The vertical wavenumber is given by the partial derivative of the interferometric phase w.r.t. height. Since it is possible (to a good approximation) to express the interferometric phase as a truncated Taylor expansion, DEM creation is possible by dividing the (unwrapped, earth/DEM-flattened) interferometric phases by the corresponding vertical wavenumber. As explained for S1TBX-SE-2, the vertical wavenumbers or (height-to-phase factors) should be calculated and exported for use in external software packages (e.g., StaMPS). This can be very well approximated by computing the central difference based on the phase expected for two scatterers positioned along the height dimension with a separation of +/- 0.5 units of measure (e.g., meter) w.r.t. the used DEM[R-12].