Method , carried out by at least one of a navigation satellite system receiver, hereinafter abbreviated as "NSS receiver", and a processing entity capable of receiving data from the NSS receiver, for estimating parameters useful to determine a position, the NSS receiver observing a NSS signal from each of a plurality of NSS satellites over multiple epochs, each of these epochs being hereinafter referred to as "receiver epoch", the method comprising: operating (s120) a first filter , hereinafter referred to as "timely estimator", and a second filter , hereinafter referred to as "precise estimator", wherein each of the timely estimator and precise estimator uses state variables; each of the timely estimator and precise estimator computes values of their state variables based on at least one of: NSS signals observed by the NSS receiver, and information derived from said NSS signals; the precise estimator computes the values of the state variables that it uses further based on at least one of: observations that are not derived from NSS signals observed by the NSS receiver, and information derived from said observations; and the precise estimator is delayed by at least one receiver epoch with respect to the timely estimator ; and characterised in recurrently replacing (s140), in the timely estimator , the value of each of some of the state variables computed by the timely estimator with: the respective value of the corresponding state variable computed by the precise estimator , a respective value computed based on the values of some of the state variables computed by the precise estimator , or a respective value computed based on: the values of some of the state variables computed by the timely estimator and the values of some of the state variables computed by the precise estimator . each of the timely estimator and precise estimator uses state variables; each of the timely estimator and precise estimator computes values of their state variables based on at least one of: NSS signals observed by the NSS receiver, and information derived from said NSS signals; the precise estimator computes the values of the state variables that it uses further based on at least one of: observations that are not derived from NSS signals observed by the NSS receiver, and information derived from said observations; and the precise estimator is delayed by at least one receiver epoch with respect to the timely estimator ; and characterised in recurrently replacing (s140), in the timely estimator , the value of each of some of the state variables computed by the timely estimator with: the respective value of the corresponding state variable computed by the precise estimator , a respective value computed based on the values of some of the state variables computed by the precise estimator , or a respective value computed based on: the values of some of the state variables computed by the timely estimator and the values of some of the state variables computed by the precise estimator . the respective value of the corresponding state variable computed by the precise estimator , a respective value computed based on the values of some of the state variables computed by the precise estimator , or a respective value computed based on: the values of some of the state variables computed by the timely estimator and the values of some of the state variables computed by the precise estimator . <EOS>