Optimizing Airborne Flight Line Spacing for Geoid Determination with Full Gravity Vectors

Abstract

The horizontal components of the airborne gravity vector are equivalent to the deflection of the vertical at the flight level and contain signals of the slope of Earth’s gravity field. We test the contribution of such components in finding the optimum flight line spacing for geoid modelling. We use the one-step integration method and create a system of linear equations containing the three components of the airborne gravity vector as observations and solve the geodetic boundary value problem on the reference ellipsoid as an overdetermined weighted least-squares problem. We test our methodology in the Colorado region in the USA given that it is one of the most challenging areas for geoid modelling. We show that by incorporating the horizontal components at the flight level, one can increase the flight line spacing by almost 40%, thereby significantly reducing the cost of airborne surveys while maintaining the same accuracy in the estimated geoid heights as when the scalar value of gravity is used.