A model-based angle unwrapper: Application to the GNSS-R Interference Pattern Technique

The estimation of circular parameters can be approached by signal processing using periodic statistic distributions. However, many existing optimal techniques for processing parameters defined on the line do not have optimal circular equivalents. Consequently, unwrapping techniques can be useful to solve circular parameters estimation problems by shifting them to the line. Nevertheless, no optimal unwrapping techniques exist when the considered data is highly noisy. This article aims at defining an original iterative unwrapping technique based on the modeling of the dynamics of the angle to process. The considered model corresponds to the evolution of Interference Pattern Technique measurements, an altimetry technique based on the use of GNSS signals. A set of simulations shows that the proposed unwrapping approach along with a linear interpolation approach permits to reach a higher accuracy and robustness to noise as compared with classical unwrapping and circular signals processing for the altimetry application.