Difficult to achieve RTK fix with ZED-F9P

GPS/GNSS Development Boards
1

Hello.

I have a Sparkfun GPS-RTK-SMA Breakout with u-blox ZED-F9P connected to an Arduino Mega in a rover.

A Raspberry Pi send RTCM Corrections to the USB port of the GPS-RTK-SMA Breakout.

I am using the SparkFun_u-blox_GNSS_Arduino_Library in order to configure the device and to receive data in Arduino board thought the UART1 port of the GPS-RTK-SMA Breakout.

But the behavior of the device is very strange:

  • Sometimes, it retrieves very incorrect data while RTK solution returns RTK fixed.

  • RTK led rarely agrees with RTK solution read with getCarrierSolutionType function.

  • Sometimes, getCarrierSolutionType function even returns 3, when the expected values are between 0 and 2.

    • Could be that behavior caused by a deficient power supply of the GPS-RTK-SMA Breakout?

    I am feeding it trough the 3.3V of the Arduino Mega. In the Hookup Guide I have read:

    “Note that if you’re provide the board with 3.3V directly it should be a clean supply with minimal noise (less than 50mV VPP ripple is ideal for precision locating)”

    If that is the case, if I feed the GPS-RTK-SMA Breakout through the 5V pin, the 3.3V regulator will reduce the 5V down to 3.3V the module requires?

    Thank you.

    2

    I believe, the Arduino mega cannot supply sufficient current to the Sparkfun GPS-RTK-SMA Breakout with u-blox ZED-F9P. You have to use a separate power supply. From the specifications, it looks like you can power up the module with 5V. The in-built voltage regulator will maintain 3.3V.