A method on a user equipment, UE, the method comprising: determining a first absolute position of the UE at a first time based on GNSS measurements from a set of satellites at the first time; determining, at a second time, a first estimate of displacement of the UE relative to the first absolute position, wherein the second time is subsequent to the first time, wherein the first estimate of displacement is determined using non-GNSS measurements; and determining, at the second time, a second estimate of displacement of the UE relative to the first absolute position based, in part, on: GNSS carrier phase measurements at the first time from the set of satellites, and GNSS carrier phase measurements at the second time from a subset comprising two or more satellites of the set of satellites, wherein, determining the second estimate of displacement comprises: determining one or more satellite pairs in the subset of two or more satellites; projecting, for each satellite pair of the one or more satellite pairs in the subset, a corresponding periodic likelihood function on to a baseline represented by the first estimate of displacement, said periodic likelihood function being generated by the carrier phase difference between said GNSS carrier phase measurements at a first time and said GNSS carrier phase measurements at the second time in the line of sight of the respective satellite of the pair of satellites; determining a combined likelihood function, the combined likelihood function being determined as a function of the corresponding periodic likelihood functions for the one or more satellite pairs; and resolving the corresponding carrier phase ambiguity for each satellite based, in part, on the combined likelihood function. determining a first absolute position of the UE at a first time based on GNSS measurements from a set of satellites at the first time; determining, at a second time, a first estimate of displacement of the UE relative to the first absolute position, wherein the second time is subsequent to the first time, wherein the first estimate of displacement is determined using non-GNSS measurements; and determining, at the second time, a second estimate of displacement of the UE relative to the first absolute position based, in part, on: GNSS carrier phase measurements at the first time from the set of satellites, and GNSS carrier phase measurements at the second time from a subset comprising two or more satellites of the set of satellites, wherein, determining the second estimate of displacement comprises: determining one or more satellite pairs in the subset of two or more satellites; projecting, for each satellite pair of the one or more satellite pairs in the subset, a corresponding periodic likelihood function on to a baseline represented by the first estimate of displacement, said periodic likelihood function being generated by the carrier phase difference between said GNSS carrier phase measurements at a first time and said GNSS carrier phase measurements at the second time in the line of sight of the respective satellite of the pair of satellites; determining a combined likelihood function, the combined likelihood function being determined as a function of the corresponding periodic likelihood functions for the one or more satellite pairs; and resolving the corresponding carrier phase ambiguity for each satellite based, in part, on the combined likelihood function. determining one or more satellite pairs in the subset of two or more satellites; projecting, for each satellite pair of the one or more satellite pairs in the subset, a corresponding periodic likelihood function on to a baseline represented by the first estimate of displacement, said periodic likelihood function being generated by the carrier phase difference between said GNSS carrier phase measurements at a first time and said GNSS carrier phase measurements at the second time in the line of sight of the respective satellite of the pair of satellites; determining a combined likelihood function, the combined likelihood function being determined as a function of the corresponding periodic likelihood functions for the one or more satellite pairs; and resolving the corresponding carrier phase ambiguity for each satellite based, in part, on the combined likelihood function.