METHOD OF MEASURING AIR TARGET RADIAL VELOCITY IN CARRIER FREQUENCY ADJUSTMENT MODE FROM PULSE TO PULSE IN ACCORDANCE WITH RANDOM LAW AT LOW SIGNAL-TO-NOISE RATIO

摘要

FIELD: physics.;SUBSTANCE: method can be used in pulsed Doppler radar with carrier frequency adjustment from pulse to pulse. The random law of variation of probing frequency is algorithmically generated from a linear-stepped law of variation of frequency in a packet of pulsed signals. The centimetre wavelength range with frequency adjustment within the limits of hundreds of MHz is used. The number of signals used in a packet equals 2^k, where k=6…8. Duration of the packet must not exceed the interval for angular correlation of rotation of the air target. Velocity is measured during one packet using a technique for finding the extremum of the multiplicative coefficient which is a product of the estimated variance and a third central moment for the complex vector of the range portrait, obtained from the frequency characteristic of the target, re-phased with complex factors which take into account selection of all possible radial velocities of the object.;EFFECT: increased accuracy of measuring radial velocity and noise-immunity due to adjustment of frequency from pulse to pulse in accordance with a random law and coherent integration of amplitude of reflected pulses during inverse Fourier transformation with a complex vector of the frequency characteristic of the target.;12 dwg, 4 tbl