RU2504800C1 - Method of forming radio portrait of object by frequency division parallel processing - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: optical system transfers into the object plane radiation of all elements of the object modulated with different frequencies and amplitudes. The modulated radiation is converted to an electrical signal which is divided into components, each representing a resultant signal received from elements whose radiation is modulated with the same frequencies. For each component, an equation is generated, which consists of a sum of products of coefficients that are proportional to amplitudes of modulating frequencies with unknown luminance values of elements. The equations generated during observation are merged into a system of equations. Solutions of said systems determine luminance of elements of the object, from which its optical image is constructed.

EFFECT: simple radio imaging system, faster operation and reliability thereof.

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Description

The present invention relates to the field of radio imaging and can be applied: for detecting objects in the MM wavelength range under human clothing, in customs control of goods, in radio astronomy for mapping the sky and long celestial objects, in remote sensing of the earth's surface, in security systems operating in poor visibility.

To date, methods for the formation of radio images are known: using a focal two-dimensional matrix of receivers, using a multi-element interferometer, using phased arrays [1].

The above methods are implemented by complex receiving systems consisting of many elements, which reduces the reliability of the systems, and the dispersion of the parameters of the elements, due to external factors and their manufacturing technology, affects the quality of radio images.

The closest analogue is the method of forming a radio portrait of an object with one detector, which is realized by scanning the object with a rotating horn, receiving radiation from the elements of the object, modulated by functions with different parameters (frequencies) for each element. The received signal is divided into components corresponding to the radiation of each element and converted into an optical image [2].

The disadvantage of this method can be attributed to the presence in it of a mechanical scanning element (rotating horn), which reduces the speed and reliability of the device. The decrease in reliability is due to the fact that for connecting a rotating horn with a fixed part of the device requires complex docking devices.

The technical result consists in the fact that the design of the radio vision system is simplified, its speed and reliability are increased.

The specified technical result in the method of forming a radio portrait of an object by parallel processing with frequency separation is achieved by the fact that the optical system transfers to the subject plane the radiation of all elements of the object, which are modulated by different frequencies and amplitudes.

Modulated radiation is converted into an electrical signal, which is divided into signals, each of them is a total signal received from elements whose radiation is modulated by the same frequencies. For each such signal, an equation is formed consisting of the sum of the products of the coefficients proportional to the amplitudes, modulating functions by the unknown brightness of the elements. The equations formed during the observation time are combined into systems of equations. As a result of the solution of these systems, the brightness of the object's elements is determined by which its optical image is built.

The method can be implemented by the device, the scheme of which is shown in figure 1, where (1) are the elements of the observed object, (2) is the object, (3) is the optical system (antenna), (4, 5) is the modulator, (6) - horn, (7) - detector, (8) - frequency filter, (9) - computing device.

The radiation of all elements (1) of the object (2) is received by the optical system (3) and transferred to the subject plane, where the modulator (positions 4, 5) is located, made in the form of two disks with slots mounted on the same axis. The slots in the disk (4) are transparent, and in the disk (5) they are closed by radiation absorbers with different absorption coefficients (in Fig. 1 they are indicated by the symbols A1, A2, A3, ..., Ak). Slots are made with a constant angular pitch and are located on concentric circles of different diameters, shown by dashed lines on the disk (5) (see figure 1). The number of slots on different circles is different among themselves. In figure 1 they are shown only on one circle. The disks rotate about the O-O axis in the direction indicated by the arrow. The speeds of their rotation are so different among themselves that the disk (4) can be considered motionless during the period of revolution of the disk (5). This is necessary in order to provide a view of the shaded elements of the object.

Amplitude and frequency modulation is realized by disk rotation (5). The radiation passing through the slots located on different circles will be modulated by different frequencies, and those passing through the slots located on the same circle will be modulated by the same frequencies and different amplitudes.

Modulated radiation is received by a horn (6), transmitted to a detector (7), converted by it into an electric signal, which is divided by components with a frequency filter (8), each of them is a total signal received from elements whose radiation is modulated by the same frequencies. The divided signal is simultaneously fed to a computing device (9), forming for each component an equation,

where: A ₁ A ₂ , A ₃ , ......., Ak - known attenuation coefficients

radiation, x ₁ x ₂ , x ₃ , ...., x _k is the brightness of the elements of the object, k is the number of elements, S _{k is the} total signal.

The equations formed during the observation time are combined into systems of equations {2}. The solutions of these systems determine the brightness of the elements of the object, on which its optical image is built.

The equations of the system {2} are formed sequentially during the period of disk revolution (5). Figure 1 shows its position in the formation of the first equation. The formation time of one equation is equal to the period of time during which the disk (5) rotates through an angle a. After this period has elapsed, the first equation will be formed and the second will begin to form, after the completion of its formation, the third will begin to form, and so on, until the disk (5) makes a complete revolution.

The opening of the shaded elements of the object is provided by the rotation of the disk (4). The formation of all systems of equations will be completed in the course of the time for which it will turn by an angle p.

Thus, the present invention allows to simplify the radio vision system and increase its speed.

Literature:

1. V.A. Godunov, A.Yu. Zrazhevsky, M.T. Smirnov, V.S. Ablyazov, A.A. Haldin, A.E. Maximov, V.P. Nesterov. Radiothermal polarized portraits of objects and covers in the MM wavelength range. // 2nd All-Russian Scientific Conference “Remote Sensing of Earth Coverings and Atmosphere by Aerospace Means”. Sat Papers, St. Petersburg, 2004, v. 1, pp. 56-59.

2. Patent for invention No. 2382382 dated February 4, 2008, IPC G01S 13/89.

Claims (1)

A method of forming a radio portrait of an object by parallel processing with frequency division, which consists in receiving stationary antenna energy reflected or emitted by the elements of the object, modulating with different frequencies of the received radiation, characterized in that the radiation received from the elements of the object is additionally modulated by different amplitudes, modulated in frequency and the amplitude of the radiation is converted into an electrical signal, which is divided into components that differ from each other by the frequency of the module and, for each component, form an equation consisting of the sum of the products of the radiation attenuation coefficients proportional to the amplitudes of the modulating functions by the unknown brightness of the object elements, the equations formed during the observation time are combined into systems of equations, the solution of which determines the brightness of the object elements from its optical image.

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