The present invention provides methods and systems that enable a mobile
navigation receiver to accurately determine its trajectory with
non-current ephemeris in stand-alone mode. In an embodiment, the receiver
computes the position for the same location using non-current ephemeris
and current ephemeris at different time instances. The receiver then
determines a position correction by finding the difference between these
two computed positions, and applies this correction to the trajectory
generated with non-current ephemeris to obtain a more accurate
trajectory. In another embodiment, the receiver computes an initial
position of the receiver using non-current ephemeris and finds the
difference between the computed initial position and an accurate
approximation of the initial position. The receiver then shifts the
subsequent receiver trajectory computed using non-current ephemeris by
the difference to obtain a more accurate trajectory.