# PPK Files

## Introduction

When operating Sentera sensors with the RTK PPK module and the Sentera GNSS configuration file, the sensor will produce two additional files, a .ubx file and a .mrk (timestamp) file. These are the files used to generate a PPK solution. 

{% hint style="info" %}
These files are generated when operating with RTK as well as a backup. 
{% endhint %}

## File Locations

These files are located within the session folder (YYYY-MM-DD\_HH\_MM\_SS) that is generated once the lights on the sensor turn green. Within each session folder the folder with the imagery and the PPK files can be found. The PPK files will have the same date pre-fix as the session folder. 

<figure><img src="/files/1hQPkqHue0fpDPr5g7BG" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/DCJYZDhIxR0zjVM84GjJ" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
If these files are not present after an RTK or PPK flight, check the configuration file of the sensor to ensure it is the Sentera GNSS version. These files will not be created without the correct configuration file.&#x20;
{% endhint %}

## UBX File

This is the file that contains the GNSS information for the rover (aircraft).&#x20;

This file can be converted to a set of Rinex files using tools like Emlid Studio or RTKlib. Many post processing suites will accept the .ubx file without conversion to Rinex.&#x20;

## MRK File

This is the file that contains the timestamp (trigger) information for when each image was captured. This is used for synchronization of the GNSS information used to generate the PPK solution.&#x20;


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