We were running some tests on RTK / DGPS / GPS these two weeks. Thought it might be interesting to share our results in image format, although the accuracy numbers are already well known.
Test setup is as below:
Below is RTK result from 3 different days; black:20150716, green:20150721, white:20150723
As RTK accuracy is centimeter level, they overlap pretty well at this zoomed-out view.
White line RTK result is used as frame of reference to compare DGPS and GPS results
Below is DGPS result from 2 different days; red:20150716, cyan:20150723. Result is quite good since distance from DGPS base station is only 1.5Km.
Below is GPS result from 2 different days; red:20150716, cyan:20150723.
The shifted red track is due to ionosphere error that changes over time, which accounts for major error in a typical 2.5m CEP accuracy GPS receiver. It just happened that ionosphere error was less on 20150723, resulting in the cyan track closer to the correct white track.
What’s noteworthy is that the two rounds made on each day overlap quite well, meaning that the GPS receiver is fairly precise, just that the accuracy is still 2.5m CEP.
Below is 20150723 result with another popular GPS receiver brand for comparison.
Overlapping all previous plots, below figure results; giving a glimpse of potential GPS error on day to day basis.