PPK Processing

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DroneDeploy Auto-PPK Solution

Available for Advanced, Teams, and Enterprise subscriptions

 

Background on PPK

PPK is a GPS corrections technology, like RTK, that corrects geotagged image location data. Observations data is collected from the base (VRS) and rover (drone) and is corrected after the drone has captured images, thus being “post-processed.” Learn more about PPK vs RTK in a recent blog update.

 

 

Value of PPK

Users in remote areas (or areas with signal interference) can create high-accuracy maps without relying on RTK connectivity. Longer flights over varied terrain can have difficulty maintaining a fixed RTK connection, in these cases we can still salvage a highly accurate map through PPK. Through our implementation making use of Virtual Reference Stations (VRS), users do not need to supply their own base for observations, which eliminates the need for costly additional hardware.

 

Earthworks and mining operations at very large sites and/or where RTK network strength and/or cellular connectivity is poor/unavailable are common users of PPK workflows.

 

Supported Drones

  1. DJI M3E RTK
  2. DJI P4P RTK
  3. DJI M300 & M350 RTK
  4. Autel Evo II Pro RTK
  5. Skydio x10

 

 

Steps to use DroneDeploy's Auto-PPK Solution

In summary, after flight the user uploads the Survey folder via Smart Uploader (containing observations data + images) from any DJI RTK drone for fully automatic high-accuracy PPK processing (US and EU only).

 

  1. Fly your mapping mission as usual, with RTK module connected to DJI drone in good repair
  2. From desktop, navigate to Upload
  3. Select New Upload to open Smart Uploader



  1. Select Choose Files

  1. Navigate to the “Survey” folder of a compatible DJI drone and select its contents (.jpeg images + .obs + .mrk data).
    1. Smart Uploader recognizes as an image set ready for PPK processing

 

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  1. Complete your upload as usual and await processing completed results.

 

Understanding the Processing Report

How to access the processing report - click here

 

This new section of the Processing Report provides details on any trajectories processed using Post Processed Kinematic (PPK) to improve map accuracy. 

 

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

Typical PPK convergence summary in Processing Report

 

PPK Status: Is the overall quality indicator of the processing status for the map. If this shows an error, contact support. 

Datum: This is the datum and epoch that the flight was processed in, this 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: Represents the delta between 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 final map absolute accuracy.

 

FAQ's and Known Limitations

  • What geographic regions are supported today?
    • The service areas are split into two regions:
      • Fast Region (Central Europe and North America)
      • Global Region (Rest of World)
    • The Global Region corrections are based on a global ionospheric model, while the Fast Region uses a denser network of reference stations to compute a regional ionospheric model for atmospheric corrections.

  • How long must I fly for?
    • Fast Region:
      • Convergence time is 1 to 2 minutes
    • Global Region:
      • Convergence time is at least 10 minutes
  • What should I expect in terms of accuracy?
    • Expected accuracy is < 3 cm horizontal RMS error and < 6 cm vertical RMS error. This is independent of the region as long as the solution has converged.
  • When is my drone collecting observations?
    • While powered on.
  • Does PPK increase my processing time?
    • Yes, but only marginally (<15 min addition in expected processing time).
  • Do I have to fly with DroneDeploy’s Flight App?
    • No, we support processing of data sets captured in a variety of ground control apps.
  • Do I still need GCPs or Checkpoints? 
    • As with RTK, PPK maps will generally be more accurate than a non-RTK/PPK map without GCPs.
    • DroneDeploy still recommends the use of GCPs for the highest level of absolute accuracy (as well as checkpoints to verify against known benchmarks).

 

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