With the Navy Navigation Satellite System (NNSS), we first started surveying directly ellipsoidal heights. This capability became universal with the GPS. Around the mid-1990s, the accuracy of a few cm for a surveyed ellipsoidal height (h) for single points and 1 ppm or better for differential heights (Dh) became realistically achievable.

Many of us started “floating” the use of ellipsoidal heights as a new approach, but without providing simple explanation(s) and/or algorithm(s). A better approach is to identify the specific applications and then show how the ellipsoidal heights can be used.

Before users will start using the ellipsoidal heights, we, the provider, have to first come out of our centuries old concept and practice(s). If they can be used, then why not!

Dr. Muneendra Kumar’s paper identifying where and how the ellipsoidal heights can be used will be published in our next issue - Editor.