METHOD OF AIRCRAFT COORDINATE DETERMINING THE COORDINATE ON THE BASIS OF RADAR PICTURE Russian patent published in 2018 - IPC G01S13/90 

FIELD: radar ranging and radio navigation.

SUBSTANCE: invention relates to radar and may be used in radio engineering systems to determine the aircraft's own coordinates by the radar image generated during the flight. This result is achieved by the fact that the flight altitude of the aircraft is measured directly by the nadir reflection signals, which are fed to the input of the receiving device along the side lobes of the receive antenna pattern. To increase the accuracy of the flight altitude measurement, an incoherent averaging of the signals of the distance portraits obtained during the aperture synthesis is performed. Received signal of the averaged distance portrait is compared with the predetermined threshold, thereby detecting the emission of the nadir reflection signal. Threshold value is selected based on the set false alarm level and the average noise level of the receiver. Position of the emission peak of the nadir reflection signal on the averaged range portrait corresponds to the flight altitude of the aircraft. Increasing the accuracy of height measurement provides an increase in the accuracy of the conversion of the primary radar frame from the coordinate system "Doppler shift – oblique range" to the normal terrestrial coordinate system, which in turn increases the accuracy of the comparison of the reference image and the transformed radar field reference area and, as a consequence, the determination of the coordinates of the aircraft.

EFFECT: increasing the accuracy and speed of determining the coordinates of the aircraft by directly measuring the altitude of flight using a radar with a synthetic antenna aperture installed on its board.

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