DGPS verse RTK
Hello,
I think I have a good idea in the differences between DGPS and RTK. Like everything else I have developed my knowledge with person research, but since I am not an expert in GPS I doubt myself from time to time. With that said, I would like to post my brief interpretation of the DGPS and RTK so this group can confirm or correct my understanding. The last thing I want to do is tell some one the wrong thing and confuse them. So here is my ‘Bird’s Eye View.’ I understand there these topics can get further in depth.
DGPS uses a static base station within a certain distance (around 6 miles) to broadcast atmospheric, clock, and ephemeris corrections to a rover via radio. The rover needs to be close in proximity of the base station in order to experience similar atmospheric conditions. This method of observations uses the L1 frequency therefore has an accuracy of 1m.
RTK uses a similar process as DGPS, but uses both L1 and L2 frequencies. The use of the additional frequencies (including L5) increases the amount computations the receiver makes to correlate the errors from the satellites. If the rover has more frequencies to measure the time delay against it can take out most of the time delay from the received message. The received message is then lined up (Delay Lock) with the Almanac stored on the rover.
The Almanac is received by the rover from the satellites in the NAV message.
Let me know if I’m on the right track. I have been thinking about this for a while and seem to read something new online each time I search for answers.
Thank you,
Dan
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