Geodetic heights obtained with satellite surveys are measured concerning which reference?

Geodetic heights obtained from satellite surveys are measured concerning the ellipsoid. An ellipsoid represents a mathematically defined surface that approximates the shape of the Earth, which is slightly flattened at the poles and bulging at the equator. This ellipsoidal model is essential in satellite geodesy because it allows for uniform height measurements that can be applied globally.

The heights measured relative to the ellipsoid are known as ellipsoidal heights. These measurements are crucial for various applications in surveying and mapping, as they provide a standardized way to express elevation above or below the reference surface. The ellipsoid serves as a consistent reference for calculating coordinates in three-dimensional space and is utilized in conjunction with Global Navigation Satellite Systems (GNSS) for determining positions accurately.

The distinction between ellipsoidal heights and other height measurements, such as orthometric heights referenced to the geoid, is important in geodesy. While the geoid represents mean sea level and is used for determining elevations in practical surveying contexts, satellite measurements primarily relate to the ellipsoidal model, which provides a global framework for positional accuracy. Understanding this relationship helps clarify the fundamental concepts in surveying and the significance of the ellipsoid in geodetic measurements.