JP2005156521A - Signal arrival direction estimation device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To directly estimate an arrival direction of a signal with high resolution. <P>SOLUTION: Two effective area antennas 12 and 14, which are rigid wave guide horn antennas having an operation band width equal to or wider than a frequency band width of a ultra-wide-band signal, are arranged and respectively connected to an input side of a wide band hybrid circuit 16 having an operation band width equal to or wider than the frequency band width of the ultra-wide-band signal. The wide band hybrid circuit 16 outputs a Σ signal 26 serving as a sum signal of a pair of antenna output signals 22 and 24, which are input from the two effective area antennas 12 and 14 to the wide band hybrid circuit 16, and a Δ signal 28 serving as a differential signal of a pair of antenna output signals 22 and 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a signal arrival direction estimation apparatus and a signal arrival direction estimation method for directly estimating the arrival direction of a wideband signal without requiring complicated signal processing, and more particularly to a specific bandwidth (bandwidth / center frequency). ) Is 0.2 or more, or suitable for estimating the direction of arrival of an ultra-wideband signal having a bandwidth of 500 MHz or more.

  In principle, the monopulse method obtains angle measurement information by processing one pulse (monopulse) at one beam position. Therefore, since it is not subject to temporal fluctuations compared to the former method, high angle measurement accuracy can be obtained. The monopulse method includes an amplitude detection method and a phase detection method, which are called an amplitude comparison monopulse and a phase comparison monopulse, respectively.

  The amplitude comparison monopulse uses two antenna beams that are partially overlapped as a set, and detects an angle error (deviation from the front direction of the antenna). When detecting angular errors for both azimuth and elevation, four antenna beams are required.

  An angular error can be detected by the sum signal (Σ) and the difference signal (Δ). The angle error voltage ε is calculated by normalizing the difference signal (Δ) with the sum signal (Σ), that is, in the form of ε = Δ / Σ. The angle error voltage is generally S-shaped, and a deviation from the front direction of the antenna can be detected. In addition, when it is going to measure an angle only with a difference signal ((DELTA)), since the signal strength changes with the magnitude | sizes or distance of a target, a correct angle cannot be measured. In order to eliminate this, a method of dividing, i.e., normalizing, a sum signal (Σ) that receives the same change as the difference signal (Δ) is used.

  Since the resolution of signal arrival direction estimation in space depends on the directivity of the receiving antenna, it is generally difficult to obtain high resolution. However, as a signal arrival direction estimation method for narrowband signals, an array antenna is used as a receiving antenna, and a high resolution comparable to that of the MUSIC (Multiple signal classification) algorithm or ESPRIT (Estimation of signal parameters via rotational invariance techniques) algorithm is used. An algorithm employing a high angular resolution such as the SAGE (Space alternating generalized expectation maximization) algorithm has been developed. Furthermore, an arrival direction estimation method for an ultra-wideband signal employing the SAGE algorithm is also currently being studied.

  Here, in the MUSIC algorithm, the eigenvector corresponding to the eigenvalue corresponding to the noise component and the direction vector corresponding to the arrival direction of the signal are orthogonal based on the eigenvalue expansion of the correlation matrix R obtained from the received signal of the array antenna. It is a direction estimation algorithm that uses properties.

  The ESPRIT algorithm uses two identical array antennas (subarrays) and estimates the direction of arrival from the phase difference between signals arriving at the two array antennas. However, the maximum likelihood estimation of parameters is based on the assumption of incoherent waves. Therefore, preprocessing such as a spatial averaging method is necessary, and the data structure is limited.

  The SAGE algorithm is a direction estimation algorithm based on maximum likelihood estimation that does not require strict conditions such as ESPRIT from the viewpoint of a data model, and can evaluate not only a plane wave but also a spherical wave by setting a coordinate system.

  In connection with this, it is conceivable to apply an array antenna and those employing these algorithms to a signal arrival direction estimation device and a signal arrival direction estimation method for estimating the arrival direction of an ultra-wideband signal. In some cases, the signal processing process becomes complicated, requiring not only an enormous amount of calculation, but also spurious that is an erroneous solution in the signal processing process is likely to occur.

  In consideration of the above facts, the present invention does not require complicated signal processing as in the above algorithm, and the monopulse pattern technology used in the narrowband radar technology is extended to the ultrawideband signal. It is an object to provide a signal arrival direction estimation apparatus and a signal arrival direction estimation method that directly estimate the arrival direction with high resolution.

The signal arrival direction estimating apparatus according to claim 1 is configured such that two aperture antennas having an operation bandwidth wider than or equal to the frequency bandwidth of the signal are arranged adjacent to each other, and the two aperture antennas are arranged. A signal arrival direction estimation device connected to each input side of a hybrid circuit having an operation bandwidth that is equal to or greater than the frequency bandwidth of the signal,
Each of the two aperture antennas is a ridged waveguide horn antenna,
The hybrid circuit outputs a sum signal and a difference signal of a pair of antenna output signals input to the hybrid circuit from two aperture antennas.

The operation of the signal arrival direction estimation apparatus according to claim 1 will be described below.
The signal direction-of-arrival estimation apparatus according to the present invention includes two aperture antennas having an operation bandwidth that is equal to or greater than the frequency bandwidth of an ultra-wideband signal, and an operation that is greater than or equal to the frequency bandwidth of an ultra-wideband signal. A monopulse antenna using a hybrid circuit having a bandwidth. Furthermore, these two aperture antennas are arranged adjacent to each other, and the two aperture antennas are connected to the input side of the hybrid circuit. Each was a ridged wave guide horn antenna.

  Then, a pair of antenna output signals are input to the hybrid circuit from the two aperture antennas, and the antenna output signal is converted by linear synthesis in this hybrid circuit and the sum signal Σ signal and the difference signal Δ signal And can be output.

  That is, this claim linearly synthesizes in-phase signals received by two aperture antennas by a hybrid circuit and converts them into a Σ signal and a Δ signal, and the two aperture antennas obtained thereby A monopulse pattern composed of a Σ pattern and a Δ pattern, which are radiation patterns, is used. The maximum of the Σ pattern is such that the value when the Δ pattern is divided by the Σ pattern and normalized is the minimum value. The direction in which the value coincides with the minimum value of the Δ pattern is estimated as the arrival direction.

  From the above, the signal arrival direction estimation device of this claim is the same as that for the conventional narrowband signal in that the monopulse pattern technology is used, but in this claim, this is extended to the ultra-wideband signal. .

The operation of the signal arrival direction estimating apparatus according to claim 2 will be described below.
The signal arrival direction estimating apparatus according to the present invention has the same effect as that of the first aspect. However, the present invention has a configuration in which two ridged waveguide horn antennas that feed power to a common reflector are used as the aperture antenna. That is, by using two ridged waveguide horn antennas that feed power to a common reflector as an aperture antenna, the direction of arrival of signals can be estimated with higher resolution.

In the signal arrival direction estimation method according to claim 3, two aperture antennas having an operation bandwidth that is equal to or larger than the frequency bandwidth of the signal are arranged adjacent to each other, and the two aperture antennas are arranged. , Connected to the input side of the hybrid circuit having an operating bandwidth that is equal to or greater than the signal frequency bandwidth,
A signal arrival direction estimation method using a signal arrival direction estimation device in which two aperture antennas are respectively ridged waveguide horn antennas,
The two aperture antennas are rotated 360 degrees with a straight line passing through the bisector of the electrical center of the two aperture antennas as the axis of rotation, and perpendicular to the plane including the maximum radiation direction of the two aperture antennas. A pair of antenna output signals are input from the planar antenna to the hybrid circuit,
Next, this hybrid circuit outputs a sum signal and a difference signal of a pair of antenna output signals.

The operation of the signal arrival direction estimation method according to claim 4 will be described below.
The signal arrival direction estimation method according to the present invention has the same effect as that of the first aspect. However, in this claim, the frequency bandwidth of the signal is divided into a plurality of bands, and in each divided band, the difference signal is divided by the sum signal at each angle along the rotation direction of the two aperture antennas. To obtain an absolute value of Δ / Σ and create a Δ / Σ pattern along the rotation direction based on the absolute value of Δ / Σ, and a curve formed by the Δ / Σ pattern in each band. In other words, the angle at which the drop of the signal coincides is estimated as the true direction of arrival of the signal.

  That is, according to the signal arrival direction estimation method according to the present claim, if there is a direction in which the drop of the curve formed by the Δ / Σ pattern in each divided band coincides, the frequency bandwidth of the signal is divided. Since the direction can be estimated as the true arrival direction of the signal, even when a reflected wave occurs in addition to the direct wave, it is possible to eliminate the spurious (wrong solution) and reliably estimate the arrival direction of the signal.

The operation of the signal arrival direction estimation method according to claim 5 will be described below.
The signal arrival direction estimation method according to the present invention has the same effect as that of the first aspect. However, in this claim, the frequency bandwidth of the signal is divided into a plurality of bands each time in such a manner that the number of divisions is sequentially increased, and the rotation directions of the two aperture antennas in each divided band The absolute value of Δ / Σ is obtained by dividing the difference signal for each angle along the sum by the sum signal, and the Δ / Σ pattern along the rotation direction is obtained based on the absolute value of Δ / Σ. Create and repeat this each time, and when the falling angle of the curve formed by the Δ / Σ pattern in each band matches, the division ends and the falling of the curve formed by the Δ / Σ pattern in each band matches The angle is estimated as the true direction of arrival of the signal.

  That is, according to the signal arrival direction estimation method according to the present claim, similarly to the fourth aspect, it is possible to eliminate the spurious (wrong solution) and reliably estimate the arrival direction of the signal.

  As described above, according to the above-described configuration of the present invention, a simple system combining two aperture antennas and a hybrid circuit can be used in the direction of arrival of an ultra-wideband signal without requiring signal processing by a complicated algorithm. A signal arrival direction estimation apparatus and a signal arrival direction estimation method capable of estimation can be provided, and in particular, two perpendicular to the plane including the maximum radiation direction of the two aperture antennas and two electrical centers of the two aperture antennas. By rotating 360 degrees with a straight line passing through the equally divided point as a rotation axis, it has an excellent effect that the arrival direction of the ultra-wideband signal can be easily estimated.

Hereinafter, an embodiment of a signal arrival direction estimation device and a signal arrival direction estimation method according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a signal arrival direction estimation apparatus 10 according to the present embodiment. As shown in FIG. 1, two systems having an operation bandwidth that is equal to or greater than the frequency bandwidth of an ultra-wideband signal. The aperture antennas 12 and 14 are arranged so as to be rotated around the central axis CL.

  The two aperture antennas 12 and 14 are ridged waveguide horn antennas having a voltage standing wave ratio of 1.5 or less within the frequency bandwidth of the signal. The central axis CL extends perpendicularly to a plane including the maximum radiation direction Z of the two aperture antennas 12 and 14, and the electric centers E1 and E2 of the two aperture antennas 12 and 14 are equal to each other. It is a straight line passing through the point to be divided.

  The two aperture antennas 12 and 14 are connected to the input side of the broadband hybrid circuit 16 which is a 180 ° hybrid circuit having an operation bandwidth that is equal to or larger than the frequency bandwidth of the ultra-wideband signal. The wideband hybrid circuit 16 converts the radiation pattern W1 of the aperture antenna 12 and the radiation pattern W2 of the aperture antenna 14 shown in FIG. 2 of the antenna output signals 22 and 24 output from the two aperture antennas 12 and 14, respectively. Are designed to be synthesized linearly.

  That is, as a result of linearly combining the antenna output signals 22 and 24, the broadband hybrid circuit 16 becomes a sum signal obtained by adding the antenna output signals 22 and 24 of the two aperture antennas 12 and 14 to each other. A Σ signal 26 and a Δ signal 28 which is a difference signal obtained by subtracting the antenna output signals 22 and 24 of the two aperture antennas 12 and 14 from each other are output from the output side.

  As described above, in this embodiment, after the pair of antenna output signals 22 and 24 are input from the two aperture antennas 12 and 14 to the broadband hybrid circuit 16, the broadband hybrid circuit 16 receives the pair of antenna output signals 22. , 24 is output as a Σ signal 26 as a sum signal of 24, and a Δ signal 28 as a difference signal.

  Further, the broadband hybrid circuit 16 is connected to the broadband receivers 18 and 19, and the broadband hybrid circuit 16 outputs the Σ signal 26 and the Δ signal 28 to the broadband receivers 18 and 19, whereby the Σ signal 26. As shown in FIG. 3, a Σ pattern P1 along the angle θ and a Δ pattern P2 along the angle θ based on the Δ signal 28 can be obtained.

  Then, the maximum value of the Σ pattern P1 shown in FIG. 3 and the minimum value of the Δ pattern P2 shown in FIG. 3 are set such that the value obtained by dividing the value of the Δ pattern P2 by the value of the Σ pattern P1 is normalized. As shown in FIG. 4, the direction in which the values match is assumed to be the arrival direction in which the signal from the broadband signal source 30 arrives, for example, with an angle θ of 0 °.

  Specifically, the two aperture antennas 12 and 14 of the signal arrival direction estimation device 10 are rotated around the central axis CL, and the data in the time domain or frequency domain is separately output as the sum signal output and the difference signal output at each angle. , And by integrating this data in the time domain or the frequency domain, the total received power at each angle is obtained, and the Σ pattern P1 and Δ pattern P2 for the ultra-wideband signal are obtained. Obtained by the broadband receivers 18 and 19.

  Based on the Σ pattern P1 and Δ pattern P2 obtained in this way, the absolute value of Δ / Σ is calculated by the computer 20 connected to the broadband receivers 18 and 19, and the Σ pattern P1 The direction in which the maximum value coincides with the minimum value of the Δ pattern P2 and becomes the minimum value in the graph shown in FIG. 3 can be estimated as the arrival direction of the signal.

  Next, in order to estimate the arrival direction of the broadband signal from the single wave source, as shown in FIG. 5, the distance L between the broadband signal source 30 serving as the single wave source and the signal arrival direction estimation device 10 is 3000 mm. An estimation result in an implementation environment in which the wave TS arrives directly from a direction in which the angle θ is −4 degrees will be described below.

  At this time, first, the two aperture antennas 12 and 14 of the signal arrival direction estimation device 10 are rotated 360 degrees around the central axis CL, and the frequency domain data is measured for each degree, and this data is integrated for the frequency. Thus, the total received power at each angle is obtained.

  The characteristic curve of the Σ pattern P1 and the characteristic curve of the Δ pattern P2 in the broadband signal obtained in the implementation environment shown in FIG. 5 are shown in the graph of FIG. In this graph, the horizontal axis indicates the angle, and the vertical axis indicates the total received power (antenna gain). In the graph of FIG. 6, the location X1 where the Σ pattern P1 becomes the maximum value and the location X2 where the Δ pattern P2 becomes the minimum coincide with each other in the direction where the angle θ is −4 degrees. From this direction, it can be estimated that an ultra-wideband signal has arrived.

  Further, the Δ signal 28 that is a difference signal for each angle is divided by the Σ signal 26 that is a sum signal to obtain an absolute value of Δ / Σ for each angle, and based on the absolute value of this Δ / Σ. .DELTA ./. SIGMA. Patterns along the rotation direction of the aperture antennas 12 and 14 are respectively created. FIG. 7 shows the .DELTA ./. SIGMA.

  In the graph of FIG. 7, since the drop portion of the characteristic curve formed by the Δ / Σ pattern occurs in a direction where the angle θ is −4 degrees, an ultra-wideband signal has arrived from the direction of −4 degrees. And can be estimated from this graph. In the graph of FIG. 7, a drop also occurs at a position where the angle θ is near +45 degrees and a position where the angle θ is near −53 degrees, but this is a spurious (wrong solution) and the correct direction of arrival. is not.

Therefore, in order to distinguish the spurious and the true arrival direction, a procedure as shown in the flowchart of FIG. 9 is adopted, and this procedure will be described below.
First, after the broadband receivers 18 and 19 of the signal arrival direction estimation apparatus 10 obtain the Σ signal 26 and the Δ signal 28 in step S1, n is set to 2 in step S2. Further, in step S3, the frequency bandwidths of the Σ signal 26 and the Δ signal 28 are equally divided into n subbands that are two bands.

  Thereafter, in step S4, the frequency is integrated in each subband, and the total received power in each subband is calculated by the computer 20, whereby the absolute value of Δ / Σ in each subband is calculated by this computer 20, respectively. Then, a Δ / Σ pattern is created based on the absolute value of Δ / Σ.

  Next, in step S5, it is determined whether or not the falling portions of the curve formed by the Δ / Σ pattern match along the rotation direction of the aperture antennas 12 and 14 of each subband. In S6, a value obtained by adding 1 to n is newly set to n, and the processes in and after step S3 are re-executed.

  Then, as a result of the number of depressions in the curve formed by the Δ / Σ pattern of each subband and the number thereof matching each other and no change in the depressions, it is determined in step S5 that the depressions match. The frequency bandwidth is divided sequentially. Thereafter, the process proceeds to step S7, and the direction in which the falling portions of the curve formed by the Δ / Σ pattern finally match is estimated as the true arrival direction of the ultra-wideband signal.

  FIG. 8 is a graph showing the Δ pattern at each frequency. Even if the frequency changes in the true arrival direction of the ultra-wideband signal, the position of the minimum value of the Δ pattern changes in the direction where the angle θ is −4 degrees. This can be confirmed from FIG. For this reason, the falling portion of each curve formed by the Δ / Σ pattern when equally divided into a plurality of subbands does not change in the true arrival direction. Therefore, it can be understood that the direction of arrival can be estimated by dividing into a plurality of subbands.

  On the other hand, FIG. 10 is a graph of a Δ / Σ pattern based on the absolute value of Δ / Σ when the frequency band of the signal is divided into two subbands, and FIG. 11 shows the frequency band of the signal in three subbands. 6 is a graph of a Δ / Σ pattern based on an absolute value of Δ / Σ when divided into two. Even when the number of divisions is increased to the three subbands shown in FIG. 11 from the division into the two subbands shown in FIG. 10, the sagging part is one place in the direction in which the angle θ is −4 degrees. There was no change in the number.

  In other words, the number of divisions when the frequency bandwidth of the signal at this time is divided into subbands is two or three. In each case, the curve drop formed by the Δ / Σ pattern of each of these subbands. Since the portions coincide with each other in the direction in which the angle θ is −4 degrees, this direction can be estimated as the true arrival direction of the ultra-wideband signal.

  Next, the arrival directions of the reflected wave HS and the direct wave TS in the implementation environment where the reflector 32 shown in FIG. 12 was installed were estimated by the same measurement method as described above. At this time, the distance L between the broadband signal source 30 and the signal arrival direction estimation device 10 is set to 3000 mm, and the wave TS arrives directly from the direction in which the angle θ is 0 degree, and the reflection from the reflection plate 32 The angle θ in the direction of arrival of the reflected wave HS was set to be +36 degrees. Further, in this implementation environment, the Σ pattern and the Δ pattern in the ultra-wideband signal can be obtained in the same manner as described above by measuring 360 degrees as described above.

  Here, in the implementation environment shown in FIG. 12, a graph of the Δ / Σ pattern based on the absolute value of Δ / Σ when the frequency band of the signal is divided into two subbands is shown in FIG. FIG. 14 shows a graph of the Δ / Σ pattern based on the absolute value of Δ / Σ when the signal frequency band is divided into three subbands in the implementation environment shown.

  Even in this implementation environment, the frequency band of the signal is increased to a plurality of frequency bands from each of the two subbands shown in FIG. 13 to the three subbands shown in FIG. When each of the bands was equally divided, the angle θ and the number of sagging portions in the curve formed by the Δ / Σ pattern of each subband did not change. For this reason, the number of sequential divisions into subbands is limited to three as shown in FIG.

  When the drop portion in the curve formed by the Δ / Σ pattern of each subband, which is each band at this time, is specifically seen, it falls in a form that coincides with the direction of the angle θ of 0 degrees and +36 degrees. . When comparing these two depressions, the depression in the 0 degree direction is larger than +36 degrees. This is because the signal intensity coming from the direction of 0 degree is strong, the drop of the Δ pattern becomes steep, and the drop of the Δ / Σ pattern becomes large. From this, the direction of 0 degree is the direct wave TS, and from the direction of +36 degree, since the optical path length is longer than the optical path length of the incoming wave from 0 degree, the signal intensity is weaker than the direct wave TS. The arrival direction of the reflected wave HS from the plate 32 can be estimated. That is, even when the reflected wave HS is generated in addition to the direct wave TS as in the present implementation environment, the arrival direction of the signal can be accurately estimated by sequentially dividing into subbands as described above.

  In addition, when dividing into two subbands shown in FIG. 13, the curve formed by the Δ / Σ pattern of each subband is depressed in the vicinity where the angle θ is −40 °. When divided into two subbands, the curve formed by the Δ / Σ pattern does not all drop in this portion, so it can be interpreted as a spurious (wrong solution). In the above embodiment, the frequency bandwidth of the signal is equally divided into subbands that are a plurality of bands, but may be simply divided into a plurality of bands instead of equal division.

  On the other hand, as a modification of the present embodiment, not only the aperture antennas 12 and 14 are ridged wave guide horn antennas, but also a parabolic antenna or the like which is a reflector common to the aperture antennas 12 and 14 is used. A structure that attaches and supplies power to the reflecting mirror may be adopted.

  In other words, as a result, the two ridged waveguide horn antennas that feed power to the common reflecting mirror are used as the aperture antennas 12 and 14, so that the arrival direction of the signal can be estimated with higher resolution. .

  Furthermore, a total of four aperture antennas having an operating bandwidth that is at least as wide as the frequency bandwidth of signals arranged in two rows horizontally and two rows vertically, and four hybrids having an operating bandwidth equivalent to this antenna If a signal arrival direction estimation device having a circuit connected in the form shown in FIG. 15 is used, it is possible to estimate the arrival direction of an ultra-wideband signal in two dimensions in the horizontal direction and the vertical direction.

It is a block diagram which shows the signal arrival direction estimation apparatus which concerns on one embodiment of this invention. It is a figure which shows the superimposition of the radiation pattern obtained by the signal arrival direction estimation apparatus which concerns on one embodiment of this invention. It is a figure which shows (SIGMA) pattern and (DELTA) pattern by the signal arrival direction estimation apparatus which concerns on one embodiment of this invention. It is a figure which shows the graph showing the characteristic curve which normalized (delta) pattern (delta) with (sigma) pattern. It is a figure which shows the implementation environment of the arrival direction estimation of the wideband signal from a single wave source. It is a figure which shows the graph showing (SIGMA) pattern and (DELTA) pattern in the implementation environment of FIG. It is a figure which shows the graph showing (DELTA) / (Sigma) pattern calculated | required from (SIGMA) pattern and (DELTA) pattern in the implementation environment of FIG. It is a figure which shows the graph showing (DELTA) pattern in each frequency. It is a flowchart showing the procedure of dividing the frequency bandwidth of a signal into subbands sequentially. FIG. 6 is a diagram illustrating a graph representing a Δ / Σ pattern obtained from a Σ pattern and a Δ pattern for a signal frequency bandwidth divided into two subbands in the implementation environment of FIG. 5. FIG. 6 is a diagram illustrating a graph representing a Δ / Σ pattern obtained from a Σ pattern and a Δ pattern for a signal frequency bandwidth divided into three subbands in the implementation environment of FIG. 5. It is a figure which shows the implementation environment of the arrival direction estimation of a reflected wave and a direct wave. FIG. 13 is a diagram showing a graph representing a Δ / Σ pattern obtained from a Σ pattern and a Δ pattern for a signal frequency bandwidth divided into two subbands in the implementation environment of FIG. 12. FIG. 13 is a diagram showing a graph representing a Δ / Σ pattern obtained from a Σ pattern and a Δ pattern for a signal frequency bandwidth divided into two subbands in the implementation environment of FIG. 12. It is a block diagram which shows the modification of the signal arrival direction estimation apparatus which concerns on one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Signal arrival direction estimation apparatus 12 Aperture antenna 14 Aperture antenna 16 Broadband hybrid circuit

Claims (5)

Two aperture antennas having an operation bandwidth that is equal to or greater than the signal frequency bandwidth are arranged adjacent to each other, and these two aperture antennas operate as wide as the signal frequency bandwidth. A signal arrival direction estimation device connected to each input side of a hybrid circuit having a bandwidth,
Each of the two aperture antennas is a ridged waveguide horn antenna,
A signal arrival direction estimation apparatus, wherein the hybrid circuit outputs a sum signal and a difference signal of a pair of antenna output signals input to the hybrid circuit from two aperture antennas.   2. The signal arrival direction estimation apparatus according to claim 1, wherein two ridged waveguide horn antennas that feed power to a common reflector are used as the aperture antenna. Two aperture antennas having an operation bandwidth that is equal to or greater than the signal frequency bandwidth are arranged adjacent to each other, and these two aperture antennas operate as wide as the signal frequency bandwidth. Connect to the input side of the hybrid circuit with bandwidth,
A signal arrival direction estimation method using a signal arrival direction estimation device in which two aperture antennas are respectively ridged waveguide horn antennas,
The two aperture antennas are rotated 360 degrees with a straight line passing through the bisector of the electrical center of the two aperture antennas as the axis of rotation, and perpendicular to the plane including the maximum radiation direction of the two aperture antennas. A pair of antenna output signals are input from the planar antenna to the hybrid circuit,
Next, the signal arrival direction estimation method, wherein the hybrid circuit outputs a sum signal and a difference signal of a pair of antenna output signals. Divide the frequency bandwidth of the signal into multiple bands,
In each divided band, the difference signal is divided by the sum signal for each angle along the rotation direction of the two aperture antennas to obtain the absolute value of Δ / Σ, and the absolute value of Δ / Σ is Based on this, create each Δ / Σ pattern along this rotation direction,
4. The signal arrival direction estimation method according to claim 3, wherein an angle at which the drop of the curve formed by the Δ / Σ pattern in each band coincides is estimated as the true arrival direction of the signal. Dividing the frequency bandwidth of the signal into multiple bands each time, increasing the number of divisions sequentially,
In each divided band, the difference signal is divided by the sum signal for each angle along the rotation direction of the two aperture antennas to obtain the absolute value of Δ / Σ, and the absolute value of Δ / Σ is Based on this, each Δ / Σ pattern along this rotation direction is created, and this is repeated each time,
When the angle at which the curve formed by the Δ / Σ pattern in each band coincides, the division ends,
4. The signal arrival direction estimation method according to claim 3, wherein an angle at which the drop of the curve formed by the Δ / Σ pattern in each band coincides is estimated as the true arrival direction of the signal.

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