GNSS-R techniques use direct and reflected signals coming from GNSS satellites to characterize the reflecting surface. In altimetry applications, the height of the surface is derived from the path difference between these two signals. The aim of this article is to propose a receiver architecture for high rate estimation of this path difference using an Interference Pattern Technique. An original receiver front-end architecture is presented, aiming at providing noisy observations of a non-linear function of the height. In order to invert this non-linear observation function and to smooth the height estimation, a particle filter is used. The proposed approach is assessed on synthetic data.