RU2442181C1 - Instrument for measuring direction-finding performance for antenna-fairing systems - Google Patents

Abstract

FIELD: radio. ^ SUBSTANCE: invention relates to radio engineering and it can be used in radio engineering testing for antenna-fairing systems. The technical result is to increase accuracy by means of eliminating errors introduced by the amplitude and phase instability of flexible microwave cable and microwave components, with simplifying a design of the measuring system for ratio between the differential signal and the total signal. This is achieved by adding to the well-known instrument for measuring direction-finding performance for antenna-fairing systems, which contain the fairing comprising swivel stand with bearing installed on the antenna, fairing and the rotation angle sensor for fairing, measurement channels and signal processing unit; connected in the formation of the options, the inputs connected to outputs of sample and hold devices, the block determining the expansion coefficients of direction-finding characteristics for the various options and choosing the optimal pack option, it's outputs are connected to the inputs of the block-making system of n-linear equations for the characteristics of the direction behavior, with microwave detectors measuring the relationship of the difference signal to the total signal directly connected to the outputs of direction-finding antenna. ^ EFFECT: improving the accuracy of measurement of direction-finding antenna system performance-fairing. ^ 1 dwg, 4 dwg

Description

The invention relates to radio engineering and can be used in radio engineering tests of antenna-fairing (A-O) systems.

A device is known for measuring direction-finding characteristics of A-O systems, comprising a rotary stand with an antenna and a cowl, a difference signal to total signal ratio meter containing microwave detectors, the output of which is the difference signal to total signal ratio [Stolbovoi VS, Kritsyn V .BUT. Device for measuring the radio characteristics of radome antenna systems. Description to patent RU 2133478 C1, 10.23.1997].

A measuring instrument for direction-finding characteristics of A-O systems is also known, comprising a rotary stand with a direction-finding antenna, a cowl and a cowl angle sensor, the output of the cowl angle sensor being connected to an angular input of the recording device, a microwave generator and a microwave switch connected in series, measuring channels , each of which contains an auxiliary antenna, the input of which is connected to the output of the microwave switch, and a sampling and storage device, a ratio meter a difference signal to the total signal containing microwave detectors, and the output of the difference signal to total signal ratio meter connected to the inputs of the sampling and storage devices, as well as a controller whose outputs are connected to the control input of the microwave switch and to the control inputs of the sampling and storage devices, a decision block systems of n-linear equations for direction-finding characteristic (where n is the number of measuring channels, n> 2), the outputs of which are connected to the inputs of the recording device and the calculation unit ornya equation of degree n-1 to DF characteristics, the inputs of which are connected to the second output of the solutions of the system of linear equations n-DF characteristics, and the output to the input of the error recording apparatus DF [Stolbovoy VS Direction finding meter for the radome antenna system. Description to patent RU 2287834 C1, 06/14/2005] - a prototype.

The disadvantages of the known devices are: firstly, the low measurement accuracy due to errors introduced by the amplitude-phase instabilities of the microwave elements included between the outputs of the direction-finding antenna and the inputs of the microwave detectors, and secondly, the technical complexity and cumbersome design of the meter of the ratio of the differential signal to the total signal due to the need to use a large number of microwave elements.

The main source of amplitude-phase instabilities are flexible microwave cables connecting the outputs of the direction-finding antenna with the inputs of the meter of the ratio of the difference signal to the total signal, since when the microwave cables are bent during pumping of the test fairing installed on the rotary device, the amplitude and phase of the transmission coefficient of each microwave vary cable. Another source of amplitude-phase instabilities are microwave elements included between the outputs of the direction-finding antenna and the inputs of the microwave detectors of the meter of the ratio of the difference signal to the total signal, since the stability of the amplitude and phase of the signals passing through them depends on the influence of the environment, supply voltages, and other factors. The presence of the aforementioned microwave elements leads to the technical complexity and cumbersome design of the meter of the ratio of the difference signal to the total signal, which results in the impossibility of its connection directly to the outputs of the direction-finding antenna, due to the inability to place the meter of the ratio of the difference signal to the total signal on the body of the direction-finding antenna. It is this factor that necessitates the use of flexible microwave cables in the known devices that connect the outputs of the direction-finding antenna with the inputs of the meter for the ratio of the difference signal to the total signal.

The aim of the invention is to increase the measurement accuracy by eliminating errors introduced by amplitude-phase instabilities of flexible microwave cables and microwave elements while simplifying the design of the meter of the ratio of the differential signal to the total signal.

This goal is achieved due to the fact that in a known measuring instrument of direction-finding characteristics of A-O systems, comprising a rotary stand with a direction-finding antenna, a cowl and a cowl angle sensor, the output of the cowl angle sensor is connected to the angular input of the recording device, connected in series Microwave generator and microwave switch, measuring channels, each of which contains an auxiliary antenna, the input of which is connected to the output of the microwave switch, and the device sampling and storage, a meter for the ratio of the difference signal to the total signal containing microwave detectors, the output of the meter for the ratio of the difference signal to the total signal connected to the inputs of the sampling and storage measuring channels, as well as a controller whose outputs are connected to the control input of the microwave switch and to the control the inputs of the sampling and storage devices, the unit for solving the system of n-linear equations for direction-finding characteristics (where n is the number of measuring channels, with n> 2), the outputs of which connected to the inputs of the recording device, and the unit for calculating the root of the equation of n-1 degree for the direction-finding characteristic, the inputs of which are connected to the second outputs of the block of the solution of the system of n-linear equations of the direction-finding characteristic, and the output to the input of the direction-finding error of the recording device, a series-connected block of formation options, the inputs of which are connected to the outputs of the sampling and storage devices, a block for determining the expansion coefficients of the direction-finding characteristic for different 's options and select the optimal variant unit which outputs are connected to inputs of the block n-making system of linear equations for the direction-finding characteristics, the microwave detector measuring the difference signal to sum signal output connected directly to the direction-finding antenna.

Figure 1 shows a block diagram of the proposed device, where

1 - direction finding antenna;

2 - fairing;

3 - rotary stand;

4 - sensor rotation angle of the fairing;

5 - meter ratio of the differential signal to the total signal;

6, 7, 8, 9, 10 — sampling and storage devices;

11 - block forming options;

12 is a block for determining the decomposition coefficients of the direction-finding characteristic for various options;

13 - block selection of the best option;

14 - block solving a system of n-linear equations for direction-finding characteristics;

15 is a block calculating the root of the equation n-1 degree for direction-finding characteristics;

16 - recording device;

17, 18, 19, 20, 21 - auxiliary antennas;

22 - microwave switch;

23 - microwave generator;

24 - the ruler.

Direction finding antenna 1 having outputs of differential signals Δ and total signal Σ, as well as a radiolucent fairing 2 are mounted on a rotary stand 3 equipped with a rotation angle sensor of the fairing 4. The outputs of the direction-finding antenna 1 are connected to microwave detectors of the meter for the ratio of the difference signal to the total signal 5. Output Δ / Σ of the meter for the ratio of the difference signal to the total signal 5 is connected to the inputs of the sampling and storage devices 6, 7, 8, 9, 10. The outputs of the sampling and storage devices 6, 7, 8, 9, 10 are connected to the inputs of the forming unit options 11. The outputs of the unit for forming options 11 are connected to the inputs of the unit for determining the decomposition coefficients of the bearing characteristic for various options 12. The outputs of the unit for determining the coefficients for the decomposition of the bearing characteristic for various options 12 are connected to the inputs of the unit for choosing the optimal option 13. The outputs of the block for choosing the optimal option 13 are connected to the inputs of the block solving the system of n-linear equations for direction finding characteristic 14, the first outputs of which are connected to the inputs of the coefficient from the direction finding characteristic of the recording device 16, and the second outputs are connected to the inputs of the root calculation block of the equation of degree n-1 for the direction finding characteristic 15. The output of the root calculation block of the n-1 degree equation for the direction finding characteristic 15 is connected to the input of the direction finding error of the recording device 16.

Auxiliary antennas 17, 18, 19, 20, 21, the number of which should be more than two, are spaced in the plane of measuring direction-finding errors by angular distances Δα _i (Fig. 1) relative to the optical axis of the direction-finding antenna within the working area of the direction-finding characteristic. The inputs of the auxiliary antennas 17, 18, 19, 20, 21 are connected to the outputs of the microwave switch 22, the input of which is connected to the output of the microwave generator 23. The outputs of the controller 24 are connected to the control input of the microwave switch 22 and to the control inputs of the sampling and storage devices 6, 7, 8, 9, 10.

The device operates as follows.

The manager 24 controls the microwave switch 22 in such a way that the output of the microwave generator 23 is alternately connected first to the auxiliary antenna 17, then 18 and so on, and at the end of the cycle, it is connected to the auxiliary antenna with serial number n. After that, the switching cycle is repeated: that is, the output of the microwave generator 23 through the microwave switch 22 is connected to the auxiliary antenna 17, then to the auxiliary antenna 18 and so on. Synchronously with connecting the auxiliary antennas 17, 18, 19, 20, 21 through the microwave switch to the output of the microwave generator 23, to the output of the differential signal ratio meter to the total signal 5, which contains information about the ratio of the difference signal to the total signal, the corresponding inputs of the sampling devices are connected in series and storage 6, 7, 8, 9, 10, controlled by the control inputs by the manager 24. As a result of such logic, switching the microwave switch 22 and connecting the inputs of the sampling and storage devices 6, 7, 8, 9, 10 at the output of the device sampling and storage 6 there is current information on the value of Δ ₁ / Σ ₁ obtained from the radiation of the first auxiliary antenna 17; at the output of the sampling and storage device 7 information about the value of Δ ₂ / Σ ₂ from the radiation of the second auxiliary antenna 18; at the output of the sampling and storage device 8 information about the value of Δ ₃ / Σ ₃ from the radiation of the third auxiliary antenna 19; at the output of the sampling and storage device 9, information about the value of Δ _i / Σ _i from the radiation of the ith auxiliary antenna and, finally, at the output of the device of sampling and storage 10, information about the value of Δn / Σ _n from the radiation of the nth auxiliary antenna.

One of the most important parameters characterizing the direction-finding characteristic of the A-O system in radar from the point of view of tracking accuracy is the direction-finding error of the A-O system, that is, the displacement of the electrical axis of the direction-finding antenna 1 relative to its optical axis, expressed in zero shift of the direction-finding characteristic, caused by the influence of fairing 2 in the A-O system compared to the case of no fairing 2.

In the proposed measuring instrument of direction-finding characteristics of A-O systems to eliminate errors introduced by amplitude-phase instabilities of microwave cables and microwave elements connected between the outputs of the microwave antenna and the inputs of the microwave detectors, the microwave detectors of the difference-to-total signal 5 meter are connected directly to the outputs of the direction-finding antenna 1 . Since with such a connection, the microwave detectors of the difference-to-total-signal ratio meter 5 respond only to the amplitude values of the detected signals without taking into account the phase relations between difference and total signals, the direction-finding characteristic characteristic of known devices and having the form of an odd function is converted to an even function. In Fig. 2, a dotted curve shows the direction-finding characteristic generated at the output of the known meter of the ratio of the difference signal to the total signal, which has the form of an odd function, and the solid curve in Fig. 2, b shows the direction-finding characteristic, formed at the output of the meter for the ratio of the difference signal to the total signal 5 when connecting microwave detectors of the differential ratio meter to the total signal 5 directly to the outputs of the direction-finding antenna 1, which is used in the present invention .

As can be seen from figure 2, b, when connecting microwave detectors directly to the output of the direction-finding antenna 1, information about the sign of the direction-finding characteristic with respect to the direction of the electrical axis of the A-O system corresponding to zero direction-finding characteristic is lost. To restore complete information about the direction-finding characteristic, including its sign and phase relations between difference and total signals, the invention additionally introduces series-connected block for forming options 11, the inputs of which are connected to the outputs of the sampling and storage devices 6, 7, 8, 9, 10 , a block for determining the expansion coefficients of the direction-finding characteristic for various options 12 and a block for selecting the best option 13, the outputs of which are connected to the inputs of the block of decisions of the system are n-linear x equations 14.

Consider the operation of the device using the example of three auxiliary antennas 18, 19, 20, two of which are spaced at angles ± Δα ₀ relative to the direction of the electrical axis of the direction finding antenna 1 in the absence of fairing 2, and the central auxiliary antenna 19 is located in the direction of the electrical axis of the direction finding antenna 1 in no fairing 2.

The purpose of the block forming options 11 is to determine possible cases of placing the direction of the electrical axis of the tested system A-O relative to the directions to the auxiliary antennas. In this case, for three auxiliary antennas 18, 19, 20, there are four possible options for placing the direction of the electric axis, the tested system A-O (Fig.3). It is assumed that the sign of the steepness of the direction-finding characteristic of the A-O system is known, in this case it is chosen positive for all measuring channels.

In the first embodiment, the direction of the electrical axis of the A-O system (Fig. 3) corresponds to direction-finding errors Δα located in the zone -∞≤Δα≤-Δα ₀ ; the second option (figure 3) corresponds to the case of placing direction-finding errors Δα in the range - Δα ₀ <Δα≤0; the third option (figure 3) corresponds to the case of the placement of direction-finding errors Δα in the range 0≤Δα <Δα ₀ ; the fourth option (Figure 3) corresponds to the case of locating direction-finding errors Δα in the range Δα ₀ ≤Δα≤∞.

In the block for determining the expansion coefficients of the direction-finding characteristic for various options 12, for the subsequent determination of the optimal variant, the decomposition coefficients of the direction-finding characteristic, presented in the form of a polynomial, are pre-computed. Moreover, for each of the options the polynomial coefficients can be determined, for example, by the least squares method. With the number of auxiliary antennas equal to n, after processing the signals received from each auxiliary antenna, it is possible to determine the coefficients of a polynomial of n-1 degree.

In particular, in the presence of three auxiliary antennas for the first embodiment (Fig. 3), the signs of the voltages P _-1 , P ₀ , P ₁ at the output of the meter of the ratio of the difference signal to the total signal 5 corresponding to the signals received from the auxiliary antennas 18, 19, 20 do not change. For the second option (figure 3), the signs of the voltages P ₀ , P ₁ at the output of the meter, the ratio of the differential signal to the total signal 5 corresponding to the signals received from the auxiliary antennas 19, 20, do not change, and the sign of the voltage P _-1 received from the auxiliary antenna 18 is reversed. For the third option (figure 3), the sign of the voltage P ₁ at the output of the meter of the ratio of the differential signal to the total signal 5, corresponding to the signal received from the auxiliary antenna 20, does not change, and the signs of the voltages P _-1 , P ₀ corresponding to the signals received from the auxiliary antennas 18, 19, are reversed. For the fourth option (figure 3), the signs of the voltages P _-1 , P ₀ , P ₁ at the output of the meter of the ratio of the difference signal to the total signal 5, corresponding to the signals received from the auxiliary antennas 18, 19, 20, are reversed.

From the signals P _-1 , P ₀ , P ₁ from three auxiliary antennas, three decomposition coefficients of the direction-finding characteristic of A-O systems can be preliminarily calculated: C _0A-O ; C _1A-O ; C _2A-O . In this case, the coefficient С _0А-О characterizes the zero offset of the direction-finding characteristic; coefficient C _1A-O characterizes the steepness of the direction-finding characteristic; the coefficient C _2A-O characterizes the distortion of the direction-finding characteristic of the second and higher order.

In the block selection of the best option 13 is an analysis of the values of the coefficient C _2A-O for various options. From the analysis of the various options in figure 3 it follows that the best option should correspond to the option in which the absolute value of the coefficient C _{2A-O is} minimal, and the direction-finding characteristic of the system A-O for the best option is best approximated to a linear relationship.

To clarify the principle of operation of the proposed device, we consider a special case corresponding to the third option (figure 3), in which the zero direction finding characteristic is in the range 0≤Δα <Δα ₀ , and the signal levels P _-1 , P ₀ , P ₁ recorded at the outputs of the corresponding sampling and storage devices are marked with the points T.A., T.V., S.S. Due to the fact that the inputs of the microwave detectors in the proposed device are connected directly to the outputs of the direction-finding antenna and the type of direction-finding characteristic corresponds to FIG. 2, b) each of the signals P _-1 , P ₀ , P ₁ has a positive value. In accordance with the processing algorithms described above, in the device for selecting the best option 13, a case will be selected in which the direction-finding characteristic passes through the points T.A ', T.V', T.C (Fig. 3), that is, it is a functional relationship, best approximating a linear, similar to direction-finding characteristic, formed in known meters. As can be seen from figure 3, the optimal option corresponds to the negative signs of the signals received from the auxiliary antennas located in the directions -Δα ₀ and 0, since the analysis of all other options, carried out in the block for selecting the optimal options 13, will show that in other cases nonlinear dependences, characterized by significantly larger absolute values of the coefficient C _2A-O in comparison with the best option.

Figure 4, as an example for the case of the three auxiliary antennas 18, 19, 20 mentioned above, shows the signal processing algorithms P _-1 , P ₀ , P ₁ implemented in the block for generating options 11, in the block for determining the decomposition coefficients of the direction-finding characteristic for various variants 12 and in the block selection of the best option 13.

Thus, the introduction of new blocks and new connections in the proposed meter of direction-finding characteristics of A-O systems, namely, the introduction of series-connected unit for forming options 11, the inputs of which are connected to the outputs of sampling and storage devices 10, a unit for determining the decomposition coefficients of direction-finding characteristics for various options 12 and the block selection of the best option 13, the outputs of which are connected to the inputs of the block solutions of the system of n-linear equations for direction-finding characteristics 14, and is also connected e microwave detectors measuring difference signal to the sum signal ratio 5 directly to the outputs DF antenna 1 makes it possible to receive in the present invention qualitatively new effect of improving the accuracy of measurements with simultaneous simplification of the construction gauge ratio of the difference signal to the sum signal 5.

Claims (1)

A direction-finding indicator of the antenna-cowl systems includes a rotary stand with a direction-finding antenna, cowl and a cowl angle sensor mounted on it, and the cowl angle sensor output is connected to the angle meter of the recording device, a microwave generator and a microwave switch are connected in series, measuring channels , each of which contains an auxiliary antenna, the input of which is connected to the output of the microwave switch, and a sampling and storage device, a ratio meter I the difference signal to the total signal containing microwave detectors, and the output of the meter of the ratio of the difference signal to the total signal is connected to the inputs of the sampling devices and storage of the measuring channels, as well as the manager, the outputs of which are connected to the control input of the microwave switch and to the control inputs of the sampling devices and storage, a unit for solving a system of n-linear equations for direction-finding characteristics (where n is the number of measuring channels, n> 2), the outputs of which are connected to the inputs of the recording the input, and the unit for calculating the root of the equation of n-1 degree for the direction-finding characteristic, the inputs of which are connected to the second outputs of the block for solving the system of n-linear equations of the direction-finding characteristic, and the output to the direction-finding error input of the recording device, characterized in that it is additionally connected with series-connected a variant formation unit, the inputs of which are connected to the outputs of the sampling and storage devices, a block for determining the expansion coefficients of the direction-finding characteristic for various variants s and a block for choosing the best option, the outputs of which are connected to the inputs of the block of solutions of the system of n-linear equations for the direction-finding characteristic, while the microwave detectors of the meter for the ratio of the difference signal to the total signal are connected directly to the outputs of the direction-finding antenna.

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