Читать книгу Global Navigation Satellite Systems, Inertial Navigation, and Integration - Mohinder S. Grewal - Страница 107

An equipotential surface is a surface of constant gravitational potential. If the ocean and atmosphere were not moving, then the surface of the ocean at static equilibrium would be an equipotential surface. Mean sea level is a theoretical equipotential surface obtained by time‐averaging the dynamic effects. Orthometric altitude is measured along the (curved) plumbline.