This project involves Low Earth Orbiter (LEO) force modelling and orbit determination for ESA's Sentinel-1 mission. This is part of a join research programme entitled 'Looking inside the Continents from Space' (LiCS). The project consortium consists of investigators from UCL, and the universities of Leeds, Oxford, Cambridge, Glasgow and Bristol. The overall scientific aim of the UCL component of the project will be to remove long wavelength errors in the estimated space vehicle trajectory through high fidelity modelling of the surface forces and the development of a phase centre variation model for the on-board GPS receivers.