Use of GPS on iPad

07-27-2021 10:04 AM
New Contributor

I have been attempting to use a Bad ELF surveyor GPS to Bluetooth data to an iPad.  The data comes in but I am not happy with the accuracy of the points.   I collected a test set of data over 2 days and at least 10min. between collections and varying the amount of collector averaging.   The ELF unit was on a tripod and always was reporting 3feet or better on the unit screen.  It is disappointing for me to see such little improvement between 1, 10, 50 and 100sec averages and that the 6pt, 100sec average seem to produce the worst mean centroid!

I set up a Trimble geoXT and over the two days collected 3pts, each with over 350, 5sec interval averages to give a "true" location.  using UTM10N.    As an aside, I ended up projecting the ELF data in ArcMap to UTM10N also and this produced a far better overlay of all GPS points over the various sat. images.

Please see the attached .jpg with T350 being the Trimble and Mon1, 10, 50, 100 averaged data.

Glad to get sny suggestion!

Lee   lee@neherconsulting

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Occasional Contributor III

I've never used one of these, but it looks like accuracy around a meter is about standard for it out of the box. Bad Elf GNSS Surveyor ( 

It looks like post-processing might be an option for the data, too? Their website should have suggestions.

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