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 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, 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, 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.