1. Method to estimate parameters derived from global navigational satellite system (GNSS) signals useful to determine a position, comprising: obtaining observations of a GNSS signal from each of a plurality of GNSS satellites; feeding the observations to a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate associated with an integer number of wavelengths of the GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received, and the filter being for estimating a float value for each float ambiguity of the state vector; assigning integer values to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets; selecting a first number of candidate sets having a quality measure better than a first threshold, wherein the first threshold is determined based on a reference quality measure of a reference candidate set; and obtaining a weighted average of the selected candidate sets, each candidate set weighted in the weighted average based on its quality measure.