RU65203U1 - SIGNAL RE-REDUCTION DEVICE SIMULATING A DOPLER SHIFT OF A RECEIVED SIGNAL FROM A MOVING GOAL - Google Patents

Abstract

The utility model relates to the field of testing radar systems, in particular to simulators of a moving target, and can be used to test anti-aircraft missile systems at the stage of their development and verification, as well as equipment for adjusting the tuning of radar stations. The utility model allows you to create a device that works reliably in all weather conditions and at any time of the day with a wide range of simulated speeds of moving targets, with changes in the direction of movement and different values of the effective scattering area (EPR) of the targets set. A signal re-emission device simulating a Doppler frequency shift of a received signal from a moving target comprises a housing 1, in front of which an antenna 2 is mounted. Antenna 2 is protected in front of a thin-walled radiolucent sheath 3. The waveguide part of antenna 2 is located inside the housing 1 and ends with isolation node 4, both waveguide the flange of which is connected to the microwave unit 5. The microwave unit 5 contains attenuator 7 connected in series through the waveguides 6, the valve 8 and the n-number of control added phase shifters 9. The control input of each of the controlled phase shifters 9 is connected to the corresponding output of the modulator 10, which is controlled from its input via the control bus. The additional paragraphs of the formula provide specific options for distinctive performance. 1 s.p. and 4 z.p. f-ly, 5 ill.

Description

The proposed utility model relates to the field of testing radar systems, in particular to simulators of a moving target, and can be used in testing anti-aircraft missile systems at the stage of their development and verification, as well as equipment for the adjustment of radar stations.

Advances in modern technology make it possible to create special devices that without the use of expensive unmanaged and remotely piloted aircraft (UAVs) in stationary conditions simulate a radar radar signal received from a moving target with different speeds and directions.

Simulators of a moving target are equipped with testing ranges for radio complexes and quotation machines, which ensure that quotation works are carried out during radar maintenance.

Until now, the solution of such problems was considered optimal using devices similar to those described in the description of the invention to the patent “Simulator of a moving target” (RU No. 2239773 C1 of 02.17.2003, 7F41J 5/08), made in the form of a drum rotating on the axis, connected to an electric motor, with metal corners installed inside the drum in a circle with mutually perpendicular sides, forming corner reflectors together with the lower and upper disks of the drum, while each corner reflector is installed without atemneniya reflection region preceding corner reflector of the radiation, and the drum casing is designed as a radio transparent thin-walled shell, and similar devices that have insignificant upgrading.

However, this simulator of a moving target, for all its merits, cannot be used for testing and testing the latest radio-controlled anti-aircraft missile systems and the adjustment of their radar stations, since it has a number of significant drawbacks.

In particular, reflecting part of the microwave energy in the direction of the radar, rotating corner reflectors modulate the reflected signal in amplitude due to a changing equivalent scattering area (EPR) and cause a frequency beat due to a change in radial velocity.

As a result, the spectrum of the signal reflected from the simulator (Doppler signal) differs significantly from the real signal reflected from the moving target, and contains a large number of combinational components, and a flickering image of the target is visually observed on the radar screen. All this is an obstacle to the configuration and verification of the radar.

In addition, the simulator has limited capabilities and cannot provide simulation of high speeds of the target (with the speed of sound or more).

The authors were faced with the task of creating a relatively simple simulator of a moving target that works reliably in all weather conditions, including in the presence of sand, dust, at any time of the day with large radio and acoustic noise, with a wider range of simulated speeds, with various EPR values and the spectral characteristic of the Doppler signal, as close as possible to the real one.

The problem is solved by implementing a device for re-emission of signals that simulates the Doppler frequency shift of the received signal from a moving target, in the form of a housing in the front of which an antenna is installed, protected by a radiolucent sheath in front, the waveguide part of the antenna is located inside the housing and

equipped at the end with a decoupling unit, the outputs of which are connected to a microwave unit, which represents an attenuator, a valve and an n-number of controlled phase shifters connected in series through waveguides, while the control input of each of the controlled phase shifters is electrically connected to the corresponding output of the modulator controlled from its input via the bus management.

The decoupling unit is made in the form of a polarizing tee.

The junction unit is made in the form of a circulator.

A waveguide coupler with a detector head connected to it is installed between the valve and the controlled phase shifter.

The housing on top and on both sides is protected by a metal sun screen.

The base is made in the form of a dovetail, and a calibrated hole is made symmetrically to its longitudinal axis.

The isolation node is made in the form of a circulator when the radar is linearly polarized, and to control the re-emitted signal between the valve and the controlled phase shifter, a waveguide coupler with a detector head connected to it is installed.

The inventive device has a combination of essential features not known from the prior art for devices of this purpose, which allows us to conclude that the criterion of "novelty" for the utility model.

The essence of the utility model is illustrated using the drawings, where:

figure 1 shows a diagram of a device;

figure 2 - the location of the structural elements of the device;

figure 3 - the location of the elements of the microwave node;

figure 4 - appearance of the modulator;

figure 5 - appearance of the device.

A signal re-emission device simulating a Doppler frequency shift of a received signal from a moving target, comprises a housing 1, in

the front of which the antenna 2 is installed. The front of the antenna 2 is protected by a thin-walled radiolucent sheath 3. The waveguide part of the antenna 2 is located inside the housing 1 and ends with the decoupling unit 4, both waveguide flanges of which are connected to the microwave unit 5. The microwave unit 5 contains an attenuator connected in series through the waveguides 6 7, valve 8 and the n-number of controlled phase shifters 9. The control input of each of the controlled phase shifters 9 is connected by an electric circuit to the corresponding ode modulator 10 which is controlled by its input through the control bus.

The housing 1 on top and on both sides is protected by a metal sun screen 11, ensuring the operation of the device in conditions of exposure to solar radiation. The housing 1 is installed on the base 12 with a guide in the form of a "dovetail" for convenience and minimum installation and removal of the device. In the center of the base 12, a calibration hole 13 is arranged symmetrically for mounting the optical alignment tube. To control the re-emitted signal in front of the valve 8, a waveguide coupler 14 with a detection head 15 connected to it is installed.

The device for re-emission of signals is installed on the tower of the test site or taken to the test site as part of the alignment machine, on the platform of which it is attached to the base 12 of the housing 1.

The device re-emission of signals works as follows.

To carry out tuning and adjustment operations, the signal re-emission device must first be aimed at the radar with the help of an alignment tube, for example, a cold sighting tube (ТХП-7-191).

To turn on the device re-emission of signals it is necessary to apply to it a supply voltage U _pit . Further along the control bus to the input of the modulator 10 are set signals, for example, in the form of a binary parallel code of speed values and the direction of the simulated target movement. After that, the device re-emission of signals is ready for operation.

The radar emits a probe signal in the direction of the signal re-emission device. The probe signal received by the antenna 2, enters through the node 4 isolation and waveguides 6 in a chain of series-connected n-number of controlled phase shifters 9 (number n≥3).

The controlled phase shifters 9 are separately controlled by applying to their inputs a corresponding control signal coming from the output (1, 2 ... n) of the modulator 10.

A modulator 10, in which a master oscillator with a controlled frequency divider, made in the form of a reversible counter, is integrated, generates at its outputs (1, 2 ... n) control signals for controlling the phase shifters 9, and the control signals follow periodically and differ in repetition frequency .

Presetting the reversible counter of the modulator 10 to the “direct count” or “inverse counting” mode creates a sequence of output signals (1, 2 ... n) at the output of the modulator 10, and he, in turn, sets the sequence of operation of the phase shifters 9, which determines direction of the simulated movement of the target.

Each controlled phase shifter 9 with the arrival of a control signal to its input provides a discrete phase shift of the probe signal, for example, by a value Δφ equal to π, π / 2, π / 4, π / 8, etc.

The function Δφ / Δt is realized at the output of the series-connected controlled phase shifters 9, where: Δφ is the structural constant, and Δt is the time interval generated by the modulator 10 and changed depending on the setting signals supplied to the input of the modulator 10 corresponding to the value of the simulated target speed.

Thus, the probe signal is shifted by the frequency fд and thereby creates the Doppler effect, which in accordance with the Doppler equation is described as:

or where: fz is the frequency of the probe signal, Vc is the target speed, s is the speed of light, λ is the wavelength.

The probe signal with a shift by the Doppler frequency fz + fd, through the valve 8 and the waveguide 6 is fed to the input of the attenuator 7. The attenuator 7 allows you to change the signal level and set it depending on the set effective scattering area (EPR) of the simulated target.

From the output of the attenuator 7, a signal of frequency fz + fd enters through the waveguide 6 and the isolation node 4 into the antenna 2, which reemits it in the direction of the radar.

The signal re-emission device does not introduce side modulations in amplitude and frequency into the re-emitted signal, as a result of which there are no combination components of a significant level in its spectrum.

The stability of the above parameters of the device for re-emission of signals provides during its operation the necessary accuracy characteristics of tuning and checking the radar.

The possibility of a wide range of changes at the output of the modulator of the repetition frequency of the control signals and their sequence provides an imitation of the movement of the target in a wide range of speeds, including with the speed of sound or more.

As part of the experimental design work, the applicant enterprise has developed the design documentation of the claimed utility model, according to which several signal reemission devices have been manufactured. Field tests of the devices were conducted under the conditions of the test site, which showed the reliability of their operation and the stability of the simulated speeds and EPR of the targets with the spectral characteristic of the reradiated Doppler signal as close to real as possible.

There is an interest on the part of the RF Ministry of Defense and individual consumers, including the prototype applicant, in equipping re-emitting devices with signals from the developed and modernized alignment machines for anti-aircraft missile systems, instead of the used simulators of a moving target.

Thus, the proposed utility model can be manufactured and used for its intended purpose when testing anti-aircraft missile systems at the stage of their development and testing, as well as equipment for radar alignment, which allows us to conclude that its criterion is “industrial applicability”.

Claims (6)

1. A device for re-emission of signals simulating a Doppler frequency shift of a received signal from a moving target, comprising a base and a thin-walled radiotransparent shell, characterized in that it is mounted on the base of the housing, in front of which there is a microwave antenna, protected by a thin-walled radiotransparent shell in front , the waveguide part of the microwave antenna is placed inside the housing and is equipped at the end with an isolation node, the outputs of which are connected to the microwave node, which is connected in series attenuator, valve, and n-number of controlled phase shifters through the waveguides, while the control input of each of the controlled phase shifters is electrically connected to the corresponding output of the modulator controlled from its input via the control bus. 2. The device re-emission of signals that simulates the Doppler frequency shift of the received signal from a moving target according to claim 1, characterized in that the decoupling unit is made in the form of a polarizing tee. 3. The device re-emission of signals that simulates the Doppler frequency shift of the received signal from a moving target according to claim 1, characterized in that the decoupling unit is made in the form of a circulator. 4. The signal re-emission device simulating a Doppler frequency shift of a received signal from a moving target according to claim 1, characterized in that a waveguide coupler with a detection head connected to it is installed between the valve and the controlled phase shifter. 5. The device re-emission of signals that simulates the Doppler frequency shift of the received signal from a moving target according to claim 1, characterized in that the housing on top and both sides is protected by a metal sun screen. 6. A device for re-emission of signals simulating a Doppler frequency shift of a received signal from a moving target in accordance with claim 1, characterized in that the base is made with a dovetail guide and a calibrated hole is made symmetrically to its longitudinal axis.