PhotoSat publishes 21 new satellite surveying accuracy studies
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PhotoSat publishes 21 new satellite surveying accuracy studies


3D WorldView-2 satellite photo of Asmara, Eritrea, showing some of the
775 ground survey points that determined the 14cm PhotoSat surveying accuracy.

21 PhotoSat surveying accuracy studies from seven different stereo satellites

Dec 14, 2016 -- PhotoSat has published 21 new satellite surveying and mapping accuracy studies, now available on our website. The studies include data from seven different stereo satellite systems. The best results show elevation surveying accuracies of better than 15cm.

The accuracy studies include stereo satellite data from the following satellites:

PhotoSat has measured accuracy on over 700 stereo satellite surveying projects

PhotoSat has delivered over 700 satellite surveying projects since 2007 and we have carried out accuracy evaluations on the majority of them. Most of the survey data on these projects belongs to our customers and cannot be shared publically; however, customers have provided feedback on many of these projects.

The results of these 21 new accuracy studies are consistent with our project accuracy evaluations and customer feedback.

PhotoSat accuracy test areas in Eritrea and California

The accuracy studies were conducted over two test areas. One test area is west of Asmara, Eritrea where PhotoSat has access to more than 45,000 ground survey points over a 50km by 20km block.

The second area is in SE California where PhotoSat uses a very accurate open source LiDAR survey.

The effect of different numbers of ground survey points

The studies employed different numbers of ground survey control points for each test area and each satellite system. For some of the satellite stereo pairs the accuracy is significantly improved by increasing the number of ground survey control points. 

For example, the WorldView-2 survey for Eritrea is accurate to 19cm in elevation with two ground control survey points, and accurate to 14cm in elevation with 21 ground control points.

In contrast, the accuracy of the WorldView-3 survey for the California test area is not improved by additional ground survey points. This WorldView-3 survey is accurate to 13cm in elevation with one ground survey control point and with 153 ground survey control points. 

PhotoSat has been continuously producing satellite accuracy studies since 2007

In order to provide objective quantifiable accuracy data for stereo satellite surveying and mapping, PhotoSat has been continuously producing accuracy studies since 2007. We have previously published nine of these studies. The rest of the studies were used for calibrating and improving our processes.

21 new accuracy studies all processed with the same version of the PhotoSat processing system

The 21 new accuracy studies were produced with the most recent version (2016) of the PhotoSat processing system. Where possible we used satellite data produced by the 2015 or 2016 versions of the satellite operators’ ground processing systems.

Summary of PhotoSat 2016 accuracy study results

    Satellite          Test area                km2            GCP          RMSE

  1. WorldView-3     California          150               1          13cm
  2. WorldView-3     California          146           153           13cm
  3. WorldView-3     Eritrea              100             21          15cm
  4. WorldView-2     California          173               1          15cm
  5. WorldView-2     California          173           153           12cm
  6. WorldView-2     Eritrea              100             21          14cm
  7. WorldView-1     California          174           153           14cm
  8. WorldView-3     Eritrea              198               2          19cm
  9. WorldView-2     Eritrea              400               2          19cm
  10. WorldView-1     Eritrea              100             21          19cm
  11. WorldView-1     California          174               1          23cm
  12. WorldView-1     Eritrea              420               9          23cm
  13. Kompsat-3A      California          144             14          21cm
  14. Pleiades-1B      Eritrea              189             74          26cm
  15. Pleiades-1B      Eritrea              189               1          28cm
  16. Kompsat-3A      California          144               1          50cm
  17. Kompsat-3A      Eritrea              130             11          48cm
  18. Kompsat-3A      Eritrea              130               1          53cm
  19. SPOT 7            Eritrea              1,458             1          1.4m
  20. ALOS PRISM     Eritrea              2,300             3          1.2m
  21. ALOS PRISM     Eritrea              2,300             1          2.4m

See PhotoSat’s accuracy studies for full details. For more information about PhotSat’s surveying accuracy, please see our satellite surveying case histories.   

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