RU2517234C2 - Multi-station passive location radio system (industrial vision) - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: multi-station passive location radio system (MRS PL) consists of a structured antenna array and a high-performance computer. The structure of the array is similar to that of the retina. The array consists of active cells which are grouped into separate antenna fields, signals from which are transmitted to controllers of a second and, further grouped likewise, to the next layers until the input of the computer. The controllers and the computer employ a spatial selection algorithm. The technical result of the operation of the MRS PL is provided by the dimensions of the separate antenna fields, which must be much larger than the operating wavelength, used to achieve the required sensitivity of the noise attenuation principle by selecting the number of array cells. To reduce the amount of computations when scanning, the computer employs a sector detection algorithm, which is the spatial selection algorithm with another input parameter.

EFFECT: high noise-immunity and accuracy of detecting received signals.

10 cl, 3 dwg

Description

Technical field

The invention relates to the use of devices intended for scanning space (for example: air, near-Earth, space), as well as continuous tracking of static and dynamic objects in it by receiving electromagnetic waves of radio-frequency, infrared, video, ultraviolet, x-ray and other ranges.

Devices with a similar structure can also be used to scan the space and the relative position of objects in it by converting waves of a different physical nature into electrical signals. It is technically possible to use them in acoustic media, hydroacoustic, in devices for receiving elastic waves in solid media, as well as in media with a mixed content of various states of aggregation, for example, in the crust; promising their use in sonar systems; in medical and industrial systems of ultrasound diagnostics.

State of the art

Several analogues of the proposed device are known from the prior art, and taking into account modern achievements in the field of genetic engineering and biology of cloning, here we can include widely studied biological systems and organs known from living nature.

The first known and closest technical analogue is the digital antenna array. Receiving antenna arrays, in which, according to a number of sources [1, 2, 3], the processing is carried out by digital processors, called digital antenna arrays (CAR). With regard to such CARs, it is noted that the same signals received from a plurality of its elements in a digital computer can be used to simultaneously generate a plurality of independent beams. “Antenna arrays forming several independent (orthogonal) rays and having an appropriate number of inputs from one radiating aperture are called multipath [1, 3].” For their intended purpose, the CARs do not always imply the presence of a transmitting (irradiating) part of the radio system, and can only serve to receive signals in a complex interference environment.

The second analogue, which is a further development of the CAR, is known as an active phased antenna array (AFAR). It also emits pulses to scan the space to increase the viewing range. “In an active antenna, each cell in the array contains its own transceiver (half-options are also possible, for example, only a receiver), which has a central control of characteristics. The key advantages of a full-fledged AFAR are: reliability is much higher (many independent transmitters and receivers), it becomes possible to work at several frequencies at once (transceivers are independent), and sensitivity is higher (because the signal is "detected" immediately by the receiver in the base element). Radars with AFAR not only easily provide full-fledged operation simultaneously for a variety of targets (10-20-30, you can do even more with simultaneous tracking and attack), but they can also conduct mapping of the surface under the plane along the way (with the detection of ground targets), very effectively rebuild from interference and immediately interfere with enemy radars ”[4].

Modern CARs, AFARs and PARs design so that “Phased arrays, like all physical objects, have limitations. The main limitation is the range of angles at which the beam can be deflected. The practical limit is 45 ... 60 degrees from the perpendicular to the plane of the antenna. It is advisable to reject the PAR beam within the main lobe of the directivity pattern (LH) of the elements of the antenna array (this beam is wider than the main lobe of the LH FAR). Going beyond or approaching the edges of the main lobe of the antenna pattern of the elements of the antenna array leads, in the first case, to the participation of the side petals of the array in the formation of the PD HEADLIGHTS, in the second case, to reduce the radiation power. As a result, at extreme angles, the beam is significantly weakened and defocused ”[3]. The lattice plane in them is turned to the scanned space sector on the same side. The opposite side is not involved in the work.

The closest, in view of the above, in terms of the hardware structure and organization of the processing of information obtained in the form of reflections, is the organ of vision. Real organs of vision in wildlife use slow physicochemical processes for processing, which is their drawback that can be eliminated by using modern ultra-fast electronic processing tools. The advantage of the eye in comparison with the two previous analogues is its high sensitivity, passive character (using natural illumination) and obtaining as a result of processing a volumetric dynamic picture of the surrounding reality, which is beyond any competition in terms of information volume.

According to various sources, the number of elements in modern headlamps reaches a thousand, and “the total number of cones in the retina of the human eye is 7 million, rods - 130 million. The rods have very high light sensitivity, provide twilight and peripheral vision. Cones perform a subtle function: central uniform vision and color sensation ”[8]. The optic nerve, which provides the transmission of nerve impulses caused by light irritation from the retina to the visual center of the brain, consists of approximately 1 million fibers [9].

Disclosure of invention

The basis for the construction and principle of operation of a multi-station radio-technical system (MPC) of a passive location (PL) is the principle of interference attenuation (PZP) according to claim 1 FI 2010117813 and the spatial selection algorithm (APS) [5]. The PPP requires to obtain a qualitative characteristic of selectivity and, as a result, to obtain a sharp beam of the beam, to satisfy the inequality condition (9) from [6] and also (2) in [7], that is, the maximum dimensions of the antenna field should be much larger than the maximum wavelength working range of frequencies MPC. The APS, in turn, in addition to the calculations, requires real-time digital processing of the necessary memory array for storing and shifting samples of signals, the volume of which increases in proportion to the cube of the linear dimensions of the antenna field (AP). Hereinafter, an antenna field means a flat or three-dimensional space in which transducers of wave processes of a corresponding physical nature are located, hereinafter referred to as Antennas.

Due to the practically difficult to eliminate shortcomings of small-scale small-area missile systems with spatial selection (MRS PS): poor longitudinal (along the beam) selectivity and the presence of a back lobe of the DD, its use as a single / unique structure (elementary unstructured NMRS PS) for a passive location system with high resolution will be ineffective. Another obstacle to using direct NMRS PS for passive location is found upon closer examination and it is not technically possible to perform an adder with such a huge number of input terms of parameters.

To eliminate these four drawbacks noted by underlining, a hardware-organized information processing structure is used that completely coincides with the structure of the organs of vision, except for the device of their converters of light into nerve impulses, instead of which Antennas are used.

Functionally, three layers of neurons are distinguished in the optical part of the retina: 1. The outer light-reflecting or neuroepithelial layer is represented by rods and cones, which transmit impulses through the nerve fiber, bypassing the nucleus of the first neuron, through the synapses to the second layer of neurons. 2. The inner second layer of neurons, the so-called bipolar cells, combines in each of the bottom up to 30 cones or up to 500 rods. 3. The third layer of ganglion neuron cells is formed by large cells with a bypass nucleus and a large nucleolus. The ganglion cell comes into contact with a group of bipolar, and one bipolar with clusters of rods and cones. The transformation of light energy in the retina is carried out thanks to a complex photochemical process, accompanied by the breakdown of photoreagents with their subsequent recovery with the participation of vitamin A and other substances. In this case, the concentration of cones increases toward the center of the retina. The layer of the external processes in the rods contains the dye rhodopsin, and in the cones - iodopsin.

By analogy with the structure of the retina, managed receivers should be attributed to the first layer of MRS submarine equipment, the antennas connected to the receiving paths with an adjustable reception band and analog-to-digital converters (ADCs) are connected to the first layer of the equipment. The second layer contains digital controllers (or processors), in which the function of synchronizing and summing signals from the first layer receivers is performed, which are combined in APs of a rather small size (single AP-EAPs), but satisfying inequality condition (9) from [6]. The delay function, or the creation of an array of samples necessary to obtain it, which is necessary to synchronize the useful signal before summing, can be organized in hardware both in receivers and in the controllers of the second layer. Similarly to the retina, Antennas for different frequency ranges, high and low, with a predominance of the number of high-frequency Antennas (the reason for which will be discussed later), can be used as Antennas in the first layer. The width of the frequency paths of the receivers is determined by the set speed of moving the objects, since with an increase in their speed, the Doppler frequency shift increases, as a result of which a virtual disappearance of the object from the field of view can occur.

The third and subsequent layers are organized similarly to the second. In this case, the delay control commands will go up, and the summation results will go down. The delay values can be calculated in each of the layer controllers based on the spatial coordinates of the central points of the EAP of the first layer. It is advisable to set the coordinates only during initial initialization of the entire MPC submarine. The last layer or processing device, depending on the amount of information summed from the entire AP, can be a high-performance supercomputer. With such hardware-based organization of the processing process, the volume of the required array of dynamic memory needed to store and shift in time the samples of information received at the input of the entire MRS submarine will be significantly reduced by several orders of magnitude. Such a structure realizes the property of associativity for sums that include more than three terms.

Depending on the amount of information received by all APs and to be processed, down to the supercomputer it is necessary to organize channels corresponding in volume. They, as in the organ of vision, can be organized according to the type of information transmitted: 1) channels for information intended for algorithms for detecting static or dynamic objects, and 2) channels for information used by APS about more detailed properties of detected objects (sizes reflecting ability, direction and speed of movement). Similarly, it is advisable to select 3) channels for transmitting command information. The first algorithms require a constant scanning of the space, and the second - a more detailed scan of the reflections from the objects selected for study (inspection).

As the first and second type of algorithms, the same APS can be used, but working in different operating modes. To distinguish between the points of reception, that is, the location of the Antennas, from the point selected in the space at which the conditional signal source is located (or is missing), the last as a point of convergence (TS). If all the TS selected by all EAPs coincide, as well as if there is a source or object reflecting the signal in it (in a single TS), the correlation maximum will appear at the output of the last APS adder.

The block diagram of the organization of information flows and the delays introduced by the controllers is shown in figure 1. The magnitude of the delays for clarity is shown in the form of the length of the linear dimensions of the adjustable delay lines (RLS). Since the object is located to the left of the flat horizontal grating, the largest delay for synchronization before summing is introduced into the left signals from the receivers. Abbreviations in the figure: PFP - controlled digital receiver, CK1-1 ... 1-N - digital controller of the first layer of controllers, CK2-1 - digital controller of the second layer of controllers, MP - multiprocessor computing device; “3D - database” is a dynamically updated structured database containing information about the coordinates and other properties of scanned points in space. A “source of external illumination" can be one or more external natural or man-made sources. The object’s own radiation can also be perceived, for example infrared radiation, acoustic, vibroacoustic radiation.

APS is used as the main, but not the only algorithm. In MRS submarines, it will also be useful to use compensation methods for suppressing concentrated noise, methods for synthesizing aperture [10] and motion detection algorithms based on the Doppler effect. The basis of the APS operation is based on a trinity: the PZP, condition (9) from [6] and the synchronization of MRS signals along an imaginary wavefront from the TS, and step by step it consists in the following.

Step 1. Create an array of received signals from the MRS with a given number n, which is determined by the necessary signal / noise attenuation, including according to [6] and for negative values in dB. The level at the input of the APS is the level at the input of the MPC, and the output is the input of the digital controller of the lower layer or in the last layer of the determinant of the signal parameters at the convergence point. The volume of the array of samples for digital processing will be equal to:

M = n · Fdisk · k · λrad / Vcp,

where n is the number of receivers or the number of antennas in the EAP;

Fdis. - sampling frequency of the ADC. The capacity of each sample is determined by the capacity of the ADC and affects the total amount of memory in the array in bits;

k = Lmax / λexv.max Lmax - the maximum size of the EAP and then layer-by-layer AP of the entire MPC;

Vcp. - signal speed in the propagation medium, for radio waves = c.

When processing the signal in real time, the array is updated (shifted) in each of the receiving channels according to the stack principle, the first to enter - the first to exit.

Step 2. Using the known coordinates, we calculate n distances Ri from the receiving points to the vehicle. Since the AP has a low longitudinal (along the beam of the beam) selectivity, the choice of the coordinates of the emitter when receiving from the far zone can be approximate.

Step 3. Determine the maximum distance Rmax. from the obtained Ri.

Step 4. We calculate the time delays, which during digital processing are expressed by the number of samples determined from:

Ni = Fdis. (Rmax-Ri) / Vcp.

The zero delay will be at the receiving point with Rmax = Ri.

Similarly, in 4 steps, the APS can be performed in the polar coordinate system, but you will have to perform a more complicated operation of taking the cosine of the angle.

The complexity of the implementation of continuous missile submarines is that for a given resolution and range of the system, the viewing time increases inversely with the area of the minimum object and in proportion to the square of the distance to it. Given the dynamic nature and multiplicity of tracked goals, the performance requirements of IFAs are becoming practically unrealizable. The way out of this collapse is the use of the sector detection algorithm (ASO) as part of the processing algorithms, which is implemented by the same APS when the vehicle is transferred to the near zone based on the expression.

φ _review = 2 · arcsin [(Lmax / 2) / R _TC ];

Where φ _review - required viewing angle;

R _TC - distance from the center of the EAP to TC.

Three selectivity characteristics obtained on a computational model with the same parameters are shown in figure 2:

- With APS, the range to TC is 10000, λiz. = 24, Lmax = 600, k = 25;

- For ASO = 24: λrad. = 24, distance R _TC = 1740, k = 25, φ _review = 20 deg.

- For ASO = 100: λrad. = 100, R _TC = 1740, k = 6, φ _review = 20 deg.

The graph shows that for different frequencies with the same distance to the vehicle, the angle of the detection sector does not change and is at a level of 0.4 - 20 degrees. But due to the more distant propagation of waves with a longer wavelength, which is characteristic of waves of any physical nature, the detection range is higher. This determines the necessity of using Antennas in MRS submarines, which allow operating at significantly different frequencies, high for APS and low for APS. In addition, the above-mentioned negative effect of the back lobes of the MD is neutralized, since their TS coincides with the TS of the main lobes of the EAP.

Brief Description of the Drawings

The figure 1 shows a structural diagram of the organization of information flows and delays introduced by the controllers. The values of the delays for clarity are shown in the form of the length of the linear dimensions of the adjustable delay lines (RLS). Since the object is located to the left of the flat horizontal grating, the largest delay for synchronization before summing is introduced into the left signals from the receivers. The following abbreviations are adopted in the figure: PFP - controlled digital receiver, CK1 ... l-N - digital controller of the first layer of controllers, CK2-1 - digital controller of the second layer of controllers, MP - multiprocessor computing device; “3D - database” is a dynamically updated structured database containing information about the coordinates and other properties of scanned points in space. A “source of external illumination" can be one or more external natural or man-made sources. The object’s own radiation can also be perceived, for example, infrared radiation, acoustic, vibroacoustic radiation.

The figure 2 shows three selectivity characteristics obtained on a computational model with the same parameters:

- With APS, the range to the vehicle is 10000, λiz. = 24, Lmax = 600, k = 25;

- For ASO = 24: λrad. = 24, distance R _TC = 1740, k = 25, φ _review = 20 deg.

- For ASO = 100: λrad. = 100, R _TC = 1740, k = 6, φ _review = 20 deg.

The graph shows that for different frequencies at the same distance to the vehicle, the detection angle does not change and amounted to 0.4-20 degrees. But due to the more distant propagation of waves with a longer wavelength, the detection range is higher. This determines the necessity of using Antennas in MRS submarines, which allow operating at significantly different frequencies, high for APS and low for APS.

The implementation of the invention

The design (hardware structure) of the MPC submarine in a static state, as well as its operation, is described in detail in the previous section of the description and is graphically presented in figure 1. The operation and modes of APS and ASO, which are sufficient to achieve a technical result, are also described in detail in the previous section and are explained figure 2. If it is necessary to obtain a more accurate three-dimensional picture, in the case of using a stationary MPC MPC, when it is impossible to use aperture synthesis methods, two or more similar structures are used, spaced at distances significantly exceeding the linear dimensions of their AP, and transmitting information for processing to a single supercomputer. To understand the technical foundations of the health of the claimed system, it is necessary to dwell briefly on the essence of the PPP and inequality (9) from [6].

. Такое различие в получаемом результате при суммировании сигнала и помехи позволяет путем выбора числа слагаемых легко преодолевать нулевой в дБ уровень отношения сигнал-шум и обеспечивает достижение заявляемого технического результата.The PPP states that the summation of independent random variables, such as noise or noise, leads to a change in the law of probability of their distribution and at infinity (with an increase in the number of terms) the process ceases to be random. In contrast to noise, the signals are synchronized before being added up and are not random, which leads to a linear increase in their sum with an increase in the number of terms. When the synchronization of signals is disturbed, they, as well as interference, undergo relative attenuation (relative to their maximum deviation). The empirically obtained “attenuation curve”, which determines the attenuation rate, for the case with the summation of white noise, is approximated with high accuracy by the expression $$f\left(n\right)=\mathrm{one}/\left(2\cdot \sqrt[]{n}\right)$$

. Such a difference in the result obtained when summing the signal and the interference makes it possible to easily overcome the zero in dB level of the signal-to-noise ratio by choosing the number of terms and ensures the achievement of the claimed technical result.

The physical meaning of inequality (9) from [6] is explained by the diffraction phenomenon, when an obstacle that is smaller or comparable in size to the wavelength is on the wave path, it is bent around by the wave without the formation of a shadow. Conversely, when the obstacle is significantly longer than the wavelength, a shadow region is formed behind it, which is elongated along the direction of wave movement. The presence of a shadow means that the wave is doing some work. This work, when synchronizing and summing the signals taken from the grating, turns into signal growth and noise damping, since for small grating sizes, the summed interference signals cease to be random with respect to each other, which in turn does not lead to an increase in the signal-to-noise ratio and is equivalent to the absence of a signal on the background of noise.

Literature

1. Chirkunova Zh.V. Abstract of dissertation for the degree of candidate of technical sciences. - M., 2009 www.spurtm.ru> nauchdeyatelnost / chirkunova.pdf

2. Phased array antenna.

http://slovari.yandex.ru/~books/BSE/Phased antenna array /

3. Phased array antenna.

http://en.wikipedia.org/wiki/Phase_antenna array

4. What is AFAR. 11/26/836 /

5. Materials of the XVIII International Scientific and Technical Conference "Radar, Navigation, Communication"., 2012, April 17-19, 2012, Voronezh. The spatial selection algorithm. Popik P.I. (p. 478).

6. Application PCT / RU 2011/000296 dated 04/27/2011, priority 04/05/2010.

www.wipo.int/pctdb published under No. WO 2011/145981

7. Innovation in the Armed Forces of the Russian Federation: Proceedings of the All-Army Scientific and Practical Conference. November 25-26, 2010, - SPb .: YOU, 2010-568 p. The principle of interference attenuation. Popik P.I. (p. 373).

8. The retina and the structure of its layers. http://www.sfe.ru/v_book_anat6.php

9. The optic nerve. Optic tract. http://www.sfe.ru/v_book_anat7.php

10. Fundamentals of the theory of synthesized apertures. http://www.tehnoinfa.ru/radiovidenie/3.html

Claims (10)

1. A passive location device designed to scan the space and the relative position of objects in it by converting waves of any physical nature into electrical signals, working under external illumination, including a digital antenna array consisting of cells, each of which contains a controlled broadband receiver , to the input of which a wave energy to electric signal converter is connected and containing an analog-to-digital converter, thereby forming an antenna field (AP) of qi front grill; processing of received signals in such a radio engineering device is carried out by digital processors, characterized in that:
a) the cells of the digital antenna array are divided into groups forming single antenna fields (EAP), so that their maximum sizes are much larger than the maximum wavelength of the main operating frequency range of the entire system, and then the information is processed in layers;
b) the first layer is controlled receivers, the digitized signals from which are fed to the second layer of computers or controllers, each of which receives signals from one of the EAPs to the inputs, and from the output after processing by the spatial selection algorithm (APS), a single signal goes to the next layer ;
c) the last layer is a high-speed computer that controls the higher layers and uses in its work as the main APS, which consists in the formation, in addition to the calculations in real time, of the necessary memory array for storing and shifting samples of signals received at the inputs, determining the necessary delays for each channel of the EAP and / or higher layer and the samples, taking them into account from the array of signals, which are then summed into a single output signal; the delay values are calculated in each of the layer controllers and the control computer, based on the spatial coordinates of the central points of the EAP of the first layer and the point of convergence (TS) of the EAP rays. 2. The device according to claim 1, characterized in that the cells of the antenna array are located in three-dimensional space, and the processing of the received signals is carried out with three-dimensional coordinates. 3. The device according to claim 1, characterized in that the EAP can overlap in space and have, depending on the location in a single AP, a different configuration and size. 4. The device according to claim 1, characterized in that the AP can contain cells operating in a different frequency range necessary for the operation of sector detection algorithms (ASO). 5. The device according to claim 1, characterized in that between the first and last layers there can be more than one layer of intermediate processing. 6. The device according to claim 1, characterized in that the delay function and the creation of an array of samples necessary to obtain it, and designed to synchronize the useful signal before summing, can be organized in hardware both in receivers and in controllers of the second layer, including including when the receivers and the controller are made structurally in a single device. 7. The device according to claim 1, characterized in that the relative coordinates of the EAP are set during initial initialization of the entire system and are periodically updated according to a predetermined algorithm. 8. The device according to claim 1, characterized in that the channels for information transmitted on the size of the delays up to the EAP and the total down, can be structured according to the type: for information intended for ASO static or dynamic objects; for information used by the MTA about more detailed properties of detected objects (sizes, reflective abilities, direction and speed of movement), and channels for transmitting command information. 9. The device according to claim 1, characterized in that the same APS is used as an ASO taking into account the movement of its vehicle to the near zone located from the center of the EAP at a distance of the same order with its linear dimensions. 10. The device according to claim 1, characterized in that to ensure a given sensitivity and noise immunity of the entire passive location system, regardless of its resolution, the principle of interference attenuation is used by selecting the required number of grid cells.

Images