JP4679075B2 - Radio wave arrival angle estimation device - Google Patents

Description

  The present invention relates to a radio wave arrival angle estimation device that estimates a radio wave arrival angle based on a phase difference between radio waves received by each antenna element of an array antenna, and in particular, a two-dimensional arrival angle using a one-dimensional arrival angle estimation algorithm. The present invention relates to a radio wave arrival angle estimation device that can reduce the cost by simplifying the circuit configuration while maintaining substantially the same performance as the case where the estimation algorithm is used.

As shown in FIG. 14, the conventional radio wave arrival angle estimation apparatus is configured to perform frequency conversion in which reception signals received by a plurality of antenna elements 1 (for example, 8 × 8 = 64 elements) arranged in a matrix are connected to each antenna element 1. After the radio frequency signal (RF signal) of the radio signal is converted to an intermediate frequency (IF band) by the unit 2, phase detection is performed, quadrature detection is performed on the baseband signal of the I / Q channel, and this detection signal is A / D converted. 3 is converted into a digital signal, and the two-dimensional arrival angle estimation unit 4 uses the digital signal to calculate a two-dimensional arrival angle based on an arrival angle designation method such as the MUSIC method using a two-dimensional arrival angle estimation algorithm. Is estimated (for example, see Patent Document 1).
JP 2000-241521 A

  However, such a conventional radio wave arrival angle estimation apparatus requires a signal processing circuit system having the frequency converter 2 and the A / D converter 3 corresponding to the number of antenna elements (64 elements in FIG. 14). It becomes. In particular, in order to obtain a high angular resolution, it is necessary to increase the number of antenna elements. As a result, the number of signal processing circuits also increases, increasing the number of circuits, increasing costs, and deteriorating the failure rate. There is a fear.

  Further, since the frequency converter 2 is an analog circuit, it is difficult to make the electrical characteristics between the circuits uniform, and it is more difficult to suppress variations in characteristics between the circuits, particularly when the number of circuits is large. . Therefore, there is a possibility that the arrival angle estimation accuracy of the radio wave is deteriorated. In order to cope with this, a high-performance circuit is required, which also causes an increase in cost.

  Furthermore, for example, when estimating the direction of arrival of radio waves by applying the MUSIC or ESPRIT algorithm called the ultra-high resolution method, generally, operations such as eigenvalue decomposition are required, which slows down digital signal processing. In the case of extension to dimension processing, the number of operations increases, so that the digital signal processing becomes slower. For this reason, a high-speed DSP (Digital Signal Processor) and a large-capacity memory are required, which also increases the cost.

  Therefore, the present invention has been made paying attention to the above-mentioned problems, and the circuit configuration is simplified while maintaining substantially the same performance as the case of using the two-dimensional arrival angle estimation algorithm using the one-dimensional arrival angle estimation algorithm. It is an object of the present invention to provide a radio wave arrival angle estimation apparatus that enables cost reduction.

To this end, the invention of claim 1 is directed to an array antenna having at least one array of antenna element arrays in a direction crossing each other, and a radio wave including terminal identification information of a transmitting terminal received by each antenna element of the array antenna. A waveform data acquisition circuit that acquires waveform data of a baseband signal that has been subjected to frequency conversion and A / D conversion, and a phase difference between adjacent antenna elements based on the waveform data, and based on the phase difference A one-dimensional arrival angle estimation unit that calculates horizontal and vertical arrival angles of the radio wave, respectively, and a two-dimensional radio wave based on the horizontal and vertical arrival angles corresponding to the same terminal identification information included in the radio wave a received signal correlator to estimate the arrival angle, a radio wave arrival angle estimating apparatus provided with the array antenna, to perpendicular to the horizontal and vertical directions Two antenna element arrays and two antenna element arrays orthogonal to the left and right diagonal directions are configured, and the waveform data acquisition circuit is configured to receive the radio waves received by the horizontal and left diagonal antenna element arrays, respectively. A first waveform data acquisition circuit that acquires each horizontal waveform data in a time-sharing manner, and each vertical waveform data of radio waves received by the antenna element array in the vertical direction and the diagonally right direction is acquired in a time-division manner. A second waveform data acquisition circuit, wherein the one-dimensional arrival angle estimation unit corresponds to the first and second waveform data acquisition circuits, respectively. And a fourth one-dimensional angle-of-arrival estimator for recording one horizontal waveform data group among the two horizontal waveform data groups acquired by the first waveform data acquisition circuit. The one horizontal waveform data group is read from the memory and input to the first one-dimensional arrival angle estimation unit, and at the same time, the output of the first waveform data acquisition circuit is switched to switch the two horizontal waveform data The other horizontal direction waveform data group is input to the second one-dimensional arrival angle estimation unit, and the first and second one-dimensional arrival angle estimation units in the horizontal direction under the same coordinate system. While estimating the angle of arrival, the one vertical waveform from the second memory that records one vertical waveform data group of the two vertical waveform data groups acquired by the second waveform data acquisition circuit. A data group is read out and input to the third one-dimensional angle-of-arrival estimator, and at the same time, the output of the second waveform data acquisition circuit is switched to switch the other vertical waveform data out of the two vertical waveform data groups. group Are input to the fourth one-dimensional arrival angle estimation unit, and the third and fourth one-dimensional arrival angle estimation units estimate the vertical arrival angle under the same coordinate system.

With such a configuration, the terminal identification information of the transmitting terminal by each antenna element of the array antenna composed of two antenna element arrays orthogonal to the vertical and horizontal directions and two antenna element arrays orthogonal to the left and right diagonal directions The horizontal waveform data of the radio waves received by the antenna elements array in the horizontal direction and the diagonally left direction are time-divided and acquired by the first waveform data acquisition circuit, and the first waveform is acquired. Of the two horizontal waveform data groups acquired by the data acquisition circuit, one horizontal waveform data group is read from the first memory that records one horizontal waveform data group, and the first one-dimensional angle-of-arrival estimation is performed. At the same time, the output of the first waveform data acquisition circuit is switched at the same time, and the other one of the two horizontal waveform data groups is the second one-dimensional arrival. Input to the estimation unit, the first and second one-dimensional arrival angle estimation units estimate the arrival angle in the horizontal direction under the same coordinate system, and received by the antenna elements array in the vertical direction and the diagonally right direction, respectively. Each vertical waveform data of radio waves is time-divisionally acquired by the second waveform data acquisition circuit, and one of the two vertical waveform data groups acquired by the second waveform data acquisition circuit One vertical direction waveform data group is read from the second memory for recording the group and input to the third one-dimensional arrival angle estimation unit, and at the same time, the output of the second waveform data acquisition circuit is switched to switch the two vertical waveform data groups. Of the direction waveform data group, the other vertical direction waveform data group is input to the fourth one-dimensional arrival angle estimation unit, and the third and fourth one-dimensional arrival angle estimation units are vertically perpendicular to each other under the same coordinate system. Estimate direction of arrival angle Estimates the two-dimensional angle of arrival of radio waves based on the horizontal and vertical directions of arrival angle corresponding to the same terminal identification information included in the radio wave reception signal correlator.

  Further, the reception signal correlator specifically receives radio waves by matching the directivity of the array antenna to the horizontal arrival angle estimated by the one-dimensional arrival angle estimation unit as in claim 2, While extracting the terminal identification information contained in the received radio wave and associating it with the horizontal arrival angle, the radio wave is received by matching the directivity of the array antenna to the vertical arrival angle estimated by the one-dimensional arrival angle estimation unit. , Extracting terminal identification information included in the received radio wave and associating it with the vertical arrival angle, and using the horizontal direction and the vertical arrival angle associated with the same terminal identification information as horizontal and vertical components, respectively. May be configured to estimate the arrival direction of the radio wave including the terminal identification information.

According to a third aspect of the present invention, the waveform data acquisition circuit has the same number of signal processing circuits for acquiring waveform data of a baseband signal as the number of antenna elements in the antenna element array. The waveform data groups in the horizontal direction and the vertical direction are acquired by time-sharing.

According to the radio wave arrival angle estimation device of the present invention, the baseband is obtained by converting the frequency of the received radio wave at a higher frequency than the conventional radio wave arrival angle estimation device using the two-dimensional arrival angle algorithm having substantially the same arrival angle estimation performance. The number of analog circuits for acquiring signals can be reduced. Therefore, it is possible to improve the accuracy of estimation of the arrival angle of radio waves by suppressing variation in characteristics between analog circuits. Further, the circuit configuration is simplified and the cost of the apparatus can be reduced. Furthermore, since the array antenna is composed of two sets of two antenna element arrays orthogonal to the vertical and horizontal directions and two antenna element arrays orthogonal to the left and right diagonal directions, for example, in a multipath reception environment, either Even if the combination of one antenna element array (for example, the antenna element array orthogonal to the vertical and horizontal directions) is difficult to receive due to fading, the other antenna element array combination (for example, an antenna orthogonal to the direction diagonally) It can be received by a set of element arrays), and there are less restrictions on the reception environment. Even when four sets of antenna element arrays are used, an increase in the number of signal processing circuits can be suppressed.

  In addition, the reception signal correlator estimates the direction in which the horizontal and vertical arrival angles associated with the same terminal identification information are the horizontal and vertical components, respectively, as the arrival direction of the radio wave including the terminal identification information. For example, the two-dimensional arrival angle can be estimated based on the one-dimensional arrival angle. Therefore, the number of operations is reduced and digital signal processing can be performed at high speed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the same elements as those in FIG. 14 are denoted by the same reference numerals.
FIG. 1 shows a block diagram of a first embodiment of a radio wave arrival angle estimating apparatus according to the present invention.
In FIG. 1, the radio wave arrival angle estimation apparatus according to the first embodiment estimates the radio wave arrival angle based on the phase difference of radio waves received by each antenna element of an array antenna in which a plurality of antenna elements are arranged. And includes an array antenna 5, waveform data acquisition circuits 6a and 6b, one-dimensional arrival angle estimation units 7a and 7b, and a received signal correlator 8.

  In order to perform frame synchronization and clock synchronization in digital wireless communication, the array antenna 5 adds, for example, identification information (terminal ID information) of a transmission terminal after a known preamble inserted at the beginning of a transmission frame. It receives radio waves that are repeatedly transmitted, and has two antenna element arrays in a single row orthogonal to the vertical and horizontal directions. Here, in FIG. 1, the horizontal array of antenna element arrays is a horizontal antenna 5a for detecting the arrival angle of radio waves in the horizontal direction (azimuth angle), and the vertical array of antenna element arrays is in the vertical direction (elevation angle). This is a vertical direction antenna 5b for detecting the arrival angle of the radio wave. FIG. 1 shows a configuration example in which a total of 15 antenna elements 1 are arranged corresponding to the two-dimensional array antenna of FIG.

  The waveform data acquisition circuits 6a and 6b are first and second waveform acquisition circuits that perform signal processing on radio waves received by the antenna elements 1 to acquire waveform data of baseband signals, respectively. The frequency signal is converted to the IF band and then phase-detected, and the signal is orthogonally detected to the baseband signal of the I / Q channel, and the analog signal input from the frequency converter 2 is converted into a digital signal. The same number of signal processing circuits having A / D converters 3 are provided corresponding to the respective antenna elements 1. For example, in FIG. 1, a waveform data acquisition circuit 6a that acquires horizontal waveform data includes eight signal processing circuits corresponding to the antenna element 1 of the horizontal antenna 5a, and generates vertical waveform data. The waveform data acquisition circuit 6b to be acquired includes seven signal processing circuits corresponding to the antenna elements 1 of the vertical antenna 5b.

Further, the one-dimensional angle-of-arrival estimation units 7a and 7b obtain phase differences between the adjacent antenna elements 1 from the waveform data obtained by the waveform data acquisition circuits 6a and 6b, and based on the phase differences, for example, a one-dimensional arrival angle by a MUSIC method, and calculated by using a one-dimensional AoA estimating algorithm, Ru determined horizontal angle of arrival of the radio waves and the vertical angle of arrival, respectively. Then, for example, a one-dimensional MUSIC spectrum as shown in FIGS. 2A and 2B is output as the horizontal arrival angle and the vertical arrival angle. Note that the five peaks shown in FIG. 2 indicate that radio waves transmitted from the five transmitting terminals have been received.

  The received signal correlator 8 is configured to detect the horizontal direction and the vertical direction of the radio wave including the same terminal ID information from the horizontal direction arrival angle and the vertical direction arrival angle input from the one-dimensional arrival angle estimation units 7a and 7b. Extracting the arrival angle and estimating the two-dimensional arrival angle based on the horizontal and vertical arrival angles. As shown in FIG. 3, the directivity changing unit 9, the detection unit 10, the arrival angle An ID association unit 11, a memory 12, and a control unit 13 are provided.

  Here, the directivity changing unit 9 changes the directivities of the horizontal and vertical antennas 5a and 5b based on the arrival angle information input from the control unit 13 to the above arrival angles. In addition, the detection unit 10 detects waveform data of radio waves received with the directivity of the horizontal and vertical antennas 5a and 5b set to the arrival angles, and detects terminal ID information included in the received signal. Is. Further, the arrival angle / ID association unit 11 associates the arrival angle input from the control unit 13 with the terminal ID information. The memory 12 temporarily stores the associated arrival angle and terminal ID information. Then, the control unit 13 outputs the arrival angle input from the one-dimensional arrival angle estimation units 7 a and 7 b to the directivity changing unit 9 and the arrival angle / ID association unit 11 and from the arrival angle / ID association unit 11. The two-dimensional arrival angle is estimated based on the input horizontal direction and vertical direction arrival angles of the same ID.

Next, the operation of the radio wave arrival angle estimation apparatus of the first embodiment will be described with reference to the flowchart of FIG.
First, in step 1 (indicated by S1 in FIG. 4 and the same hereinafter), radio waves are received by the horizontal and vertical antennas 5a and 5b orthogonal to each other shown in FIG.

  Next, in step 2, waveform data of the received radio baseband signal is acquired by the waveform data acquisition circuits 6a and 6b. In this case, the radio waves received by the antenna elements 1 of the horizontal antennas 5a in the horizontal row shown in FIG. 1 are input to the signal processing circuits in each system of the waveform data acquisition circuit 6a, and the vertical rows in the vertical row shown in FIG. The radio wave received by each antenna element 1 of the direction antenna 5b is input to the signal processing circuit of each system of the waveform data acquisition circuit 6b.

  In the waveform data acquisition circuits 6a and 6b, the RF signal of the radio signal received by each antenna element 1 is frequency-converted to the IF band by the frequency converter 2 and then phase-detected to obtain an I / Q channel baseband signal. Perform quadrature detection. Further, the A / D converter 3 converts the detected signal into a digital signal, thereby acquiring waveform data of the baseband signal. The waveform data acquired by the waveform data acquisition circuit 6a is input to the one-dimensional arrival angle estimation unit 7a that calculates the horizontal arrival angle of radio waves, and the waveform data acquired by the waveform data acquisition circuit 6b calculates the vertical arrival angle. To the one-dimensional angle-of-arrival estimator 7b.

In step 3, the phase difference between each said antenna element 1 which adjoins each input waveform data by the one-dimensional arrival angle estimation part 7a, 7b, respectively is calculated | required. Based on the phase difference, the one-dimensional arrival angle estimation unit 7a calculates the horizontal arrival angle of radio waves by, for example, the MUSIC method, and the one-dimensional arrival angle estimation unit 7b calculates the vertical arrival angle. 2 One-dimensional MUSIC spectra as shown in (a) and (b) are output. At this time, each peak of each one-dimensional MUSIC spectrum is defined as an arrival angle, and the number of arrival waves is derived. For example, in FIG. 2, the horizontal arrival angles are four waves of θ ₁ , θ ₂ , θ ₃ , θ ₄ , and the vertical arrival angles are four waves of φ ₁ , φ ₂ , φ ₃ , φ ₄ . It is.

  In step 4, the received signal correlator 8 estimates a two-dimensional arrival angle based on the horizontal and vertical arrival angles. Here, the two-dimensional angle-of-arrival estimation method in the reception signal correlator 8 will be described with reference to the flowcharts shown in FIGS.

First, in step 11, the horizontal arrival angle is input from the one-dimensional arrival angle estimation unit 7 a to the control unit 13. The controller 13 first outputs the arrival angle information of the horizontal arrival angle θ ₁ to the directivity changing unit 9.

In step 12, the directivity of the horizontal antenna 5a is set to the arrival angle θ ₁ based on the arrival angle information input by the directivity changing unit 9, and the radio wave reception sensitivity at the arrival angle θ ₁ is maximized. To be.

In step 13, receives radio waves in a state of setting the directivity of the horizontal antennas 5a to the arrival angle theta _1, the radio wave of the waveform data thus received input from the waveform data acquiring circuits 6a to directed changing unit 9 The signal is detected by the detection unit 10. Then, ID information (for example, ID “1”) of the transmission terminal included in the signal is extracted.

In step 14, the arrival angle / ID association unit 11 extracts the extracted ID information (ID “1”) and the arrival angle information θ ₁ corresponding to the ID information (ID “1”) input from the control unit 13. Associate.

In step 15, the ID information (ID “1”) and the corresponding arrival angle information θ ₁ are stored in the memory 12.

In step 16, the control unit 13 determines whether or not the arrival angle / ID association of all the arrival wave numbers has been completed. Here, when the determination is “NO”, the process returns to step 12 and repeatedly executes steps 12 to 16 to receive signals corresponding to the horizontal arrival angles θ ₂ , θ ₃ , and θ ₄ shown in FIG. The terminal ID information and the angle of arrival are sequentially associated and stored in the memory 12. In the first embodiment, the arrival angle theta ₂ is ID "2", the ID "3" is the angle of arrival theta _3, the arrival angle theta ₄ will be described as corresponding the ID "4" . On the other hand, if “YES” determination is made in step 16, the process proceeds to step 17 shown in FIG.

Next, as shown in FIG. 6, in step 17, the vertical direction arrival angle is input from the one-dimensional arrival angle estimation unit 7 b to the control unit 13. The controller 13 first outputs the arrival angle information of the vertical arrival angle φ ₁ to the directivity changing unit 9.

In step 18, the directivity of the vertical antenna 5b is set to the arrival angle φ ₁ based on the arrival angle information input by the directivity changing unit 9, and the radio wave reception sensitivity at the arrival angle φ ₁ is maximized. To be.

In step 19, a radio wave is received with the directivity of the vertical antenna 5b set to the arrival angle φ ₁ , and the waveform data of the received radio wave is input to the directivity changing unit 9 from the waveform data acquisition circuit 6b. The received signal is detected by the detection unit 10. Then, ID information (for example, ID “1”) of the transmission terminal included in the received signal is extracted.

In step 20, the arrival angle / ID association unit 11 extracts the extracted ID information (ID “1”) and the arrival angle information φ ₁ corresponding to the ID information (ID “1”) input from the control unit 13; Associate.

In step 21, the ID information (ID “1”) and the arrival angle information φ ₁ corresponding thereto are stored in the memory 12.

In step 22, the control unit 13 determines whether or not the arrival angle / ID association of all the arrival wave numbers has been completed. When “NO” is determined, the process returns to step 18 and steps 18 to 22 are repeatedly executed, and the received signals corresponding to the vertical arrival angles φ ₂ , φ ₃ , and φ ₄ shown in FIG. The terminal ID information and the angle of arrival are sequentially associated and stored in the memory 12. In the first embodiment, the arrival angle phi ₂ is ID "3", the ID "4" is the angle of arrival phi _3, the arrival angle phi ₄ will be described as corresponding the ID "2" . On the other hand, if YES is determined in step 22, the process proceeds to step 23.

In step 23, the horizontal arrival angle and the vertical arrival angle associated with the same ID are read from the memory 12, and the control unit 13 estimates a two-dimensional arrival angle based on both arrival angles. For example, when the horizontal arrival angle θ ₁ and the vertical arrival angle φ ₁ corresponding to the ID “1” of the transmission terminal are read from the memory 12, the transmission terminal with ID “1” as shown in FIG. The two-dimensional angle of arrival is the direction of arrow A, which is a combination of the direction vectors of both angles of arrival.

In step 24, the control unit 13 determines whether or not the derivation of the two-dimensional angle of arrival has been completed for all IDs. Here, when the determination is “NO”, the process returns to step 23 and the estimation of the two-dimensional arrival angle is continuously performed in the same manner as described above. For example, when the horizontal arrival angle θ ₂ and the vertical arrival angle φ ₄ corresponding to the ID “2” of the transmission terminal are read from the memory 12, the two-dimensional arrival angle is in the direction of arrow B in FIG. When the horizontal arrival angle θ ₃ and the vertical arrival angle φ ₂ corresponding to ID “3” are read, the horizontal arrival angle θ ₄ and the vertical arrival angle corresponding to ID “4” are read. If the phi ₃ is read, the arrow D direction.
If the determination in step 24 is “YES”, the estimation of the two-dimensional arrival angle ends.

  As described above, according to the first embodiment, radio waves are received by the horizontal antenna 5a and the vertical antenna 5b arranged orthogonal to each other, and the arrival angles in the horizontal and vertical directions are determined based on the received signals. By calculating and estimating the two-dimensional arrival angle based on the horizontal and vertical arrival angles corresponding to the same ID, the conventional radio wave arrival angle estimation device using the two-dimensional arrival angle estimation unit 4 In addition, the number of analog circuits (frequency conversion unit 2) of the waveform data acquisition circuits 6a and 6b can be reduced. Therefore, the circuit configuration is simplified and the cost of the apparatus can be reduced.

  In addition, since the one-dimensional arrival angle estimation units 7a and 7b estimate the one-dimensional arrival angles in the horizontal direction and the vertical direction, the number of computations of the phase difference between the adjacent antenna elements 1 can be increased. The angle estimation unit is eight times in the front / rear / left / right and diagonal directions with respect to one antenna element 1, whereas the one-dimensional arrival angle estimation unit 7a, 7b only needs four times in the front / rear / left / right directions, thereby improving the signal processing speed. To do.

  In the first embodiment, the horizontal and vertical antennas 5a and 5b are arranged so as to intersect each other at the ends as shown in FIG. 1, but the present invention is not limited to this. You may arrange | position so that it may cross | intersect and may arrange | position so that it may cross | intersect diagonally.

Next, a second embodiment of the radio wave arrival angle estimating apparatus according to the present invention will be described with reference to FIG. Here, the same elements as those in FIG. 1 are denoted by the same reference numerals, and different parts from the first embodiment will be described.
In FIG. 8, the radio wave arrival angle estimation apparatus of the second embodiment intersects with the horizontal and vertical antennas 5a and 5b (horizontal: 8 elements, vertical: 7 elements in FIG. 8) orthogonal to each other in an oblique direction. An array antenna 5 including left and right diagonal antennas 5c and 5d (in the figure, left diagonal; 7 elements, right diagonal; 6 elements), antenna element 1 of each antenna, and the first in the subsequent stage and second waveform data acquiring circuit 6a as waveform data acquiring circuit, 6b and the high-frequency switch (hereinafter, RF switches and wherein) for switching the connection path 14a, and 14b, and waveform data acquired by the waveform data acquiring circuit 6 a first memory 12 via path and the second one-dimensional AoA estimating input to one-dimensional AoA estimating portion 7 c of b as the first one-dimensional AoA estimating section through as a memory described later A third one-dimensional AoA estimating unit through the memory 12c of the path directly input to the one-dimensional AoA estimating unit 7d, and the waveform data acquired by the waveform data acquiring circuit 6b as a second memory which will be described later as Changeover switches 14c and 14d for switching between a route input to the one-dimensional arrival angle estimation unit 7e and a route input directly to the one-dimensional arrival angle estimation unit 7f as the fourth one-dimensional arrival angle estimation unit , and a waveform data acquisition circuit A memory 12b for recording waveform data corresponding to the horizontal direction acquired in 6a, 6b and a memory 12c for recording waveform data corresponding to the vertical direction, and waveform data corresponding to the horizontal and vertical antennas 5a, 5b and the left Waveform data corresponding to the diagonal and right diagonal antennas 5c and 5d can be acquired in a time-sharing manner. In FIG. 8, the waveform data acquisition circuit 6a includes eight signal processing circuits, and the waveform data acquisition circuit 6b includes seven signal processing circuits.

Next, the operation of the second embodiment configured as described above will be described with reference to the flowchart of FIG.
First, in step 31, radio waves are received by the horizontal and vertical antennas 5a and 5b orthogonal to each other and the left and right diagonal antennas 5c and 5d intersecting the diagonal direction shown in FIG.

  In step 32, the horizontal antenna 5a and the waveform data acquisition circuit 6a are connected by the RF switch 14a, and the horizontal and vertical antennas 5b and the waveform data acquisition circuit 6b are connected by the RF switch 14b. The waveform data of radio waves received by the antenna elements 1 of the direction antennas 5a and 5b are acquired by the waveform data acquisition circuits 6a and 6b. At this time, the data changeover switch 14c connects the waveform data acquisition circuit 6a and the memory 12b, and the data changeover switch 14d connects the waveform data acquisition circuit 6b and the memory 12c.

  In step 33, the horizontal waveform data acquired by the waveform data acquisition circuit 6a is recorded in the memory 12b, and the vertical waveform data acquired by the waveform data acquisition circuit 6b is recorded in the memory 12c.

  In step 34, the RF switches 14a and 14b and the data changeover switches 14c and 14d are switched synchronously, and the left diagonal antenna 5c and the waveform data acquisition circuit 6a, and the right diagonal antenna 5d and the waveform data acquisition circuit 6b are switched. Connect. Furthermore, the waveform data acquisition circuit 6a and the one-dimensional arrival angle estimation unit 7d, and the waveform data acquisition circuit 6b and the one-dimensional arrival angle estimation unit 7f are connected.

  In step 35, waveform data of radio waves received by the antenna elements 1 of the left and right diagonal antennas 5c and 5d are acquired by the waveform data acquisition circuits 6a and 6b.

  In step 36, the waveform data corresponding to the horizontal antenna 5a recorded in the memory 12b is input to the one-dimensional arrival angle estimation unit 7c, and the waveform data corresponding to the vertical antenna 5b recorded in the memory 12c is one-dimensional. At the same time, the waveform data corresponding to the left oblique direction antenna 5c is directly input from the waveform data acquisition circuit 6a to the one-dimensional arrival angle estimation unit 7d, and further input from the waveform data acquisition circuit 6b to the right diagonal direction. Waveform data corresponding to the antenna 5d is directly input to the one-dimensional arrival angle estimation unit 7f.

  In step 37, the phase difference between each adjacent antenna element 1 of each one-dimensional array antenna is calculated | required by each one-dimensional arrival angle estimation part 7c-7f for each input waveform data. Based on the phase difference, the one-dimensional arrival angle estimation units 7c and 7d calculate the horizontal arrival angle of radio waves by, for example, the MUSIC method, and the one-dimensional arrival angle estimation units 7e and 7f calculate the vertical arrival angle. In this case, the one-dimensional arrival angle estimation unit 7d outputs a one-dimensional MUSIC spectrum in the horizontal direction as shown in FIG. 2A, for example, converted into the same coordinate system as the one-dimensional arrival angle estimation unit 7c. . The one-dimensional arrival angle estimation unit 7f outputs a one-dimensional MUSIC spectrum in the vertical direction as shown in FIG. 2B, for example, converted into the same coordinate system as the one-dimensional arrival angle estimation unit 7e. At this time, each peak of each one-dimensional MUSIC spectrum is defined as an angle of arrival.

  In step 38, the reception signal correlator 8 extracts an arrival angle having the same ID information from the horizontal and vertical arrival angles, estimates a two-dimensional arrival angle based on the arrival angle, and determines the direction of the transmitting terminal. Identify. The estimation of the two-dimensional angle of arrival is executed according to the procedure shown in FIGS.

  As described above, according to the second embodiment, the same effects as those of the first embodiment are provided, and the left and right diagonal antennas 5c and 5d intersecting the diagonal direction are provided. Even if reception is difficult due to fading in one of the one-dimensional array antenna combinations (for example, horizontal and vertical antennas 5a and 5b) in the reception environment, the other one-dimensional array antenna combination (for example, diagonally leftward) And the right diagonal antennas 5c, 5d), and the reception environment is less restricted.

  Further, if all the four one-dimensional array antennas are used in combination, the correlation calculation can be performed more precisely, and it can be more accurately determined whether or not the signals are from the same terminal.

  Furthermore, the waveform data of the horizontal and vertical antennas 5a and 5b and the waveform data of the left and right diagonal antennas 5c and 5d are switched by the RF switches 14a and 14b and acquired by time division. Although the number of antenna elements is larger than that of the first embodiment, the circuit scale can be made substantially equal to that of the first embodiment.

  In the second embodiment, the memories 12b and 12c are shown as recording waveform data corresponding to the horizontal and vertical antennas 5a and 5b, respectively. However, the left and right diagonal antennas 5c and 5d are shown. Waveform data corresponding to may be recorded.

Next, a third embodiment of the radio wave arrival angle estimating apparatus according to the present invention will be described with reference to FIG. Here, the same elements as those in FIG. 1 are denoted by the same reference numerals, and different parts from the first embodiment will be described.
In FIG. 10, the radio wave arrival angle estimating apparatus of the third embodiment alternately acquires radio waves received by the antenna elements 1 of the horizontal antenna 5a and the vertical antenna 5b of the array antenna 5, and acquires waveform data in the subsequent stage. and RF switches 14a to be transmitted to the circuit 6, a path for transmitting the route directly dimensional AoA estimating section 7b for transmitting to the one-dimensional AoA estimating portion 7a through the Rume memory 12a to be described later to output the waveform data acquisition circuit 6 And a memory 12a for recording waveform data corresponding to the horizontal direction among the waveform data acquired by the waveform data acquisition circuit 6, and acquiring waveform data corresponding to the horizontal and vertical directions in a time division manner. I can do it. In FIG. 10, the waveform data acquisition circuit 8 includes eight signal processing circuits.

Next, the operation of the third embodiment configured as described above will be described with reference to the flowchart of FIG.
First, in step 41, radio waves are received by the horizontal and vertical antennas 5a and 5b orthogonal to each other shown in FIG.

  In step 42, the waveform data acquisition circuit 6 receives the waveform data of radio waves received by the antenna elements 1 of the horizontal direction antenna 5a in a state where the horizontal direction antenna 5a and the waveform data acquisition circuit 6 are connected by the RF switch 14a. get. At this time, the data selector switch 14c connects the waveform data acquisition circuit 6 and the memory 12a.

  In step 43, the horizontal waveform data acquired by the waveform data acquisition circuit 6 is recorded in the memory 12a.

  In step 44, the RF switch 14a and the data changeover switch 14c are switched in synchronism, and the vertical direction antenna 5b and the waveform data acquisition circuit 6 are connected. Furthermore, the waveform data acquisition circuit 6 and the one-dimensional arrival angle estimation unit 7b are connected.

  In step 45, the waveform data acquisition circuit 6 acquires the waveform data of the radio wave received by each antenna element 1 of the vertical antenna 5b.

  In step 46, the waveform data corresponding to the horizontal antenna 5a recorded in the memory 12a is input to the one-dimensional arrival angle estimation unit 7a, and the waveform data corresponding to the vertical antenna 5b is simultaneously received from the waveform data acquisition circuit 6. Directly input to the one-dimensional arrival angle estimation unit 7b.

  In step 47, a phase difference between the adjacent antenna elements 1 is obtained from the input waveform data by the one-dimensional arrival angle estimators 7a and 7b. Based on the phase difference, the one-dimensional arrival angle estimation unit 7a calculates the horizontal arrival angle of radio waves by, for example, the MUSIC method, and the one-dimensional arrival angle estimation unit 7b calculates the vertical arrival angle. In this case, the one-dimensional arrival angle estimation unit 7a outputs a one-dimensional MUSIC spectrum in the horizontal direction as shown in FIG. 2A, for example, and the one-dimensional arrival angle estimation unit 7b displays, for example, FIG. The vertical one-dimensional MUSIC spectrum shown in At this time, each peak of each one-dimensional MUSIC spectrum is defined as an angle of arrival.

  In step 48, the received signal correlator 8 extracts an arrival angle having the same ID information from the horizontal and vertical arrival angles, estimates a two-dimensional arrival angle based on the arrival angle, and determines the direction of the transmitting terminal. Identify. Also in the third embodiment, the estimation of the two-dimensional angle of arrival is executed according to the procedure shown in FIGS.

  As described above, according to the third embodiment, the same effect as that of the first embodiment is obtained, and the waveform data in the horizontal direction and the vertical direction are switched by the RF switch 14a and acquired by time division. Although the number of antenna elements is the same as in the first embodiment, the signal processing circuit including the analog circuit (frequency conversion unit 2) can be reduced to, for example, eight systems, and the circuit scale is reduced compared to the case of the first embodiment. can do.

  In the third embodiment, the memory 12a is shown as recording waveform data corresponding to the horizontal antenna 5a. However, the waveform data corresponding to the vertical antenna 5b may be recorded.

Next, a fourth embodiment of the radio wave arrival angle estimating apparatus according to the present invention will be described with reference to FIG. Here, the same elements as those in FIG. 1 are denoted by the same reference numerals, and different parts from the first embodiment will be described.
In FIG. 12, the radio wave arrival angle estimating apparatus of the fourth embodiment sequentially switches the radio waves received by each antenna element 1 from the array antenna 5 in which the antenna elements 1 are arranged in a matrix form (64 elements in FIG. 12). and RF switch 14a for transmitting the waveform data acquiring circuit 6 Te, and Rume Mori 12d to sequentially stores the waveform data of the received radio wave by the antenna elements 1 obtained by the waveform data acquiring circuit 6, the horizontal and vertical from the memory 12d one-dimensional AoA estimating portion 7 of each waveform data corresponding to the direction selectively reads computes the horizontal and vertical angle of arrival, Rume memory to later waveform data from the one-dimensional AoA estimating section 7 A data changeover switch 14c for switching between a path input to 12e and a path input to the received signal correlator 8, and a horizontal direction output from the one-dimensional arrival angle estimation unit 7 And a memory 12e for temporarily storing the corner, and can be acquired in a time-division waveform data of each antenna element 1. In FIG. 12, the waveform data acquisition circuit 6 includes one system of signal processing circuits.

Next, the operation of the fourth embodiment configured as described above will be described with reference to the flowchart of FIG.
First, in step 51, the number of the antenna element 1 is initialized.
Next, in step 52, the RF switch 14a is switched so that the n = 1st antenna element 1 and the waveform data acquisition circuit 6 are connected, and the waveform data acquisition circuit 6 sets the n = 1st antenna element 1. Get waveform data.

In step 53, the acquired waveform data is stored in the memory 12d.
In step 54, the control unit of the radio wave arrival angle estimation device (not shown) determines whether or not the antenna element number n has reached the maximum antenna element number N (for example, 64 in FIG. 12). If “NO” determination is made here, the process proceeds to step 55.

  In step 55, the n = 2nd antenna element 1 and the waveform data acquisition circuit 6 are connected by switching with the RF switch 14a. Then, returning to step 52, the waveform data of the n = 2nd antenna element 1 is acquired, and at step 53, this waveform data is stored in the memory 12d. Thereafter, similarly, steps 52 to 55 are repeatedly executed until n = N (for example, 64), and when “YES” determination is made at step 54, the process proceeds to step 56.

  In step 56, the waveform data corresponding to the antenna element array in the horizontal row is sequentially read from the memory 12d to the one-dimensional arrival angle estimation unit 7.

  In step 57, the one-dimensional arrival angle estimator 7 sequentially obtains the phase difference between adjacent antenna elements 1 for all the antenna element arrays in a horizontal row, and based on the phase difference, for example, the MUSIC method. To calculate the horizontal arrival angle of radio waves. In this case, for example, a combined output of the horizontal MUSIC spectrum of the entire antenna element array as shown in FIG.

  In step 58, the calculated horizontal arrival angle is stored in the memory 12d by switching the data selector switch 14c.

  In step 59, the waveform data corresponding to the antenna element array in the vertical column is sequentially read from the memory 12d to the one-dimensional arrival angle estimation unit 7.

  In step 60, in the same manner as in step 57, the input waveform data is sequentially obtained by the one-dimensional arrival angle estimator 7 for the phase difference between adjacent antenna elements 1 for all the antenna element arrays in a single column. Based on the phase difference, for example, the vertical arrival angle of radio waves is calculated by the MUSIC method. In this case, for example, a combined output of the vertical MUSIC spectrum of the entire antenna element array as shown in FIG.

  In step 61, the horizontal arrival angle is read from the memory 12e and the data changeover switch 14c is switched to input the vertical arrival angle calculated by the one-dimensional arrival angle estimation unit 7 to the received signal correlator 8. The input signal waveforms at the horizontal and vertical arrival angles at this time are MUSIC spectra as shown in FIG. 2, for example.

  In step 62, the reception signal correlator 8 extracts an arrival angle having the same ID information from the horizontal and vertical arrival angles, estimates a two-dimensional arrival angle based on the arrival angle, and determines the direction of the transmitting terminal. Identify. Also in the fourth embodiment, the estimation of the two-dimensional angle of arrival is executed according to the procedure shown in FIGS.

  As described above, according to the fourth embodiment, the waveform data acquisition circuit has the same effect as that of the first embodiment, and is configured by one signal processing circuit by time division by sequentially switching the outputs of the plurality of antenna elements 1. The waveform data of all the antenna elements 1 acquired is temporarily recorded in the memory 12d, the waveform data corresponding to the horizontal direction is read out, the horizontal arrival angle is calculated, and the waveform data corresponding to the vertical direction is further calculated. By reading and calculating the vertical arrival angle and estimating the two-dimensional arrival angle based on both arrival angles, the number of antenna elements is the same as that of the array antenna 5 of the conventional radio wave arrival angle estimation device. The number of signal processing circuits including the analog circuit (frequency conversion unit 2) can be reduced to one, and the circuit scale can be further reduced. As a result, errors due to variations between analog circuits are eliminated, and the arrival angle can be estimated with higher accuracy.

In the fourth embodiment, the memory 12e is shown as recording the arrival angle in the horizontal direction. However, the arrival angle in the vertical direction may be recorded.
The fourth embodiment can also be applied to the array antenna 5 of the first and second embodiments.

It is a block diagram which shows schematic structure of 1st Embodiment of the electromagnetic wave arrival angle estimation apparatus by this invention. It is a figure which shows a MUSIC spectrum, for example in the output of a one-dimensional arrival angle estimation part. It is a block diagram which shows the structure of a received signal correlator. It is a flowchart which shows operation | movement of the said 1st Embodiment. It is a flowchart which shows the first half part of the two-dimensional arrival angle estimation method in the said received signal correlator. It is a flowchart which shows the second half part of the two-dimensional arrival angle estimation method in the said received signal correlator. It is explanatory drawing which shows the method of estimating a two-dimensional arrival angle from the horizontal and vertical direction arrival angle. It is a block diagram which shows schematic structure of 2nd Embodiment of the electromagnetic wave arrival angle estimation apparatus by this invention. It is a flowchart which shows operation | movement of the said 2nd Embodiment. It is a block diagram which shows schematic structure of 3rd Embodiment of the electromagnetic wave arrival angle estimation apparatus by this invention. It is a flowchart which shows operation | movement of the said 3rd Embodiment. It is a block diagram which shows schematic structure of 4th Embodiment of the electromagnetic wave arrival angle estimation apparatus by this invention. It is a flowchart which shows operation | movement of the said 4th Embodiment. It is a block diagram which shows the structure of the conventional radio wave arrival angle estimation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Antenna element 5 ... Array antenna 6, 6a, 6b ... Waveform data acquisition circuit 7, 7a-7f ... One-dimensional arrival angle estimation part 8 ... Received signal correlator 12, 12a-12e ... Memory

Claims (3)

Array antennas each having at least one array of antenna element arrays in a direction intersecting each other;
A waveform data acquisition circuit that converts the frequency of a radio-frequency high-frequency signal including terminal identification information of a transmission terminal received by each antenna element of the array antenna and acquires waveform data of an A / D-converted baseband signal;
A one-dimensional arrival angle estimation unit that obtains a phase difference between adjacent antenna elements from the waveform data, and calculates a horizontal direction and a vertical direction arrival angle of the radio wave based on the phase difference,
A received signal correlator for estimating a two-dimensional arrival angle of the radio wave based on the horizontal and vertical arrival angles corresponding to the same terminal identification information included in the radio wave;
A radio wave arrival angle estimation device comprising:
The array antenna is composed of two sets of two antenna element arrays orthogonal to the vertical and horizontal directions and two antenna element arrays orthogonal to the left and right diagonal directions,
The waveform data acquisition circuit includes: a first waveform data acquisition circuit that acquires, in a time-division manner, horizontal waveform data of radio waves received by the antenna elements array in the horizontal direction and the diagonally left direction; and the vertical direction and the right A second waveform data acquisition circuit for time-divisionally acquiring each vertical waveform data of radio waves respectively received by the diagonal antenna element array;
The one-dimensional arrival angle estimation unit corresponds to the first and second waveform data acquisition circuits, respectively, and the first and second one-dimensional arrival angle estimation units and the third and fourth one-dimensional arrival angle estimation units, respectively. And one horizontal waveform data group from a first memory that records one horizontal waveform data group of the two horizontal waveform data groups acquired by the first waveform data acquisition circuit. Is input to the first one-dimensional angle-of-arrival estimator, and at the same time, the output of the first waveform data acquisition circuit is switched to select the other horizontal waveform data group of the two horizontal waveform data groups. The second waveform is input to the second one-dimensional arrival angle estimation unit, and the first and second one-dimensional arrival angle estimation units estimate the horizontal arrival angle under the same coordinate system. Two vertical directions acquired by the data acquisition circuit The one vertical waveform data group is read from a second memory that records one vertical waveform data group of the shape data group and is input to the third one-dimensional arrival angle estimation unit, and at the same time, The other waveform data group of the two vertical waveform data groups is input to the fourth one-dimensional angle-of-arrival estimation unit, and the third and fourth waveform data acquisition circuits are switched. In the one-dimensional arrival angle estimation unit, the vertical arrival angle is estimated under the same coordinate system.
A radio wave arrival angle estimation device.   The received signal correlator receives a radio wave by matching the directivity of the array antenna to the horizontal arrival angle estimated by the one-dimensional arrival angle estimation unit, and extracts terminal identification information included in the received radio wave. Corresponding to the horizontal arrival angle, the radio wave is received by matching the directivity of the array antenna to the vertical arrival angle estimated by the one-dimensional arrival angle estimation unit, and terminal identification information included in the received radio wave is extracted. Then, the direction in which the horizontal direction and the vertical direction arrival angle associated with the vertical direction arrival angle are respectively associated with the horizontal direction and the vertical direction arrival component is estimated as the arrival direction of the radio wave including the terminal specification information. The radio wave arrival angle estimation apparatus according to claim 1, wherein the radio wave arrival angle estimation apparatus is configured as described above. The waveform data acquisition circuit has the same number of signal processing circuits for acquiring waveform data of baseband signals as the number of antenna elements of the antenna element array, and switches the antenna element arrays to generate horizontal and vertical waveforms. The radio wave arrival angle estimation apparatus according to claim 1 or 2 , wherein the data group is acquired by time division.

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