RU2194288C2 - Radar system - Google Patents

Abstract

FIELD: radiolocation. SUBSTANCE: radar system is designed for use in the capacity of coastal and shipborne radar for surveillance of terrestrial and sea surfaces and for detection of objects on them, small-sized objects included. Technical result of invention consists in reduction of time of synthesis and time of reception of radar information in comparison with known radar having same size of synthesized antenna aperture as proposed radar system has. No mechanical translation of antenna is required to maintain function of generation of high angular resolution in azimuthal plane. It is achieved by insertion into radar system of antenna built non-traditionally. In said antenna installed immobile beam of antenna radiation pattern is imparted with motion in horizontal plane with parallel translation. Phase center of antenna moves in plane perpendicular to electrical axis. Each range element is irradiated with motion of antenna beam and coherent summation of reflected signals is conducted. Artificial (synthesized) aperture of antenna is formed as result of coherent summation markedly exceeding aperture of real antenna and high angular resolution is secured. Possibility of coherent summation of received signals is provided by compensation for phase changes of received signal. EFFECT: reduced time of synthesis and time of reception of radar information. 7 dwg

Description

 The invention relates to the field of radar and is intended for use in coastal and shipborne radar stations for the detection of ground and surface objects.

Known radar stations - coastal, ship or airfield, designed to survey the earth and water surface and detect objects located on it, performing a survey by sectorial swing of the antenna beam in the azimuthal plane. The coverage area of such a radar is a sector with a radius corresponding to the range of the radar. However, their use for detecting reflected signals from small targets (σ _c ≤ 5 m) in conditions of reflections from the underlying surface is ineffective.

где Р_с - отраженная мощность сигнала от объекта;
Р_ш - мощность собственных шумов приемного канала;
Р_ф - мощность отражений от подстилающей поверхности.When detecting land and sea objects against the background of the underlying surface, the detection characteristics depend on the signal-to-noise + background ratio:

where P _c is the reflected power of the signal from the object;
R _W - power of the noise floor of the receiving channel;
R _f - power reflections from the underlying surface.

где σ_ц - эффективная площадь отражения от объекта;
σ_ф - эффективная площадь отражений подстилающей поверхности.At a low level of the receiver's own noise compared to the background component of the signal Psh <Pf, the signal-to-noise + background ratio will be determined:

where σ _C is the effective area of reflection from the object;
σ _f - the effective area of reflections of the underlying surface.

Given that the effective area of reflection of the underlying surface is determined by:
σ _f = d _L • d _Z • σ ₀ ,
where σ ₀ is the specific EPR of the underlying surface,
d _L - resolution element in azimuth,
d _Z is the element of range resolution.

 Therefore, the characteristics of detection of objects against the underlying surface will significantly depend on the resolution of the radar.

Calculations show that even with a small reflection coefficient σ _{0, the} detection of small objects against the background of the sea can be provided only with a very high resolution.

 Existing ground and ship radars are not capable of detecting reflected signals from small targets in conditions of reflection from the underlying surface even of medium intensity due to low angular resolution.

 In order to improve the characteristics of target detection, the development of such radars in recent years has been carried out in the direction of increasing the aperture of the antenna and applying a wavelength in the millimeter wavelength range. However, in the traditional design of antennas to fulfill the conditions for detecting small targets, the use of an antenna with a practically unrealizable aperture size is required.

Currently, radars similar to those used on sea ships are used to review the Russian maritime borders. Therefore, as an analogue of such radars, you can bring the river navigation station KCLVINHUGHES R, SR 1000, Electron-Sperry MK-3217r, designed to ensure the safety of navigation on rivers and other bodies of water, consisting of an antenna, transmitter, receiver, indicator and power supply. These stations have a circular view in azimuth. A distinctive feature is the large opening of a real antenna L = 2.1-2.4 m with a beam width in azimuth of 0.95-1 degrees. and range resolution d _Z = 7.5 m.

 An analogue can also be a ship station of the company Racul Marine Electronics RACAL - DECCA RM2090BT, RM2070BT.

 This radar consists of an antenna, transmitter, receiver, indicator and power supply. To obtain high resolution of this station, antennas with different aperture sizes in the azimuthal plane are used: L = 1.2; 1.8; 2.7 and 3.6 m using wavelengths λ = 3 cm and 10 cm.

 A ship’s DON-type radar can also be considered as an analogue (see Shipborne radar stations and their use, vol. 3, p. 19. Reference manual. Authors V.Ya. Averyanov et al., Edited by Doctor of Technical Sciences Rakova V.I. Shipbuilding, Leningrad, 1970).

 The task of increasing the angular resolution of ground-based radars has always been relevant. The construction of such a radar was proposed by the authors in the radar according to patent 2151407, class. G 01 S 13/00; 06/13. In this radar system, high angular resolution is provided by synthesizing the aperture of the antenna when moving a real antenna. Therefore, it seems appropriate to consider this radar as a prototype.

 The prototype block diagram is shown in figure 1, where 1 is the antenna, 2 is the transmitter, 3 is the receiver, 4 is the frequency synthesizer, 5 is the indicator, 6 is the circulator, 7 is the angle sensor, 8 is the speed meter, 9 is the signal processor , 10 - data processor, 11 - master oscillator.

 Compared with the analogues in the prototype, the antenna is mounted on a movable base and the antenna is set to translate in the horizontal direction along its guides, while its electric axis is installed perpendicular or at an angle to the direction of movement of the antenna. Such an antenna system allows you to implement the synthesis mode of the antenna aperture and provide a higher angular resolution. However, the disadvantage of such a system is the use of mechanical devices for moving the antenna. The mechanical system of movement along the guides in practice leads to a limitation of the maximum speed and, consequently, to an increase in the synthesis time (for a given aperture length) and an increase in the time for obtaining radar information. In addition, the operation of such a mechanical antenna movement system in difficult climatic conditions leads to additional labor costs.

 The objective of the invention is to reduce the time of synthesis and the time to obtain radar information without mechanical movement of the antenna while maintaining a high angular resolution of the radar in the azimuthal plane.

 The solution is achieved by the fact that in a radar system containing a transmitter, a circulator, a receiver, a frequency synthesizer, a signal processor, a data processor, a master oscillator, an indicator and an antenna consisting of a stationary forming mirror, a rotating reflecting mirror, a stationary irradiator, a motor for rotating the reflecting mirror and rotation angle sensor, the antenna beam moves in a horizontal plane with parallel movement of the radiation pattern, while the phase center of the antenna moves in the plane, perpend acous- electrical axis DN

 During the movement of the beam, the antenna emits coherent pulses from the transmitter and receives reflected signals from the object. When the antenna beam moves by processing and coherently summing the signals reflected from the object, an artificial (synthesized) antenna opening is created, significantly exceeding the opening of the real antenna beam.

 The possibility of coherent summation of the received reflected signals when the beam moves is provided by compensating for phase changes in the received Doppler frequency signals. Compensation of phase changes is carried out on the basis of measuring the speed of the antenna beam during the synthesis time. Signal processing is carried out by the method of harmonic analysis. In this case, the complex signals reflected from the object at the input of the processing system are multiplied by the signals of the reference function, complex conjugate with the signals reflected from the object.

где Н(τ) - весовая функция, определяющая заданный уровень боковых лепестков,
τ - время,
V_лч - составляющая скорости движения фазового центра луча антенны в направлении на объект:
V_лч = V_л Cosα_i,
где V_л - скорость движения луча антенны,
α_i - угол в азимутальной плоскости между вектором V и направлением на объект,
a_r(t) - составляющая ускорения движения фазового центра луча антенны:

,
R - расстояние до объекта.To this end, based on the set and measured parameters, the support function h (τ) is calculated:

where N (τ) is a weight function that determines a given level of side lobes,
τ is the time
V _LF is the component of the velocity of the phase center of the antenna beam in the direction of the object:
V _lch = V _l Cosα _i ,
where V _l - the speed of the beam of the antenna,
α _i is the angle in the azimuthal plane between the vector V and the direction to the object,
a _r (t) is the component of the acceleration of the phase center of the antenna beam:

,
R is the distance to the object.

As a result of coherent summation, an output signal is generated corresponding to the signal received by the synthesized radiation pattern with a width θ _c substantially smaller than the width of the radiation pattern of a real antenna θ.

 The role of the linear size of the antenna aperture in this case is played by the length of the path of the radar antenna beam.

 The coherent processing time τ is determined by the speed of the antenna beam and the path length.

 The radar resolution is determined by the length L of the path of the antenna beam, i.e. the length of the forming fixed mirror (figure 4). However, it should be noted that with the same aperture size, the resolution with a synthesized aperture is two times better than in an antenna with a real beam.

 Obtaining high azimuthal resolution in the proposed radar system is provided using a processing procedure similar to the radar of the prototype.

 The task of reducing the synthesis time in the present invention is realized due to the higher linear velocity of the phase center of the antenna, achieved by using the practically feasible high angular velocity Ω of the reflecting antenna of the antenna. The absence in the proposed antenna of mechanical guides and means of movement of the antenna can significantly reduce the labor costs of operating the antenna, especially used in regions with difficult climatic conditions.

 Figures 1-6 show explanatory drawings.

 Figure 1 shows the block diagram of the device of the prototype.

 Figure 2 presents a block diagram of the proposed radar.

 In FIG. 3-1 and 3-2 show a detailed structural diagram of the proposed radar, which illustrates in detail the process of generating and processing signals in each of the blocks and the radar as a whole.

 Figure 4 shows the structural diagram of the antenna displaying the movement of the beam of the antenna.

 Figure 5 shows a diagram of the antenna profile in the vertical plane.

 In FIG. 6 shows a diagram of the implementation of the antenna profile in the horizontal plane.

 The proposed radar system contains (Fig. 2) 1 - antenna, 2 - transmitter, 3 - receiver, 4 - frequency synthesizer, 5 - indicator, 6 - circulator, 7 - rotation angle sensor of the reflecting mirror, 8 - motor of rotation of the reflecting mirror, 9 - signal processor, 10 - data processor, 11 - master oscillator.

 In the proposed radar, the antenna beam is given translational motion in the horizontal plane with parallel movement of the electric axis of the radiation pattern. This is achieved by its special implementation.

 The antenna (see Fig. 4) consists of a stationary forming mirror 1ph, a rotating reflecting mirror 1h, a stationary irradiator 1o, a rotation motor of the reflecting mirror 8, and a rotation angle sensor of the rotating mirror 7.

где Y, X - оси координат,
ρ_o - радиус окружности в горизонтальной плоскости, равный половине фокусного расстояния,
М - в общем случае смещение начала кривой от фокальной точки F.The antenna mirror forming the beam is made in the form of a surface of double curvature (see FIGS. 5 and 6). In the vertical plane, this is a parabolic curve -

where Y, X are the coordinate axes,
ρ _o - the radius of the circle in the horizontal plane equal to half the focal length,
M - in the General case, the offset of the beginning of the curve from the focal point F.

зависит от угла поворота отражающего плоского зеркала, вращающегося относительно вертикального оси OY₂. Для каждого угла зеркальное изображение фокальной точки F размещается на окружности радиусом ρ_o (F', F", F"' и т.д.). Каждому углу φ соответствует

и фокусное расстояние эквивалентной параболы, равное (2ρ_oCosΦ+MCosΦ).
При этом учитывается, что ось эквивалентной параболы смещается параллельно оси О₁X.In the horizontal plane, the profile is formed in the form of an envelope of the parabola system. The radius of the vector generating curve

depends on the angle of rotation of the reflecting flat mirror rotating relative to the vertical axis OY ₂ . For each angle, the mirror image of the focal point F is placed on a circle of radius ρ _o (F ', F ", F"', etc.). Each angle φ corresponds to

and the focal length of the equivalent parabola equal to (2ρ _o CosΦ + MCosΦ).
It is taken into account that the axis of the equivalent parabola shifts parallel to the axis O ₁ X.

Рабочая зона углов выбирается из конструктивных соображений и составляет сектор [0 - +-π/4].The analytical expression for a radius vector with a beginning at point O (for β ₀ = 0) has the form:

The working area of the corners is selected from design considerations and constitutes the sector [0 - + -π / 4].

 The rotating reflecting mirror 1z provides the transmission of energy radiated from the irradiator to the portion of the stationary forming mirror 1ph. The rotation of the reflecting mirror 1z by an angle Φ provides irradiation of the portion of the forming mirror 1f corresponding to the angle 2Φ, and the rotation of the reflecting mirror 1z provides the movement of the irradiation section of the stationary forming mirror 1f along its entire length. As a result, the beam formed in space moves in the horizontal plane within the size L. In this case, the electric axis of the moving beam formed by the antenna will be parallel to the X axis.

 As follows from figure 4, the rotation of the reflecting mirror is made by the engine. Moreover, the higher the rotation speed of the reflecting mirror, the higher the linear velocity V of the beam moving in the horizontal plane.

- угловая скорость вращения отражающего зеркала;
ρ(Φ) - величина радиус-вектора, равного:

Угол Φ меняется в интервале ±45^o.In this case, the linear velocity is determined by:
V _l = ρ (Φ) Ω
Where

- the angular velocity of rotation of the reflecting mirror;
ρ (Φ) is the value of the radius vector equal to:

The angle Φ varies in the range of ± 45 ^o .

ρ _o = ρ (o) Cosβ ₀ is the projection of the radius vector ρ (Φ) onto the XOZ plane at Φ = 0.

 The antenna design, its construction are determined by the specific requirements and conditions of use of the radar. The implementation of such an antenna is carried out by engineering methods using known materials and structural elements.

 Figure 3-1 and 3-2 presents a detailed structural diagram of the proposed radar system.

The radar system includes:
antenna - 1,
transmitter - 2,
receiver - 8,
frequency synthesizer - 4,
indicator - 5,
circulator - 6,
the angle sensor of the reflecting mirror - 7,
engine of a reflecting mirror - 8,
signal processor - 9,
data processor - 10,
master oscillator - 11,
power amplifier - 12,
modulator - 13,
Microwave receiver - 14,
intermediate frequency amplifier - 15,
phase detector - 16,
phase detector - 17,
ADC - 18,
ADC - 19,
memory - 20,
memory - 21,
the multiplier is 22,
the multiplier is 23,
the multiplier is 24,
the multiplier is 25,
the difference node is 26,
knot of the sum - 27,
FFT processor - 28,
calculator - 29,
node module Cos - 30,
divider - 31,
the difference node is 32,
the multiplier is 33,
the multiplier is 34,
the multiplier is 35,
Cos node - 36,
the multiplier is 37,
the multiplier is 38,
the multiplier is 39,
multiplier - 40,
the multiplier is 41,
knot of the amount - 42,
stole the amount - 43,
Sin Node - 44,
Cos node - 45,
memory node - 46,
memory node - 47,
the multiplier is 48,
the multiplier is 49,
the multiplier is 50,
Sin Node - 51,
data setter - 52
Radar works as follows.

 During the movement of the beam of the antenna 1, moving due to the rotation of the rotating reflecting mirror 1z and formed on the stationary forming mirror 1f, the power amplifier 12 amplifies the high-frequency pulses coming to it from the modulator 13 and passes them through the circulator 6 to the antenna 1. By the antenna 1, these pulses are emitted into space and propagate in the direction of the selected area.

The coherence of the signal is determined by the master oscillator 11. The modulator 13 modulates the high-frequency signal f and generates pulses supplied to the power amplifier having a given duration (τ _and ) and a repetition period T _p defined by a unique range.

 The high-frequency signal f is generated by a frequency synthesizer 4, developed by well-known design methods and manufactured using a well-known element base.

.From the master crystal oscillator 11, a signal with an input frequency fg enters the frequency synthesizer 4, is multiplied to a higher frequency f and is used as the carrier frequency of the radar signal emitted by the antenna. Also, during the movement of the beam, signals reflected from objects and the surface are received by the antenna and fed through the circulator 6 to the microwave receiver 14. In the microwave receiver 14, these signals in the receiver mixer are mixed with the synthesizer signal fc, resulting in the formation of intermediate frequency signals fpr. The intermediate frequency signals in the intermediate frequency amplifier UPCH 16 are amplified and fed to phase detectors 16 and 17, which receive a signal from the synthesizer with a frequency fpr equal to the intermediate frequency fpr. Moreover, to one of the phase detectors, the synthesizer signal "fpr" comes with a shift of

.

Due to the movement of the beam of the antenna 1, in-phase I and quadrature Q Doppler frequency signals are formed at the outputs of the phase detectors. Further, both signals I and Q are converted to digital form by means of analog-to-digital converters 18 and 19, controlled by the clock signal fca. From the outputs of the ADCs 18 and 19, an array of two quadrature signals entering the signal processor 9, synchronized by the signal tsp from block 4, is accumulated in the memory 20 and 21 for each element of the range and each repetition period. Simultaneously, in the process of moving the antenna to compensate for phase changes in the data processor 10, synchronized by the signal fпd, a support function is formed that is complexly coupled with the signal reflected from the object in accordance with the formula [1]. To do this, in a discrete form, a linear term of the phase change Δφ _{l of the} support function and its quadratic term Δφ _sq .

в узле разности 32 вычисляется

и в узле умножителя 33, на который из задатчика данных 5 поступает начальное значение радиус-вектора ρ_o, вычисляется радиус-вектор ρ(Φ)

Это значение радиус-вектора поступает на умножитель 35, куда поступает значение угловой скорости вращения радиус-вектора Ω из узла 34. Значение угловой скорости вычисляется в узле 34 путем нахождения производной

. Для этого с датчика угла 7 в узел 34 поступает значение угла "Φ". В узле 35 определяется значение линейной скорости луча V_л = ρ(Φ)Ω.To form the linear term Δφ _l , the value of the radius vector ρ (Φ) is first calculated by the formula [2]. For this, from the angle sensor 7, the value of the angle of rotation of the reflecting mirror Φ is received at the node СosΦ 30, and then the dividers 31 are sequentially calculated in the node

in the difference node 32 is calculated

and in the node of the multiplier 33, on which the initial value of the radius vector ρ _{o is} received from the data pickup 5, the radius vector ρ (Φ) is calculated

This value of the radius vector is fed to the multiplier 35, which receives the value of the angular velocity of rotation of the radius vector Ω from node 34. The value of the angular velocity is calculated in node 34 by finding the derivative

. To this end, the angle value “Φ” is supplied from the angle sensor 7 to the node 34. At node 35, the linear beam velocity V _l = ρ (Φ) Ω is determined.

From node 36, the value of the linear velocity V _l arrives at node 37, which also receives the value Cosα _i generated in node 36 when an angle α _i is sent to its input from data setter 5 in the direction of which the synthesis is performed.

поступающую из задатчика данных 52. Значение

поступает на умножитель 40, где умножается на номер элемента дальности ε, поступающего из задатчика данных 52. В результате на выходе умножителя 40 формируется конкретное изменение фазы для каждого элемента дальности в периоде повторения

В умножителях 39 и 41 формируется изменение фазы от периода к периоду Т_п для всех элементов дальности. Для этого из умножителя 37 значение V_л Cosα_i последовательно в умножителях 39 и 41 умножается сначала на коэффициент

, а затем на коэффициент К_п, равный номеру периода Т_п, в результате чего на выходе умножителя 41 будет

.The value of the product V _{l of} Cosα _{i is} supplied to the multiplier 38, where it is multiplied by the value

coming from data setter 52. Value

arrives at the multiplier 40, where it is multiplied by the number of the range element ε coming from the data setter 52. As a result, at the output of the multiplier 40 a specific phase change is generated for each range element in the repetition period

In multipliers 39 and 41, a phase change is formed from period to period T _p for all range elements. For this, from the multiplier 37, the value of V _l Cosα _{i is} successively multiplied in the multipliers 39 and 41 first by the coefficient

, and then by the coefficient K _p equal to the period number T _p , as a result of which the output of the multiplier 41 will be

.

 In the node of the sum 42, a linear term of the phase change is formed for each element of the range for the Kth repetition period.

Для формирования квадратичного изменения фазы Δφ_кв опорной функции используются умножители 48, 49, 50, а также узел Sin²α_i 51. В умножителе 48 значение скорости V_л из узла 35 вначале умножается само на себя, а затем умножается на коэффициент КТ_п, поступающий из задатчика данных 52 (линия е), затем величина V_л (КТ_п) поступает на умножитель 49, куда поступают коэффициент

и коэффициент

из задатчика данных 52 (линия k). Затем эта величина поступает в умножитель 50, где умножается на значение Sin²α_i, поступающее из узла Sin²α_i51.

To form a quadratic change in the phase Δφ _{kv of the} support function, multipliers 48, 49, 50, as well as a node Sin ² α _i 51 are used. In the multiplier 48, the velocity value V _l from the node 35 is first multiplied by itself, and then multiplied by the coefficient CT _p , coming from the data setter 52 (line e), then the value of V _l (CT _p ) goes to the multiplier 49, where the coefficient

and coefficient

from data setter 52 (line k). Then this value goes to the multiplier 50, where it is multiplied by the value of Sin ² α _i coming from the node Sin ² α _i 51.

поступает на узел суммы 43, где суммируется с линейным членом каждого элемента дальности в каждом периоде Т_п. С выхода узла суммы изменение фазы опорной функции Δφ = Δφ_л+Δφ_кв для каждого элемента дальности ε в каждом периоде повторения Т_п поступают в узлы SinΔφ и СоsΔφ и накапливаются в памяти для каждого элемента дальности и каждого периода повторения.C output multiplier 50 quadratic term phase change

arrives at the node of the sum 43, where it is summed with the linear term of each element of range in each period T _p . From the output of the sum node, the phase change of the support function Δφ = Δφ _l + Δφ _kv for each element of the range ε in each repetition period T _{p is} sent to the nodes SinΔφ and СsΔφ and accumulated in the memory for each element of the range and each repetition period.

 At the end of the movement of the antenna beam, the signal samples of each range element of each period from the memory 20 and 21 are multiplied in the multipliers 22, 23, 24, and 25 with the samples for each element of the range and the repetition period of the reference function, coming from the memory 46 and 47. From the outputs of the nodes difference 26 and sum 27, the signals of two quadratures are fed to the FFT processor, where they are subjected to harmonic analysis using the fast Fourier transform algorithm.

 The result of the conversion of signals from the time domain to the frequency domain is the azimuthal readings of two quadratures of radar information in each range element. Then the readings of the two quadratures arrive at node 29, where a module is formed from them. Next, the signals enter the display system 5.

The technical and economic efficiency of the proposed invention consists in two aspects
- in reducing the synthesis time (respectively, reducing the time for receiving radar information),
- to reduce labor costs for operation due to the exclusion of mechanical devices for moving the antenna.

где L_синт - линейный размер траектории движения луча антенны,
V_л - линейная скорость движения луча антенны.As you know, the synthesis time (respectively, the time of receipt of radar information) is determined:

where L _synth is the linear size of the path of the antenna beam,
V _l - linear velocity of the antenna beam.

- угловая скорость вращения отражающего зеркала.In the proposed radar system, the linear velocity of the beam V _l is determined by:
V _l = ρ (φ) Ω
Where

- the angular velocity of rotation of the reflecting mirror.

Given the initial value of the vector ρ (о) = 4 m and the angular velocity of rotation of the reflecting mirror Ω = 300 g / s, we obtain the value of the linear beam velocity V _l = 42 m / s.

According to the estimates of the possibility of obtaining the maximum speed of the antenna when using mechanical means of movement along the rails, you can get a linear speed of movement of not more than V _l = 20 m / s.

 Thus, the synthesis time, and hence the time to receive radar information in the proposed radar compared to the radar of the prototype is two times less.

 The second indicator is an indicator of the economic efficiency of the proposed radar compared to the radar of the prototype is determined by the fact that in the proposed radar there are no mechanical means of moving the antenna along the guides, which means that in the proposed radar there are no additional costs for the mechanical maintenance of such a mechanical system.

Claims (1)

A radar system consisting of an antenna, transmitter, circulator, receiver, frequency synthesizer, and the signals in the receiver mixer are mixed with the signal of the frequency synthesizer f _c , signal processor, data processor, master oscillator and indicator, while the antenna input-output through the circulator is connected to the output of the transmitter and the first input of the receiver, the output of which is connected to the first input of the signal processor, while the third and fourth inputs of the receiver are connected respectively to the second and third outputs of the synthesizer one whose fourth output is connected to the second input of the signal processor, the sixth and seventh outputs of the frequency synthesizer are connected respectively to the first and second inputs of the transmitter, and the fifth output of the frequency synthesizer is connected to the first input of the data processor, while the input of the frequency synthesizer is connected to the output of the master oscillator, the output of the data processor is connected to the third input of the signal processor, the output of which is connected to the input of the indicator, characterized in that the antenna comprises a stationary forming mirror made in the vertical plane is parabolic, and in the horizontal plane, with the envelope profile of the system of biased parabolas, a stationary irradiator and a rotating reflecting mirror, which ensures the transmission of energy radiated from the stationary irradiator to the stationary forming mirror, while the output of the rotation angle sensor of the rotating reflecting mirror is connected to the second input of the processor data.

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