RU2834603C1 - Method of assessing impact of unintentional interference on quality of functioning of radio-electronic facility for detecting objects with scanning airspace and system for implementation thereof - Google Patents

Abstract

FIELD: measuring.

SUBSTANCE: invention relates to measurement equipment and can be used in surveillance and sector radioelectronic equipment (REE) for solving problems in the interest of ensuring electromagnetic compatibility. Technical result is achieved due to continuous analysis of the estimated value of the unintentional interference effect, which shows how many times the REE reception threshold should be increased in conditions of interference, in order to maintain probability of false alarm at the same level. Identifying the source of the UI originator for taking measures aimed at ensuring EMC, in agreement with the services.

EFFECT: preservation of maximum range of detection of aerial objects of radio-electronic equipment due to preservation of value of probability of false alarms in conditions of unintentional interference (UI).

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Description

Field of technology to which the invention relates

The invention relates to the field of measurement technology and can be used in survey and sector radio-electronic means (RES) using space scanning by emitting powerful probing signals (PS) (at letter frequencies in the permitted range) to determine the location of airborne objects in the interests of ensuring their electromagnetic compatibility (EMC).

State of the art

Methods for assessing the effectiveness of electronic equipment in conditions of unintentional interference and systems for implementing them are known [1 - Method for assessing the effectiveness of electronic equipment in conditions of unintentional interference and a system for implementing it RU 2686582 C1 2019], [2 - Method for assessing the effectiveness of integrated radar systems in conditions of unintentional interference and a system for implementing it RU 2727343 C1 2006], which have the ability to assess the effectiveness of RES based on an analysis of the technical condition of RES by determining the total time of action of unintentional interference (UI) created by RES that exceeded the established detection threshold of RES.

The disadvantage of the methods considered is the lack of the possibility of application in RES using space scanning by emitting powerful probing signals (at letter frequencies in the permitted range) to determine the location of airborne objects, due to the lack of a mathematical apparatus for determining the level of impact of unintentional interference on the interference receptor in each azimuthal direction of the space scanning sector.

A group of inventions (1-2) was selected as prototypes.

The claimed method has the following advantages:

1) the ability to assess the electromagnetic environment in real time;

2) precise determination of the bearing of the source of unintentional interference;

3) application to any type of radio electronic equipment.

Disclosure of invention

The problem to be solved (technical result) is to maintain the specified detection range of airborne electronic systems by reducing the probability of false alarms under conditions of exposure to unintentional interference (UI).

The specified technical result is achieved by the fact that after threshold processing of the received signal, the quality of the functioning of the RES is assessed, a frequency map is formed, showing the presence of the influence of the NP on the letter frequencies of the RES.

The essence of the proposed method is as follows.

The coefficient of unintentional interference (CUI) k _cu is used as an evaluation indicator of the impact of NP on the RES, the value of which shows how many times on average it is necessary to increase the reception threshold under NP conditions in order to maintain the required excess of the threshold signal level over the interference the same as it was without NP (the specified value of the probability of false alarms) formula 1.

Where - the threshold of receiving the radio electronic device under the influence of the NP; z ₀ - the threshold of the receiving device of the radio electronic device in the absence of interference.

The selected evaluation indicator is related to the detection range of the RES formula 2. It characterizes the quality of operation and can act as an indicator of the quality of operation of the RES:

Where - current value of the maximum detection range, D _RES - maximum detection range specified by technical requirements.

The dependence of the value of the quality indicator of the radio electronic system operation on the value of k _np is shown in Fig. 1.

In the proposed method, k _нп is used as an evaluation indicator when implementing an assessment of the impact of NP on the quality of the functioning of the RES by continuously analyzing its value.

For one scan of the RES coverage area, a vector of values k _np (β,ƒ _n ) is formed, which contains the measured values of k _np for each angular direction along the azimuth of the coverage area P at a fixed RES frequency ƒ _n for one scan of the RES space, formula 3:

where k _np (β _n ,ƒ _n ) is the value of the KNP for the current angular direction in azimuth β _n (n is the direction number from 0° to 360°) of the formation of the radiation pattern (RP) of the RES antenna at a fixed frequency ƒ _n .

Since the impact of the NP is a probabilistic process, to test the statistical hypothesis about the presence of the NP influence on the RES, the values k _NP (β ₃₆₀ ,ƒ _n ) are accumulated for each angular azimuthal direction of the antenna RP over a period of time t. The vectors k _NP (β ₃₆₀ ,ƒ _n ) for each period M _n (n is the period number) of scanning the RES form a matrix of values k _NP (t,β,ƒ _n ) at the end of each scanning period T _{ob of} the antenna directional diagram of the established coverage area of the RES, formula 4:

where M is the number of times of scanning the established scanning zone of the RES, T _ob is the time of complete scanning of the scanning zone of the RES, k _np1 (β _n ,ƒ _n ,M _n ) is the KNP for the angular direction along the azimuth of the DN at a fixed frequency for n - the scan of M.

By analyzing the samples of the KNP values for each angular direction along the azimuth, the average value of the random variable and the standard deviation are estimated (Fig. 2). The value of the KNP corresponding to the critical point of the region with a confidence probability of p=0.99 is selected as significant. In this case, the value of the Student's coefficient t is selected from the table according to the number of KNP values, formula 6:

Where - mathematical expectation of the KNP in the estimated angular azimuthal direction; - standard deviation of the KNP in the estimated azimuthal direction; t _W-1 - Student's t-test; W - number of coefficient values in the sample.

The criterion for the influence of unintentional interference on the radio electronic system is the fulfillment of the condition formula 7:

Where - the threshold value of the KNP at which the specified value of the probability of false alarms in the radio receiving device of the RES is maintained.

where Z _{0 max} is the maximum permissible threshold of the receiving device of the RES for stabilizing false alarms.

If expression (7) is satisfied, then a decision is made about the impact of the NP on the operating frequency of the RES from the direction p. At the angular directions for which expression (7) is satisfied, matches are checked with the bearing to neighboring RES that may be sources of NP, in accordance with the data on the location of the RES grouping in the positional area and the possibility of their mutual influence is assessed.

Calculations at other operating frequencies (in the case of operation of the radio electronic means in random frequency hopping mode or manual mode), in the permitted frequency range of the radio electronic means, it is carried out in a similar manner.

The vector of values of the KNP k _{knp RES} at all possible carrier frequencies of the RES has the form formula 9:

The essence of the claimed technical solution lies in the sequential implementation of the following operations:

- formation of the vector k _np (β _n ,ƒ _n ) at a fixed frequency of the RES ƒ _n for one review of the RES space (3);

- testing statistical hypotheses about the presence of NP at a fixed frequency ƒ _n (4);

- assessment of the impact of NP on RES (7);

- determination of the bearing to the NP source.

The implementation of the method for determining the impact of NP in the permitted frequency range of operation of the radio electronic means is carried out by the system shown in Fig. 3, in 4 stages.

Stage 1 of the formation of the KNP RES for each angular direction of the RP RES for one survey of the working sector at a fixed frequency. Unintentional interference arrives at the input of the radio receiving device (RPD), in which the alarm generation algorithm regulates the sensitivity threshold set in the RPD depending on the level of its impact. The decision on the presence of UI is made if an increase in the threshold level of reception is recorded. At this stage, for the current angular direction of scanning the RP in the survey sector of the RES, k _{NP n} (ƒ _n ,β _n ) is formed. For one survey of the RES sector, the KNP vector is formed at a fixed frequency, expression (3).

Since the component of electromagnetic interference depends not only on the characteristics of the interference source, but also on a number of factors, such as the type of RES, the terms and conditions of its operation, the time of year, the surrounding EMO. In most cases, the influence of all these factors can be characterized only from the position of probability theory.

At stage 2 of testing statistical hypotheses about the presence of NP during operation of the RES at a fixed frequency, the accumulation of KNP vectors is carried out over several surveys, and a matrix of values is formed for time t, where t=MT _ob . Samples of KNP values for azimuthal directions β _n are estimated, the average value of the random variable and its standard deviation are estimated

Stage 3 of the assessment of the impact of the NP RES. At this stage, the impact of the NP on the detection range of the RES and the ability to perform its functional tasks as intended is assessed. If expression (7) is satisfied, then a decision is made on the impact of the NP at the operating frequency, on the RES from the direction β _n , the current value of the KNP and β _n is recorded.

During the assessment of the impact of the NP on the RES, a frequency map is formed on the letter frequencies provided in the RES (Fig. 4), which records the fact of the impact of the NP on the letter frequencies of the RES.

Stage 4 of determining the bearing to the NP source. For angular directions where the NP impact is determined, the possible location of the RES located in these directions is specified. After determining the location of the RES (probable NP source), its affiliation, type and technical characteristics are specified for developing recommendations aimed at ensuring the electromagnetic compatibility of the RES in agreement with the services.

The structural diagram of the system for determining the level of impact of NP in the permitted frequency range of operation of the RES, shown in Fig. 3, implements the four stages listed above. Input signals are designated by numbers, and output signals are designated by numbers in square brackets.

The system includes an automated workstation (AWS), a measuring device (MD), a computing complex (CC), a radio transmitting device (RTD), a radio receiving device (RRD), and angular position measurement equipment (APME). The listed devices are part of the RES.

The system works as follows.

The 10th RPU RES input receives the NP in the form s _i (ƒ _n ,t). The 5th VK input receives information on the RES operating mode from the output [1] of the automated workplace. The inputs: 1st RPU, 2nd RPU, 3rd IU, 4th AIP receive information on the set parameters and the RES operating mode from the output [2] of the VK. The input 6th IU receives processed signals from the output [3] for analysis and operation of the alarm generation machine. The input 8th IU receives information on the angular position of the RES antenna pattern from the output [5] of the AIP. The results of measurements k _np (β _n ,ƒ _n ) for the survey are sent to the input 7th VK, where they are accumulated, the average value of the random variable and the standard deviation are estimated. comparison with The result of the assessment of the impact of the NP on the functioning of the RES in various combinations of letter frequencies is sent to input 9 of the automated workplace from the output [6] of the VK for display on the video monitor of the RES operator in the form of a frequency map. The operator selects the frequency at which the NP has the least impact on the quality of the tasks being solved by the RES. Or, in the automatic mode, the VK automatically selects the frequency least affected by the NP.

The performance test, as well as the assessment of the reliability and accuracy of the proposed technical solution, were carried out by statistical simulation modeling on a computer and natural tests. An increase in the probability of a false alarm was revealed during the operation of the RES at a frequency with neighboring RES, which resulted in a large number of false marks from targets, a violation of the EMC during the operation of the RES at individual frequencies led to a decrease in the signal-to-noise ratio and a decrease in the probability of correct detection at ranges greater than 29.3 km, which is confirmed by the facts of tracking failure of two of the four tracked targets. The violation of the EMC led to a decrease in the maximum detection range by 38%, which is 18% more than the permissible value when exposed to interference with a power density of an equivalent source of up to 3 kW/MHz from an equivalent setting range of 200 km.

LITERATURE

1. Patent 2686582 C1 Russian Federation, IPC G01R 29/08 (2019.02). Method for assessing the effectiveness of radio electronic means in conditions of unintentional interference and a system for its implementation / Mikheev V.A., Vasiliev A.V., Teterukov A.G., Kulik I.V., Tupchenko I.N.; applicant and patent holder JSC Radio Engineering Concern Vega.

2. Patent 2727343 C1 Russian Federation, IPC G01R 29/08 (2006.01) Method for assessing the effectiveness of integrated radio-electronic systems under conditions of unintentional interference and a system for its implementation / Mikheev V.A., Vasiliev A.V., Teterukov A.G., Kulik I.V., Tupchenko I.N.; applicant and patent holder JSC Radio Engineering Concern Vega.

3. Aporovich A.F. Statistical theory of electromagnetic compatibility of radio-electronic means. / Ed. V.Ya. Averianov. - Mn.: Science and Technology. 1984.

4. Feoktistov Yu.A., Matasov V.V., Baturin L.I. et al. Theory and methods for assessing the electromagnetic compatibility of radio-electronic equipment, / edited by Yu.A. Feoktistov. / - M.: Radio and Communications, 1988.

5. Sai P.A. Electromagnetic compatibility of radio-electronic means and radio control: Moscow Radio Engineering, 2015. - 395 p.

6. Posokhin N.I., Sonnikov V.G., Maksimov Yu.N. Electronic warfare: St. Petersburg, 2004. - 522 p.

7. Emelianov V.E. Evaluation of radar detection characteristics when exposed to interference from similar systems // Scientific Bulletin of Moscow State Technical University of Civil Aviation 2000 No. 24 160 p.

Claims (2)

1. A method for determining unintentional interference (UI) affecting a radio electronic means (REM) for detecting objects with airspace scanning, characterized in that after threshold processing of the received signal in the receiving device (RP), continuous analysis and calculation of the values of the unintentional interference coefficient (UIC) for each azimuthal scanning direction of the antenna pattern (AP) of the REM operating at the current letter frequency occurs, a comparison of the standard deviation of the UIC with the threshold value, followed by the formation of frequency maps showing the presence of an influence of UI on the letter frequencies of the REM, making a decision on the impact of UI on the REM and its ability to perform its intended functions, determining the probable direction to the UI source, and developing recommendations aimed at ensuring the electromagnetic compatibility of the REM. 2. A system for determining the impact of unintentional interference on a radio electronic device, implementing the method according to paragraph 1, consisting of a hardware and software complex implemented in the RES, characterized in that it contains a measuring device (MD) configured to measure the KNI for each angular position of the RES antenna, a computing complex (CC) implementing an estimate of the average value of a random variable and the standard deviation of the KNI, comparing it with a threshold value, making a decision on the impact of the NP on the RES and assessing the impact of the NP on the detection range of the RES, an automated workstation (AWS) for entering parameters, operating modes of the RES, generating frequency maps, and displaying the results of assessing the impact of the NP on the RES, and developing recommendations aimed at ensuring their EMC.