RU2627550C1 - Three-dimensional coherent doppler radar - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: three-dimensional coherent doppler radar comprises a supermode gas continuous wave laser that is attached to the detected object, and to the heterodyne-type photodetector by means of the light-dividing element and of the send-receive lens. It also has a multiple-duct information handling unit, that is linked to the heterodyne-type photodetector outlet, a scan unit in azimuth of a probe radiation, that is formed by the send-receive lens in the fan-like shape emission, where the lens is wide-angled in elevation and narrow-angle in azimuth, and a topographic survey unit that is linked to the last mentioned one. With regard to the above mentioned, the heterodyne-type photodetector is matrix-shaped made from the set of the photosensitive members, the channel wide-band amplifiers, the multilink matched compression filters on the basis of the dispersive delay lines, the channel compensating amplifiers, the channel amplitude demodulators that are linked to the base clippers. The photosensitive members' outlets are attached to the relevant inlets of the multiple-duct information handling unit, which is composed of the placed in series channel frequency rectifiers of the actuating signals with the signal of the linear-frequency modulated heterodyne oscillator. The radar also comprises a multiple-duct unit of the angular coordinates determination on the detected object, that is parallel-connected to the outlets of the multiple-duct information handling unit, and glaring elements of the sea surface and a multichannel measurement unit of the Doppler frequency shifts of the probe radiation rereflections received by the detected object for itself and for the relevant glaring elements of the sea surface. The outlets of the multiple-duct units of the angular coordinates determination and of the multichannel measurement unit of the Doppler frequency shifts for the relevant received emissions are respectively attached to the first and the second inlets of the detected object signature evaluator - its flying height, slant distance and speed vector, the third inlet of which is linked to the topographic survey unit. The outlets of the detected object signature evaluator are linked to the statistical average of the test features at a current time. The reflected radiations detection is achieved just as directly from the detected object so from the sea lights that are formed by the probe radiation dispersion by the detected object surface at different dispersion angles. The monofrequent continuous wave gas laser is complementarily added into radar construction under the collinearity of the optical axes of both transmitting and receiving lenses. This laser is fitted with a piezocorrector of the adjustment of its beam resonator. The piezocorrector forms a transmitting stereo channel based on the additional transmitting lens with the stereo base h. The outlets of both lasers are complementarily linked through the low-reflection mirrors with high transmission to the optical mixer, the outlet of which is attached to the in series affiliated circuit made of the synchronous rectifier (slope detector), the integrating device and the direct-current control amplifier, the outlet of which is attached to the piezocorrector of the additional laser. Upon that, the outlet of the reference quartz-crystal oscillator of the difference adjustment frequency of the primary and additional continuous wave lasers is attached to the second inlet of the synchronous rectifier. Moreover, the same outlet of the reference quartz-crystal oscillator is attached to the third inlet of the detected object signature evaluator - the low altitude naval missile.

EFFECT: detected object correct coordinate measuring probability rise.

7 dwg

Description

The invention relates to the field of measurement technology and instrumentation and can be used as a laser locator to detect and measure the coordinates and speed of low-flying sea-based missiles in the interests of the Navy of the country.

Traditionally, the measurement of the flight speed of diffraction limited objects is carried out using Doppler radars with a continuous mode of unmodulated radiation, however, solving the problem of measuring the slant range requires the use of radiation modulation (pulsed, frequency, etc.), which significantly reduces the limiting range of these measurements, introduces radiation losses by the modulator [ 1-4]. The triangulation methods for measuring the slant range using unmodulated radiation, which provides the highest energy potential of the locator at a given working power of the emitting laser, are associated with the need to disperse at sea groups of locators forming a triangulation network, which reduces the efficiency of such a network on ships due to the requirement of tight mutual reference coordinates of the ships in the conditions of their movement in a combat situation.

It is known to use consistent filtering of location signals based on dispersion delay lines to increase the signal-to-noise ratio [5-21], as well as the use of laser stabilization means to increase the detectability of laser locators with a continuous radiation mode [22-26].

The author also proposed various options for constructing laser Doppler locators based on low-flying sea-based missiles and means for simulating glare reflections of laser scattered radiation from a sea surface for testing and field testing of such Doppler locators [27-36].

The closest technical solution of the proposed locator (prototype) should be considered “Laser coherent locator” [28], containing a single-frequency gas laser of continuous operation, for example, a CO ₂ laser connected to a located object, for example, a low-flying sea-based cruise missile and a heterodyne photodetector through a beam splitter element and receiving-transmitting lens, as well as a multi-channel information processing unit connected to the output of the heterodyne photodetector, azimuth scanning unit the probe radiation formed by the receiving-transmitting lens in the form of a fan-shaped radiation - wide-angle in elevation and narrow-angle in azimuth, and a topographic reference unit associated with the latter, characterized in that the heterodyne photodetector is made in the form of a matrix from a set of photosensitive elements, for example, based on liquid-cooled elements of the KdHgTl-connection, the outputs of which are connected to the corresponding inputs of the multi-channel information processing unit, consisting of The channel includes frequency converters of input signals with a linear-frequency-modulated local oscillator signal, channel broadband amplifiers, a multi-channel matched “compression” filter based on dispersion delay lines, channel compensating amplifiers, channel amplitude detectors associated with minimum limiters, and also includes parallel connected to the outputs of the multichannel information processing unit, the multichannel unit for determining angular coordinates on the positioned object and bl forging elements of the sea surface and a multichannel unit for measuring Doppler frequency shifts of received re-reflections of the probing radiation by the locating object for itself and the corresponding glare elements of the sea surface, and the outputs of multichannel units for determining angular coordinates and measuring Doppler frequency shifts for the corresponding received emissions are connected respectively to the first and second inputs calculator of the characteristics of the located object - its flight altitude, slant range and a velocity factor, the third input of which is connected to the topographic reference unit, and the outputs of the characteristics calculator of the located object are connected to the statistical averager of the measured characteristics at the current time, while the reception of reflected radiations is carried out both directly from the located object and from sea glare generated from scattering of the probe radiation from the surface of the located object at different scattering angles.

The disadvantages of the prototype device include the high complexity of processing information about the instantaneous coordinates of a detected rocket, which is associated with a possible significant number of glare reflections of the laser radiation scattered by the rocket from the sea surface recorded on the radar array photodetector, while the efficiency of the reflecting glare of the sea surface is reduced, which reduces the likelihood correct measurement of the coordinates of the located object.

These disadvantages are eliminated in the claimed technical solution.

The aim of the invention is to increase the likelihood of correctly determining the instantaneous coordinates of a low-flying sea-based missile.

This goal is achieved in a stereoscopic coherent Doppler locator containing a single-frequency continuous-wave gas laser, such as a CO ₂ laser, coupled to a located object, such as a low-flying sea-based cruise missile, and a heterodyne photodetector through a beam-splitting element and a transmitting and receiving lens, as well as a multi-channel an information processing unit connected to the output of the heterodyne photodetector, a scanning unit in the azimuth of the probe radiation, formed A receiver-transmitting lens in the form of a fan-shaped radiation - wide-angle in elevation and narrow-angle in azimuth, and a topographic reference unit connected to the latter, while the heterodyne photodetector is made in the form of a matrix of a set of photosensitive elements, for example, based on KdHgTl elements cooled with liquid nitrogen -connections whose outputs are connected to the corresponding inputs of a multichannel information processing unit, consisting of channel converters the frequencies of the input signals with a signal of a linearly-frequency-modulated local oscillator, channel wideband amplifiers, a multi-channel matched “compression” filter based on dispersion delay lines, channel compensating amplifiers, channel amplitude detectors associated with minimum limiters, and also includes parallel connections to the multi-channel outputs information processing unit multichannel unit for determining angular coordinates on the positioned object and glare elements of the sea surface and many the channel unit for measuring the Doppler frequency shifts of the received reflections of the probing radiation by the located object for itself and the corresponding glare elements of the sea surface, and the outputs of the multi-channel blocks for determining the angular coordinates and the measurement of Doppler frequency shifts for the corresponding received emissions are connected respectively to the first and second inputs of the calculator of the characteristics of the target object - its flight altitude, slant range and velocity vector, the third input of which is connected topographic reference unit, and the outputs of the calculator of the characteristics of the located object are connected to the statistical averager of the measured characteristics in the current time, and the reception of reflected radiation is carried out both directly from the located object and from sea glare formed by the scattering of probe radiation by the surface of the located object at different scattering angles, different in that the composition additionally introduced locator single frequency continuous gas laser such as CO ₂ laser, CH The settings of its optical resonator, forming a transmitting stereo channel based on an additional transmitting lens with a stereo base h, with collinearity of the optical axes of both transmitting and receiving lenses, the outputs of both lasers are additionally connected through weakly reflecting high transmittance mirrors with a photo mixer, the output of which is connected to a series-coupled circuit from a phase-sensitive detector (discriminator), integrator and control DC amplifier, output on to the piezoelectric corrector of the additional laser, while the output of the reference crystal oscillator of the difference frequency of tuning the main and additional lasers of continuous operation is connected to the second input of the phase-sensitive detector, in addition, the same output of the reference crystal oscillator is connected to the third input of the calculator of characteristics of the located object.

The achievement of these objectives of the invention is due to irradiation of the rocket with a stereoscopic radiating system, which increases the representativeness of the glare elements of the sea surface.

The action of the proposed technical solution is illustrated by the following figures.

In fig. 1 shows a functional diagram of the device. It contains:

1 - single-frequency gas laser of continuous action, for example a CO ₂ laser,

2 - transceiver lens,

3 - reflective plate with a low transmittance for the formation of a heterodyne channel,

4 - scattering reflector, correcting the heterodyne flow to the heterodyne photodetector;

5 - heterodyne photodetector (FPU) in the form of a matrix of elements, for example, based on the elements of the KdHgTl compounds cooled by liquid nitrogen,

6 - information processing unit (discussed below in Fig. 2),

7 - multi-channel determinant of angular coordinates,

8 - multi-channel meter Doppler frequency shifts,

9 - calculator characteristics of the located object,

10 is a statistical averager of the measured characteristics, operating in the current time, the output of which is formed updated data on the flight altitude (N), slant range (D) and velocity vector (V) of the located object,

11 is a scanning unit in azimuth of the probe radiation generated by the receiving-transmitting lens in the form of a fan-shaped radiation - wide-angle in elevation and narrow-angle in azimuth,

12 - associated with block 11 block topographic binding,

13 - a locating object that creates reflections from its surface irradiated with sounding radiation both in the direction of the locator and on the sea surface 14,

14 - the surface of the sea, forming a flashing re-reflection of laser radiation, the flashing surface of which allows you to implement the triangulation principle of measuring the location of the located object,

15 is an additional single-frequency gas laser of continuous operation, for example, a CO ₂ laser equipped with a piezocorrector of an optical resonator for tuning the radiation frequency,

16 is an additional transmitting lens, the optical axis of which is collinear to the optical axis of the transceiver lens with a horizontal base h to the last,

17 and 18 are beam splitting plates with low reflectivity and high transmittance,

19 is a photo mixer, emitting the difference frequency of the radiation of both lasers 1 and 15,

20 - phase-sensitive detector (discriminator),

21 - reference crystal oscillator of the differential frequency settings of the primary and secondary continuous lasers 1 and 15,

22 - integrator

23 is a control DC amplifier connected to a piezoelectric corrector of an additional continuous laser 15.

Elements 19-23 form a system for automatically adjusting the frequency (AFC) of the radiation of the additional laser 15 to the frequency difference with the radiation frequency of the main laser 1, equal to the frequency of the reference crystal oscillator 21.

In fig. 2 shows the structure of a multi-channel information processing unit 6, which consists of channel frequency converters (mixers) 24, 25, 26, ... 27, channel broadband amplifiers 28, 29, 30, ... 31, a multi-channel matched “compression” filter from dispersion delay lines 32 , 33, 34, ... 35, channel compensating amplifiers 36, 37, 38, ... 39, channel amplitude detectors 40, 41, 42, ... 43 with the corresponding limiters to a minimum of 44, 45, 46, ... 47. The unit uses a local oscillator of linear-frequency-modulated oscillations 48, the output connected with the second inputs of the mixers 24, 25, 26, ... 27 and launched on frequency scanning from the output of the pulse generator 49.

In fig. Figure 3 shows a block diagram of a multi-channel determinant of 7 angular coordinates on the target object and glare elements of the sea surface — their azimuth β and elevation angle ε. The circuit contains a matrix of binary storage elements (triggers) 50, 51, 52, ... 53 - by the number of elements in the matrix of the heterodyne photodetector 5 with the same topology of the arrangement of elements, that is, with the same number of rows and columns in the matrices. Elements of the first row of this matrix of triggers 50, 51, 52, ... 53 form the general output of the first row, elements 54, 55, 56, ... 57 form the output of the second row of the matrix, elements 58, 59, 60, ... 61 - the general output of the third row of the matrix , and elements 62, 63, 64, ... 65 - form the output of the last row of the matrix. Elements of the first column of the matrix 50, 54, 58, ... 62 form the general output of the first column, elements 51, 55, 59, ... 63 form the general output of the second column, elements 52, 56, 60, ... 64 - the general output of the third column of the matrix, and elements 53, 57, 61, ... 65 - form the common output of the last column of the trigger matrix. All k common outputs of the columns of the matrix are connected to the first memory shift register 66, forming an information channel about azimuths β, and all m common outputs of the rows of the matrix are connected to the second storage register of shift 67, forming an information channel about elevation angles ε. The trigger matrix with the dimension of km elements is connected to the corresponding km outputs of the multichannel information processing unit 6 and its elements are sequentially interrogated using the generator-decoder 68, clocked by the pulse sequence - the signal "Polling cycle".

In fig. 4 is a block diagram of a multi-channel Doppler shift meter of frequency 8, which includes km of "I" elements (matching schemes) 60, 61, 62, ... 63, the first inputs of which are connected to the corresponding outputs of the multi-channel information processing unit 6, and to their second inputs a high-frequency clock pulse generator 64 is connected. The outputs of the “And” elements are connected to the control recording binary codes of the multi-bit memory elements 65, 66, 67, ... 68, the information inputs of which are simultaneously fed sequentially changing during neither binary codes from the recounting circuit 69 (binary counter), to the counting input of which are pulsed signals from the output of the high-frequency clock pulse generator 64. The rate of the write-read cycle of these codes in multi-bit memory elements is determined by the pulse signal "Reset Cycle" from the output of the pulse generator 40 located in the multi-channel information processing unit 6. The same signal “Reset Cycle” overwrites the codes from the multi-bit storage elements 65, 66, 67, ... 68, folded with the codes of numbers for of cells of the FPU 5 matrix in binary adders 70, 71, 72, ... 73, the aggregate code information is transferred upon completion of this cycle to memory cells 74, 75, 76, ... 77, the processing of which is carried out during the next “write-read” cycle , but the processing results are attributed to the time interval in which data was recorded. Using the polling generator 78 from memory cells 74, 75, 76, ... 77, which contain "non-zero information", these data are sequentially written into the shift register-encoder 79, which generates information about Doppler frequency shifts for all cells of the FPU 5 matrix, which are This cycle of “write-read” was irradiated by radiation reflected from the target object and reflected from the glare of the sea surface. The output signal of the shift-encoder register 79 in each "write-read" cycle contains sequentially issued information in the code representation of the cell numbers of the FPU 5 matrix subjected to irradiation and the corresponding Doppler frequency shifts. Information on cell numbers here is duplicated with data from the multi-channel determinant of 7 angular coordinates, considered in Fig. 3, in order to increase the reliability of counting the numbers of irradiated cells of the FPU 5 matrix.

In fig. Figure 5 shows diagrams showing the procedure for measuring the Doppler frequency shift in a received signal in one or another cell of the FPU 5 matrix, during its “compression” by a matched filter on the dispersion delay line (Fig. 2) with an example for one of the types of location problems. In fig. 5a shows a sequence of clock pulses that determine the period of the write-read cycle and are referred to as “Reset Cycle” pulses generated in the pulse generator 40 (Fig. 2). In fig. 5b shows the process of periodically reproduced LFM scanning in a local oscillator of linear-frequency-modulated oscillations 48 (Fig. 2) with a frequency range from 80 to 130 MHz. In fig. 5c, the straight bold horizontal line shows the signal from the output of the corresponding cell of the FPU 5 matrix in the “frequency-time” coordinates, for example, with a frequency of 53 MHz (from the estimated possible frequency range of 50-60 MHz), the bold sawtooth line depicts the LFM equivalent formed by the corresponding output of the mixer from the number of mixers 24, 25, 26, ... 27 (Fig. 2), the frequency in which varies from 80-53 = 27 MHz to 130-53 = 77 MHz. Parallel to the sawtooth frequency change in the LFM equivalent, the dashed line shows the variation range of the latter when the input signal frequency changes in the range of 50-60 MHz (this range is denoted by ΔF _Σ ), and the passband of the matched filter on one of the dispersion delay lines is indicated by the extreme horizontal dashed lines ( DLZ) 32, 33, 34, ... 35, in this example it is 40 MHz. In fig. 5g there are two graphs, the first of which shows the impulse response in bold vertical line at the output of the corresponding limiter to the minimum of the number used in the multi-channel information processing unit 6 (with numbers 44, 45, 46, ... 47 in Fig. 2), namely one of them for the corresponding cell of the FPU matrix 5. On the same graph, dashed vertical lines show the boundaries of the variation in the time of occurrence of impulse responses when the input signal frequency changes in the frequency range of Doppler shifts from 50 to 60 MHz. It can be seen that the Doppler frequency shift is converted into the time shift of the response pulse relative to the triggering clock indicated in Fig. 5a. This circumstance is reflected in the second graph of Fig. 5d, which is a rectangular pulse with a duration of τ _ass equal to the difference in the times of the appearance of the response pulse and the preceding sync pulse. Note that this pulse duration is then encoded in a multi-channel Doppler frequency shift meter 8 (Fig. 1), in particular, in one of the multi-bit memory elements 74, 75, 76, ... 77 (Fig. 4) for the corresponding cell of the FPU 5 matrix.

In fig. 6, the triangulation principle of the locator according to the method declared earlier by the author is explained. For simplicity, the plane problem is considered when opening the locator 89 (point A), the glare of the sea surface (points C and D) and the diffraction-limited object 90 (point B is the located object 13 in Fig. 1) are on the same OABCDG plane. Note that in this formulation of the simplified problem, it is possible to construct a locator with a single-column FPU 5 instead of a matrix, however, this reduces the probability characteristics of the measurements made, and the use of matrix FPU 5 is still preferable, although it significantly increases the amount of equipment.

In fig. 6, three directions of scattering by a diffraction limited object 90 of the probe radiation from the 89 radar are highlighted - direct reflected 91 and two scattered at different angles to the straight - 92 and 93, which glare on the sea surface at points C and D. The aperture height of the locator 89 is denoted as h ₀ = AO is a known quantity, the flight altitude of an object 90 above sea level is denoted as H (t) = BG as a function of the current time t, the horizontal velocity vector of the object and its radial velocity are denoted as V * and V.

In fig. 7 shows a schematic flowchart of the known prototype method, namely: a location method characterized in that the radiation received from several glare of the sea surface additionally and simultaneously subjected to coherent reception and processing (94), arriving at the photodetector matrix from different randomly distributed angular directions, is determined (95) in the corresponding channels associated with the matrix photodetector, the Doppler frequency shifts in the received radiation for those reflected from the glare of the sea signal surfaces and the corresponding angular coordinates for these glare, calculate (96) the current coordinates of the location of the object and its true speed, and also statistically average (97) the results of calculations of the entire set of joint measurements of these parameters.

Consider the theoretical foundations of the claimed technical solution.

It is known that when the reflector moves with speed V in the direction of the laser radar radiation with a frequency ν ₀ (this speed is called radial), a frequency increment occurs in the radiation directly reflected from the object - Doppler shift - Δν ₀ = ν ₀ (1 + 2V / s) - ν ₀ = 2ν ₀ V / s, where c is the speed of light. The magnitude of this shift Δν ₀ determine the radial velocity V of the object, which is trivial. If the radiation incident on the object is reflected from it at a certain angle θ relative to the line of the indicated direction of irradiation of the object from the locator, then the Doppler shift frequency is expressed by the formula Δν (θ) = Δν ₀ cosθ under the assumption that the object is not relativistic, i.e. 2V / s << 1, which is always performed in relation to a location. Since the located object is considered as diffraction limited, it can be considered that the radiation reflected by it is quasispherical by virtue of the Huygens principle, that is, it occurs in all directions that are not obscured by the object’s body itself. Actually, the head part of the rocket has a shape that creates re-reflections, in particular, in the directions to the sea surface even stronger than re-reflections in the direction directly to the locator (especially if the rocket flies directly to the locator). Depending on what angle θ the component of the radiation reflected from the moving object illuminates this or that sea glare that creates a mirror (i.e., strong) reflection towards the locator, in the signals received from such glare, the Doppler frequency shifts will differ between themselves and the Doppler shift (largest) for direct reflection from the object Δν ₀ . This allows us to determine the parameters of interest to the object — its radial speed, slant range and flight altitude above sea level — using the well-known geometry of the radiation coming to the photodetector matrix from the object and from a series of sea glares. The angular coordinates of the object when it is detected are determined by the data of the angular sensors of the scanning system attached to the given location of the locator, as well as by the cell number of the FPU 5 matrix, in which the signal from direct re-reflection of radiation from the located object is fixed.

The locator system scanning in angular coordinates, operating in automatic tuning mode when capturing a detected object, always leads to the reception in the FPU of direct radiation reflected from the object to the central channel of the photodetector matrix of the FPU, conventionally taken as zero. With respect to this zero number of the central channel of the photodetector array located in the plane of the image of the receiving lens of the locator, the appearance of signals from flare reflections in other cells of the photodetector matrix with known numbers allows us to determine (from the difference in the number of cells with respect to the central cell) the angular direction to this marine flare in relation to the direction directly to the object. In this case, uncertainty arises in determining the position of a given sea flare associated with the a priori lack of information about the slant range to the object (and the height of its flight above the sea surface, which is uniquely associated with the magnitude of the slant range to the object). The disclosure of this uncertainty is achieved on the basis of a joint solution of a system of three (at least) independent equations, one of which is associated with direct reemission, and two (or more) others are associated with flare reflections.

Let us turn to the consideration of Fig. 6, in which the locator 89 with a known location in a given coordinate system detects a moving object 90 in the scanning mode, captures it in the auto tracking mode by angular coordinates and measures the radial speed V of the object by the magnitude of the Doppler frequency shift Δν ₀ . In this case, the angular coordinates on the object with respect to the reference point of the locator 89 (its opening) are considered known, the coordinates of which (in particular, its height h ₀ above sea level) are known - X ₀ , Y ₀ and Z ₀ = h ₀ . We believe that the directional line of direct reradiation of 91 from the target object passes through this reference point A. The specified line 91 has known angular coordinates - azimuth α ₀ (t) and elevation angle ε ₀ (t), the values of which over time t can continuously change over account of the movement of the object, but always remain known functions of time. Therefore, to determine the current coordinates of the object X (t), Y (t) and Z (t), it is only necessary to determine the current oblique range D (t) to the object 90 along line 91, and then, according to well-known rules, the coordinates of the object can be easily calculated (for for simplicity, we assume that the locator is motionless in a given coordinate system):

If the object moves not exactly in the direction of the line 91 to the locator, but at some arbitrary angle, then the calculation of the horizontal velocity of the object V * (t) can be found by the rules of addition of mutually orthogonal vectors, whose modules are derivatives of the corresponding coordinates:

and it is obvious that the radial velocity V as a vector coinciding with the line 91 along which the inclined range D (t) changes, is also, generally speaking, a function of time V = V (t) and is expressed by a simple formula:

Note that the velocities - horizontal V * (t) and radial V (t) in the general case are not the same in magnitude and different in direction, | V * (t) | ≥ | V (t) |. The change in the magnitude of the radial velocity occurs as a result of maneuvering the object in space, while the magnitude of the Doppler frequency shift Δν ₀ = Δν ₀ (t) also changes. Knowledge of the object’s speed of movement V * (t) is necessary for identifying an analysis of the type of this object, since this speed of the object is its important feature. If expression (2) is solved taking into account the system of equations (1), then it turns out that the speed V * (t) of the object is a function of not only the known radial velocity, azimuth and elevation angle to the object, but also the unknown slant range to it, i.e. V * (t) = F [Δν ₀ (t), α ₀ (t), ε ₀ (t), D (t)], which means that it is impossible to determine this speed of the object without measuring the slant range to it. It follows from this that at the stage of detecting an object and measuring its radial velocity (without measuring the current slant range), errors can be made in recognizing the type of object and incorrect decisions can be made regarding its further auto tracking along angular coordinates according to the criterion of a significant difference between the measured radial velocity and horizontal (yet unknown) speed of the object of interest to us. Therefore, the task of simultaneously measuring the oblique range D (t) is very relevant already in the early stages of detecting an object.

Consider the issue of measuring the slant range D (t), the magnitude of which in Fig. 6 is represented by the segment AB (where point A is the reference point of the locator, and point B is the point of rereflection of the object, which seems to be diffraction limited for the optical location system). The height of the reference point with coordinates X ₀ , Y ₀ , Z ₀ is equal to h ₀ = Z ₀ . Let, for simplicity of reasoning, we assume that sea glare at points C and D illuminated by secondary radiation from object 90 along the straight lines BC and BD respectively lie in the same plane (drawing plane) with the line AB of direct re-reflection from the object, i.e., azimuths for all three reflections from the object — one direct and two flare — are the same, which allows them not to be considered in this simplified version of the geometric construction. All three directions of re-emission coming to the locator 89 along the direct lines VA, DA and SA (directly from the object and from the glare at points D and C of the sea surface) are determined by the corresponding elevation angles ε ₀ (t) - for direct reflection from the object 90, ε ₁ ( t) - for re-reflection from the glare at point C along the line SA and ε ₂ (t) - for re-reflection from the glare at point D along the line DA. Since the height of the reference point AO = h _{0 is} known, then the distances of the OS and OD are found (the distances to the glare points of the sea surface C and D from the projection of the reference point of the locator A on the sea surface line). Since the elevation is counted from the horizon line passing through the reference point A, it is easy to understand that the indicated distances are found from simple expressions:

However, the location of the object 90 remains unknown so far, so it is not clear at what angles the secondary radiation from the object comes to the flare points C and D, since the angular orientation of the flare surfaces is a priori unknown. There are countless combinations at a known elevation angle ε ₀ (t) (that is, for a definitely known direction of the object’s vision by the locator) for the position of point B on line AB, at which the CB lines (position 92) and DB (position 93 in Fig. 6) when the height of the object H (t) is varied above the sea surface (OG line), which has not yet been determined, but is clearly related to the value of the inclined range by the ratio:

и

, зная, что угол

по определению, легко находим углы при вершинах указанных прямоугольных треугольников, в частности, угол при вершине треугольника ΔBCG равен

, а угол при вершине ΔBDG равен

. При этом высота H(t)=BG вычисляется какFrom geometric constructions in Fig. Figure 6 shows that the height of the object H (t) above sea level can be expressed differently from the right angles ΔBCG and ΔBDG (in which the angle OGB is the straight line) through the angles respectively between the lines AB and BC for ΔBCG and the lines AB and BD for ΔBDG. Marking the corners

and

knowing that angle

by definition, we easily find the angles at the vertices of the indicated right-angled triangles, in particular, the angle at the vertex of the triangle ΔBCG is

, and the angle at the vertex ΔBDG is

. In this case, the height H (t) = BG is calculated as

In expression (6), the segment CG can be expressed in terms of the known value of the segment CD = OD-OS = h ₀ [ctgε ₂ (t) -ctgε ₁ (t)]. Then expression (6) can be written in the form

from which the unknown segment DG can be expressed in terms of the known and measured quantities as

Substituting (8) in (7), we obtain an expression for the height of the object in the form:

According to (9), to calculate the height H (t), all three elevation angles should be measured using elevation determinants for the corresponding three cells of the FPU matrix and the elevation sensor of the scanning system by angular coordinates, and two a priori unknown angles θ ₁ and θ _{2 should} be determined. These unknown angles are found from the measured Doppler frequency shifts, using the general expression for the Doppler frequency shift depending on the angle of reflection from a moving object relative to the direction of direct reflection:

from which we easily find the desired angles from the values of the Doppler frequency shifts Δν (θ ₁ ) and Δν (θ ₂ ) measured in the corresponding channels of the information processing path:

Substituting the calculated values of the angles from (11) into (9), we obtain the desired object height H (t) above the sea surface, and then the oblique range value D (t), using expression (5) and taking into account the equality Δν ₀ = 2ν ₀ (V / s), the value of which is calculated in the central channel of the FPU according to the results of direct re-reflection of radiation from the object. Substituting the obtained value for D (t) into the system of equations (1), we find the current coordinates of the object X (t), Y (t) and Z (t), and calculating the corresponding derivatives of the current coordinates, we find the true velocity V * (t ) of the object according to expression (2). Due to the cumbersome calculations of the final coordinates and the true speed of the object, we omit them in this description, but these calculations are easily carried out using the characteristics calculator 9 (Fig. 1) of the located object.

It is easy to see that a complete solution of the location problem of locating a moving object and its velocity vector (the most important sign of its type) is achieved by measuring azimuths and elevation angles in at least three directions of re-emission — direct and two glare, as well as measuring three Doppler frequency shifts along these same directions. Such a solution to the problem was obtained, as described above, when all three directions lie in the same plane, that is, they give a response in the cells of the FPU matrix located in the same column. In this case, the matrix can be degenerate — consist of one column of photosensitive cells, and the radiation itself in the transmitting laser channel has a “fan-shaped” shape of the radiation diagram — narrow in azimuth and wide in elevation. However, this reduces the likelihood of simultaneously organizing two active flare channels in comparison with the case of using a FPU matrix with several columns, when the azimuthal components α ₀ (t), α ₁ (t) and α ₂ (t) should be taken into account in a similar calculation which will further complicate the algorithm of settlement operations.

Glare of the sea surface almost always exists on the sea - both in a storm and storm, and in calm. The sizes of reflective glare can vary significantly, but all of them are diffraction limited (point) sources of secondary radiation. In coherent reception according Zernike theorem Van Tsittera [27] coherence radius r _coh characterizing the object size d and the distance L before it related by r _coh ≈λL / d, where λ - length of laser radiation (λ = C / ν ₀ ), so that at the forced reduction of L with the proviso that the site FPA cell σ satisfies σ >> π (λF / D _v) ^2/2, there is a danger receiving radiation from an object and glare that are considered as extended rather than point if on the aperture of the receiving lens is placed simultaneously or sequentially during s integration time signal processing path few coherence areas (the number is equal to (D _Stock / 2r _coh) ^2). This indicates the feasibility of performing cells of the photodetector matrix of small sizes. The same circumstance should be taken into account when evaluating the resolution of the locator by the angular coordinates Δγ≈σ ^1/2 / F (here D _ob is the diameter of the receiving lens, F is its focal length, and the FPU cell is assumed to have the shape of a square with negligible gaps between adjacent cells )

An increase in the detecting ability of the laser coherent locator is achieved by reducing the spectral noise power G _w due to the choice of the type of FPU and the cooling mode of the photosensitive matrix area. It is important to take into account the efficiency of photo mixing, in particular, attenuation of the influence of noise from an optical local oscillator. The author carried out a rather complicated physical and mathematical analysis [18] of optimizing the signal-to-noise ratio for coherent reception, as a result of which it was shown that the photosensitive area matrix should not be installed in the plane of the Airy disk, but at a certain distance from it Δz≈1.952λ (F / D _rev ) ² with fairly high accuracy. So, for the emissions of CO ₂ lasers (λ = 10.6 μm) when using a lens with D _about = 200 mm, F = 286 mm, this shift is only Δz = 42.3 μm, and the installation accuracy should not be worse than 10 microns. This allows you to increase the sensitivity of the FPU by approximately 50%.

при круговом обзоре с разрешающей способностью Δγ в когерентных локаторах с многоканальной обработкой в согласованных фильтрах на основе дисперсионных линий задержки (ДЛЗ) с полосой пропускания ΔF_лз и базой В=ΔF_лзτ_лз, где τ_лз - длительность импульсной характеристики ДЛЗ, предельная дальность L_max обнаружения и измерения параметров объекта (координат и истинной скорости) по рассмотренному алгоритму находится из решения трансцендентного уравнения:It can be shown that when an object is detected in an elevation zone

in a round-robin survey with a resolution of Δγ in coherent locators with multi-channel processing in matched filters based on dispersion delay lines (DLS) with a passband ΔF _lz and a base B = ΔF _lz τ _lz , where τ _lz is the duration of the impulse response of the DLZ, the limiting range L _max detection and measurement of object parameters (coordinates and true speed) according to the considered algorithm is found from the solution of the transcendental equation:

where η is the extinction of the medium, P is the power of a continuous-wave emitting laser, k is the transmittance in the transmitting and receiving paths of the locator, y is the mixing efficiency (y≤1), S is the effective reflection surface of the object (EPO), μ is the signal-to-noise ratio according to the voltage at the input of the deciding device in the multi-channel processing path, T ₀ is the period of the circular view, ΔF _additional is the uncertainty band for the Doppler frequency shift in the processing channel at the DLZ. When estimating the coherence radius r _coh, we can assume the size of the object is d≈ (EPO) ^1/2 . The value ΔF _add = 2 | ΔV | / λ, where ΔV is the difference between the maximum and minimum speeds of the object. The ratio μ signal // noise is calculated according to the given probabilistic characteristics of detection and false alarms. Note that expression (12) refers to locators with various types of radiation diagrams, in particular, to a “fan-shaped” one, when using a single-column photosensitive matrix (as the simplest one to fabricate by design).

It should be specially noted that in the central channel of the FPU associated with the reception of a signal directly reflected from the object, the latter is quasi-continuous, which significantly distinguishes it from signals from the glare of the sea surface, which have the form of relatively short pulse signals taking into account the dynamics of the object's movement in space. Therefore, the processing of flare signals is carried out in the corresponding channels, structurally different from the channel of the quasi-continuous signal.

As is known, the signal-to-noise ratio μ uniquely determines the probabilistic probabilistic characteristics of the locator [19, 20]. So, the probability of detecting P _obn signal against a background of normal (Gaussian) noise in accordance with the Neumann-Pearson criterion is determined by the signal-to-noise ratio μ at the input of the solver with the normalized threshold α _p = U _p / σ _w set in it, where σ _w - the rms noise voltage at the input of the decider, U _p is the threshold voltage, calculated from the expression:

Where

is the probability integral, and the probability of false alarms P _lt is

For the values of the probabilities of detection and false alarms that are usually set when calculating location systems, the required signal-to-noise ratio is determined from the expression:

where Φ ^-1 (x) is the inverse probability integral.

If the quality of the FPU is known (the value of the noise spectral density G _W ), then based on (16), it is possible to calculate the amount of signal energy required at the input of the FPU, which is sufficient for processing in a matched filter:

Instead of the probability of false alarms, the value of the frequency of false alarms F _l , which is determined by the expression

where <f _w> - the rms value of the noise band, which in the relative path narrowband assumption has expression <f _w> = (f ₀ + Δf ^{2 2/12) 1/2,} wherein f ₀ - signal carrier frequency (or center frequency tract ), Δf is the passband of the receive path with respect to which the noise band is calculated, and from the expression (18) the threshold voltage U _{p is} usually calculated, which is equal to:

The threshold voltage value obtained from (19) is substituted into expression (13) and the probability of detection of P _{obn is} found. For the obtained signal-to-noise ratio at the output of the matched filter μ. Depending on the conditions set, they either decide to increase the viewing time at a given solid angle, or, conversely, to reduce this time or to increase the limiting detection range of the locator (or to increase the accuracy of the measured parameters of the object).

We turn to the consideration of the technical essence of the action of the claimed locator.

The radiation of a single-frequency gas laser 1 (Fig. 1) of continuous operation, for example, a CO ₂ laser with a wavelength of λ = 10.6 μm, is formed using a receiving-transmitting lens 2 with a radiation diagram of a fan-shaped shape - wide-angle in an elevation plane with a width Δε and narrow in the azimuthal plane with a width Δβ using special optics, including spherical-cylindrical gluing [27]. A narrow diagram in the azimuthal plane provides the required resolution of the locator in azimuth and is consistent with the rate of angular scanning of the probe radiation with an angular velocity Ω and the cycle time of the write-read information T _c , so that the equality T _c = Δβ / Ω is fulfilled. The wide-angle radiation pattern in the elevation plane provides parallel reception over all the elements of the central column of the FPU 5 matrix, which eliminates the need to scan radiation by elevation, which significantly increases the cycle time T _c at a given scan rate in azimuth. This reduces the likelihood of missing a target in the viewing space.

A small part of the laser radiation 1 passes through a reflection plate 3 with a low transmittance, is formed as necessary in the scattering reflector 4, and is directed to the FPU 5 array by the reflection plate 3, acting as a photo-heterodyne signal, which is mixed with the received radiation reflected directly from the target object 13 , and from glare on the surface of the sea 14, formed due to scattering of the probe 13 by the locating object at different angles. Considering that the located object is relatively small in size, such as, for example, a sea-based cruise missile, one should consider such an object as diffraction limited, while maintaining coherence and single-mode mode in the received radiation, which allows it to be coherently processed by the method of heterodyning (photo mixing) of optical signals in the cells of the FPU 5 matrix, at the output of which an electric signal of a difference frequency arises between the frequencies of the probing and reflected radiations.

In fig. 1 it is shown that six optical signals arrive at the FPU 5 matrix at an arbitrary given time — one reflected from the positioned object 13 and always placed on the central column of the matrix, and five from glare of the sea surface. These cells of the FPU 5 matrix are shown blackened. According to the position of such working cells, it is possible to unambiguously determine the corresponding azimuths and elevation angles of all directions of the radiation coming to the locator, which is justified by geometric constructions of the ray path in the receiving lens 2 relative to the image plane, which is practically in the focal plane of the transceiving lens 2.

The FPU matrix 5 has the dimension of km elements (k is the number of columns, m is the number of rows in the matrix); therefore, the multi-channel information processing unit 6 is km-channel (Fig. 2). All processing channels are identical in construction and characteristics, so it is enough to consider the action of one of these channels. In the current time, only a small part of the km-channels are actually working, for example, K (t) - channels, where K (t) << km, which indicates equipment redundancy during parallel processing of information, but its necessity is caused by a random distribution K (t) of working channels in their total number equal to km.

Since in the write-read cycle of information it is a priori unknown which of the channels will turn out to be working, it is necessary to simultaneously use all the channels at the same time. This is achieved by using at the block input (Fig. 2) km of frequency converters (mixers) 24, 25, 26, ... 27, the first inputs of which are connected to the outputs of the cells of the FPU 5 matrix, and the second inputs are connected in parallel to the linear-frequency-modulated local oscillator output oscillations 48 (HLFM), triggered by clock pulses (Fig. 5a) from the output of the pulse generator 49, which forms the period of the write-read cycle T _C for this series of measurements of the characteristics of the located object. The time-frequency form of the HFM signal is shown in Fig. 5b, and in fig. 5c, bold lines show the frequency of the input signal (horizontal line) and the time-frequency form of the signal at the output of the corresponding mixer of the working channel — the LFM equivalent of the input signal. The input signal converted in frequency and spectrum, acting, for example, at the input of the mixer 24, in the form of an LFM equivalent is supplied from the output of the mixer 24 to the input of a broadband amplifier 28, and then it is input to a filter 32 matched with the LFM equivalent made on the dispersion line delay, providing "compression" of the LFM equivalent to an ultrashort radio pulse of duration t _imp (Fig. 5d). The specified dispersion delay line is consistent with the time-frequency characteristic of the LFM equivalent, that is, it has the same rate of change of frequency with time, has a passband ΔF _lz and a duration of the impulse response τ _lz with a base of B = ΔF _lz τ _lz , which is about 1000 or more, which determines the high efficiency of such a coordinated filtering, since the signal-to-noise ratio at the output of the DLZ increases by ^1/2 times in comparison with that at its input. The bandwidth of the DLZ is shown in Fig. 5c in horizontal dashed lines. The strip adjustment chirped _eq equivalent ΔF corresponds with a bandwidth ΔF DLA _LZ by the rule ΔF _eq -ΔF ≥ΔF _{LZ Rin,} where _Rin ΔF - scatter band Doppler frequency mixer input 24. The duration of the impulse response DLA _LZ τ corresponds to the period read-write cycle T _U T _U by the rule ≥τ _{LZ eq} ΔF / ΔF _LZ, as is seen from Fig. 5c. Duration generated output _pulses radiopulse DLA t determined bandwidth ΔF DLA and _LZ is t _imp = 1 / ΔF _LZ. So, at ΔF _ls = 40 MHz, as in the one shown in Fig. 5 in the example, the pulse duration of the response DLS t _imp = 25 ns. If the duration of the impulse response of the DLZ is assumed to be τ _lz = 50 μs for the DLZ base B = 40 MHz * 50 μs = 2000, then for the input signal uncertainty band (spread of Doppler frequency shifts) ΔF _I = 10 MHz the cycle period T _C ≥65 μs at the duration of the reverse sawtooth GLFM signal is about 2.5 μs. In this case, the frequency tuning frequency of the LFM equivalent is ΔF _lz / τ _lz = 0.8 * 10 ¹² Hz / s, so that the frequency range of the input signal ΔF _in = 10 MHz corresponds to the time interval of the time location of the DLZ response pulse indicated in Fig. 5g with dashed vertical lines equal to ΔT = τ _lz ΔF _input / ΔF _lz = 12.5 μs. At the indicated DLZ response pulse duration t _{imp, the} number of possible independent samples R is R = ΔT / t _imp = τ _lz ΔF _in = 500. This determines the possible frequency resolution equal to Δf = ΔF _in / R = 1 / τ _lz = 20 kHz, which corresponds to the resolving power of a radar with a CO ₂ laser ΔV = Δf * λ / 2 = 0.1 m / with, which is an excellent result. During the cycle ΔT = 65 μs, a cruise missile having a speed of the order of 300 m / s will fly the path ΔD = V * ΔТ = 0.02 m = 2 cm, which ensures the stability of the glare signal throughout the measurement cycle, especially considering the stereoscopic mode radiation locator.

The signal from the output of the DLZ 23 (Fig. 2) after wideband amplification in the compensating amplifier 36 is detected in the amplitude detector 31, and then the threshold minimum limit in the limiter 44, the limiting threshold in which U _{p is} set in accordance with expression (19). Then, the K (t) pulsed signals from the corresponding outputs of the multichannel information processing unit 6 are simultaneously sent to the inputs of the multichannel determinant 7 of the angular coordinates to the positioned object and the glare elements of the sea surface and the multichannel meter of Doppler frequency shifts 8 (Fig. 3 and Fig. 4, respectively).

Multichannel determinant 7 (Fig. 3) is a matrix with the dimension km of memory devices (DU), such as D-flip-flops, 50 ... 65, the counting inputs of which are connected to the km outputs of the multichannel information processing unit 6. The structure of this array of the memory repeats the structure of the FPU matrix 5 by the location of its cells. The outputs of all memory form two groups of buses - column (their number is k) and lower (their number is m). Column buses are connected to the first memory shift register 66, which stores binary azimuth codes in a given sequence K (t), and horizontal buses are connected to the second memory shift register 67, which stores binary elevation codes for K in the same sequence K (t) (t) directions of arrival to the locator of reflections emitted by the locating object and glare of the sea surface with Doppler-shifted frequencies. In this case, the polling sequence of the memory 50 ... 65 is carried out using the generator-decoder 68, clocked by the pulse sequence - the signal "Polling cycle", coming from the output of the polling generator 87 (Fig. 4). The decoder generator generates at its km outputs polling signals km of memory 50 ... 65 sequentially in time, for example, a binary unit sequentially switches from output to output for all km outputs for a period of time significantly shorter than the cycle time T _C , so as not to interfere with the new set information in the memory in the next cycle, for example, during the time T _C / 2 (for the considered example - during the time of the order of 30 μs). Then, the polling frequency F _OPR is found from the expression F _OPR = 2km / T _C , that is, it is determined by the dimension of the FPU matrix 5. If k = 32 and m = 32 (km = 1024), and the internal oscillator in the device 68 must generate pulsed signals with a frequency F _OPR ≈60 MHz, which starts the conversion circuit (binary counter), and the code combinations formed at its outputs start the encoder with km output buses connected to the data read inputs from the sequence of all km memory 50 ... 65. The results of the survey are recorded in parallel in the first 66 and second 67 memory shift registers, which allows parallel to write information in the memory sequentially in time to process all K (t) records of the working channels. Information on azimuths of the radiation directions received by the locator is transmitted from register 66 in a code representation and sequentially in time, and information on elevation angles for the same directions of radiation coming to the locator in this cycle K (t) is transmitted from register 67. And these two code streams are mutually synchronized, so that code information about the azimuth and elevation angle of the same registered direction is instantly displayed.

In fig. 3 the oblique arrows to the memory 50 ... 65 show the connections to the multi-channel information processing unit 6, and the arrows from the outputs of the generator-encoder 68 are not shown connected to these memory so that the block diagram is more readable.

We note that the pulse signal “Cycle Reset” generated in the pulse generator 49 (Fig. 2) and the pulse signal “Polling Cycle” generated in the polling generator (at its second output!) 87 (Fig. 4) are strictly identical in frequency, but have a time delay of the pulse sequences relative to each other (different phases), which is associated with the difference in the times of the formation of the LFM signal in the GLFM 48 and the start of processing the received information of the previous cycle in a new cycle.

The structure of the multichannel meter of Doppler frequency shifts 8 (Fig. 1) is shown in Fig. 4. It is intended for parallel recording of K (t) temporal positions of response pulses for the corresponding K (t) working DLs, characterizing the values of Doppler frequency shifts by the specifically designated cell numbers of the FPU 5 matrix, with subsequent sequential sampling of these data and contains km elements And "(coincidence schemes) 69, 70, 71, ... 72, the first inputs of which are connected to the outputs of the multi-channel information processing unit 6, and the second inputs are connected in parallel to the output of the high-frequency clock pulse generator 73, using In addition, all the incoming information on K (t) from km of processing channels can be simultaneously recorded in multi-bit memory elements 74, 75, 76, ... 77. The clock frequency of the generator 73 should be such that it does not miss a single time interval of duration t _imp from the full interval ΔT, that is, for the considered example, it should be no lower than ΔF _ls = 40 MHz. Recording of information about time instants t of occurrence on one or another multi-bit storage elements 74, 75, 76, ... 77 of the response pulses of the corresponding working DLZs occurs at the recording inputs from sequentially changing codes coming from the output of the counting circuit 78 (binary counter), to the input which receives counting pulses from the output of the high-frequency clock pulse generator 73 At the end of the cycle of recording information in the cycle in question in multi-bit memory elements 74, 75, 76, ... 77 there is a parallel shift this code information into binary adders 83 84, 85, ... 86, each of which is rigidly codes recorded numbers FPA cell array 5, which summarizes the information on multibit storage elements 74, 75, 76, ... 77. Thus, the binary-code 79, 80, 81, ... 82, contains data both on the cell number of the FPU 5 matrix, which is irradiated in the cycle under consideration by reflected radiation, and on the Doppler frequency shift in the considered radiation (in this direction).

This code information from binary adders 79, 80, 81, ... 82 is transmitted in parallel through multi-bit memory cells 83, 84, 85, ... 86, which are overwritten in a new cycle to free up space for new entries in multi-bit memory elements 74, 75 , 76, ... 77, into the accumulation shift register - encoder 88, which generates information on Doppler frequency shifts for all cells of the FPU 5 matrix, and then is sequentially transmitted to the input of the characteristics calculator of the located object 9 (Fig. 1), synchronously with the data transmitted to this calculation an amplifier from the output of the multichannel determinant of angular coordinates 7. Writing to the shift register 88 occurs when a parallel signal is input to the multi-bit memory cells 83, 84, 85, ... 86 of the pulse signal from the output of the polling generator 87, next with the clock frequency of the Polling Signal s corresponding initial phase.

The code signals from the outputs of the multichannel determinant 7 of the angular coordinates to the target object and the glare elements of the sea surface and the multichannel meter of Doppler frequency shifts 8 are transmitted cyclically with a period T _C to the characteristics calculator of the located object 9, the operation of which is theoretically considered above for the particular case of glare, the locator’s opening and the located object on the same plane. Similarly, the characteristics of the located object in the general case of an arbitrary arrangement of glare on the sea surface can be calculated. The theoretical consideration, due to its bulkiness, is omitted in this application. When calculating many glare randomly distributed on the sea surface in each cycle in calculator 9, K (t) - 2 particular problems are solved sequentially with the arrival of code information to find the characteristics of the located object, and these combined solutions then arrive separately through three channels - heights H, inclined range D and velocity vector V - in the statistical averager of the measured characteristics 10, with which these data are refined by known statistical methods, in particular, the mathematical expectation measurement characteristics and variance, the maximums and minimums of the corresponding characteristics are determined, a decision is made to remove erroneously obtained measurement results from the calculations, etc. In addition, the statistical averager 10 smoothes out the time functions that characterize the parameters of the motion of the located object over several measurement cycles, which allows us to clarify the trajectory and rate of motion of the located object in time. This makes it possible to make an appropriate decision on the defeat of this enemy object and calculate the time of the opening of barrage fire.

In the calculations performed by the calculator 9, it is necessary to take into account the known parameters of the ship’s topographic reference, the aperture of the locator (its reference point) above the sea surface and the azimuth of the radiation pattern orientation, which can constantly change when the ship moves, for which the topographic reference block 12 and the scanning unit according to azimuth 11 of the probing radiation is connected with the calculator 9 (Fig. 1). It is also necessary to take into account the inevitable rolling of the ship, which causes a spatial displacement of the reference point A (Fig. 6). The solution of the complete location problem, taking into account the dynamics of the ship’s movement, makes the use of the statistical averager 10 of the measured characteristics of the located object especially relevant. The accuracy of these characteristics is improved by reducing the angular divergence of the generated radiation pattern in the azimuth plane Δβ, which is provided, as a first approximation, by the aperture size of the receiving lens of the locator and the cell diameter of the FPU 5 matrix matched with it, however, it should be borne in mind that narrowing the radiation pattern in azimuth to reduce the angular velocity of azimuth search target, since Ω. = Δβ / Tc, and the above example at Δβ = 0,1 mrad and T _u = 65 microseconds angular velocity space by scanning asu utu reaches Ω. = 1,5 rad / s, i.e. about one revolution per four seconds, which is quite acceptable.

Introduction to the considered coherent Doppler locator circuit of an additional single-frequency continuous-wave laser 15, for example, similar to laser 1, with an additional transmitting lens 16, allows to increase the energy efficiency of the locator. Lasers 1 and 15 generate radiation at different frequencies. This frequency difference is equal to the frequency of the reference crystal oscillator 21 and is maintained unchanged due to the operation of the AFC system on elements 19-23. With an average frequency of laser radiation ν _О = 3.10 ¹³ Hz and a difference laser tuning frequency of 1 and 15 equal to Δν = 3.10 ^{7, the} difference in the Doppler shifts recorded in FPU 5 does not exceed 10 Hz, that is, does not affect the detection characteristics of measurements in the process of pulse compression in DLZ (Fig. 5). The base h between the transmitting lenses of the stereoscopic system for irradiating the target object is selected so that in the range of detection and auto-tracking of a flying rocket (for example, in the range of 2 ... 10 km) the radiation completely overlap each other while minimizing the angular divergence of the probe radiation in azimuth. So, at h = 2 m for a range of 2 km, the angular divergence in azimuth should be at least Δβ = 5.10 ^-4 rad. Irradiation of sea glare with a stereoscopic radiating system increases the likelihood of a correct measurement (makes the glare seem to be voluminous). The plane polarization of the radiation from lasers 1 and 15 should coincide or differ by some small angle. The radiation diagram is fan-shaped (narrow in azimuth and elevated in elevation, which is achieved by using cylindrical lenses in the transmitting lenses, and the receiving lens diagram is wide in some solid angle to ensure reception from different arbitrary directions from glare from the sea surface. Presence of matrix elements at the output FPU 5 of the difference frequency component of laser radiation 1 and 15 confirms that this flare is consistent (obtained as a result of diffuse reflection t of the missile being launched.) Therefore, the signal from the reference crystal oscillator 21 is applied to the third input of the characteristics calculator of the located object 9 as a pilot signal to confirm the flare reliability by comparing it with the signal component received at the output of each of the FPU matrix elements that are currently operating 5.

This technical solution can be implemented at specialized enterprises with the involvement of organizations of the electronic, optical-mechanical and radio-technical industries. It is necessary to develop transmit-receive optics, which allows generating fan-shaped radiation from a high-power single-frequency gas laser of continuous operation, a low-noise matrix FPU on MCT elements with liquid nitrogen cooling, stabilizing the laser radiation in frequency (to ensure high short-term stability), and developing dispersion delay lines on strip lines in the integral design with a large base size and acceptable attenuation, to develop elements of digital technology for information processing units , calculator and statistical averager taking into account multichannelity. Of particular importance is the work on the theoretical and experimental study of the statistical problem of the glare of the sea surface, the identification of the characteristics of the effective scattering area of glare and the scattering characteristics of located objects for energy calculations of the maximum detection range of small targets such as sea-launched cruise missiles "Harpoon ”And“ Tomahawk ”of the probable enemy and measuring the coordinates of such objects such as are for the same time with their discovery. Such locators can be used in the Baltic and the Black Sea to deter a missile attack from the armed forces of NATO.

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Claims (1)

A stereoscopic coherent Doppler locator containing a single-frequency continuous-wave gas laser, such as a CO ₂ laser, coupled to a located object, such as a low-flying sea-based cruise missile, and a heterodyne photodetector through a beam splitting element and a transmitting and receiving lens, as well as a multi-channel information processing unit, connected to the output of the heterodyne photodetector, the scanning unit in the azimuth of the probe radiation formed by the transmitter-receiver In the form of a fan-shaped radiation - wide-angle in elevation and narrow-angle in azimuth, and a topographic reference unit connected to the latter, the heterodyne photodetector is made in the form of a matrix of a set of photosensitive elements, for example, based on elements of the KdHgTl compound cooled by liquid nitrogen, the outputs of which connected to the corresponding inputs of the multichannel information processing unit, consisting of series-connected channel frequency converters of input signals with a signal ohms of a linearly-frequency-modulated local oscillator, channel wideband amplifiers, multi-channel matched “compression” filter based on dispersion delay lines, channel compensating amplifiers, channel amplitude detectors associated with minimum limiters, and also includes multi-channel information processing parallel to the outputs of the multi-channel information processing unit block for determining angular coordinates on the positioned object and glare elements of the sea surface and a multi-channel block for measuring Doppler frequency shifts of the received reflections of the probing radiation by the locating object and the corresponding glare elements of the sea surface, and the outputs of the multichannel angular coordinates and measuring Doppler frequency shifts for the corresponding received radiations are connected respectively to the first and second inputs of the calculator of the characteristics of the located object - its flight height , oblique range and velocity vector, the third input of which is connected to the topographic snap block and, and the outputs of the calculator of characteristics of the located object are connected to the statistical averager of the measured characteristics at the current time, and the reception of reflected radiation is carried out both directly from the located object and from sea glare formed by the scattering of probe radiation by the surface of the located object at different scattering angles, characterized in that an additional single-frequency continuous-wave gas laser, for example a CO ₂ laser equipped with a piezo-corrector its optical cavity, forming a transmitting stereo channel based on an additional transmitting lens with a stereo base h, with the optical axes collinearity of both transmitting and receiving lenses, the outputs of both lasers are additionally connected through weakly reflecting mirrors with high transmission with a mixer, the output of which is connected to a series-connected circuit from a phase-sensitive detector (discriminator), an integrator and a control DC amplifier, with an output connected to the piezoelectric corrector a laser, while the second input of the phase-sensitive detector is connected to the output of the reference crystal oscillator of the differential frequency setting of the main and additional continuous lasers, in addition, the same output of the reference crystal oscillator is connected to the third input of the calculator of the characteristics of the located object.

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