$GPGSV,3,1,11,3,11,22,26,296,29,27,01,142,,32,17,042,23*48
$GPGLL,4107.32485,N,00831.79799,W,110827.00,A,A*7F

There are different types of NMEA sentences. The type of message is indicated by the characters before the first comma.

The GP after the $ indicates it is a GPS position. The $GPGGA is the basic GPS NMEA message, that provides 3D location and accuracy data.

In the following sentence:

$GPGGA,110827.00,41XX.32485,N,008XX.XXXXX,W,1,07,0.99,123.1,M,50.1,M,,*48

• 110827 – represents the time at which the fix location was taken, 11:08:27 UTC
• 41XX.32845,N – latitude 41 deg XX.32845,N
• 00831.79799,W – Longitude 008 deg XX.XXXXX′ W
• 1 – fix quality (0 = invalid; 1= GPS fix; 2 = DGPS fix; 3 = PPS fix; 4 = Real Time Kinematic; 5 = Float RTK; 6 = estimated (dead reckoning); 7 = Manual input mode; 8 = Simulation mode)
• 07 – number of satellites being tracked
• 0.99 – Horizontal dilution of position (less than one is ideal)
• 123.1, M – Altitude, in meters above the sea level
• 50.1, M – Height of geoid (mean sea level) above WGS84 ellipsoid
• empty field – time in seconds since last DGPS update
• empty field – DGPS station ID number
• *48 – the checksum data, always begins with *

The other NMEA sentences provide additional information:

• $GPGSA – GPS DOP and active satellites
• $GPGSV – Detailed GPS satellite information
• $GPGLL – Geographic Latitude and Longitude
• $GPRMC – Essential GPS pvt (position, velocity, time) data
• $GPVTG – Velocity made good

You can use this Online NME Analyser and paste your sentences there to interpret the GPS data.

However, the easiest way to get and interpret the GPS data you want is to parse your NMEA sentences directly in the code. For that, we’ll use the micropyGPS module.

Uploading the micropyGPS Module

To parse the NMEA sentences from the GPS module and get GPS data easily, we’ll use the micropyGPS module. This library isn’t part of the standard MicroPython library by default. So, you need to upload the following file to your Raspberry Pi Pico board (save it with the name micropyGPS.py).

"""
# MicropyGPS - a GPS NMEA sentence parser for Micropython/Python 3.X
# Copyright (c) 2017 Michael Calvin McCoy ([email protected])
# The MIT License (MIT) - see LICENSE file
"""

# TODO:
# Time Since First Fix
# Distance/Time to Target
# More Helper Functions
# Dynamically limit sentences types to parse

from math import floor, modf

# Import utime or time for fix time handling
try:
    # Assume running on MicroPython
    import utime
except ImportError:
    # Otherwise default to time module for non-embedded implementations
    # Should still support millisecond resolution.
    import time


class MicropyGPS(object):
    """GPS NMEA Sentence Parser. Creates object that stores all relevant GPS data and statistics.
    Parses sentences one character at a time using update(). """

    # Max Number of Characters a valid sentence can be (based on GGA sentence)
    SENTENCE_LIMIT = 90
    __HEMISPHERES = ('N', 'S', 'E', 'W')
    __NO_FIX = 1
    __FIX_2D = 2
    __FIX_3D = 3
    __DIRECTIONS = ('N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE', 'S', 'SSW', 'SW', 'WSW', 'W',
                    'WNW', 'NW', 'NNW')
    __MONTHS = ('January', 'February', 'March', 'April', 'May',
                'June', 'July', 'August', 'September', 'October',
                'November', 'December')

    def __init__(self, local_offset=0, location_formatting='ddm'):
        """
        Setup GPS Object Status Flags, Internal Data Registers, etc
            local_offset (int): Timzone Difference to UTC
            location_formatting (str): Style For Presenting Longitude/Latitude:
                                       Decimal Degree Minute (ddm) - 40° 26.767′ N
                                       Degrees Minutes Seconds (dms) - 40° 26′ 46″ N
                                       Decimal Degrees (dd) - 40.446° N
        """

        #####################
        # Object Status Flags
        self.sentence_active = False
        self.active_segment = 0
        self.process_crc = False
        self.gps_segments = []
        self.crc_xor = 0
        self.char_count = 0
        self.fix_time = 0

        #####################
        # Sentence Statistics
        self.crc_fails = 0
        self.clean_sentences = 0
        self.parsed_sentences = 0

        #####################
        # Logging Related
        self.log_handle = None
        self.log_en = False

        #####################
        # Data From Sentences
        # Time
        self.timestamp = [0, 0, 0.0]
        self.date = [0, 0, 0]
        self.local_offset = local_offset

        # Position/Motion
        self._latitude = [0, 0.0, 'N']
        self._longitude = [0, 0.0, 'W']
        self.coord_format = location_formatting
        self.speed = [0.0, 0.0, 0.0]
        self.course = 0.0
        self.altitude = 0.0
        self.geoid_height = 0.0

        # GPS Info
        self.satellites_in_view = 0
        self.satellites_in_use = 0
        self.satellites_used = []
        self.last_sv_sentence = 0
        self.total_sv_sentences = 0
        self.satellite_data = dict()
        self.hdop = 0.0
        self.pdop = 0.0
        self.vdop = 0.0
        self.valid = False
        self.fix_stat = 0
        self.fix_type = 1

    ########################################
    # Coordinates Translation Functions
    ########################################
    @property
    def latitude(self):
        """Format Latitude Data Correctly"""
        if self.coord_format == 'dd':
            decimal_degrees = self._latitude[0] + (self._latitude[1] / 60)
            return [decimal_degrees, self._latitude[2]]
        elif self.coord_format == 'dms':
            minute_parts = modf(self._latitude[1])
            seconds = round(minute_parts[0] * 60)
            return [self._latitude[0], int(minute_parts[1]), seconds, self._latitude[2]]
        else:
            return self._latitude

    @property
    def longitude(self):
        """Format Longitude Data Correctly"""
        if self.coord_format == 'dd':
            decimal_degrees = self._longitude[0] + (self._longitude[1] / 60)
            return [decimal_degrees, self._longitude[2]]
        elif self.coord_format == 'dms':
            minute_parts = modf(self._longitude[1])
            seconds = round(minute_parts[0] * 60)
            return [self._longitude[0], int(minute_parts[1]), seconds, self._longitude[2]]
        else:
            return self._longitude

    ########################################
    # Logging Related Functions
    ########################################
    def start_logging(self, target_file, mode="append"):
        """
        Create GPS data log object
        """
        # Set Write Mode Overwrite or Append
        mode_code = 'w' if mode == 'new' else 'a'

        try:
            self.log_handle = open(target_file, mode_code)
        except AttributeError:
            print("Invalid FileName")
            return False

        self.log_en = True
        return True

    def stop_logging(self):
        """
        Closes the log file handler and disables further logging
        """
        try:
            self.log_handle.close()
        except AttributeError:
            print("Invalid Handle")
            return False

        self.log_en = False
        return True

    def write_log(self, log_string):
        """Attempts to write the last valid NMEA sentence character to the active file handler
        """
        try:
            self.log_handle.write(log_string)
        except TypeError:
            return False
        return True

    ########################################
    # Sentence Parsers
    ########################################
    def gprmc(self):
        """Parse Recommended Minimum Specific GPS/Transit data (RMC)Sentence.
        Updates UTC timestamp, latitude, longitude, Course, Speed, Date, and fix status
        """

        # UTC Timestamp
        try:
            utc_string = self.gps_segments[1]

            if utc_string:  # Possible timestamp found
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
                self.timestamp = [hours, minutes, seconds]
            else:  # No Time stamp yet
                self.timestamp = [0, 0, 0.0]

        except ValueError:  # Bad Timestamp value present
            return False

        # Date stamp
        try:
            date_string = self.gps_segments[9]

            # Date string printer function assumes to be year >=2000,
            # date_string() must be supplied with the correct century argument to display correctly
            if date_string:  # Possible date stamp found
                day = int(date_string[0:2])
                month = int(date_string[2:4])
                year = int(date_string[4:6])
                self.date = (day, month, year)
            else:  # No Date stamp yet
                self.date = (0, 0, 0)

        except ValueError:  # Bad Date stamp value present
            return False

        # Check Receiver Data Valid Flag
        if self.gps_segments[2] == 'A':  # Data from Receiver is Valid/Has Fix

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[3]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[4]

                # Longitude
                l_string = self.gps_segments[5]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[6]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Speed
            try:
                spd_knt = float(self.gps_segments[7])
            except ValueError:
                return False

            # Course
            try:
                if self.gps_segments[8]:
                    course = float(self.gps_segments[8])
                else:
                    course = 0.0
            except ValueError:
                return False

            # TODO - Add Magnetic Variation

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            # Include mph and hm/h
            self.speed = [spd_knt, spd_knt * 1.151, spd_knt * 1.852]
            self.course = course
            self.valid = True

            # Update Last Fix Time
            self.new_fix_time()

        else:  # Clear Position Data if Sentence is 'Invalid'
            self._latitude = [0, 0.0, 'N']
            self._longitude = [0, 0.0, 'W']
            self.speed = [0.0, 0.0, 0.0]
            self.course = 0.0
            self.valid = False

        return True

    def gpgll(self):
        """Parse Geographic Latitude and Longitude (GLL)Sentence. Updates UTC timestamp, latitude,
        longitude, and fix status"""

        # UTC Timestamp
        try:
            utc_string = self.gps_segments[5]

            if utc_string:  # Possible timestamp found
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
                self.timestamp = [hours, minutes, seconds]
            else:  # No Time stamp yet
                self.timestamp = [0, 0, 0.0]

        except ValueError:  # Bad Timestamp value present
            return False

        # Check Receiver Data Valid Flag
        if self.gps_segments[6] == 'A':  # Data from Receiver is Valid/Has Fix

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[1]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[2]

                # Longitude
                l_string = self.gps_segments[3]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[4]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            self.valid = True

            # Update Last Fix Time
            self.new_fix_time()

        else:  # Clear Position Data if Sentence is 'Invalid'
            self._latitude = [0, 0.0, 'N']
            self._longitude = [0, 0.0, 'W']
            self.valid = False

        return True

    def gpvtg(self):
        """Parse Track Made Good and Ground Speed (VTG) Sentence. Updates speed and course"""
        try:
            course = float(self.gps_segments[1]) if self.gps_segments[1] else 0.0
            spd_knt = float(self.gps_segments[5]) if self.gps_segments[5] else 0.0
        except ValueError:
            return False

        # Include mph and km/h
        self.speed = (spd_knt, spd_knt * 1.151, spd_knt * 1.852)
        self.course = course
        return True

    def gpgga(self):
        """Parse Global Positioning System Fix Data (GGA) Sentence. Updates UTC timestamp, latitude, longitude,
        fix status, satellites in use, Horizontal Dilution of Precision (HDOP), altitude, geoid height and fix status"""

        try:
            # UTC Timestamp
            utc_string = self.gps_segments[1]

            # Skip timestamp if receiver doesn't have on yet
            if utc_string:
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
            else:
                hours = 0
                minutes = 0
                seconds = 0.0

            # Number of Satellites in Use
            satellites_in_use = int(self.gps_segments[7])

            # Get Fix Status
            fix_stat = int(self.gps_segments[6])

        except (ValueError, IndexError):
            return False

        try:
            # Horizontal Dilution of Precision
            hdop = float(self.gps_segments[8])
        except (ValueError, IndexError):
            hdop = 0.0

        # Process Location and Speed Data if Fix is GOOD
        if fix_stat:

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[2]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[3]

                # Longitude
                l_string = self.gps_segments[4]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[5]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Altitude / Height Above Geoid
            try:
                altitude = float(self.gps_segments[9])
                geoid_height = float(self.gps_segments[11])
            except ValueError:
                altitude = 0
                geoid_height = 0

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            self.altitude = altitude
            self.geoid_height = geoid_height

        # Update Object Data
        self.timestamp = [hours, minutes, seconds]
        self.satellites_in_use = satellites_in_use
        self.hdop = hdop
        self.fix_stat = fix_stat

        # If Fix is GOOD, update fix timestamp
        if fix_stat:
            self.new_fix_time()

        return True

    def gpgsa(self):
        """Parse GNSS DOP and Active Satellites (GSA) sentence. Updates GPS fix type, list of satellites used in
        fix calculation, Position Dilution of Precision (PDOP), Horizontal Dilution of Precision (HDOP), Vertical
        Dilution of Precision, and fix status"""

        # Fix Type (None,2D or 3D)
        try:
            fix_type = int(self.gps_segments[2])
        except ValueError:
            return False

        # Read All (up to 12) Available PRN Satellite Numbers
        sats_used = []
        for sats in range(12):
            sat_number_str = self.gps_segments[3 + sats]
            if sat_number_str:
                try:
                    sat_number = int(sat_number_str)
                    sats_used.append(sat_number)
                except ValueError:
                    return False
            else:
                break

        # PDOP,HDOP,VDOP
        try:
            pdop = float(self.gps_segments[15])
            hdop = float(self.gps_segments[16])
            vdop = float(self.gps_segments[17])
        except ValueError:
            return False

        # Update Object Data
        self.fix_type = fix_type

        # If Fix is GOOD, update fix timestamp
        if fix_type > self.__NO_FIX:
            self.new_fix_time()

        self.satellites_used = sats_used
        self.hdop = hdop
        self.vdop = vdop
        self.pdop = pdop

        return True

    def gpgsv(self):
        """Parse Satellites in View (GSV) sentence. Updates number of SV Sentences,the number of the last SV sentence
        parsed, and data on each satellite present in the sentence"""
        try:
            num_sv_sentences = int(self.gps_segments[1])
            current_sv_sentence = int(self.gps_segments[2])
            sats_in_view = int(self.gps_segments[3])
        except ValueError:
            return False

        # Create a blank dict to store all the satellite data from this sentence in:
        # satellite PRN is key, tuple containing telemetry is value
        satellite_dict = dict()

        # Calculate  Number of Satelites to pull data for and thus how many segment positions to read
        if num_sv_sentences == current_sv_sentence:
            # Last sentence may have 1-4 satellites; 5 - 20 positions
            sat_segment_limit = (sats_in_view - ((num_sv_sentences - 1) * 4)) * 5
        else:
            sat_segment_limit = 20  # Non-last sentences have 4 satellites and thus read up to position 20

        # Try to recover data for up to 4 satellites in sentence
        for sats in range(4, sat_segment_limit, 4):

            # If a PRN is present, grab satellite data
            if self.gps_segments[sats]:
                try:
                    sat_id = int(self.gps_segments[sats])
                except (ValueError,IndexError):
                    return False

                try:  # elevation can be null (no value) when not tracking
                    elevation = int(self.gps_segments[sats+1])
                except (ValueError,IndexError):
                    elevation = None

                try:  # azimuth can be null (no value) when not tracking
                    azimuth = int(self.gps_segments[sats+2])
                except (ValueError,IndexError):
                    azimuth = None

                try:  # SNR can be null (no value) when not tracking
                    snr = int(self.gps_segments[sats+3])
                except (ValueError,IndexError):
                    snr = None
            # If no PRN is found, then the sentence has no more satellites to read
            else:
                break

            # Add Satellite Data to Sentence Dict
            satellite_dict[sat_id] = (elevation, azimuth, snr)

        # Update Object Data
        self.total_sv_sentences = num_sv_sentences
        self.last_sv_sentence = current_sv_sentence
        self.satellites_in_view = sats_in_view

        # For a new set of sentences, we either clear out the existing sat data or
        # update it as additional SV sentences are parsed
        if current_sv_sentence == 1:
            self.satellite_data = satellite_dict
        else:
            self.satellite_data.update(satellite_dict)

        return True

    ##########################################
    # Data Stream Handler Functions
    ##########################################

    def new_sentence(self):
        """Adjust Object Flags in Preparation for a New Sentence"""
        self.gps_segments = ['']
        self.active_segment = 0
        self.crc_xor = 0
        self.sentence_active = True
        self.process_crc = True
        self.char_count = 0

    def update(self, new_char):
        """Process a new input char and updates GPS object if necessary based on special characters ('$', ',', '*')
        Function builds a list of received string that are validate by CRC prior to parsing by the  appropriate
        sentence function. Returns sentence type on successful parse, None otherwise"""

        valid_sentence = False

        # Validate new_char is a printable char
        ascii_char = ord(new_char)

        if 10 <= ascii_char <= 126:
            self.char_count += 1

            # Write Character to log file if enabled
            if self.log_en:
                self.write_log(new_char)

            # Check if a new string is starting ($)
            if new_char == '$':
                self.new_sentence()
                return None

            elif self.sentence_active:

                # Check if sentence is ending (*)
                if new_char == '*':
                    self.process_crc = False
                    self.active_segment += 1
                    self.gps_segments.append('')
                    return None

                # Check if a section is ended (,), Create a new substring to feed
                # characters to
                elif new_char == ',':
                    self.active_segment += 1
                    self.gps_segments.append('')

                # Store All Other printable character and check CRC when ready
                else:
                    self.gps_segments[self.active_segment] += new_char

                    # When CRC input is disabled, sentence is nearly complete
                    if not self.process_crc:

                        if len(self.gps_segments[self.active_segment]) == 2:
                            try:
                                final_crc = int(self.gps_segments[self.active_segment], 16)
                                if self.crc_xor == final_crc:
                                    valid_sentence = True
                                else:
                                    self.crc_fails += 1
                            except ValueError:
                                pass  # CRC Value was deformed and could not have been correct

                # Update CRC
                if self.process_crc:
                    self.crc_xor ^= ascii_char

                # If a Valid Sentence Was received and it's a supported sentence, then parse it!!
                if valid_sentence:
                    self.clean_sentences += 1  # Increment clean sentences received
                    self.sentence_active = False  # Clear Active Processing Flag

                    if self.gps_segments[0] in self.supported_sentences:

                        # parse the Sentence Based on the message type, return True if parse is clean
                        if self.supported_sentences[self.gps_segments[0]](self):

                            # Let host know that the GPS object was updated by returning parsed sentence type
                            self.parsed_sentences += 1
                            return self.gps_segments[0]

                # Check that the sentence buffer isn't filling up with Garage waiting for the sentence to complete
                if self.char_count > self.SENTENCE_LIMIT:
                    self.sentence_active = False

        # Tell Host no new sentence was parsed
        return None

    def new_fix_time(self):
        """Updates a high resolution counter with current time when fix is updated. Currently only triggered from
        GGA, GSA and RMC sentences"""
        try:
            self.fix_time = utime.ticks_ms()
        except NameError:
            self.fix_time = time.time()

    #########################################
    # User Helper Functions
    # These functions make working with the GPS object data easier
    #########################################

    def satellite_data_updated(self):
        """
        Checks if the all the GSV sentences in a group have been read, making satellite data complete
        :return: boolean
        """
        if self.total_sv_sentences > 0 and self.total_sv_sentences == self.last_sv_sentence:
            return True
        else:
            return False

    def unset_satellite_data_updated(self):
        """
        Mark GSV sentences as read indicating the data has been used and future updates are fresh
        """
        self.last_sv_sentence = 0

    def satellites_visible(self):
        """
        Returns a list of of the satellite PRNs currently visible to the receiver
        :return: list
        """
        return list(self.satellite_data.keys())

    def time_since_fix(self):
        """Returns number of millisecond since the last sentence with a valid fix was parsed. Returns 0 if
        no fix has been found"""

        # Test if a Fix has been found
        if self.fix_time == 0:
            return -1

        # Try calculating fix time using utime; if not running MicroPython
        # time.time() returns a floating point value in secs
        try:
            current = utime.ticks_diff(utime.ticks_ms(), self.fix_time)
        except NameError:
            current = (time.time() - self.fix_time) * 1000  # ms

        return current

    def compass_direction(self):
        """
        Determine a cardinal or inter-cardinal direction based on current course.
        :return: string
        """
        # Calculate the offset for a rotated compass
        if self.course >= 348.75:
            offset_course = 360 - self.course
        else:
            offset_course = self.course + 11.25

        # Each compass point is separated by 22.5 degrees, divide to find lookup value
        dir_index = floor(offset_course / 22.5)

        final_dir = self.__DIRECTIONS[dir_index]

        return final_dir

    def latitude_string(self):
        """
        Create a readable string of the current latitude data
        :return: string
        """
        if self.coord_format == 'dd':
            formatted_latitude = self.latitude
            lat_string = str(formatted_latitude[0]) + '° ' + str(self._latitude[2])
        elif self.coord_format == 'dms':
            formatted_latitude = self.latitude
            lat_string = str(formatted_latitude[0]) + '° ' + str(formatted_latitude[1]) + "' " + str(formatted_latitude[2]) + '" ' + str(formatted_latitude[3])
        else:
            lat_string = str(self._latitude[0]) + '° ' + str(self._latitude[1]) + "' " + str(self._latitude[2])
        return lat_string

    def longitude_string(self):
        """
        Create a readable string of the current longitude data
        :return: string
        """
        if self.coord_format == 'dd':
            formatted_longitude = self.longitude
            lon_string = str(formatted_longitude[0]) + '° ' + str(self._longitude[2])
        elif self.coord_format == 'dms':
            formatted_longitude = self.longitude
            lon_string = str(formatted_longitude[0]) + '° ' + str(formatted_longitude[1]) + "' " + str(formatted_longitude[2]) + '" ' + str(formatted_longitude[3])
        else:
            lon_string = str(self._longitude[0]) + '° ' + str(self._longitude[1]) + "' " + str(self._longitude[2])
        return lon_string

    def speed_string(self, unit='kph'):
        """
        Creates a readable string of the current speed data in one of three units
        :param unit: string of 'kph','mph, or 'knot'
        :return:
        """
        if unit == 'mph':
            speed_string = str(self.speed[1]) + ' mph'

        elif unit == 'knot':
            if self.speed[0] == 1:
                unit_str = ' knot'
            else:
                unit_str = ' knots'
            speed_string = str(self.speed[0]) + unit_str

        else:
            speed_string = str(self.speed[2]) + ' km/h'

        return speed_string

    def date_string(self, formatting='s_mdy', century='20'):
        """
        Creates a readable string of the current date.
        Can select between long format: Januray 1st, 2014
        or two short formats:
        11/01/2014 (MM/DD/YYYY)
        01/11/2014 (DD/MM/YYYY)
        :param formatting: string 's_mdy', 's_dmy', or 'long'
        :param century: int delineating the century the GPS data is from (19 for 19XX, 20 for 20XX)
        :return: date_string  string with long or short format date
        """

        # Long Format Januray 1st, 2014
        if formatting == 'long':
            # Retrieve Month string from private set
            month = self.__MONTHS[self.date[1] - 1]

            # Determine Date Suffix
            if self.date[0] in (1, 21, 31):
                suffix = 'st'
            elif self.date[0] in (2, 22):
                suffix = 'nd'
            elif self.date[0] == (3, 23):
                suffix = 'rd'
            else:
                suffix = 'th'

            day = str(self.date[0]) + suffix  # Create Day String

            year = century + str(self.date[2])  # Create Year String

            date_string = month + ' ' + day + ', ' + year  # Put it all together

        else:
            # Add leading zeros to day string if necessary
            if self.date[0] < 10:
                day = '0' + str(self.date[0])
            else:
                day = str(self.date[0])

            # Add leading zeros to month string if necessary
            if self.date[1] < 10:
                month = '0' + str(self.date[1])
            else:
                month = str(self.date[1])

            # Add leading zeros to year string if necessary
            if self.date[2] < 10:
                year = '0' + str(self.date[2])
            else:
                year = str(self.date[2])

            # Build final string based on desired formatting
            if formatting == 's_dmy':
                date_string = day + '/' + month + '/' + year

            else:  # Default date format
                date_string = month + '/' + day + '/' + year

        return date_string

    # All the currently supported NMEA sentences
    supported_sentences = {'GPRMC': gprmc, 'GLRMC': gprmc,
                           'GPGGA': gpgga, 'GLGGA': gpgga,
                           'GPVTG': gpvtg, 'GLVTG': gpvtg,
                           'GPGSA': gpgsa, 'GLGSA': gpgsa,
                           'GPGSV': gpgsv, 'GLGSV': gpgsv,
                           'GPGLL': gpgll, 'GLGLL': gpgll,
                           'GNGGA': gpgga, 'GNRMC': gprmc,
                           'GNVTG': gpvtg, 'GNGLL': gpgll,
                           'GNGSA': gpgsa,
                          }

if __name__ == "__main__":
    pass

View raw code

These are the general instructions to upload the micropyGPS library to your board:

1. First, make sure your board is running MicroPython firmware—check the Prerequisites section.
2. Create a new file in your IDE with the name micropyGPS.py and paste the previous code there. Save that file.
3. Establish a serial communication with your board using your IDE.
4. Upload the micropyGPS.py file to your board. In Thonny IDE, go to File > Save as… and select MicroPython Device/Raspberry Pi Pico.
5. At this point, the library should have been successfully uploaded to your board. Now, you can use the library functionalities in your code by importing the library import micropyGPS.

Raspberry Pi Pico with NEO-6M: Getting GPS Data with MicroPython

The micropyGPS library makes it easier to get GPS data in a format that is easy to understand.

The following code shows how to use the library to get GPS data like latitude, longitude, altitude, date and time, number of visible satellites and HDOP (a measurement of how precise the signal is).

After importing the micropyGPS library to your board, you can run the following code.

# Rui Santos & Sara Santos - Random Nerd Tutorials
# Complete project details at https://RandomNerdTutorials.com/raspberry-pi-pico-neo-6m-micropython/

from machine import UART, Pin
from time import sleep
from micropyGPS import MicropyGPS

# Instantiate the micropyGPS object
my_gps = MicropyGPS()

# Define the UART pins and create a UART object
gps_serial = UART(1, baudrate=9600, tx=Pin(4), rx=Pin(5))

while True:
    try:
        while gps_serial.any():
            data = gps_serial.read()
            for byte in data:
                stat = my_gps.update(chr(byte))
                if stat is not None:
                    # Print parsed GPS data
                    print('UTC Timestamp:', my_gps.timestamp)
                    print('Date:', my_gps.date_string('long'))
                    print('Latitude:', my_gps.latitude_string())
                    print('Longitude:', my_gps.longitude_string())
                    print('Altitude:', my_gps.altitude)
                    print('Satellites in use:', my_gps.satellites_in_use)
                    print('Horizontal Dilution of Precision:', my_gps.hdop)
                    print()
            
    except Exception as e:
        print(f"An error occurred: {e}")

View raw code

How Does the Code Work?

Continue reading to learn how the code works, or skip to the demonstration section.

First, import the required modules, including the MicropyGPS class from the micropyGPS module you imported previously.

from machine import UART, Pin
from time import sleep
from micropyGPS import MicropyGPS

Create an instance of the MicropyGPS class called my_gps.

# Instantiate the micropyGPS object
my_gps = MicropyGPS()

Then, initialize a UART instance for serial communication with the module. We’re using UART 1 and GPIO 4 for TX and GPIO 5 for RX. We also define the baud rate for the GPS module (the NEO-6M uses 9600).

gps_serial = UART(1, baudrate=9600, tx=Pin(4), rx=Pin(5))

Then, we create an infinite loop to continuously read GPS data.

We check if there is new data available to read. If there is, we read the data and pass it to the my_gps instance using the update() method.

while gps_serial.any():
    data = gps_serial.read()
    for byte in data:
        stat = my_gps.update(chr(byte))

The update() method returns valid GPS sentences or None if that’s not the case. So, we check if we have valid data before proceeding.

if stat is not None:

Then, we can access the GPS data by using the micropyGPS methods on the my_gps object that should contain the data gathered from the GPS module.

The following lines show how to get time, date, latitude, longitude, altitude, number of satellites used, and HDOP.

# Print parsed GPS data
print('UTC Timestamp:', my_gps.timestamp)
print('Date:', my_gps.date_string('long'))
print('Latitude:', my_gps.latitude_string())
print('Longitude:', my_gps.longitude_string())
print('Altitude:', my_gps.altitude)
print('Satellites in use:', my_gps.satellites_in_use)
print('Horizontal Dilution of Precision:', my_gps.hdop)
print()

The micropyGPS library supports other methods to get more GPS data and in different formats. We recommend you take a look at the documentation and see all the available options.

Demonstration

After uploading the micropyGPS module to your board, you can run this previous code to get GPS data.

Make sure you place your board or antenna next to a window, or preferably outside so that it can get data from satellites. You may need to wait a few minutes until it gets a position fix and can send valid data. The NEO-6M GPS module’s blue LED will start blinking when it’s ready.

In the MicroPython shell, you should get information about your current location, date and time in UTC, number of satellites, and HDOP. The higher the number of satellites and the lower the HDOP the better.

Wrapping Up

In this tutorial, you learned how to use the NEO-6M GPS module with the Raspberry Pi Pico using MicroPython. You learned how to get your current location and date and time.

Now, you can take this project further and display the data on an OLED display or LCD. You can check the following tutorials to learn how to use these displays with the Raspberry Pi Pico:

• Raspberry Pi Pico: SSD1306 OLED Display (MicroPython)
• Raspberry Pi Pico with I2C LCD Display (MicroPython)

We hope you find this guide useful. If you want to learn more about the Raspberry Pi Pico, make sure to take a look at our eBook:

• Learn Raspberry Pi Pico/PicoW with MicroPython (eBook)
• Free Raspberry Pi Pico projects and tutorials

Thanks for reading.