GNSS RTK click

GNSS RTK Click is a compact add-on board used to enhance the precision of position data derived from satellite-based positioning systems. This board features the ZED-F9P, a multi-band GNSS module with integrated multi-band Real Time Kinematics (RTK) technology offering centimeter-level accuracy from U-blox. This module concurrently uses GNSS signals from all four GNSS constellations (GPS, GLONASS, Galileo, and BeiDou), and provides multi-band RTK with fast convergence times, reliable performance, and easy integration. It also includes moving base support, allowing both base and rover to move while computing a centimeter-level accurate position between them.

click Product page

Click library

• Author : Stefan Filipovic
• Date : Jul 2023.
• Type : UART/I2C/SPI type

Software Support

We provide a library for the GNSS RTK Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for GNSS RTK Click driver.

Standard key functions :

• gnssrtk_cfg_setup Config Object Initialization function.

  void gnssrtk_cfg_setup ( gnssrtk_cfg_t *cfg );

• gnssrtk_init Initialization function.

  err_t gnssrtk_init ( gnssrtk_t *ctx, gnssrtk_cfg_t *cfg );

• gnssrtk_default_cfg Click Default Configuration function.

  err_t gnssrtk_default_cfg ( gnssrtk_t *ctx );

Example key functions :

• gnssrtk_reset_device This function resets the device by toggling the RST pin.

  void gnssrtk_reset_device ( gnssrtk_t *ctx );

• gnssrtk_generic_read This function reads a desired number of data bytes from the module.

  err_t gnssrtk_generic_read ( gnssrtk_t *ctx, uint8_t *data_out, uint8_t len );

• gnssrtk_parse_gngga This function parses the GNGGA data from the read response buffer.

  err_t gnssrtk_parse_gngga ( char *rsp_buf, uint8_t gngga_element, char *element_data );

Example Description

This example demonstrates the use of GNSS RTK click by reading and displaying the GNSS coordinates.

The demo application is composed of two sections :

Application Init

Initializes the driver and resets the click board.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    gnssrtk_cfg_t gnssrtk_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );

    // Click initialization.
    gnssrtk_cfg_setup( &gnssrtk_cfg );
    GNSSRTK_MAP_MIKROBUS( gnssrtk_cfg, MIKROBUS_1 );
    err_t init_flag = gnssrtk_init( &gnssrtk, &gnssrtk_cfg );
    if ( ( UART_ERROR == init_flag ) || ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    log_info( &logger, " Application Task " );
}

Application Task

Reads the received data, parses the GNGGA info from it, and once it receives the position fix it will start displaying the coordinates on the USB UART.

void application_task ( void )
{
    gnssrtk_process( &gnssrtk );
    if ( app_buf_len > ( sizeof ( GNSSRTK_RSP_GNGGA ) + GNSSRTK_GNGGA_ELEMENT_SIZE ) ) 
    {
        gnssrtk_parser_application( app_buf );
    }
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.GNSSRTK

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.