AbstractAtomic clocks did reacha perfection during the last years that it becomes likely to have position fixing by such clocks in the near future. Theoretically this was proposed sometimes in the past decades.Now we have two systems used for navigational purposes, the McDonnell Collision Avoidance System, well known to air navigation experts, using crystal clocks, and a geophysical surveying system, ANA,* developed by the “Gesellschaft für praktische Lagerstättenforschung”, Hannover, using Rubidium atomic clocks. Two ground stations are equipped with such clocks, a third is installed in an aircraft for time comparison with the ground‐based clocks. The difficulty to use the mentioned systems over longer periods as it would be necessary for maritime use, consists in the synchronization. There exist some proposals, till now not realistic and rather complicated, which would render possible to extend both methods to a general use for aircraft and ships. The further development of atomic clocks seems to be very pr