ArcPad 10 on Ashtech Mobile Mapper 10

Question

Created a project in ArcMap 10.1, exported for ArcPad 10 on Ashtech Mobilemapper 10. Using NAD 1983 StatePlane Louisiana South FIPS 1702 (US Feet), NAVD 88. The file is not returning accurate Z values. I have double checked my antenna height and geoid separation. Any suggestions on how to get an accurate Z value?

MartinMajnerick · Answer

The horizontal accuracy of the MM10 is 1-2 meters, so the vertical accuracy will be roughly 2-4 meters. The Z value it is reporting is an ellipsoid height, not orthometric. You would have to apply a geoid model or geoid separation value to your ellipsoid height in order to get an orthometric height.

Thanks, it is not providing values that are even consistent with themselves. I take two shot not even 50' apart and they have a difference in z value of +/- 40 which is incorrect. I have double checked my geoid height and antenna height as well.

BrettBlack · Answer

The horizontal accuracy of the MM10 is 1-2 meters, so the vertical accuracy will be roughly 2-4 meters. The Z value it is reporting is an ellipsoid height, not orthometric. You would have to apply a geoid model or geoid separation value to your ellipsoid height in order to get an orthometric height.