GEOG 862
GPS and GNSS for Geospatial Professionals

Lesson 8 Overview



Most, not all, GPS surveying relies on the idea of differential positioning. The mode of a base or reference receiver at a known location logging data at the same time as a receiver at an unknown location together provide the fundamental information for the determination of accurate coordinates. While this basic approach remains today, the majority of GPS surveying is not done in the static post-processed mode. Post-processing is most often applied to control work. Now, the most commonly used methods utilize receivers on reference stations that provide correction signals to the end user via a data link sometimes over the Internet, radio signal, or cell phone and often in real-time. 


At the successful completion of this lesson, students should be able to:

  • explain the uses of real-time kinematic GPS/GNSS and DGPS/GNSS;
  • describe WAAS;
  • define RTCM SC-104;
  • recognize the use of the radio licensing and cell phones in RTK;
  • recognize some practical RTK suggestions; and
  • recognize precise point positioning PPP.


If you have any questions now or at any point during this week, please feel free to post them to the Lesson 8 Discussion Forum. (To access the forum, return to Canvas and navigate to the Lesson 8 Discussion Forum in the Lesson 8 module.) While you are there, feel free to post your own responses if you, too, are able to help out a classmate.