One of the available scenario settings is the “Refine Station Coordinates” check box. When this is checked, magicGNSS will estimate the station coordinates, yet keeping a constraint to their initial value, as provided by ITRF (or the IGS). This refinement can compensate for some inaccuracies, such as some mismodelling of the Earth motion, thus helping to achieve better performances.

On the other hand, when the observability is not good enough (e.g. when the number of stations/data is insufficient or their distribution is poor) the estimation of the coordinates may be correlated with other parameters and lead to a degradation of performances! So, should one check the box or not?

The rule of thumb is: if you are using a well-distributed network of stations providing a good DOC (4 or above overall, e.g. when you use all the Core Stations), then checking the box should be a good idea.

The ODTS Report can help you find out whether it actually was, as it provides a comparison of the a-priori coordinates with the refined ones. If the difference is significant (say, more than some 5cm, and you are sure that the station has not moved!), this may indicate that the conditions for refining coordinates were not good enough and it might be a good idea to uncheck the box and run again.

A-priori vs refined coordinates

Tags: ODTS, Tips & Tricks

This entry was posted on Friday, October 3rd, 2008 at 12:06 am and is filed under Tips & Tricks. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.