Study of the gravity field spectrum in Canada in view of cm-geoid determination

The local behaviour of the gravity field spectrum in Canada is studied in this paper, using the EGM96 geopotential model (GM) coefficients, point gravity anomaly data, and Digital Elevation Model (DEM) grids down to spatial resolution of 1 arcmin. The classic FFT-based periodogram method is used to estimate the local covariance and power spectral density functions for various gravity field signals, using gridded gravity and height data. Kaula-type parametric models are fitted to various bands of the local gravity field spectrum in order to model its decay rate. The corresponding covariance functions are also studied in detail through their estimated characteristics parameters. The analysis is done separately for flat and mountainous areas, and the required data grid spacings are derived for dm- and cm-geoid, as well as the estimates for the geoid aliasing error at various data resolution levels. The same analysis is also carried out for relative geoid accuracy at the 1 ppm level or better