SU800931A1 - Angle discriminator - Google Patents

Description

(54) ANGULAR DISCRIMINATOR

The invention relates to radar and can be used to determine the range of objects by transmitting impulse-modulated oscillations, in which information about the range, elevation and azimug are extracted from one common sounding pulse.

Known angular discriminator containing a phased antenna array (HEADLIGHTS) of N receiving elements, the first and second adders of intermediate frequency pulses, the outputs of which are connected to the inputs of the phase discriminator, the output of which is connected to the control inputs of the receiving elements of the HEADLIGHT, the delay unit and amplitude detector lU

However, in this discriminator, the presence of a two-step measurement of the angle of arrival of a broadband signal leads to a decrease in its speed.

The purpose of the invention is to increase the speed of measurement of the angular coordinates and to ensure invariance with respect to re-emitted signals with simulated amplitude.

This goal is achieved by the fact that, in an angle discriminator containing a phased antenna array (PAA) of N receiving elements, the first and second intermediate-frequency pulse adders, the outputs of which are connected to the inputs of the phase discriminator, whose output is connected to the control the inputs of receiving elements PAR, delay unit and amplitude 1 detector, two adders of video pulses, N-1 additional amplitude detectors and series-connected first difference block, entered the highest peak, the second difference block, the minimum limiter, the peak detector and the antenna control block,

0 moreover, the outputs of the first and second halves of the receiving elements of the HEADLIGHTS are connected to the inputs of the first and second adders of intermediate frequency pulses and through amplitude detectors

5 are connected to the inputs of the first and second adders. video pulses, the outputs of which are connected to the input of the first block of the difference, the output of the limiter to the maximum through the block

0 delay is connected to the second input of the second difference unit, the output of the antenna control unit is connected to the HEADLIGHT.

Figure 1 shows the structural electrical circuit of the proposed discriminator; 2 shows timing diagrams for an explanation of his work.

The discriminator contains a phased antenna array of 2 N receiving elements 1, amplitude detectors 2, adders 3 and 4 video pulses, first block 5 of difference, limiter 6. maximum, second, block 7 of difference, limited to minimum, peak. Detector 9, block) О delay, accumulators 11 and 12 intermediate frequency pulses, phase shifter control unit 13, phase discriminator 14 and antenna control unit 15.

The discriminator works as follows.

The broadband signal reflected from the target is received by receiving elements 1 of the HEADLIGHTS in which the received signals are amplified at a high frequency, transferred to an intermediate frequency with a corresponding gain in the intermediate frequency amplifier with automatic gain control (AGC) and matched filtering of the signals. The radio signals from the outputs of the first half of the receiving elements 1 of the HEADLAMPS are fed to the INPUTS: the adder has 11 pulses of the intermediate frequency, and, driven by the amplitude detectors 2, are fed to the inputs of the adder 3 video pulses. The radio signals from the outputs of the second half of the receiving elements 1 of the HEADLIGHTS arrive at the inputs of the adder 12 pulses of intermediate frequency and, detected by the amplitude detectors 2, arrive at the inputs of the adder 4 video pulses. If the direction of arrival of the signal does not coincide with the equal signal direction (PCH) of the HEADLIGHTS, the signals at the outputs of the receiving elements 1 are turned off in the delay of the envelopes as well as willows. initial phases. The signals at the outputs of the amplitude detectors 2 for a six-piece HEADLAMP are shown in Fig. 2a2e.

Let us first consider the action of the SSTJ s ttJ measuring the angular coordinate of the delayed envelopes at the output of the receiving elements of the phased array. In order to obtain a discriminatory characteristic of the angular information, the LO time of the latency of the signals received by elements 1 of the PAR, summation of the envelopes of the signals from the outputs of the first half of the PAR (fig. 2g) and the envelopes of the signals of the second half of the elements of the PAR, {fig. 2h). The output signals of the adders 3 and 4 video pulses are fed to the inputs of block 5. Differences and subtraction. (Fig. 2i). The differential signal from the output of block 5 is fed to the input q of the limiter b by the maximum, which performs a two-way limit on the maximum (Fig. 2i; the level of restriction is indicated by a dotted line). The limited signal (Fig. 2k) from the output of the limiter 6 reaches the maximum at the first input of the difference unit 7 directly and at the second input of the unit 7 through the delay unit 10 delayed by the pulse duration tTu (Fig. 2l).

Unit 7 subtracts incoming signals at its inputs. The differential signal from the output of the block 7 (Fig. 2m) is fed to the input of the limiter 8 by a minimum, which performs a two-way limitation of the signals arriving at its input to the minimum. The porrgs of restriction limiter B at the minimum (in Fig. 2m are dotted) have the same. magnitude, like the limiter b to the maximum. The output signal of the limiter 8 (FIG. 2n) has a duration proportional to the magnitude of the deflection angle of the object from the PCH HEADLIGHT, and its polarity depends on the direction of the bias relative to the PCH HEADLIGHT. Further, in order to obtain discriminatory characteristics, the pulse duration (fig.2n) taken from the output of the limiter 8 is converted into the voltage amplitude. This conversion is carried out with a peak detector 9, which is the output element of the discriminator operating on the angular information contained in the delay of the envelopes of the signals at the outputs of the elements 1 of the HEADLAMP. The output voltage of the peak detector 9 is shown in Figure 2o. The constant charge time of the peak detector 9 is selected based on the maximum specified possible angle of arrival of the object signal. Such a choice of the constant charge time of the peak detector 9 makes it possible to obtain an unambiguous relationship between the angle of arrival of the reflected signal and the magnitude of the voltage at the discriminator output by the delay of the envelopes received by the elements of the PAR signal. In this way, monopulse measurement of the angular coordinate is performed. targets for angular information contained in the latency time of the envelopes of the signals received by the elements 1

0 The pulse duration at the output of limiter 8 at minimum is defined as:

G (N-l) d sin V / s, where N is the number of receiving Elamenes 5 in the HEADLIGHTS}

d - step PAR;

 - the angle of arrival of the signal from the object relative to the PCN HEADLIGHT; c is the speed of light in the air. Then the discriminatory characteristic at the output of the peak detector 9, provided that it is perfectly integrated, has the form

.sina) where

(N-l) d / c.

This makes it possible to unambiguously measure the coordinate by a single-pulse method in a wider angular range than the known device.

To obtain information about the yi target position contained in the phase difference of the signals received by the first and second halves of elements 1 of the PAR, the sum of radio pulses taken from the first half of the elements 1 of the PAR and the output of the adder 11 pulses the intermediate frequency arrives at the first input of the phase discriminator 14 To the second input of the phase discriminator 14 with the output. Yes, the adder 12 pulses of the intermediate frequency receives the sum of radio pulses taken from the second half of the elements 1 phased array. At the output of the phase discriminator 14, which can be performed by any of the known schemes of phase dis.kriminato-. ditch, a discriminatory characteristic is obtained by the phase mismatch of the signals received by the first and second halves of the elements 1

Sharing the discriminatory characteristics obtained at the outputs of phase discriminator 14 and peak detector 9 makes it possible to construct a non-next monopulse meter measuring the angular coordinate of an object with wideband received signals, which maintains the accuracy of determining the angular coordinate of the phase discriminator in a wide range of angles. In order to monitor the change in the angular position of the target, the signals removed from you; the stroke of the limiter 8 at the minimum / go through the peak detector 9 to the input of the antenna control unit 15. The block-15 rotates the HEADLAMP so as to compensate for the time lag of the envelopes of the signals that are received by the 1 HEADLIGHT elements. The signals from the output of the phase discriminator 14 are fed to the input of the phase shifter control unit 13. Unit 13 generates control voltages on the controlled phase shifters of the receiving elements 1 of the HEADLAMP in such a way as to compensate for the phase difference of the signals received by the elements of the first l of the second half of the HEADLIGHT.

In the proposed angular discriminator, in comparison with the known,

there is no time spent in the first step of measuring the angular coordinate and no time is spent scanning the specified viewing sector by changing the setting of the delay lines. The gain in measurement time depends on the magnitude of the angular sector of the possible object and the accuracy of a priori information about the angle of the object. Angular discriminator is invariant

SG to re-emitted signals with modulated amplitude, while the known device at the first stage of rough measurement of the angular coordinate — scanning is sensitive to

5 to a re-emitted signal with a modulated amplitude, which leads to significant errors in determining the angular position of the object.

0

Claims (1)

1. Amientov I.I., Selected questions of the statistical theory of communication. M., .Soviet radio, b971, pp.39-42 (prototype). L / one . jL / y.fjSi2 / 2/2. MLLiJ.//-L/LL//UJ22./JjL/JJ 7777 / / 77/7/7777:  t 777Г7ГГ / 7Т / 77ГГ