> For the complete documentation index, see [llms.txt](https://drotek.gitbook.io/rtk-f9p-positioning-solutions/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://drotek.gitbook.io/rtk-f9p-positioning-solutions/tutorials/precise-post-processing-ppp.md).

# Precise Post Processing (PPP)

GNSS modules can be configured to continuously stream data in raw data format for PPP purposes. The data is initially recorded via u-center with the below configuration messages. Then the file can be used for post-processing with the help of RTKLib. 

![](/files/sh7cM8nowQcoS4zHrlAG)

For raw data recording, you may activate the following messages to obtain .ubx data:

![](/files/y0OuImsbPcSURSiKEGXP)

* UBX to USB
* UBX to UART (We prefer using UART1, whilst UART2 is not viable for raw data processing)

Menu -> View → Configuration View → MSG (Messages):\
1\. Select Message “02-10 RXM-RAW”, and check USB. \
Then click on the “Send” button at the bottom left of the Messages window.\
\
2\. Select Message “02-11 RXM-SFRB”, and check USB. \
Then click on the “Send” button at the bottom left of the Messages window.\
\
3\. Select Message “02-30 RXM-ALM” and check USB. \
Then click on the “Send” button at the bottom left of the Messages window.\
\
4\. Select Message “02-31 RXM-EPH” and check USB. \
Then click on the “Send” button at the bottom left of the Messages window.

![](/files/HV1iNiVobpb4ZwkrGerT)

Finally, Menu -> View → Configuration View → CFG (Configuration): Save to current configuration, Select all devices.\
Then click on the “Send” button at the bottom left of the Configuration window.