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Maquoketa, Iowa 52060 | The US NGS has only one GEOID model for all of North America called GEOID12A. it is accurate to 2 cm absolute and much more accurate than that for reliative elevations [elevations difference from point A to point B within a couple miles].
GPS receiver GEOIDS are very inaccurate and should never be used for applications requiring vertical accuracy. you should always use the current NGS model.
With all this said even with a poor geoid or no GEOID, a GPS receiver is still more accurate over LARGE distances for elevation than a laser as there is no curvature adjustment in a laser system. But over a very small area a laser is more accurate than GPS because there is less drift to a laser signal. | |
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Earth's curvature
