Abstract: It is proposed in connection with a method for the interferometric radar measurement in conjunction with a helicopter operating in accordance with the ROSAR principle (Heli-Radar) that two coherent receiving antennas with receiving channels are associated with a transmitter of the ROSAR-system mounted on the revolving rotary cross; and that the difference (?R) between the two distances (R+?R, R) from the measured impact point P are calculated, in the manner known per se, based on the wavelength ? of the emitted radar signal and the measured phase difference of the receiving echo of the two coherent receive channels.

Abstract: A helicopter-borne radar system has a synthetic aperture with rotating antennae (ROSAR). The antennae for transmitting and receiving radar pulses are arranged at the end of each arm rotating with the rotor, and are connected with the radar system which has at least one transmitting module, one electronic module with a central control device and an image processor as well as a display. In order to align the imaging on the display of the radar system with an inertial axis of the helicopter, and to limit the influence of a change of the rotational rotor on the imaging, a signal generator arranged at the rotor of the helicopter generates signals indicative of rotating positions of the rotor. The latter signals are transmitted to an electronic module of the radar system, which marks the flank of an individual signal from the signal sequence for a rotation of the rotor. This flank of a signal is defined as a “basic position” and is counted.

Abstract: The present invention pertains to a device for motion compensation for a radar with synthetic aperture based on rotating antennas (ROSAR) for helicopters, with which the flight guidance of the helicopter is made possible according to a radar image on a ROSAR basis, because this device substantially improves the quality of this radar image.