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the Netherlands | That's a tricky one. OmniSTAR uses ITRF2008 as a reference frame, where you might want to use WGS84 or NAD83. A little simplified, a geodetic reference frame is just a way of agreeing on where on this piece of rock we call Earth the points (lat=0, lon=0), (lat=0, lon=90) and (lat=90, lon=0) are located and how these points are being displaced over time due to the movement of the Earth's various large land masses ("tectonic plates") relative to each other.
A little dependent on your location, the difference between the various reference frames may be a few inches to several feet, so if you have been using an uncorrected GPS average as your base location and are now going to update the location by using OmniSTAR, you may find your base location to be off by quite some distance, which will definitely show in your year-to-year repeatability "before" and "after" the resurvey.
We (i.e. OmniSTAR technical support Europe) are getting quite a lot of questions about this "mismatch" between the various geodetic reference systems in use and we have to explain over and over again that the difference between the position of a "known" reference point in one reference system and the position of that same reference point when using OmniSTAR does not mean that the OmniSTAR position is faulty and not meeting its claimed accuracy specs, it just means that the position of the reference point has not been recalculated for the ITRF2008 reference frame.
Back to the question: will an OmniSTAR HP converged location be more accurate than an uncorrected averaged position? If you take into account the difference between the two different reference frames used and correct/compensate for it, it definitely will. If you don't correct/compensate for the difference, you'll be stuck with a systematic error (offset), that will grow larger over time every time you do a resurvey. | |
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RTK Base Station Position
