Beside measuring changes of distance by means of the doppler effect on frequencies transmitted by a satellite, it is possible to observe altitudes and azimuths or the rates of change of these quantities. Advantages and disadvantages of such observations are compared with the Transit programme; the formulae for position lines determined by rates of change of altitude and azimuth are derived and discussed. Measurements of distance, at present feasible only by radar, may be possible in future by comparison of atomic clocks; the evaluation is simpler than for all other observations of satellites.