The present invention regards a method of operation of a real aperture radar system for surveillance of the Earth's surface, said real aperture radar system being installed on a space vehicle/platform that moves in a direction of flight and comprising a transceiving antenna, or a transmitting antenna and a receiving antenna, which is/are electronically steerable. All the radar pulses are transmitted: with a predefined pulse repetition frequency and a predefined timing of the scanning cycle such that to guarantee a complete coverage of each of the N swaths parallelly to the direction of flight; and by using a frequency agility technique.