A method comprising, performed by an apparatus (100, 300): computing a first plurality of locations of a satellite of a satellite navigation system for a plurality of points in time based on a first set of parameter values of an orbit model, the first set of parameter values broadcast by the satellite for a first validity period; computing a second plurality of locations of the satellite for the plurality of points in time based on at least one second set of parameter values of an orbit model, the at least one second set of parameter values broadcast by the satellite earlier than the first set of parameter values for at least one second validity period, wherein for computing the first plurality of locations and the second plurality of locations of the satellite, the first validity period or the at least one second validity period is extended by an equation of motion for the satellite, which includes at least one force acting on the satellite; computing a value of at least one error component for each of the plurality of points in time by comparing the computed first plurality of locations of the satellite with the computed second plurality of locations of the satellite; fitting parameter values of a model having at least one periodic component to the computed values of the at least one error component to obtain a model of a time-evolution of values of the at least one error component; and providing the model of the time-evolution of the values of the at least one error component as a basis for a correction of locations of the satellite that are computed based on the first set of parameter values for points in time outside of the first validity period; the method further comprising receiving by the apparatus the first and the at least one second set of parameter values directly from the satellite by means of a satellite signal receiver of the apparatus or from the satellite via a satellite signal receiver of a device comprising the apparatus, or from a separate entity. computing a first plurality of locations of a satellite of a satellite navigation system for a plurality of points in time based on a first set of parameter values of an orbit model, the first set of parameter values broadcast by the satellite for a first validity period; computing a second plurality of locations of the satellite for the plurality of points in time based on at least one second set of parameter values of an orbit model, the at least one second set of parameter values broadcast by the satellite earlier than the first set of parameter values for at least one second validity period, wherein for computing the first plurality of locations and the second plurality of locations of the satellite, the first validity period or the at least one second validity period is extended by an equation of motion for the satellite, which includes at least one force acting on the satellite; computing a value of at least one error component for each of the plurality of points in time by comparing the computed first plurality of locations of the satellite with the computed second plurality of locations of the satellite; fitting parameter values of a model having at least one periodic component to the computed values of the at least one error component to obtain a model of a time-evolution of values of the at least one error component; and providing the model of the time-evolution of the values of the at least one error component as a basis for a correction of locations of the satellite that are computed based on the first set of parameter values for points in time outside of the first validity period; the method further comprising receiving by the apparatus the first and the at least one second set of parameter values directly from the satellite by means of a satellite signal receiver of the apparatus or from the satellite via a satellite signal receiver of a device comprising the apparatus, or from a separate entity. computing a second plurality of locations of the satellite for the plurality of points in time based on at least one second set of parameter values of an orbit model, the at least one second set of parameter values broadcast by the satellite earlier than the first set of parameter values for at least one second validity period, wherein for computing the first plurality of locations and the second plurality of locations of the satellite, the first validity period or the at least one second validity period is extended by an equation of motion for the satellite, which includes at least one force acting on the satellite; computing a value of at least one error component for each of the plurality of points in time by comparing the computed first plurality of locations of the satellite with the computed second plurality of locations of the satellite; fitting parameter values of a model having at least one periodic component to the computed values of the at least one error component to obtain a model of a time-evolution of values of the at least one error component; and providing the model of the time-evolution of the values of the at least one error component as a basis for a correction of locations of the satellite that are computed based on the first set of parameter values for points in time outside of the first validity period; the method further comprising receiving by the apparatus the first and the at least one second set of parameter values directly from the satellite by means of a satellite signal receiver of the apparatus or from the satellite via a satellite signal receiver of a device comprising the apparatus, or from a separate entity.