KR100785056B1 - Method for direction finding using correlation vector - Google Patents

Abstract

A direction finding method using a correlation vector is provided to find an accurate direction even when a burst error exists in a received signal by using a correlation vector. A difference between a phase difference, which is predetermined in a direction finding system, and a phase difference, which is measured during a direction finding process, are calculated, and correlation coefficients among the phase differences smaller than a threshold value is calculated(S40). A peak value of the correlation coefficients is detected(S50). A final incident angle is estimated from the peak values(S60,S70). When the number of antennas is smaller than a threshold value required for detecting the correlation coefficients, a burst error message is outputted.

Description

Direction detection method using correlation vector {METHOD FOR DIRECTION FINDING USING CORRELATION VECTOR}

1 is a flowchart illustrating a direction detection method using a correlation vector according to an embodiment of the present invention.

2 to 6 are diagrams showing an example of an antenna array for explaining a direction detection method using the correlation vector of FIG.

<Explanation of symbols for the main parts of the drawings>

1 to 5: dipole antenna 21 to 25: base line

31, 33: phase change 32, 34: signal to noise ratio

30: phase difference measurement system

The present invention relates to a direction detection method using a correlation vector. More particularly, the present invention relates to a direction detection method using a correlation vector that can normally detect a direction even when an error occurs and to detect a failed antenna. .

Direction Finding (DF) device is a core device of Electronic Support (ES) equipment. It is used to find the direction of radar, guided weapons, or communication equipment using electromagnetic waves. to be. The direction information obtained from the direction detecting apparatus is largely used for two purposes.

First, it is used as preprocessing data of signal processor to improve the efficiency of signal analysis in case of many signals. Second, it is to select the direction of arrival of transmission device used in Electronic Attack (EA) equipment. It is used as information to enable effective jamming.

Direction detection methods include rotation direction detection methods, amplitude comparison methods, phase comparison methods, and amplitude-phase comparison complex methods, and various methods are used according to the purpose, purpose, and installation structure.

Also, a communication direction finder for detecting the direction of radio waves of shortwave (HF), ultrahigh frequency (VHF), and ultrahigh frequency (UHF) according to a range of electromagnetic waves received and a radio wave of a microwave band. It can be divided into electromagnetic direction detection (Electronic DF). In the short wave (HF) band, the amplitude comparison method is generally used for phase comparison direction detection in the ultra high frequency (VHF) band and the ultra high frequency (UHF) band, and the correlation vector direction detection is a method for tactical fast direction detection among phase comparison direction detection. (Correlation Vector Direction Finding) algorithm is used.

However, in the conventional correlation vector direction detection algorithm, when a burst error occurs or an antenna fails, the direction detection using the correlation vector cannot be normally performed.

Accordingly, an object of the present invention is to provide a direction detection method using a correlation vector to improve the above problems.

Another object of the present invention is to provide a direction detection method using a correlation vector that can normally perform direction detection even when a burst error occurs.

Another object of the present invention is to provide a direction detection method using a correlation vector that can normally perform direction detection even when an antenna fails or another element on a path fails.

A direction detection method using a correlation vector between a plurality of antennas in an antenna array according to an aspect of the present invention for achieving the above objects, by calculating the difference between the phase difference preset in the direction detection system and the phase difference measured at the direction detection If exceeding a tolerance, calculating correlation coefficients between phase differences except for the phase difference exceeding the tolerance; Detecting peaks of the correlation coefficients; And estimating a final incident angle from the peak values.

According to another aspect of the present invention, a direction detection method using a correlation vector between a plurality of antennas in an antenna array includes: Calculating a difference of phase differences between the antennas to determine the number of phase differences within an allowable range; Estimating a final incident angle from the measured phase differences between the antennas when the phase differences between the antennas to be measured are all within an allowable range; Calculating correlation coefficients between phase differences within an allowable range when the number of phase differences within an allowable range is within a predetermined number range as a result of the determination; And detecting peak values of the correlation coefficients.

According to yet another aspect of the present invention, a direction detection method using a correlation vector between a plurality of antennas in an antenna array includes: measuring phase differences between the antennas at different time points; Comparing each of the measured phase differences with corresponding phase differences preset in the direction detection system to determine the number of phase differences within an allowable range; Estimating a final angle of incidence from all of the measured phase differences when all of the measured phase differences are within an allowable range as a result of the determination; Calculating correlation coefficients between phase differences within an allowable range when the number of phase differences within an allowable range is within a predetermined number range as a result of the determination; And detecting peak values of the correlation coefficients and estimating a final incident angle therefrom.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following descriptions are only examples and illustrated without any other intention, except for the purpose of helping a person having ordinary knowledge in the art to which the present invention pertains, to limit the scope of the invention It should not be used as an alternative.

1 is a flowchart illustrating a direction detection method using a correlation vector according to an embodiment of the present invention.

Referring to FIG. 1, a direction detection method using a correlation vector between a plurality of antennas in an antenna array calculates a difference between phase differences between the antennas preset in a direction detection system and phase differences between the antennas measured in the direction detection. In operation S10 (S20) of determining the number of phase differences M within an allowable range, if the phase differences between the antennas to be measured are all within the allowable range, the results are determined from the phase differences between the antennas measured. Estimating an incident angle (S60) (S70). The direction detecting method using the correlation vector may include calculating correlation coefficients between phase differences within an allowable range when the number of phase differences within an allowable range is within a predetermined number range (M = 3 or 4). (S40) and detecting the peak values of the correlation coefficients (S50). In addition, the direction detection method using the correlation vector includes estimating a final incident angle from the peak values (S60 and S70).

The direction detection method using the correlation vector may further include outputting a burst error message when the number of antennas exceeding the allowable value is less than a predetermined number for which a correlation coefficient cannot be detected (S80).

The plurality of antennas may be dipole antennas arranged in an equal interval.

The phase difference is preferably a phase difference between antennas having the longest separation distance to improve the accuracy of the direction detection.

2 to 6 are diagrams illustrating an example of an antenna array for explaining a direction detection method using the correlation vector of FIG. 1.

2 is a view showing the structure of the antenna array arranged in a uniform interval, Figure 3 is a view showing the principle of the direction detection phase difference measurement, Figures 4 to 6 is a view showing the array sequence when switching.

Reference numerals 1 to 5 denote dipole antennas, and reference numerals 21 to 25 denote baselines between dipole antennas.

In Fig. 3, D ₁₃ sin θ ₁₃ is a path difference between the dipole antenna 1 and the third dipole antenna of the incident signal, τ is a phase change with the phase difference measurement system 30, and SNR is a signal-to-noise ratio in the phase difference measurement.

In general, it is important to increase the separation distance between dipole antennas as much as possible to improve the accuracy of the direction detection. However, since the ambiguity problem occurs when the distance exceeds the proper distance, the antenna separation distance should be selected in consideration of the accuracy of the direction detection in the antenna design. That is, the antenna separation distance should be physically increased in the range where ambiguity does not occur.

Therefore, as shown in FIG. 2, it is preferable to use a long baseline rather than a short baseline in an antenna that is circularly arranged at equal intervals. In general, if one baseline is secured, sufficient direction detection accuracy is not secured. Therefore, five baselines are secured to secure five phase differences as shown in Equation 1, and then direction detection using a correlation vector is performed. .

To remove ambiguity with respect to the phase difference measured in Equation 1, cos and sin are taken in Equation 1, and Equation 2 is constructed. Divide by magnitude to calculate the correlation coefficient value.

The peak value is detected from the calculated correlation coefficient and parabolic approximation is performed.

Through this process, the incident angle is finally estimated. The parabolic approximation and the final incidence angle estimation process are used in the conventional manner.

At this time, the search interval can be adjusted to k. If the search interval is extended, the direction detection can be made faster, but the direction detection accuracy is lowered. To solve this problem, parabolic approximation is performed. In fact, parabolic approximation has the effect of greatly improving the direction detection accuracy.

As shown in FIGS. 2 to 6, in order to perform a direction detection algorithm using a general 5-channel correlation vector, a phase difference corresponding to a long baseline must be simultaneously received, but a method using switching may be used to reduce an RF cable.

Accordingly, the direction detection method using the correlation vector between the plurality of antennas in the antenna array according to the present invention includes measuring the phase differences between the antennas at different viewpoints (S10 of FIG. 1).

When the measured equation (5) is obtained by performing a dot product with the stored vector as in Equation (4) to obtain a correlation coefficient and detecting the peak value, the direction can be normally detected. It is common to configure a correction table while switching in order to use the effect of switching as a correction table. However, assuming that a stable signal appears normally, the correction table does not need to be reconfigured. This is because, in Equation 5, only the phase error follows the Gaussian distribution. This Gaussian distribution can be assumed to be when a signal is received statically.

Above, it is assumed that the signal comes in statically during switching. However, although stochasticly low, there may be a case where a burst error is introduced, and a case in which the phase difference is more than expected due to a failure of the antenna may occur.

Ξ _Threshold by performing the algorithm of Equations 6 to 10 Assuming that the number of equations present in M is followed by the same method as in FIG. 1, when M = 5, no burst error occurs, and thus the final incident angle can be estimated through parabolic approximation as in the prior art. .

If M = 3 or M = 4, the direction detection using the correlation vector is performed again with only the phase differences satisfying the above equations.

For example, if the equation 10 is not satisfied and only the equations 6 to 9 are satisfied, a burst error occurs in the second swing.

For example, if the equations 6 and 7 are not satisfied and only the equations 8 to 10 are satisfied, then the second dipole path is abnormal.

Thus, the direction detection method using the correlation vector according to the present invention enables the direction detection to be normally performed not only when the antenna fails but also when another element in the path fails.

In addition, the present invention can secure the direction detection accuracy not only at the time of developing a portable direction detection system using switching, but also when the signal is lost during the switching time.

Orientation detection method using a correlation vector according to the present invention is not limited to the above embodiment, it can be variously designed and applied within the scope without departing from the basic principles of the present invention is common knowledge in the art It will be obvious to those who have.

Φ ₁₃ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₁₃ ) = (2πD ₁₃ / λ) sinθ ₁₃ + Δ ₁₃ ⁽⁰⁾

Φ ₃₅ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₃₅ ) = (2πD ₃₅ / λ) sinθ ₃₅ + Δ ₃₅ ⁽⁰⁾

Φ ₅₂ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₅₂ ) = (2πD ₅₂ / λ) sinθ ₅₂ + Δ ₅₂ ⁽⁰⁾

Φ ₂₄ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₂₄ ) = (2πD ₂₄ / λ) sinθ ₂₄ + Δ ₂₄ ⁽⁰⁾

Φ ₄₁ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₄₁ ) = (2πD ₄₁ / λ) sinθ ₄₁ + Δ ₄₁ ⁽⁰⁾

Φ _ij = phase difference between the i-th dipole antenna and the j-th dipole antenna

Δ _ij = phase error between the i th dipole antenna and the j th dipole antenna

λ: wavelength of the incident signal

θ _ij : Incident angle with respect to the ij baseline of the incident signal

D _ij : distance between the i th dipole antenna and the j th dipole antenna

D _ij sinθ _ij : Path difference between the i th dipole antenna and the j th dipole of the incident signal

Φ _ij ^{(k), Conv} : Phase difference between the i-th dipole antenna and the j-th dipole antenna at k-th switching using conventional system

Δ _ij ^(k) : Phase error between the i-th dipole and the j-th dipole during the k-th switching

a = ( cos (Φ ₁₃ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₁₃ )), cos (Φ ₃₅ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₃₅ )), cos (Φ ₅₂ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₅₂ )), cos (Φ ₂₄ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₂₄ )), cos (Φ ₄₁ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₄₁ )), sin (Φ ₁₃ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₁₃ )), sin (Φ ₃₅ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₃₅ )), sin (Φ ₅₂ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₅₂ )), sin (Φ ₂₄ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₂₄ )), sin (Φ ₄₁ ^{(0), Conv} (mea, f _c , PA, θ ₁₃ , D ₄₁ )) ]

b _k = ( cos (Φ ₁₃ ^{(0), Conv} (stored, f _c , PA, k, D ₁₃ )), cos (Φ ₃₅ ^{(0), Conv} (stored, f _c , PA, k, D ₃₅ )), cos (Φ ₅₂ ^{(0), Conv} (stored, f _c , PA, k, D ₅₂ )), cos (Φ ₂₄ ^{(0), Conv} (stored, f _c , PA, k, D ₂₄ )), cos ( Φ ₄₁ ^{(0), Conv} (stored, f _c , PA, k, D ₄₁ )), sin (Φ ₁₃ ^{(0), Conv} (stored, f _c , PA, k, D ₁₃ )), sin (Φ ₃₅ ^{(0), Conv} (stored, f _c , PA, k, D ₃₅ )), sin (Φ ₅₂ ^{(0), Conv} (stored, f _c , PA, k, D ₅₂ )), sin (Φ ₂₄ ^{(0 ), Conv} (stored, f _c , PA, k, D ₂₄ )), sin (Φ ₄₁ ^{(0), Conv} (stored, f _c , PA, k, D ₄₁ )) ]]

cosθ _k = a · b / ｜ a ｜ b ｜

Φ ₂₄ ⁽⁰⁾ , ^SW (mea, f _c , PA, θ ₁₃ , D ₂₄ ) = 2πD ₂₄ sinθ ₂₄ / λ + Δ ₂₄ ⁽⁰⁾

Φ ₅₂ ⁽⁰⁾ , ^SW (mea, f _c , PA, θ ₁₃ , D ₅₂ ) = 2πD ₅₂ sinθ ₅₂ / λ + Δ ₅₂ ⁽⁰⁾

Φ ₁₃ ⁽¹⁾ , ^SW (mea, f _c , PA, θ ₁₃ , D ₁₃ ) = 2πD ₁₃ sinθ ₁₃ / λ + Δ ₁₃ ⁽¹⁾

Φ ₃₅ ⁽¹⁾ , ^SW (mea, f _c , PA, θ ₁₃ , D ₃₅ ) = 2πD ₃₅ sinθ ₃₅ / λ + Δ ₃₅ ⁽¹⁾

Φ ₄₁ ⁽²⁾ , ^SW (mea, f _c , PA, θ ₁₃ , D ₄₁ ) = 2πD ₄₁ sinθ ₄₁ / λ + Δ ₄₁ ⁽²⁾

Φ ₂₄ ^{(0), SW} (mea, f _c , PA, θ ₁₃ , D ₂₄ )-Φ ₂₄ ^{(0), SW} (stored, f _c , PA, θ ₁₃ , D ₂₄ ) ｜

<Ξ _Threshold

Φ ₅₂ ^{(0), SW} (mea, f _c , PA, θ ₁₃ , D ₅₂ )-Φ ₅₂ ^{(0), SW} (stored, f _c , PA, θ ₁₃ , D ₅₂ ) ｜

<Ξ _Threshold

Φ ₁₃ ^{(1), SW} (mea, f _c , PA, θ ₁₃ , D ₁₃ )-Φ ₁₃ ^{(1), SW} (stored, f _c , PA, θ ₁₃ , D ₁₃ ) ｜

<Ξ _Threshold

Φ ₃₅ ^{(1), SW} (mea, f _c , PA, θ ₁₃ , D ₃₅ )-Φ ₃₅ ^{(1), SW} (stored, f _c , PA, θ ₁₃ , D ₃₅ ) ｜

<Ξ _Threshold

Φ ₄₁ ^{(2), SW} (mea, f _c , PA, θ ₁₃ , D ₄₁ )-Φ ₄₁ ^{(2), SW} (stored, f _c , PA, θ ₁₃ , D ₄₁ ) ｜

<Ξ _Threshold

Accordingly, the present invention provides a direction detection method using a correlation vector, so that even if a failed antenna occurs among the array antennas, the direction detection can be normally performed, and even if a burst error occurs, the direction detection can be normally performed. .

In addition, the present invention has the effect of ensuring the direction detection accuracy even when the signal is lost during the switching time.

Claims (16)

In the direction detection method using a correlation vector between a plurality of antennas in an antenna array: Calculating a correlation between a phase difference preset in the direction detection system and a phase difference measured at the time of direction detection and calculating correlation coefficients between phase differences except for phase differences exceeding the allowable value; Detecting peaks of the correlation coefficients; And Estimating a final angle of incidence from the peak values. The method of claim 1, And outputting a burst error message if the number of antennas exceeding the allowable value is less than a predetermined number that cannot detect a correlation coefficient. The method of claim 2, And the plurality of antennas are dipole antennas arranged in an equal interval. The method of claim 3, And the phase difference is a phase difference between antennas having the longest separation distance. In the direction detection method using a correlation vector between a plurality of antennas in an antenna array: Determining a number of phase differences within an allowable range by calculating a difference between phase differences between the antennas preset in the direction detection system and phase differences between the antennas measured at the direction detection; Estimating a final incidence angle from the phase differences between the antennas to be measured when the phase differences between the antennas to be measured are all within an allowable range; Calculating correlation coefficients between phase differences within an allowable range when the number of phase differences within an allowable range is within a predetermined number range as a result of the determination; And Detecting the peak values of the correlation coefficients. The method of claim 5, And a plurality of antennas are dipole antennas. The method of claim 6, And a plurality of antennas in the antenna array are circularly spaced at equal intervals. The method of claim 7, wherein And the number of antennas is five. The method of claim 8, The number of direction detection method using a correlation vector, characterized in that 3 to 4 in the allowable range. The method of claim 9, And outputting a burst error message if the number within the allowable range is less than three. In the direction detection method using a correlation vector between a plurality of antennas in an antenna array: Measuring phase differences between the antennas at different viewpoints; Comparing each of the measured phase differences with corresponding phase differences preset in the direction detection system to determine the number of phase differences within an allowable range; Estimating a final angle of incidence from all of the measured phase differences when all of the measured phase differences are within an allowable range as a result of the determination; Calculating correlation coefficients between phase differences within an allowable range when the number of phase differences within an allowable range is within a predetermined number range as a result of the determination; And Detecting peak values of the correlation coefficients and estimating a final angle of incidence therefrom. The method of claim 11, And a plurality of antennas are dipole antennas. The method of claim 12, And a plurality of antennas in the antenna array are circularly spaced at equal intervals. The method of claim 13, And the number of antennas is five. The method of claim 14, The number of direction detection method using a correlation vector, characterized in that 3 to 4 in the allowable range. The method of claim 15, And outputting a burst error message if the number within the allowable range is less than three.

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