Eads Deutschland Gmbh

Astrium Gmbh

Aribert P Wolframm

Helmut Klausing

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 (&#x394;R) between the two distances (R+&#x394;R, R) from the measured impact point P are calculated, in the manner known per se, based on the wavelength &#x3bb; of the emitted radar signal and the measured phase difference of the receiving echo of the two coherent receive channels.

Method for interferometric radar measurement

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 &ldquo;basic position&rdquo; and is counted. The invention permits azimuthally phase-accurate synchronization between the viewing angle of a helicopter-borne radar system and an inertial axis of the helicopter, as well as a defined alignment of the image on the video screen with respect to an inertial axis of the helicopter (and thus with respect to the flight direction of the helicopter). The viewing direction of the radar system (ROSAR) can be adjusted by means of an electric regulator wheel, so that the pilot can set a desired defined viewing direction of the radar image on the video screen.

Helicopter-borne radar system

In conjunction with an arrangement for the interferometric radar measurement in connection with a radar system operating according to the ROSAR principle, comprising one coherent transmitting antenna and two coherent receiving antennas and their receiving channels, in connection with which the difference in the path between the two distances of the antennas and the measured points of impact is calculated by the wavelength &lgr; of the emitted radar signal and the measured phase difference of the receiving echo of the two coherent receiving channels, it is proposed that the interferometric ROSAR system is integrated in or on a rotating device and positioned in such a way that each relevant area of the field to be measured can be detected.

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Landsberg, Germany

Aribert P Wolframm