1. Method to estimate parameters derived from global navigational satellite system (GNSS) signals useful to determine a position, comprising obtaining observations of each of received frequencies of a GNSS signal from a plurality of GNSS satellites to obtain observations at a plurality of instances in time; feeding the time sequence of observations to a filter to estimate a state vector at least comprising float ambiguities, wherein each float ambiguity constitutes a real number estimate of an integer number of wavelengths for a received frequency of a GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received and wherein the float ambiguities of the state vector are updated over time on the basis of the observations; determining that an interruption in tracking of at least one signal of a satellite occurred; maintaining the float ambiguity of the state vector for the at least one signal for which an interruption in tracking occurred at the value before the interruption in tracking occurred; assigning integer values to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets; determining a quality measure for each of the candidate sets; and forming a weighted average of the candidate sets.