GNSS¶

Overview¶

The GNSS sample demonstrates how to use the GNSS interface to control the GNSS module.

The sample first initializes the GNSS module. Then it handles events from the interface, reads the associated data and outputs information to the console. Because NMEA data needs to be read as soon as an NMEA event is received, a Zephyr message queue is used for buffering the NMEA strings. The event handler function reads the received NMEA strings and puts those into the message queue. The consumer loop reads from the queue and outputs the strings to the console.

Requirements¶

Before you start, check that you have the required hardware and software:

• 1x nRF9151 Connect Kit
• 1x nano-SIM card with LTE-M or NB-IoT support
• 1x U.FL cabled LTE-M/NB-IoT/NR+ Flexible Antenna (included in the box)
• 1x U.FL cabled GNSS Antenna (included in the box)
• 1x USB-C Cable
• A computer running macOS, Ubuntu, or Windows 10 or newer

Set up your board¶

1. Insert the nano-SIM card into the nano-SIM card slot.
2. Attach the U.FL cabled LTE-M/NB-IoT/NR+ Flexible Antenna.
3. Attach the U.FL cabled GNSS Antenna.
4. Connect the nRF9151 Connect Kit to the computer with a USB-C cable.

Building the sample¶

To build the sample, follow the instructions in Getting Started Guide to set up your preferred building environment.

Use the following steps to build the GNSS sample on the command line.

1. Open a terminal window.

2. Go to NCS-Project/nrf9151-connectkit repository cloned in the Getting Started Guide.

3. Build the sample using the west build command, specifying the board (following the -b option) as nrf9151_connectkit/nrf9151/ns.

   west build -p always -b nrf9151_connectkit/nrf9151/ns samples/gnss
   

   The -p always option forces a pristine build, and is recommended for new users. Users may also use the -p auto option, which will use heuristics to determine if a pristine build is required, such as when building another sample.

   Note

   This sample has Cortex-M Security Extensions (CMSE) enabled and separates the firmware between Non-Secure Processing Environment (NSPE) and Secure Processing Environment (SPE). Because of this, it automatically includes the Trusted Firmware-M (TF-M).

4. After building the sample successfully, the firmware with the name merged.hex can be found in the build directory.

Flashing the firmware¶

Set up your board before flashing the firmware. You can flash the sample using west flash:

west flash

pyocd load --target nrf91 --frequency 4000000 build/merged.hex

Testing¶

After programming the sample, test it by performing the following steps:

1. Open up a serial terminal, specifying the correct serial port that your computer uses to communicate with the nRF9151 SiP:

   WindowsmacOSUbuntu

   1. Start PuTTY.

   2. Configure the correct serial port and click Open:

      

   Open up a terminal and run:

   screen <serial-port-name> 115200
   

   Open up a terminal and run:

   screen <serial-port-name> 115200
   

2. Press the DFU/RST button to reset the nRF9151 SiP.

3. Observe that the following information is displayed in the terminal:

   Terminal
   1 2 3 4 5 6 7 8 9 10 11 12	Tracking: 0 Using: 0 Unhealthy: 0 ----------------------------------- Seconds since last fix: 5 Searching [/] NMEA strings: $GPGGA,000005.14,,,,,0,,99.99,,M,,M,,*66 $GPGLL,,,,,000005.14,V,N*4A $GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,1*2D $GPGSV,1,1,0,,,,,,,,,,,,,,,,,1*54 $GPRMC,000005.14,V,,,,,,,060180,,,N,V*08

4. Observe that the following information is displayed upon acquiring a fix:

   Terminal

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

   Tracking: 12 Using: 10 Unhealthy: 0 ----------------------------------- Latitude: 22.693996 Longitude: 113.941899 Accuracy: 1.6 m Altitude: 104.9 m Altitude accuracy: 3.5 m Speed: 0.2 m/s Speed accuracy: 0.4 m/s V. speed: 0.2 m/s V. speed accuracy: 0.5 m/s Heading: 0.0 deg Heading accuracy: 180.0 deg Date: 2025-02-22 Time (UTC): 07:27:23.089 PDOP: 2.7 HDOP: 1.1 VDOP: 2.5 TDOP: 1.9 NMEA strings: $GPGGA,072723.09,2241.63975,N,11356.51394,E,1,10,1.08,104.91,M,,M,,*7C $GPGLL,2241.63975,N,11356.51394,E,072723.09,A,A*62 $GPGSA,A,3,01,03,14,17,19,22,30,194,195,199,,,2.72,1.08,2.50,1*2C $GPGSV,5,1,18,1,38,035,36,2,36,238,,3,40,099,37,6,33,230,26,1*6E $GPGSV,5,2,18,7,39,211,,8,06,078,,9,-2,153,25,14,62,341,43,1*42 $GPGSV,5,3,18,17,42,323,40,19,24,291,24,21,04,042,,22,41,330,38,1*60 $GPGSV,5,4,18,30,42,225,39,31,45,231,,194,61,091,34,195,63,056,39,1*60 $GPGSV,5,5,18,196,23,125,,199,59,149,33,1*65 $GPRMC,072723.09,A,2241.63975,N,11356.51394,E,0.30,0.00,220225,,,A,V*29 ...