Apparatus and method for communication in non-terrestrial networks are disclosed. A set of Doppler shift curves for different distances to one or more satellite orbits is obtained. Measurements of satellite transmission are performed to obtain estimate of instantaneous Doppler shift of the transmission, the measurements including a timestamp. A Doppler shift curve corresponding to the measurements is calculated. A time offset on the selected curve is determined utilising the timestamps of the measurements, the time offset indicating the position of the Doppler shift of the apparatus on the curve. The Doppler shift of the satellite transmission is determined utilising the selected curve and the time offset.