RU2101717C1 - Method for measurement of effective scattering area and device which implements said method - Google Patents

Abstract

FIELD: remote control systems for object recognition. SUBSTANCE: method involves measurement of maximal and minimal values of total amplitude of interference of two electromagnetic waves which run in same direction, are reflected from reflector and reference object and from reflector and marker for tow different values of impedance of its antenna. First claim of invention describes method in which phase shift between coherent reference wave and wave reflected from reference object and between reference wave and wave which is reflected from marker by at least 2π. Second claim of invention describes method in which reference object is exposed to flat modulated wave with frequency deviation Δf, wave which is reflected from reference object is delayed in phase with respect to reference wave by means of transmission line which length is not less than C/4 Δf, which amplitude is greater than amplitude of wave which is reflected from reference object. In addition wave which is reflected from marker is delayed by means of same transmission line. Measured values of amplitudes of interference of waves which are reflected from reference object and reference wave as well waves which are reflected from marker for two different values of impedance of load of marker antenna and reference waves as well as measured phase difference between envelopes provide effective scattering area of marker according to given equations. Device which measures effective scattering area of marker has generator of electromagnetic waves, direction unit, which input is connected to output of generator, receiving-transmitting antenna, serial circuit of detector, low-frequency amplifier and indicator, and marker support. Third claim of invention describes device which has reflector of electromagnetic waves, phase shifter, drive of phase shifter. Antenna, phase shifter and reflector are connected in series. Reflector is connected to main arm of direction unit which side arm is connected to input of detector. Drive of phase shifter is connected to control input of phase shifter and indicator. Fourth claim of invention describes device which has reflector of electromagnetic waves, delay line and modulator of waves of generator. Generator is equipped with electronic frequency tuning, output of modulator is connected to control input of generator and indicator. Antenna, delay line and reflector are connected in series. Output of main arm of direction unit is connected to reflector. EFFECT: increased functional capabilities. 4 cl, 7 dwg

Description

 The invention relates to a technique for measuring the effective scattering area (EPR) and can be used to measure the EPR of a marker of a telemetric volume identification system. The load impedance of the marker antenna is measured with a certain frequency from one value to another, corresponding in binary notation to logical "zero" and "one" (US patent N 4 739 328, 1988). When a marker is irradiated with an electromagnetic wave, the wave reflected from its antenna contains information embedded in the marker encoder. Under the technical conditions, such markers stipulate the lowest permissible value of the variable component of the EPR marker, which determines the radius of action of the volume identification system and the possibility of separation by this system of code signals of different markers.

 A device and method for measuring EPR are known (E. N. Mayzels, V. A. Torganov. Measuring the scattering characteristics of radar targets. M. Sov. Radio, 1972, pp. 148 and 149, Fig. 5.1). This device contains a microwave generator, a directional device, a transceiver antenna, a phase shifter and an attenuator made in the form of a waveguide complex load, a receiver, a recorder indicator, and a support for supporting and rotating in azimuth of the measured object.

 The device operates as follows. The antenna emits unmodulated electromagnetic waves in the direction of the support. In the absence of the measured object with the help of the load, the waves reflected from local objects are compensated in the receiver. After that, a reference with a known EPR value is installed on the support. Using the value of the EPR standard using an attenuator calibrate the chart recorder in the values of the EPR. In place of the standard set the measured object. Using the support, the measured object is rotated in azimuth, and the ESR values of the object are recorded on the tape of the recorder. This method and device do not allow to measure the EPR of the marker due to a change in the phase of the wave in accordance with the code of the permanent storage device of the marker and reflected from its antenna.

Also known is a method of measuring the EPR of an anechoic chamber (BEC) background and a device for its implementation (Microwave 9, 1963 p. 69 75, Fig. 5), adopted as a prototype of the invention. This method is as follows. In BEC emit unmodulated electromagnetic waves in the direction of the support for the measured object. A reference metal ball is mounted on a support asymmetrically to its axis. By rotating the support, the phase of the wave reflected from it is measured, while the interference amplitudes are measured at the maximum (E _{e, 1, max} ) and minimum (E _{e, 1, min} ) waves reflected from the reference and BEC. The possible values of the amplitudes of the interfering waves determined by the reflection from the BEC (E ₁ ) and the standard (E ₂ ) are determined by the formula (I)
E ₁ (E _{e, 1, max} + E _{e, 1, min} ) / 2
E ₂ (E _{e, 1, max} E _{e, 1, min} ) / 2 (1)
To resolve the uncertainty, what values of the amplitudes belong to which reflected waves, carry out similar measurements with a second standard, the ESR of which is not equal to the ESR of the first standard.

In this case, other amplitudes are obtained at the maximum and minimum of the interfering waves, namely, E _{e, 2, max} and E _{e, 2, min} .

Determine other possible values of the amplitudes of the interfering waves caused by the reflectors from the BEC and the reference (E ₃ and E ₄ ), according to the formula (2)
E ₃ (E _{e, 2, max} + E _{e, 2, min} ) / 2
E ₄ (E _{e, 2, max} E _{e, 2, min} ) / 2 (2)
Two identical values of the four E _i (i 1, 2, 3, 4) will correspond to the reflection from the BEC, and two different values to the reflections from the standards. According to the known values of the EPR of the standards, the EPR of BEC is determined by the formula (3).

Устройство для измерения ЭПР БЭК по этому способу содержит генератор немодулированных электромагнитных волн, направленное устройство, приемопередающую антенну, устройство для перемещения антенны, опору для эталонов, детектор, усилитель и индикатор.

A device for measuring the EPR of a BEC by this method comprises an unmodulated electromagnetic wave generator, a directional device, a transceiver antenna, a device for moving the antenna, a support for standards, a detector, an amplifier, and an indicator.

 The prototype does not allow the measurement of the EPR marker, due to a change in the phase of the wave reflected from the load of its antenna.

 The technical result of the invention is the ability to measure the variable component of the EPR marker, due to a change in the module (amplitude) and argument (phase) of the load impedance of its antenna. This result is achieved in two versions of the device and the measurement method associated with one inventive concept.

 I embodiment of the method.

A method of measuring the EPR of a marker due to a change in the impedance (module and argument) of the load of its antenna, based on measuring the maximum and minimum values of the interference amplitudes of two electromagnetic waves propagating in one direction, which consists in the fact that a stationary standard with a known value of EPR (σ _e ) irradiated with an unmodulated, quasi-plane wave, change the phase difference between the coherent reference wave and the wave reflected from the standard, whose amplitude is less than the amplitude of the reference wave, by at least 2π. At the same time, the maximum and minimum values of the interference amplitudes of the two waves (E _{e, max} and E _{e, min} ) are measured, after which the measured marker is fixedly in place of the standard, the phase difference between the reference wave and the waves reflected is changed by at least 2π from the marker at two different values of the load impedance of its antenna, at the same time measure the maximum and minimum values of the envelopes of the resulting amplitudes of interference of the two wave pairs (E _{1, max} , E _{2, max} and E _{1, min} , E _{2, min} ), in addition R connectivity phase (ΔΦ) between the envelopes. Then determine the EPR of the marker, due to a change in the load impedance of its antenna, according to the formula (4).

(4)
где σ_м переменная составляющая ЭПР маркера;
σ_э ЭПР эталона;
E_э,макс и E_э,мин максимальное и минимальное значения амплитуд интерференции волны, отраженной от эталона и опорной волны;
E_1,макс и E_1,мин максимальное и минимальное значения огибающей амплитуд интерференции волны, отраженной от маркера, при одном значении импеданса нагрузки его антенны и опорной волны;
E_2,макс и E_2,мин максимальное и минимальное значения огибающей амплитуд интерференции волны, отраженной от маркера, при другом значении импеданса нагрузки его антенны и опорной волны.

(4)
where σ _{m is the} variable component of the EPR marker;
σ _e EPR standard;
E _{e, max} and E _{e, min the} maximum and minimum values of the amplitudes of the interference of the wave reflected from the standard and the reference wave;
E _{1, max} and E _{1, min the} maximum and minimum values of the envelope of the amplitudes of the interference of the wave reflected from the marker, at one value of the load impedance of its antenna and the reference wave;
E _{2, max} and E _{2, min the} maximum and minimum values of the envelope of the amplitudes of the interference of the wave reflected from the marker, with a different value of the load impedance of its antenna and the reference wave.

 Distinctive features of the invention are the measurement of the maximum and minimum values of the interference of the reference wave with waves reflected from the reference and the antenna of the marker, at different values of the impedance of its load, as well as the measurement of the phase difference between the envelopes of the amplitudes of interference of the reference wave with waves reflected from the antenna, at different values impedance of its load.

 I embodiment of the device.

 A device for implementing the method according to I embodiment comprises: a microwave generator of unmodulated electromagnetic waves, a directional device, a reflector of electromagnetic waves, a phase shifter, a transceiver antenna, a detector, an amplifier, an indicator, a phase shifter drive and a support for a marker.

 The generator, the main arm of the directional device, reflector, phase shifter and antenna are connected in series. The output of the lateral arm of the directional device is connected to the input of the detector, the output of which, through an amplifier, is connected to the signal input of the indicator. The output of the phase shifter drive is connected to the control inputs of the phase shifter and indicator.

 Distinctive features of the invention are: a reflector, a phase shifter, a phase shifter drive, as well as electrical communications due to the introduction of new devices.

 II variant of the method.

A method for measuring the EPR of a marker due to a change in the impedance (module and argument) of the load of its antenna, based on measuring the maximum and minimum values of the interference amplitudes of two electromagnetic waves propagating in one direction, consisting in the fact that a non-dispersive, stationary reference with a known value of EPR (σ _e ) irradiate with a quasi-plane, frequency-modulated wave with a frequency deviation Δf delay the phase reflected wave from the reference in phase with respect to the reference wave on the transmission line of at least h we take at C / 4f, (where C is the speed of light) whose amplitude is greater than the amplitude of the wave reflected from the standard. The maximum (E _{e, max} ) and minimum (E _{e, min} ) interference amplitudes of the mentioned waves are measured in the frequency panorama, after which a motionless marker is installed in place of the standard, the maximum and minimum values of the amplitudes of the envelopes of interference are measured (E _{1, max} , E _{2 ,} and E _{max 1, min,} E _{2, m)} of the reference wave with the wave reflected from the marker, at different values of load impedance of its antenna, simultaneously measure the phase difference between said envelopes (ΔΦ) after which the ESR marker due to the impedance change and loading its antenna, according to the formula (4).

 Distinctive features of the invention are: irradiation of a non-dispersive standard and marker with frequency-modulated waves, phase delay of waves reflected from the standard and marker with respect to the reference wave, measurement of the maximum and minimum amplitudes of interference of pairs of waves of one wave reflected from the stationary standard and marker at two states of the impedance of its antenna and the reference wave, as well as measuring the phase difference between the envelopes.

 II embodiment of the device.

 A device for implementing the method according to the second embodiment comprises: a microwave generator of frequency-modulated electromagnetic waves, a directional device, a reflector of electromagnetic waves, a delay line, a transceiver antenna, a generator modulator, a detector, an amplifier, an indicator, and a marker support.

 The generator, the main arm of the directional device, the reflector, the delay line and the antenna are connected in series. The output of the lateral arm of the directional device is connected to the input of the detector, the output of which, through an amplifier, is connected to the signal input of the indicator. The output of the generator modulator is connected to the control inputs of the microwave generator and indicator.

 Distinctive features of the invention are: a frequency modulated microwave generator, a generator modulator, a delay line, as well as communications due to the introduced devices.

 The technical result of the invention is achieved due to the fact that the phase shifter (in the I embodiment) and the delay line (in the II version) provides a change in the phase of the waves reflected from the marker relative to the phase of the reference wave by 2π radians and, thus, from the measured values of the maximum and minimum values of the interference amplitudes of the mentioned waves and the phase difference of the envelopes due to a change in the load impedance of the antenna, allows you to determine the variable component of the EPR marker.

 Methods of measuring the EPR of the marker and device for their implementation are illustrated in FIG.

In FIG. 1 is a structural diagram of a device according to an I embodiment of the invention; in FIG. 2 is a structural diagram of a device according to a second embodiment of the invention; in FIG. 3 block diagram of the marker; in FIG. 4 oscillogram of the interference amplitude of the wave reflected from the standard and the reference wave reflected from the reflector, when the phase difference between these waves changes by 2π according to I and II embodiment of the invention; in FIG. 5 - oscillograms of the amplitudes of interference of waves reflected from the marker at two different phase values of the wave reflectors from the load of its antenna, and the reference wave reflected from the reflector; in FIG. Fig. 6 is a vector diagram of the amplitudes of the waves at the detector input reflected from the reflector (E _on ) and two waves reflected from the marker when the phase difference between them is p / 2 [E (0) and E (π / 2)] one of which is ahead of the vector E _on by π / 4 and the other behind by π / 4 • (E _{Σ, 1} and E _{Σ, 2} ) - total vectors equal in absolute value to each other); in FIG. 7 is a vector diagram of the amplitudes of the waves at the detector input reflected from the reflector (E _on ) and two waves reflected from the marker when the phase difference between them is π / 2 [E (0) and E (π / 2)], one of which is behind phase from the vector E _on to π / 4 and the other to 3π / 4 • (E _{Σ, 1} and E _{Σ, 2} total vectors (not equal to each other).

 In FIG. The following notations are adopted: 1 generator of microwave unmodulated electromagnetic waves (G); 2 directional device (NU); 3 reflector of electromagnetic waves (OTR); 4 phase shifter (PV); 5 transceiver antenna of the device (A); 6 detector (D); 7 amplifier (U); 8 indicator (Indus); 9 phase shifter drive (PF); 10 support of the measured marker; 11 - modulator of the microwave generator (MG); 12 measured marker (Mr); 13 - marker transceiver antenna (AM); 14 variable load antenna marker (NP); 15 read-only memory marker (ROM); 16 - power supply marker.

 The microwave generator 1 can be performed according to one of the known schemes of the oscillator, for example, transistors, with a working frequency of the measured marker 950 MHz with a capacity of several mW.

 The directional device 2 can be made in the form of a directional coupler, or a hybrid ring, etc. on waveguides, coaxial lines or strip lines.

 Reflector 3 can be made in the form of a pin inserted into the line between NU 2 and PV 4.

 Phase shifter 4 can be made in the form of a trombone on waveguide or coaxial transmission lines.

 Antenna 5 can be made horn, vibrator, lens, etc.

 The detector 6 can be performed on a semiconductor diode.

 The amplifier 7 can be made in the form of an AC amplifier on transistors according to known schemes tuned to the modulation frequency of the waves reflected from the marker.

 Indicator 8 can be made in the form of an oscilloscope with vertically and horizontally deflecting devices.

 The phase shifter drive 9 can be made mechanical or electrical or combined.

 The support 10 can be made in the form of a stand made of dielectric.

 The modulator of the generator 11 can be performed according to known schemes of the oscillator on transistors with a sawtooth change in voltage at its output.

 Marker 12 may be made as shown in FIG. 3.

 The antenna 13 of the marker can be made in the form of a half-wave vibrator.

 The variable load 14 can be made in the form of a tunable resonant circuit, the resonant frequency of which varies, for example, varicap.

 ROM 15 can be performed on chips 536 series.

 The power source 16 may be made in the form of an electric battery. The standard can be made in the form of a metal ball.

 The device and method of its operation according to the I embodiment of the invention. The device comprises: a microwave generator 1 of unmodulated electromagnetic waves, a directional device 2 made in the form of a directional coupler on strips, a reflector 3 made in the form of a metal pin inserted into the transmission line between the coupler and the phase shifter 4, made in the form of a ramp on a coaxial transmission line, antenna 5, made in the form of a horn, detector 6, made on a semiconductor diode, amplifier 7 sound frequency (frequency modulation of the load of the marker), made on transistors, indicator 8, completed in the form of an oscilloscope, the phase shifter drive 9, made combined (mechanical and electrical), and the support 10, made in the form of a wooden stand.

 The generator 1, the main arm of the coupler 2, the reflector 3, the phase shifter 4 and the antenna 5 are connected in series. The output of the side arm of the coupler is connected to the input of the detector 6, the output of which through the amplifier 7 is connected to a vertically deflecting device of the oscilloscope 8. The mechanical output of the drive 9 is connected to a phase shifter 4, and the electric output to a horizontally deflecting device of the oscilloscope 8.

 The marker is mounted on a support 10 in front of the antenna at a distance that provides a quasi-plane wave front.

 Unmodulated electromagnetic waves of the generator 1 through the directional coupler 2, reflector 3, phase shifter 4 and antenna 5 are partially emitted in the direction of the standard or measured marker 12, the other part is reflected from the reflector 3.

 The waves reflected from the reflector and the reference or marker go to the input of the detector 6, and from its output through the amplifier 7 to the vertically deflecting device of the oscilloscope 8. Voltage is applied to the horizontally deflecting device of the oscilloscope 8, which is proportional to the phase change of the phase shifter 4. The resultant pattern the amplitude of interference of waves reflected from the reflector and the reference or marker is observed on the screen of the oscilloscope 8 (Fig. 4 and 5).

The method of measuring the variable component of the EPR marker is as follows. In front of the antenna 5, a reference is fixedly mounted on the support 10 and irradiated with unmodulated electromagnetic waves of the generator 1. Using the drive 9 and the phase shifter 4, the phase difference between the waves reflected from the marker 12 and the reflector 3 is changed. At the same time, the oscilloscope 8 is aligned along the vertical scale of the CRT (Fig. 4) note the maximum and minimum value of the resulting amplitude of the interfering waves (E _{e, max} and E _{e, min} ). In place of the standard, the measured marker is fixedly installed, the phase difference between the waves reflected from the marker 12, which always work when the power is turned on, and the reflector 3 are measured in the same way. At the same time, the maximum and minimum values of the envelopes of the resulting the interference amplitudes of two pairs of waves reflected from the marker at two different values of the load impedance of its antenna 13 (E _{1, max} , E _{2, max} and E _{1, min} , E _{1, min} , E _{2, min} ) and from the reflector 3. In addition addition on the horizon On the CRT scale, the phase difference between these envelopes ΔΦ
The variable component of the EPR marker is determined by the formula (4).

 The device and method of its operation according to the II embodiment of the invention. The device comprises: a microwave generator 1 with electronic frequency tuning, a directional device 2 made in the form of a directional coupler on strips, a reflector 3 made in the form of a metal pin inserted into the transmission line between the coupler and the delay line 9, made in the form of a cable bay, an antenna 5, made in the form of a horn, detector 6, made on a semiconductor diode, an amplifier of sound frequency (frequency modulation of the load of the marker), made on transistors, indicator 8, made in the form of an oscilloscope, mode the heater 11 of the generator 1 with a sawtooth voltage at its output.

 The generator 1, the main arm of the coupler 2, the reflector 3, the delay line 9 and the antenna 5 are connected in series. The output of the lateral arm of the coupler 2 is connected to the input of the detector 6, the output of which through the amplifier 7 is connected to a vertically deflecting device of the oscilloscope 8. The output of the modulator 11 is connected to the control input of the generator 1 and the horizontally deflecting device of the oscilloscope 8.

 The marker is mounted on the support 10 in front of the antenna 5 at a distance providing a quasi-plane wave front.

 Frequency-modulated electromagnetic waves of generator 1 through a directional coupler 2, reflector 3, delay line 9 and antenna 5 are partially emitted in the direction of the standard or measured marker 12, the other part is reflected from reflector 3.

 The waves reflected from the reflector and the reference or marker go to the input of the detector 6, and from its output through the amplifier 7 to the vertically deflecting device of the oscilloscope 8. A sawtooth voltage from the output of the modulator 11 is applied to the horizontally deflecting device of the oscilloscope 8, proportional to the change in the frequency of the generator 1. The picture of the resulting the amplitudes of interference of waves reflected from the reflector and the reference or marker are observed on the screen of a CRT oscilloscope 8 (Fig. 4 and 5).

The method of measuring the variable component of the EPR marker is as follows. In front of the antenna 5, a fixedly non-dispersive standard is mounted on the support 10 and irradiated with frequency-modulated electromagnetic waves of the generator 1. On the vertical CRT scale of the oscilloscope 8 (Fig. 4), the maximum and minimum values of the resulting amplitude of the interfering waves (E _{e, max} and E _{e, min} ) reflected from the reflector and the standard. The measured marker is fixedly installed in place of the standard. On the vertical CRT scale of the oscilloscope 8 (Fig. 5), the maximum and minimum values of the envelopes of the resulting interference amplitudes of two pairs of waves reflected from the marker are noted for two different values of the load impedance of its antenna and reflector (E _{1, max} , E _{2, max} and E _{1 min} , E _{2 min} ). In addition, the phase difference between these envelopes (DF) is measured on a horizontal CRT scale of the oscilloscope.

 The variable component of the EPR marker is determined by the formula (4).

Claims (4)

1. The method of measuring the effective scattering area (EPR) of a marker due to a change in the load impedance of its antenna, based on measuring the maximum and minimum values of the resulting interference amplitude of two electromagnetic waves propagating in the same direction, consisting in the fact that the standard is irradiated with a non-modulated, quasi-plane wave, change by at least 2π the phase difference between the coherent reference wave and the wave reflected from the standard, at the same time measure the maximum and minimum values of the results tiruyuschey their interference amplitudes (E _{e, m a to c} and E _{e, m and n),} characterized in that the amplitude of the reference wave is greater than the wave amplitude reflected from the reference, to place a reference fixedly mounted measured marker alter at least 2π a phase difference between a reference wave and the wave reflected from the marker at two different values of load impedance of its antenna, simultaneously measure the maximum and minimum values of the envelopes of the resultant amplitudes of the interference of said two waves couples (E _{1, m a to c,} E _{2, m and k with} and E _{1 m and n ,} E _{2 m and n} ), in addition, the phase difference (ΔΦ) between the envelopes is measured, after which the EPR of the marker, determined by the change in the load impedance of its antenna, is determined by the formula

Where

σ _e - EPR standard;
σ _m - a variable component of the EPR marker;
E _{e, m and} E _{to a} and _{e, m and n} the maximum and minimum amplitude values rezultruyuschey interference waves reflected from the sample and the reference wave;
E _{1, m and} E _{to a} and _{1, m and n} the maximum and minimum values of the amplitude envelope of the resulting interference waves reflected from the audio marker at one value of the load impedance of its antenna, and the other of the reference wave;
E _{2, m a to c} and E _{2, m and n} the maximum and minimum values of the envelope amplitude of the resultant wave interference, one reflected from the marker at a different load impedance of its antenna, and the other of the reference wave. 2. A method of measuring the effective scattering area (EPR) of a marker due to a change in the load impedance of its antenna, based on measuring the maximum and minimum values of the resulting interference amplitude of two electromagnetic waves propagating in one direction, characterized in that the non-dispersive, stationary reference is irradiated with a quasi-plane, modulated in frequency by a wave with a frequency deviation Δf, the phase-reflected wave from the reference is delayed in phase with respect to the reference wave on a transmission line of at least than C / 4Δf, where C the speed of light, the amplitude of which is greater than amplitude of the wave reflected from the sample, while measuring the maximum and minimum values of the resultant interference of the mentioned wave (E _{e, m a to c} and E _{e, m and n),} after which to place a reference fixedly mounted measured marker delayed reflected from the marker wave on said transmission line, simultaneously measure the maximum and minimum values of the amplitudes of the envelopes interference (E _{1, m a to c,} E _{2, m and k with,} E _{1, m and n ,} E _{2, m and n)} of the reference wave with the wave reflected the marker at different values of load impedance of its antenna, in addition measured phase difference ΔF between said envelopes, after which the ESR marker due to the change of the load impedance of its antenna according to the formula

Where

σ _m - a variable component of the EPR marker;
σ _e - EPR standard;
_{E E, a ma with} E and _{e, m and n} minimum and maximum values of the amplitude of the resultant interference of waves reflected from the sample and the reference wave;
E _{1, m and} E _{to a} and _{1, m and n} the maximum and minimum values of the envelope amplitude of the resultant wave interference, one reflected from the marker for a single value of the load impedance of its antenna, and the other of the reference wave;
E _{2, m a to c} and E _{2, m and n} minimum and maximum values of the envelope of the amplitude of the resultant wave interference, one reflected from the marker at a different load impedance of its antenna, and the other of the reference wave.  3. A device for measuring the EPR of a marker due to a change in the load impedance of its antenna, comprising a generator of unmodulated electromagnetic waves, a directional device, the input of which is connected to the output of the generator, a transceiver antenna, a series-connected detector, a low-frequency amplifier, and an indicator and marker support, characterized in that a reflector of electromagnetic waves, a phase shifter and a phase shifter drive are introduced into it, in addition, to the output of the main arm of the directional device in series with a reflector, a phase shifter and an antenna are connected, and a detector input is connected to the output of the lateral arm of the directional device, and the output of the phase shifter drive is connected to the control input of the phase shifter and indicator.  4. A device for measuring the EPR of a marker due to a change in the load impedance of its antenna, comprising an electromagnetic wave generator, a directional device whose input is connected to the generator output, a transceiver antenna, a detector connected in series, a low-frequency amplifier and an indicator, and a marker support, and the detector input connected to the output of the lateral shoulder of a directional device, characterized in that a reflector of electromagnetic waves, a delay line and a generator modulator of waves are introduced into it, in addition, the generator is electronically tuned, the output of the main arm of the directional device, the reflector, the delay line and the antenna are connected in series, and the output of the modulator is connected to the control input of the generator and indicator.

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