PPK Processing

Overview

Post-Processed Kinematic (PPK) is a GPS correction technology that corrects geotagged image location data after the flight. Unlike Real-Time Kinematic (RTK), which requires a constant connection between the drone and a base station, PPK processes the data after the drone captures the images. This makes it an ideal solution for remote areas with signal interference or long-range flights where maintaining an RTK link is difficult.
 

Availability: Who has access?

• PPK processing is available for Advanced, Teams and Enterprise customers.

• Supported drones include any DJI RTK model and the Skydio X10 with an RTK module attached.

  • DJI M3E RTK
  • DJI Matrice 4 Enterprise/Thermal
  • DJI P4P RTK
  • DJI M300 & M350 RTK
  • Autel Evo II Pro RTK
  • Skydio X10 RTK

• Automatic processing is currently optimized for the United States and the European Union.

  • Fast Region (Central Europe and North America)
  • Global Region (Rest of World)
  • The Global Region corrections are based on a global ionospheric model. At the same time, the Fast Region uses a denser network of reference stations to compute a regional ionospheric model for atmospheric corrections.

  

How to upload PPK & Base Data

Follow these steps to upload your data for PPK processing.

1. Log in to DroneDeploy. Access your account via a web browser and navigate to your project.

2. Open the Upload tab. Click New Upload
   

3. Select your files. Select all drone images along with the satellite observation files. For most DJI drones, these are the .OBS and .MRK files found in the Survey folder.
   

4. Confirm PPK detection. A small target icon appears in the uploader to indicate that DroneDeploy recognizes the PPK data.
   

5. You can also choose Add Base Data under the 3 dot menu. Drag and drop your Base Station's OBS file or .0-23O. Click Process
    

   

6. Start the upload. Click Upload to begin the process. DroneDeploy will send an email once the map completes processing.

Setting Up Base Data

Here are some key requirements to keep in mind:

• The base does not need to be set up on a known point, 
• The base must record for a minimum of 1 hour (completely overlapping the drone's flight)
• The base must export an OBS file or *.*o file (e.g. .25o)
• The timestamps in the base station’s file must be whole number integers, without decimals
   

Understanding the Processing Report

To access the processing report, click here. This new section of the Processing Report details any trajectories processed using Post Processed Kinematic (PPK) to improve map accuracy. 

The chart shows the image coordinates' standard deviation (estimated accuracy) for each axis. As a general rule, one can expect the Z-axis accuracy to be triple that of the X and Y. This is due to the positions of the satellites relative to the receiver.

PPK Status: This is the overall quality indicator of the map's processing status. If it shows an error, contact support. 

Datum: This is the datum and epoch in which the flight was processed. It can be used to compensate for tectonic plate movement when re-projecting to a different coordinate system.

Successful Trajectories: When a map is processed with multiple trajectories, some or all may fail to process. A trajectory is created for each battery change. If any have failed, contact support.

Median Standard Deviation: This represents the delta between the initial and solved camera positions. As with RTK, it's important to note that these figures represent the deviation of the solved camera position before photogrammetry, NOT the final map's absolute accuracy.

Key Features

• Centimeter-Level Precision: Achieve < 3 cm horizontal RMS error and < 6 cm vertical RMS error once the solution converges.

• Autonomous Correction: The system automatically selects the best correction source (VRS or local base station) to process your trajectories.

• Resilience: Salvage high-accuracy maps even if your RTK connection dropped during the mission.

• Detailed Processing Report: Review standard deviation for each axis and verify the success of individual trajectories.

Limitations

• Data Size: The .OBS file cannot exceed 500MB.

• Flight Duration: You must be in the air capturing images for at least 10 minutes to allow the PPK solution to converge.

• Hardware Requirement: You must mount the RTK module on the drone even when flying specifically for PPK.

• Internet Connection: A stable internet connection is required to upload the large datasets to the DroneDeploy website.

FAQs

Q: How long must I fly for?
A: Fast Region: Convergence time is at least 10 minutes. Global Region: Convergence time is at least 20 minutes

Q: What if my map time is under 10 minutes? 
A: Convergence occurs as images and their corresponding locations are logged. In our PPK graph, you can see that convergence (when the standard deviation drops) is a function of the number of images taken. Time is how we reflect the image count. You will need to be in the air capturing images for at least 10 minutes for PPK to apply to your dataset. 



Q: Does PPK increase my processing time? 
A: Yes. PPK processing typically adds approximately 15 minutes to the total processing time.

Q: Do I still need Ground Control Points (GCPs)? 
A: PPK maps provide high relative accuracy. However, DroneDeploy recommends using at least one GCP to localize the map or multiple checkpoints to verify absolute accuracy against known benchmarks.

Q: Can I use PPK with third-party flight apps? 
A: Yes. DroneDeploy supports datasets captured in various ground control applications as long as the required satellite data files are included.
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