RU2234109C1 - Radar interrogator - Google Patents

Abstract

FIELD: radar equipment, in particular, interrogators of systems with an active response.

SUBSTANCE: the device uses a channel containing a directional coupler and a reply signal conditioner making it possible to measure the time and take into account the signal delay time in the interrogator receiver, and a controllable attenuator changing the level of radiated power, depending on the distance between the interrogator and the transponder.

EFFECT: enhanced accuracy of measurement of distance by radar systems with an active reply, which enhances the accuracy of the aids of extra-trajectory measurements required for tests of high-accuracy weapon.

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Description

The invention relates to radar technology, and in particular to systems with an active response, and can be used to create systems that provide high accuracy in measuring the distance between objects on which the interrogator and responder are mounted.

Known [1] p. 110-113, Fig. 3, 37, secondary radars designed to determine the coordinates of the aircraft and obtain additional information on the response signals of the airborne transponders installed on them and containing a transmitting device, antenna system, antenna switch , block of dividers and bridges, receiver and equipment for decoding and converting signals.

The closest analogue (prototype) in technical essence is the radar interrogator of the secondary radar system described in USSR author's certificate (SU) No. 1309754 [2], comprising the transceiver antenna 1 connected in series, a circulator decoupling unit 2, a response signal receiver 3, a response signal decoder 4, the memory unit 5, the information display unit 6, the encoder 7 and the transmitter 8 connected in series, the output of which is connected to the second input of the decoupling unit 2 (Fig. 1).

The disadvantage of this interrogator is the large error in measuring the distance between the aircraft and the interrogator, caused by an error in determining the delay time between the interrogation pulse and the pulse generated by the transponder, which is caused by the instability of the delay time in the interrogator receiver and transmitter circuits and the instability of the transponder signal relay time, caused, including , and a change in the power level of the interrogation signal due to a change in the distance between the interrogator and the transponder, which, according to [3], p. 13, t reach ± 0.1 μs, which corresponds to the error in measuring the range D between the interrogator by the responder ± 15 m, and the total error in measuring the range of such a system consisting of an aircraft interrogator of the SOD-75 type and a responder beacon, according to [4], p. 220 , can reach ± 200 m.

Such an error is unacceptable in slip measurement systems, mooring, etc.

The aim of the invention is to increase the accuracy of measuring the distance between objects on which the interrogator and the responder are installed.

This goal is achieved in that a measuring unit, a directional coupler, a response signal shaper and a controlled attenuator are introduced into the device containing the transmitter, the transceiver antenna, the decoupling unit and the receiver in series, the first input of the measurement unit is connected to the output of the receiver, and the first output to the first the input of the transmitter, the first output of which is connected to the second input of the measurement unit, the second output of the measurement unit is connected to the second input of the receiver, the first input-output of the directional response the driver is connected to the input-output of the decoupling unit, and the second input-output to the input-output of the transceiver antenna, the input-output of the response driver is connected to the third input-output of the directional coupler, the first input of the controlled attenuator is connected to the second output of the transmitter, the second input is to the third output of the measurement unit, and the output to the input of the decoupling unit, and the signal "Calibration" is sent to the second input of the response signal shaper.

The input-output device is a transceiver antenna, and the output is the output of the measurement unit.

The essence of the invention lies in the fact that the newly introduced blocks: the measuring unit, the directional coupler and the driver of the response signal form a circuit that allows you to measure and take into account changes in the delay time of the signal in the receiver of the interrogator, and the newly introduced controlled attenuator reduces the error caused by the change in the level of the request signal by the input of the defendant.

Comparison of the claimed device with the prototype shows the presence of newly introduced blocks: measuring units of a directional coupler, driver of a response signal and controlled attenuator.

The introduction of such blocks to increase the accuracy of measuring range by the interrogator from public sources is unknown, which allows us to conclude that the proposed solution meets the criterion of "Novelty." The newly introduced blocks, the directional coupler and the controlled attenuator are described in the well-known literature in [5], pp. 57-58, and in [6], pp. 140-141, respectively, and the response driver can be performed according to the circuit shown figure 3 and consisting of well-known functional blocks described pin-switches in [8], p. 50-72, Y - circulators [5], p. 44-46, mixers in [9], p. 314-324 in [9], pp. 340-349, filters in [9], pp. 187-194. The measurement unit can be performed according to the scheme shown in figure 4 and consisting of well-known functional blocks described: tracking system in [7], p. 39, time-code converter in [10], p. 235-239, code converter -voltages, random access memory and subtractor in [11], p. 447-450, p. 392 and p. 313, respectively.

However, their inclusion in accordance with the above relationships makes it possible to measure the delay time of the signal in the receiver circuit of the interrogator and take it into account when generating output information about the range and reduce the error introduced by the responder by changing the level of the interrogation signal at its input.

Such a solution does not explicitly follow from the prior art, which meets the criterion of "Inventive step".

The device can be used in active high-precision range-measuring systems, for example, miss-slip systems used in the development of missile systems, in the mooring of ships, for determining the location of technical fleet vessels on working sections of sea channels, etc.

Figure 1 presents a diagram of a prototype; figure 2 - diagram of the proposed device; figure 3 is a possible diagram of the implementation of the response driver; figure 4 is a possible diagram of the measurement unit; figure 5 is a possible diagram of the transmitter; figure 6 is a possible diagram of a tracking system; 7 is a diagram of stresses explaining the operation of the interrogator.

The device (figure 2) contains a transceiver antenna 1, a directional coupler 2, a response signal shaper 8, a decoupling unit 3 connected in series, a receiver 4, a measurement unit 5, a transmitter 6, a controlled attenuator 7, the output of a controlled attenuator 7 connected to the input of the decoupling unit 3 the input-output of which is connected to the first input-output of the directional coupler 2, the input-output of the transceiver antenna 1 is connected to the second input-output of the directional coupler 2, the second output of the measurement unit 5 is connected to the second input receiver 4, and the third output is with the second input of the controlled attenuator 7, the first output of the transmitter 6 is connected to the second input of the measuring unit 5, and the second output is with the input of the controlled attenuator 7, the input-output of the response signal shaper 8 is connected to the third input-output of the directional coupler 2, and its second input receives the command "Calibration".

The response signal generator 8 (FIG. 3) contains a pin switch 9, Y a circulator 10, a mixer 11, a shear frequency generator 12, a microwave bandpass filter 13 of frequency f ₀ .

The measuring unit 5 (Fig. 4) contains a synchronizer 14, a servo system (CC) 15, a time to code converter 16 (PVC), a code-voltage converter 7 (PCN), random access memory (RAM) 18, and a subtractor (WU) ) 19.

The transmitter 6 (figure 5) contains a series-connected modulator 20, a microwave generator 21, a second directional coupler 22, a microwave detector 23.

The tracking system 15 (Fig.6) contains a time discriminator (VD) 24, a control circuit (DU) 25, a generator 26 of a measuring pulse (GIZ), a driver 27 of a signal for automatic gain control of the receiver (AGC), a driver 28 of the signal "Capture" (FSZ) )

поступают на третий вход-выход направленного ответвителя 2, а через время

- на вход-выход развязывающего блока 3 (импульсы "ж"). Здесь и далее электрические длиныThe device has two operating modes: “Calibration” and “Measurement”. In the "Calibration" mode, which is carried out during the pre-launch check and (or) immediately before the measurement, the device operates as follows. The synchronizer 14 of the measuring unit 5 generates the pulses "a", (Fig.7), the first of which triggers the tracking system 15 of the measuring unit 5, and the second - the transmitter 6, forming the pulse "b" of high-frequency oscillations of frequency f ₃ and the detected pulse "in" , which is used as the start of the pulse and enters the PVC 16, eliminating the errors caused by the instability of the delay time in the transmitter circuits. Impulse "b" comes through a controlled attenuator 7, decoupling unit 3, a high-frequency cable of electric length l ₁ to the first input-output of the directional coupler 2, pulses "g". The third input-output of the directional coupler 2 is connected by a high-frequency cable of electric length l ₃ with the input-output of the response signal shaper 8, which generates pulses "d" when the pulses "g" arrive, the frequency of which f _{0 is} different from the frequency f _{3 of the} request pulses and is equal to the frequency f ₀ transponder signals. In the "Calibration" mode, the shift frequency generator 12 is turned on, the pin switch 9 is attenuated, and the frequency fluctuations f ₃ pass through the input-output of the Y-circulator 10 and its output goes to the first input of the mixer 11, to the second input of which the oscillations of the frequency generator 12 are supplied shear f _c . The oscillations of the total frequency f ₀ = f ₃ + f _{c that} occur at the output of the mixer 11 are selected by a band-pass filter 13 tuned to the frequency f ₀ and fed through the Y-circulator 10, the second input-output of the pin switch 9 to the input-output of the response signal shaper 8. Impulses "e" of oscillations of this frequency through time

arrive at the third input-output of the directional coupler 2, and after a while

- to the input-output of the decoupling unit 3 (pulses "g"). Hereinafter, electric lengths

where l ₁ , l ₂ , l ₃ are the electric lengths of the RF cables l ₁ , l ₂ , l ₃ are, respectively;

l _Г1 , l _Г2 , l _Г3 - geometrical lengths of high-frequency cables l ₁ , l ₂ , l ₃ , respectively;

ξ is the dielectric constant of the material of the RF cables;

c is the speed of light.

From the output of the decoupling unit 3, the microwave pulses arrive at the input of the receiver 4. After amplification and conversion of these pulses by the receiver 4, pulses "and" appear at its output, delayed relative to the pulses "g" for a time t _pp , where t _pp is the delay time of the signal in the receiver . These pulses are fed to the first input of the VD 24 of the tracking system 15 of the measuring unit 5. The measuring pulse generator 26, triggered by the first pulse a _{0 of the} synchronizer 14 (Fig. 7), generates a search pulse "k", delayed relative to the pulse a ₀ and arriving at the second input temporary discriminator 24.

Under the influence of the signal taken from the output of the control circuit 25, the delay of the search pulse "k" relative to the pulse a ₀ increases until it coincides with the pulse "and", after which the SS 15 goes into tracking mode. Thus, the tracking system searches for the “and” impulse; when it is detected, the FSZ 28 generates a “Capture” signal, which indicates the interrogator is working and receives output information about the range to the consumer. Converter time-code 16 measurement unit 5 converts time

between the leading edge of the pulse "in" and the trailing edge of the pulse "k", in the code that is recorded in RAM 18, which stores the result of measuring the time 1 _k in digital for its subsequent subtraction in the subtractor 19 from the data obtained in the measurement mode. The code-voltage converter 17 converts the range code into a voltage U _D supplied to the controlled attenuator 7. At the second input of the receiver, to ensure a constant amplitude of the video signal signals taken from its output, the voltage U of the _AGC from the output of the tracking system is supplied.

импульсы будут приняты антенной ответчика, который через время t₀ излучит импульсы частоты f₀, которые поступят на вход приемопередающей антенны запросчика через времяIn the “Measurement” mode, the “Calibration” command is not given, the attenuation of the pin switch 9 of the response signal conditioner 8 increases and the shift frequency generator 12 is turned off. Therefore, the signal of the response signal conditioner 8 will be lower than the threshold sensitivity of the receiver and will not be detected by the tracking system 15 of the measurement unit. In this mode, the synchronizer generates two transmitter start pulses, shifted together by a time t _b . Request pair pulses “l” of the transmitter 6 having a base t _b , after a time t ₁ = l ₁ / c the first input-output of the directional coupler 2 is reached, and after a time t ₅ = l ₂ / s - the input-output of the transceiver antenna 1 and it will emit pulses of "n". If the respondent is located at a distance R from the interrogator, then after a while

the pulses will be received by the antenna of the transponder, which after time t _{0 will} emit pulses of frequency f ₀ , which will be received at the input of the transceiver antenna of the interrogator through time

where t ₀ is the signal delay time in the transponder circuits.

These pulses "o" are received by the transceiver antenna 1 of the interrogator and after time t ₅ = l ₂ / s are fed to the second input-output of the directional coupler 2 pulses "p", after time t ₁ = l ₁ / c - to the input-output of the decoupling unit 3 pulses "p", and after a time t _pp - at the output of the receiver 4 there are video pulses "c". In this mode, the measuring unit 5 will measure the time between the detected pulse "in" and the search pulse "t" of the tracking system 15

Corresponding to the time code output from the STC 16 is supplied to a subtractor 19 where it is subtracted from a time code t _to

If l ₂ = l ₃ , which can be ensured by the choice of lengths and types of RF cables, then

those. independent of the delay time of the signal in the receiver of the interrogator. The received range code from the output of the subtractor 19 and the signal “Capture” from the output of the CC 15 is issued to the consumer.

To reduce the instability of the transponder time t ₀ caused by the instability of the level of the interrogation signal, the attenuation of the controlled attenuator 7 increases quadratically with a decrease in the distance R between the interrogator and the transponder.

If, for example, R _max = 200 m, and R _min = 2 m, then the change in attenuation ΔN should be

Such a change in attenuation can be implemented on several pin diodes controlled by voltage U _D taken from the output of the control panel 17 of measurement unit 5.

To reduce the error caused by a change in the signal level at the input of the measurement unit, automatic gain control of the receiver 4 is used.

Ensuring a constant amplitude of the output pulse at the output of the receiver is achieved by adjusting the gain of the intermediate frequency amplifier (IFA) of the receiver by changing the control voltage supplied to the input of the first stages of the IF, as described in [9], p. 422.

The main advantage of the claimed device is the greater accuracy of range measurement, because the errors of range measurement introduced by the instability of the delay time of the signal in the receiver transmitter circuits and the cable system of the interrogator are eliminated, as well as the error of the responder caused by a change in the level of the interrogation signal at the input of the transponder receiving device when the distance between the interrogator and the transponder is reduced.

In addition, the introduction of a response signal shaper 8 makes it possible to increase the completeness of the interrogator control during pre-launch checks, since in the “Calibration” mode the power of the transmitter 6, the sensitivity of the receiver 4 and the operability of the measurement unit 5 are checked. In fact, if the power of the transmitter 6 or the sensitivity of the receiver 4 If they fall below the norm, then the tracking system of the measuring unit 5 will not detect the pulse of the driver 8 of the response signal and will not give a signal "Capture", indicating the interrogator is working. If the time-to-code converter 16 of measurement unit 5 is malfunctioning, then the received code will not correspond to the calculated one, and a sign of serviceability will not be issued in the code.

The newly introduced blocks can be made using thin-film technology and will not lead to a significant increase in the volume and mass of the interrogator compared to the prototype.

The proposed interrogator can find application in slip measurement systems for firing at air and sea targets, in ship mooring systems.

Literature

1. Aviation radar. Directory edited by P.S.Davydov. - M .: Transport, 1984, p. 110-113.

2. Shapiro EM and other secondary radar system. USSR author's certificate (SU) No. 130974 for an application for an invention No. 394560 / 00-09 (22) dated 08.22.85. Inventions of the world, No. 22, no. 85. MKI GOIR, RS, 1992, p.22.

3. Product 24G6. Specifications GU1.000.54 TU / "UPKB" Detail ", 1982, p.13.

4. Technical requirements for aircraft equipment. Appendix to Chapter 8 ENLG-S “Aircraft Equipment”, 1987, p.220.

5. Microelectronic devices microwave. / Edited by prof. G.I. Veselova. - M.: Higher School, 1988, p. 57-58.

6. Gassanov L.G. and other solid-state microwave devices in communication technology. - M .: Radio and communications, 1988, p. 44-46, 140-141.

7. Mityashev B.N. Determination of the temporary position of pulses in the presence of interference. - M .: Soviet Radio, 1962, p. 39.

8. Weissblat A.V. Microwave switching devices on semiconductor diodes. - M .: Radio and communications, 1987, p. 50-72.

9. Design of radio receivers. / Edited by A.P. Sivers. - M .: Soviet Radio, 1976, p. 187-194, 314-323, 340-349, 402.

10. Gitis E.I. "Information converters for electronic digital computing devices." - M .: Energy, 1975, p. 235-239.

11. Titz U., Schenk K. "Semiconductor circuitry." - M .: Mir, 1982, p.331, 392, 447-450.

Claims (1)

A radar interrogator comprising a transmitter, a transceiver antenna, a decoupling unit and a receiver connected in series, characterized in that a measurement unit, a directional coupler, a response driver and a controlled attenuator are introduced, the first input of the measurement unit is connected to the output of the receiver, and the first output to the first input transmitter, the first output of which is connected to the second input of the measurement unit, the second output of the measurement unit is connected to the second input of the receiver, the first input-output directional response The amplifier is connected to the input-output of the decoupling unit, the second input-output to the input-output of the transceiver antenna, and the third input-output to the input-output of the response shaper, the first input of the controlled attenuator is connected to the second output of the transmitter, the second input to the third the output of the measuring unit, and the output with the input of the decoupling unit, and the “Calibration” command is sent to the second input of the response signal former.

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