RU2533789C1 - Polarisation characteristic definition method for high frequency signal propagation environment - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: within each probing period, after radiation by a transmitting antenna, two time-shifted, structurally orthogonal radio signals come through the propagation environment between the transmitting and receiving antennas at corresponding orthogonal polarisations and on one and the same carrier. After receiving, shifting to an intermediate frequency and amplification, the orthogonally polarised components of the signals are converted to a digital form, subjected to the fast Fourier transform, obtaining complex spectra of the said components. Then these spectra are divided by a complex spectrum of the corresponding radiated radio signal, thus defining the Jones matrix elements for each frequency count that characterise polarisation parameters of the high frequency signal propagation environment in the frequency range, defined by the radiated signal spectrum width.

EFFECT: faster operation.

1 dwg

Description

The invention relates to measuring technique and can be used to determine the polarization characteristics of the propagation medium of high-frequency (HF) signals.

The well-known "Multi-polarization method for recognizing air targets" (RF patent No. 2139553, G01S 13/30, 1999), which consists in emitting a sequence of RF signals having different polarization (linear, circular, elliptical polarization of various types), receiving orthogonally polarized components reflected from the purpose of the signals on each of the polarizations, the analysis of their amplitudes, the accumulation and averaging of the received information and the formation on its basis of the recognition sign (polarization portrait) of the target.

The disadvantages of this method include the lack of speed of measurement of the polarization characteristics of the propagation medium in the frequency range due to the need to repeatedly carry out a large number of measurements using multiple probe signals with different carrier frequencies and their subsequent digital processing.

The well-known "Method of measuring the polarization matrix of the scattering of the object (PMR)" (DB Kanareikin, MV Pavlov, VA Potekhin. Polarization of radar signals. M: Sov. Radio, 1966, p.118-124, 282-293), consisting in the simultaneous emission of radio signals orthogonal in structure at the corresponding orthogonal polarizations at different carrier frequencies, the reception of orthogonally polarized components of the radio signals reflected from the object, the polarized components of the reflected radio signals received by each receiving channel, I divide by the use of filters tuned to the frequencies corresponding to the frequencies of the emitted signals measured amplitude and phase of each of the selected orthogonal polarized components of the reflected signals and obtained plurality of measurement results, which determines the measured value of the TMR object.

The disadvantages of this method include the lack of speed and the difficulty of implementing this method for measuring the polarization characteristics of the propagation medium in the frequency range (due to the use of a large number of sounding signals with different carrier frequencies, it is necessary to have as many receiving channels tuned to these frequencies by appropriate filters). Also, the ambiguity of measuring the polarization characteristics of the propagation medium at each frequency, because the measurement of one PMR at two frequencies does not characterize the polarization properties of the propagation medium at any frequency.

The well-known "Method of measuring the polarization matrix of the scattering of the object" (RF patent No. 2190239, G01S 13/95, G01S 13/04, 2002), selected as a prototype, which consists in the fact that in each sensing period emit two time-shifted orthogonal in structure the radio signal at the corresponding orthogonal polarizations on one carrier frequency, remember the initial phases of the emitted radio signals, receive the orthogonally polarized components of the radio signals reflected from the object, measure the parameters of the radio signals that characterize the polarization matrix of the scattering of the object, exclude the delay in the time of measurement of the parameters, which is due to different times of radiation of the radio signals at different polarizations, and get a set of results that determines the measured value of the polarization matrix of the scattering of the object,

The disadvantage of this method is the lack of measurement of the polarization characteristics of the propagation medium in the frequency range, due to the use of a large number of sounding signals with different carrier frequencies.

The basis of the invention is to create a method for measuring the polarization characteristics of the propagation medium in the high frequency range.

The technical result, in the implementation of the claimed invention is to increase the speed of the proposed method.

The technical result is achieved by the fact that, in each sensing period, two time-shifted, orthogonal in structure of the radio signals at the corresponding orthogonal polarizations on one carrier frequency are sequentially emitted, orthogonally polarized components of the radio signals are received, transferred to the intermediate frequency and amplified orthogonally polarized components of the radio signals, according to the invention time-shifted orthogonal in the structure of the radio signal after radiation from the transmitting antenna there is a propagation medium between the transmitting and receiving antennas, after receiving, transferring to the intermediate frequency and amplification, the orthogonally polarized components of the radio signals are digitized, fast Fourier transforms are applied, complex spectra of the orthogonally polarized components of the radio signals are obtained, the complex spectra of the orthogonally polarized components of the radio signals are divided into complex corresponding emitted radio signal, thereby determining the elements of the Jones matrix for each frequency reference, which characterize the polarization characteristics of the propagation medium of the RF signals in the frequency range determined by the width of the spectrum of the emitted radio signal.

The technical result is achieved due to the fact that in each sounding period, the propagation medium is irradiated with two time-shifted radio signals orthogonal in structure at the corresponding orthogonal polarizations and at one carrier frequency: S _x1 (t) - radio signal with horizontal polarization, S _y1 (t) - vertical polarized radio signal.

The analysis of the prior art by the applicant has established that there are no analogues that are characterized by a combination of features that are identical to all the features of the claimed “Method for determining the polarization characteristics of the propagation medium of high-frequency signals”. Therefore, the claimed invention meets the criterion of "novelty."

Search results for known technical solutions in this and related fields of technology in order to identify features that match the distinctive features of the claimed invention from the prototype showed that they do not follow explicitly from the prior art.

From the prior art determined by the applicant, the influence of the envisaged essential features of the claimed invention on the achievement of the specified technical result was not revealed. Therefore, the claimed "Method for determining the polarization characteristics of the propagation medium of high-frequency signals" corresponds to the "inventive step".

The essence of the method is illustrated in the drawing, where figure 1 shows the structural diagram of the device, allowing to implement the proposed method.

The device comprises serially connected synchronizer 1, a signal shaper 2, a channel switch 3 and a polarized two-channel antenna 4, the second input of which is connected to the second output of the channel 3 switch, the second input of which is connected to the second output of the synchronizer 1. The outputs of the horizontal horizontal receiving antenna 5, the receiving vertical polarization antennas 6, receiving antenna 7 are connected to a two-channel spectrum analyzer 8, the output of which is connected to the input of the processing unit 9, and its output is the output stroystva. Testing medium 10.

In each sensing period, the synchronizer 1 generates a start pulse, which is fed to the channel switch 3. Through the channel switch 3, the start pulse arrives in one of the channels of the two-channel polarized antenna 4, depending on the polarization structure of the first sounding medium of the propagation of the radio signal generated by the shaper of radio signals 2 . After the start-pulse of a two-channel polarized antenna 4 is emitted from the first output of the synchronizer 1, a pair of shifted time synchronizing pulses. The radio signal generator 2, using a pair of time-shifted clock pulses, generates two time-shifted and orthogonal in structure radio signals S _1x (t) and S _1y (t). As orthogonal radio signals, two step-frequency-modulated (MFM) signals can be used. The pulses of the synchronizer 1, arriving at the input of the shaper of radio signals 2, ensure its synchronous operation with the switch channel 3.

In each sensing period, the channel 3 switch, using the pulses arriving at its first input from the second output of the synchronizer 1, connects the output radio signals of the signal shaper 2 to the corresponding polarization two-channel polarized antenna 4, which emits them into the propagation medium 10.

и $${\dot{S}}_{1y}\left({\omega }_n\right)$$

заранее известны, и информация о них находится в блоке обработке 9.Complex spectra of 4 radio signals emitted by a two-channel polarized antenna $${\dot{S}}_{\mathrm{one}x}\left({\omega }_n\right)$$

and $${\dot{S}}_{\mathrm{one}y}\left({\omega }_n\right)$$

known in advance, and information about them is in the processing unit 9.

The polarization characteristics of the propagation medium in the frequency range are characterized by 2 × 2 Jones matrices on the corresponding frequency samples of the complex spectra of the emitted radio signals that are orthogonal in structure [1]:

. $$\left\{I_M\left({\omega }_n\right)\right\}=\left\{\left[\begin{array}{cc}{\dot{M}}_{\mathrm{eleven}}\left({\omega }_n\right)& {\dot{M}}_{12}\left({\omega }_n\right)\\ {\dot{M}}_{21}\left({\omega }_n\right)& {\dot{M}}_{22}\left({\omega }_n\right)\end{array}\right]\right\}$$

.

The start pulse passing through the propagation medium enters the input of the receiving antenna 7, from the output of which it enters the third input of the two-channel spectrum analyzer 8 and starts it.

, $${\dot{S}}_{2y}{\left({\omega }_n\right)}^x$$

, $${\dot{S}}_{2x}{\left({\omega }_n\right)}^y$$

, $${\dot{S}}_{2y}{\left({\omega }_n\right)}^x$$

, которые подают на вход блока обработки 9, где комплексные спектры ортогонально поляризованных составляющих радиосигналов, прошедших среду распространения 10, например $${\dot{S}}_{2x}{\left({\omega }_n\right)}^x$$

, $${\dot{S}}_{2y}{\left({\omega }_n\right)}^x$$

, делят на комплексный спектр излученного радиосигнала, например $${\dot{S}}_{x1}\left({\omega }_n\right)$$

, в результате определяют элементы матрицы Джонса на каждом частотном отсчете:After passing through the propagation medium 10, the polarization structure of the signals S _1x (t) and S _1y (t) changes. The horizontal horizontal receiving antenna 5 and vertical polarizing receiving antenna 6 sequentially receive the orthogonally polarized components of the radio signals after passing through the propagation medium 10: S _2x (t) ^x and S _2y (t) ^x are the orthogonally polarized components of the radio signal S _1x (t), S _2x ( t) ^y , and S _2y (t) ^y are the orthogonally polarized components of the radio signal S _1x (t). The orthogonally polarized components of the radio signals are fed to the input of a two-channel spectrum analyzer 8, where they are transferred to an intermediate frequency, amplified, digitized, and subjected to fast Fourier transform operations, as a result of which the signals of the complex spectra of the orthogonally polarized components of the radio signals are obtained at the output of the two-channel spectrum analyzer 8 $${\dot{S}}_{2x}{\left({\omega }_n\right)}^x$$

, $${\dot{S}}_{2y}{\left({\omega }_n\right)}^x$$

, $${\dot{S}}_{2x}{\left({\omega }_n\right)}^y$$

, $${\dot{S}}_{2y}{\left({\omega }_n\right)}^x$$

which are fed to the input of the processing unit 9, where the complex spectra of orthogonally polarized components of the radio signals that have passed the propagation medium 10, for example $${\dot{S}}_{2x}{\left({\omega }_n\right)}^x$$

, $${\dot{S}}_{2y}{\left({\omega }_n\right)}^x$$

, divided by the complex spectrum of the emitted radio signal, for example $${\dot{S}}_{x\mathrm{one}}\left({\omega }_n\right)$$

, as a result, the elements of the Jones matrix are determined at each frequency sample:

; $${\dot{M}}_{\mathrm{eleven}}\left({\omega }_n\right)=\frac{{\dot{S}}_{2x}{\left({\omega }_n\right)}^x}{{\dot{S}}_{x\mathrm{one}}\left({\omega }_n\right)}$$

;

; $${\dot{M}}_{12}\left({\omega }_n\right)=\frac{{\dot{S}}_{2x}{\left({\omega }_n\right)}^y}{{\dot{S}}_{y\mathrm{one}}\left({\omega }_n\right)}$$

;

; $${\dot{M}}_{21}\left({\omega }_n\right)=\frac{{\dot{S}}_{2y}{\left({\omega }_n\right)}^x}{{\dot{S}}_{x\mathrm{one}}\left({\omega }_n\right)}$$

;

. $${\dot{M}}_{22}\left({\omega }_n\right)=\frac{{\dot{S}}_{2y}{\left({\omega }_n\right)}^y}{{\dot{S}}_{y\mathrm{one}}\left({\omega }_n\right)}$$

.

The generated set of Jones matrices, the elements of which are determined in the processing unit 9, characterizes the polarization characteristics of the propagation medium of the RF signals in the frequency range, which is determined by the spectral width of the emitted radio signals, and is issued to the consumer.

As can be seen from the foregoing, performance is achieved through the use of broadband signals, which allows only one measurement cycle to determine the polarization properties of the propagation medium in the frequency range.

The proposed method allows you to quickly obtain information about the polarization properties of the propagation medium of RF signals.

The set of essential features of the invention ensures the achievement of a technical result in the implementation of the invention due to the fact that in each sensing period the propagation medium is irradiated with two time-shifted orthogonal in structure radio signals at corresponding orthogonal polarizations and at one carrier frequency.

Thus, the above information proves that when implementing the claimed invention, the following conditions are met:

- for the proposed method in the form in which it is described in the independent claim, the possibility of its implementation using the means described before the filing date of the application is confirmed;

- actions embodying the claimed invention in its implementation, are able to provide the specified technical result.

Therefore, the claimed invention meets the condition of patentability "industrial applicability".

Information sources

1. O.D. Moskaletz, A.S. Vershinina Polarization transformations of pulse electromagnetic signals / O.D. Moskaletz, A.S. Vershinina // XVI International Conference "Wave electronics and its applications in the information and telecommunication systems". Preliminary program and abstracts, Saint-Petersburg, 2-6 June, 2013.

Claims (1)

A method for determining the polarization characteristics of the propagation medium of high-frequency signals, which consists in the fact that in each sensing period two time-shifted ones are successively emitted, orthogonal in the structure of the radio signal at the corresponding orthogonal polarizations on the same carrier frequency, the orthogonally polarized components of the radio signals are received, transferred to the intermediate frequency and amplified orthogonally polarized components of the radio signals, characterized in that two shifted in time, orthogonal in the structure of the radio signal after the radiation of the transmitting antenna, the propagation medium passes between the transmitting and receiving antennas, after receiving, transferring to the intermediate frequency and amplification, the orthogonally polarized components of the radio signals are digitized, fast Fourier transform is applied, complex spectra of orthogonally polarized components of the radio signals are obtained, and complex the spectra of the orthogonally polarized components of the radio signals per complex spectrum correspond of the emitted radio signal, thereby determining the Jones matrix elements for each frequency sample, which characterize the polarization characteristics of the propagation medium of high-frequency signals in the frequency range determined by the spectral width of the emitted radio signal.