RU1840928C - Multiplicative antenna - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: device comprises two receiving apertures, the outputs of which are connected to inputs of a first signal multiplier, and an integrator. The device also includes two narrow-band filters matched with a passive jamming spectrum, a second signal multiplier, a subtractor and a delay line, wherein the output of the subtractor is connected to the input of an integrator, the first input of the subtractor is connected through the delay line to the output of the first multiplier, and the second input of the subtractor is connected to the output of the second signal multiplier, the inputs of which are connected to the outputs of the receiving apertures through said narrow-band filters.

EFFECT: selection of moving targets.

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Description

The proposed multiplicative antenna is intended for use in radar and radio navigation equipment, sonar, radio astronomy, etc., in particular, can be used in radar based on the PAR.

The use of a multiplicative antenna in a radar has an advantage over an additive antenna, because allows you to increase the accuracy of measuring the angular coordinates or for a given accuracy of measuring the angular coordinates - to halve the linear dimensions of the aperture due to the narrowing of the radiation pattern when multiplying the signals.

The multiplicative antenna (see, for example, Lavrov A.S., Reznikov GB, Antenna-feeder devices, "Soviet Radio", Moscow, 1974, p. 273) has been studied relatively well (see, for example, the thesis for competition for the degree of candidate of technical sciences "Some issues of the statistical theory of multiplicative signal processing in radar receivers" by Sinitsyna Yu.P., All-Russian Research Institute "Altair", M., 1972).

However, the use of the aforementioned multiplicative antennas is associated with one of the drawbacks in that there are no methods for dealing with passive interference for them. All known methods of dealing with passive interference are based on the difference in the spectral characteristics of the reflected signals from a moving target and stationary passive interference.

Since when multiplying the signals and isolating the low-frequency component in the multiplicative antenna, information about the frequency and phase of the signals is lost, the application of known methods to combat passive interference becomes impossible.

As a prototype, the device described in the aforementioned book by A. Lavrov was selected. and Reznikova G.B. The multiplicative antenna contains two receiving apertures, a signal multiplier and a generator, the outputs of the receiving apertures connected to the inputs of the multiplier, and the output of the multiplier with the input of the integrator. Along with achieving some advantages in the accuracy of measuring angular coordinates, this device eliminates the possibility of selecting moving targets at its output, since signals of any frequency at the inputs of the multiplier provide only a constant component at the output of the multiplicative antenna. This is a disadvantage of the known device.

The aim of the present invention is to enable the selection of moving targets.

This goal is achieved by the fact that in the multiplicative antenna containing two receiving apertures (or a shaper of two receiving beams of the common aperture), the outputs of which are connected to the inputs of the signal multiplier, and an integrator of the output signal of the multiplicative antenna, two narrow-band filters are matched to the signal from the fixed target and receiving apertures connected to the outputs, a signal multiplier, the inputs of which are connected to the outputs of narrow-band filters, a subtracting device, the inputs of which are connected to the output the first multiplier through the delay line and to the output of the second multiplier, and the output of the subtractor is connected to the integrator.

The essence of the solution to the problem of suppressing passive interference is that from the total spectrum of the useful signal and passive interference, the easily distinguished spectrum of only passive interference transmitted through narrow-band filters is subtracted. Thus, in the case of the presence of a target, an uncompensated component of the spectrum of the useful signal will be present at the output of the subtractor, otherwise, there is no signal at the output of the subtractor.

Figure 1 shows a functional diagram of the inventive device. The inventive device comprises two receiving apertures 1 and 2, a signal multiplier 3, an integrator 4, narrow-band filters 5 and 6, a signal multiplier 7, a subtractor 8 and a delay line 9, the outputs of the receiving apertures connected to the inputs of the multiplier 3 and narrow-band filters 5 and 6 the outputs of which are connected to the inputs of the signal multiplier 7, the output of which is connected to one of the inputs of the subtractor 8, the second input of which is connected to the output of the multiplier 3 through the delay line 9, and the output of the subtractor is connected to go integrator 4.

The device operates as follows. The signals from the receiving apertures 1 and 2 are multiplied by the multiplier 3 and through the narrow-band filters 5 and 6 are fed to the multiplier 7.

Since filters 5 and 6 are consistent with the spectrum from a stationary passive noise, the output of the multiplier 7 contains only the components of the frequency spectrum of signals from stationary objects. These components are subtracted from the total spectrum obtained at the output of the multiplier 3, which leads to the exclusion of interfering signals from stationary objects at the output of the multiplicative antenna. A delay line 9 is introduced to compensate for the delay of the signals in the filters 5 and 6.

The proposed device compares favorably with the prototype in the ability to effectively reduce interference from stationary objects. To do this, it is enough to match the filters introduced with the spectrum of passive interference, which is easy to do when setting up. The proposed scheme can be implemented at an intermediate frequency of the receiver, where the practical implementation of narrow-band high-quality active filters and signal multipliers does not cause difficulties. When implemented on microwave, microwave strip filters and microwave multipliers, e.g. according to US patent No. 3737686, publ. 06/05/1973, to measure the speed of targets can easily be used (without additional pre-processing) the device of the authors Stryunova B.A. and Zvereva Yu.M., 567150, 2111504, publ. 03/10/1975, M. cl. G01S 9/44 called: "Speed meter", where high measurement accuracy is achieved by the introduction of a frequency discriminator.

When tuning filters 5 and 6 to the frequency of moving targets (which is easily feasible in active R-C filters), you can get a well-cleaned signal from stationary objects (clouds, local objects). Such a task is relevant in radio meteorology and in the preparation of a training flight plan.

Claims (1)

A multiplicative antenna containing two receiving apertures, the outputs of which are connected to the inputs of the first signal multiplier, and an integrator, characterized in that, in order to select moving targets, two additional narrow-band filters are matched to the passive interference spectrum, a second signal multiplier, a subtractor and a delay line, wherein the output of the subtractor is connected to the input of the integrator, the first input of the subtractor through the delay line is connected to the output of the first multiplier, and the second th input of the subtractor is connected to the output signal of the second multiplier having inputs connected to the outputs of receiving apertures through the narrow-band filters.

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