There are some GPS modules that we can apply on the ESP32 board. The GPS module usually uses the UART interface to communicate to the board. UART is a serial communication model that can send and receive data per byte sequentially. Our board waits for incoming messages from the GPS module via UART.
The following code block is an example of the data output from a GPS module. This data shows that our GPS module cannot detect our location from the satellite. All GPS data is defined in NMEA format; further information about NMEA can be found at http://www.nmea.org/content/nmea_standards/nmea_0183_v_410.asp.
$GPGLL,,,,,,V,N*64
$GPRMC,,V,,,,,,,,,,N*53
$GPVTG,,,,,,,,,N*30
$GPGGA,,,,,,0,00,99.99,,,,,,*48
$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
$GPGSV,1,1,01,04,,,13*7E
$GPGLL,,,,,,V,N*64
$GPRMC,,V,,,,,,,,,,N*53
$GPVTG,,,,,,,,,N*30
You may not get the position of the data from the GPS module; here is a sample of GPS data with the GPGGA format:
$GPGGA,215322.000,5003.8239,N,12584.1234,W,1,07,1.6,1581.9,M,-20.7,M,,0000*5F
For example, we can read the GPS data with the GPGGA format as follows:
- Time: 215322.000 is 21:53 and 22.000 seconds in Greenwich Mean Time (GMT)
- Longitude: 5003.8240,N is latitude in degrees.decimal minutes, north
- Latitude: 12584.1234,W is longitude in degrees.decimal minutes, west
- Number: The number of satellites seen: 07
- Altitude: 1,581 meters
For the GPS module, we can use SparkFun. You can find out about SparkFun GPS-RTK2 Board – ZED-F9P (Qwiic) at https://www.sparkfun.com/products/15136. Figure 7-3 shows a form of parkFun GPS-RTK2 Board:
You also can find cheap GPS modules on AliExpress. I recommend using the GPS module from u-blox's modules. You can see u-blox's modules for GPS at https://www.u-blox.com/en/positioning-chips-and-modules.