Abstract

The methods of radar with narrow-band radiation by switching the antenna pattern around the equi-signal zone or in orthogonal planes are considered, which significantly (by tens of dB) reduce the power of the transmitter by narrowing the receiver bandwidth. The range to the target is determined by calculating the phase difference of the received signal at the switching frequency of the reference signal of this frequency by a stabilized quartz oscillator. It is shown that it is possible to increase the accuracy of measuring the range by introducing two scales: coarse, determined by the switching frequency, the wavelength of which corresponds to a double range to the target, and accurate, with a higher switching frequency.Since the required radiation power of the transmitter in the narrowband case is determined by the noise immunity of phase measurements, then at a given range of the system, by increasing the power of the transmitter, it is possible to reduce the error of measuring the range. As is known, in the pulsed radar method, the accuracy of the range estimation is limited by the duration of the emitted pulse and practically does not depend on the power of the transmitter. For this reason, the radars used do not allow for the accuracy of estimating their coordinates better than tens of meters. A possible solution to such a problem is the use of continuous signals with partial modulation, but requiring a wide bandwidth of receivers determined by frequency deviation, which significantly reduces the noise immunity of the system. The disadvantage of the narrowband radar method described below with spatial signal modulation is the inability to distinguish targets located at the same azimuth. However, in a number of tasks, for example, when used in altimeters, over-the-horizon radar, high-precision radio geodesic measurements, etc., the radar options described in the article make it possible to increase the accuracy of measuring the range not achieved by other methods. The main advantage of the new method is: stealth; high noise immunity; minimum radiation power of the transmitter; the ability to quickly change the carrier frequency, independence from the speed of movement of the target, since the measurement of the signal phase is determined only by the switching frequency.

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