RU2321015C1 - Mode of direction finding and direction finder for its realization - Google Patents

Abstract

FIELD: proposed invention refers to radiolocation and may be used for definition of position and movement of sources of radiation of complex signals.

SUBSTANCE: achieved technical result of invention is increase of trustworthiness of reception of useful signals with a priori known carrier frequency and removal of ambiguity of direction finding by suppression false signals (interference) not interesting for radio control and coming from other directions. At that proposed arrangement has receiving antenna with circle diagram of radiation pattern , receiving antenna with cardioidic diagram of radiation pattern, block for control over diagram of radiation pattern, first and second receiving sets, division block, threshold block, former of control pulse, first and second keys, meter of frequency, memory block, block for comparison of codes, motor and register block.

EFFECT: increases trustworthiness of direction finding.

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Description

The proposed technical solutions relate to radar and can be used to determine the location and movement of radiation sources of complex signals.

Known methods of direction finding and direction finders for their implementation (RF patents Nos. 2,003.131, 2.006.872, 2.010.258, 2.012.010, 2.134.429, 2.155.352, 2.175.770; Space trajectory measurements. Under the general editorship of P. A. Agadzhanova et al. M: Sov. Radio, 1969, p. 244-245; Kinkulkin I.E. et al. Phase method for determining coordinates. M: Sov. Radio, 1979; Space radio engineering complexes. Edited by C. I.I. Bychkova, M .: Sov. Radio, 1967, p.134-137, fig. 2.3.9, b, and others).

Of the known methods and devices closest to the proposed are the method and device of phase direction finding (Space radio systems. Edited by S. I. Bychkov. M: Sov. Radio, 1967, p.134-137, Fig. 2.3.9, b ), which are selected as the base objects.

According to the known method, the reception of signals is carried out on two antennas, remote from each other by a distance d. The received vibrations are amplified and limited, after which the phases of the oscillations that have passed through two channels are compared in the phase discriminator (detector). The phase shift is determined by the ratio

Δφ = 2πd / λ * Cosα,

where α is the angle between the measuring base and the direction of the signal radiation source;

d is the distance between the antennas (measuring base);

λ is the wavelength.

In a phase direction finder with a moving (rotating) base (Fig. 2.3.9, b), the mismatch voltage is used to generate the voltage controlling the motor connected through the gearbox to the antenna system.

Known technical solutions do not provide reliable reception and direction finding of signals with a priori known carrier frequency. This is due to the fact that a large number of false signals (interference) that are not of interest for radio monitoring and come from other directions fall into the passband of the receiver-direction finder.

In addition, the well-known technical solution is characterized by a contradiction between the accuracy and uniqueness of direction finding of the signal radiation source. Indeed, according to the above formula, to increase the direction finding accuracy, it is necessary to increase the relative size of the measuring base d / λ. However, with an increase in d / λ, the phase shift Δφ exceeds 2π, i.e. the ambiguity of reading the angular coordinate α occurs.

An object of the invention is to increase the reliability of the reception and direction finding of useful signals with an a priori known carrier frequency and to eliminate the ambiguity of direction finding by suppressing false signals (interference) that are not of interest for radio monitoring and coming from other directions.

The problem is solved in that the direction finding method, based, in accordance with the closest analogue, on receiving signals to two antennas and amplifying them, while one of the antennas is rotated, differs from the closest analogue in that the radiation pattern of the rotating antenna is selected in the form of a cardioid, rotate the antenna with a cardioid radiation pattern until the direction of zero reception coincides with the direction to the radiation source of useful signals with a priori known carrier frequency, the detected receiving apparatus is divided With a circular radiation pattern, the voltage to the voltage detected by the receiving equipment with a cardioid radiation pattern compares the voltage proportional to the quotient from the division with the threshold voltage when the threshold voltage is exceeded, which corresponds to the coincidence of the direction of zero reception with the direction to the radiation source of useful signals with an a priori known frequency, form a control pulse, which allows the measurement of the carrier frequency of the received signals, compare the code measured of the carrier frequency with a code of an a priori known frequency and if they are equal, they stop the rotation of the antenna with a cardioid radiation pattern and fix the true bearing to the radiation source of useful signals with an a priori known frequency.

The problem is solved in that the direction finder, containing, in accordance with the closest analogue, two receivers with antennas, one of which is made rotating and connected through the radiation pattern control unit to the motor, differs from the closest analogue in that it is equipped with a division unit, a threshold unit , a driver pulse generator, two keys, a frequency meter, a memory unit, a code comparison unit and a registration unit, and a diagram control unit is connected in series to the output of the rotating antenna my focus, the second receiver, the division unit, the second input of which is connected to the output of the fixed antenna through the first receiver, the threshold block, the driver pulse shaper, the first key, the second input of which is connected to the second output of the first receiver, the frequency meter and code comparison unit, the second input which is connected to the output of the memory unit, and the output is connected to the control input of the motor, the second key, the second input of which is connected to the second output of the control unit of the radiation pattern comparing the output code block, and recording block.

A device that implements the proposed method contains (Fig. 1) a receiver antenna 2 with a cardioid radiation pattern, a radiation pattern control unit 3, a second receiver 5, a division unit 6, the second input of which is connected through the first receiver 4 to the output of the receiving antenna 1 s a circular radiation pattern, a threshold block 7, a driver 8 of the control pulse, a first key 9, the second input of which is connected to the second output of the first receiver 4, a frequency meter 10, a code comparison unit 12, the second input to which is connected to the output of the memory unit 11, and the motor 13, the output of which is connected to the second input of the block, the radiation pattern control unit 3, is connected in series to the second output of the radiation pattern control unit 3, a second key 14, the second input of which is connected to the output of the code comparison unit 12 , and block 15 registration.

The proposed method is implemented as follows.

The receiving antenna 1 is stationary and has a circular radiation pattern, the receiving antenna 2 rotates, is connected through the radiation pattern control unit 3 (gearbox) to the motor 12 and has a cardioid radiation pattern, which is formed using a frame and a vertical vibrator (figure 2).

Each receiver 4 (5) consists of a series-connected high-frequency amplifier and an amplitude detector. The amplitude of the received signals at the output of the receiver 4 does not depend on the direction of their arrival due to the circular pattern of the first receiving antenna 1 (figure 4). The amplitude of the received signals at the output of the receiver 5 depends on the direction of their arrival due to the cardioid radiation pattern of the second receiving antenna 2. The envelopes of the input signals from the outputs of the amplitude detectors (first outputs of the receivers 4 and 5) go to the two inputs of the division unit 6, respectively.

To implement the selection of useful signals in the direction using the motor 12 and the control unit 3 of the radiation pattern control cardioid radiation pattern of the receiving antenna 2 is rotated to combine the zero dip with the direction of arrival of the signals (figure 4). The amplitude of the signals from this direction at the output of the receiver 5 is close to zero, therefore, at the output of the division unit 6, dividing the amplitude of the signal from the output of the receiver 4 by the amplitude of the signal from the output of the receiver 5, the voltage will be maximum at this point in time.

The threshold value is set so that the threshold unit 7 is triggered only by signals coming from the zero direction.

When the threshold block 7 is activated, the shaper 8 generates a pulse, which is supplied to the control input of the key 9, opening it. In the initial state, keys 9 and 14 are always closed.

The high-frequency signal from the second output of the first receiver 4 (from the output of the high-frequency amplifier) through the public key 9 is fed to the input of the frequency meter 10. The code of the measured carrier frequency of the received signals is fed to the first input of the code comparison unit 12, the second input of which receives a code of an a priori known frequency previously stored in the memory unit 11.

If the codes of the indicated frequencies are equal, then the code comparison unit 12 generates a control pulse, which is supplied to the control input of the motor 13, stopping it, and to the control input of the key 14, opening it.

In this case, the value of the angular coordinate α _p , which determines the direction of the useful signal to the radiation source (true bearing), is transmitted through the public key 14 to the input of the registration unit 15, where it is fixed.

The dependence of the output voltages U _o (α) of the receivers 4 and 5 on the direction of arrival of electromagnetic waves represents direction-finding characteristics (figure 3).

The receiving antenna 2 has a high direction-finding sensitivity, which is the steepness of the direction-finding characteristic in the direction of zero reception

but low signal to noise ratio.

The joint use of two antennas 1 and 2 with a circular and cardioid radiation patterns eliminate this disadvantage, while maintaining dignity.

Thus, the proposed technical solutions in comparison with the basic objects provide an increase in the reliability of reception and direction finding of useful signals with an a priori known carrier frequency and elimination of direction finding ambiguity. This is achieved by increasing the signal-to-noise ratio when using an antenna with a cardioid radiation pattern having high direction-finding sensitivity, suppressing false signals (interference) that are not of interest for radio monitoring and coming from other directions, and measuring the carrier frequency of the received signals at the maximum signal-to-noise ratio .

Claims (1)

A direction finder comprising two receivers with antennas, one of which is rotatable and connected through the radiation pattern control unit to a motor, characterized in that it is equipped with a division unit, a threshold unit, a control pulse shaper, two keys, a frequency meter, a memory unit, a comparison unit codes and a registration unit, and a radiation pattern control unit, a second receiver, a division unit, the second input of which through the first receiver with it is single with the output of a stationary antenna with a circular radiation pattern, a threshold block, a control pulse shaper, a first key, the second input of which is connected to the second output of the first receiver, a frequency meter and a code comparison unit, the second input of which is connected to the output of the memory block, and the output is connected to the control input of the motor, to the second output of the radiation pattern control unit, a second key is connected in series, the second input of which is connected to the output of the code comparison unit, and the registration unit.

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