Estimation device and estimation method

Abstract

To provide an estimation device and an estimation method capable of precisely estimating an azimuth angle of an arrival direction of a signal even under an environment having different antenna heights among transceivers.SOLUTION: An estimation device 1 includes: a reception device 10 having multiple antenna elements Rx_0 to Rx_N-1 for receiving a transmission signal transmitted from a transmission antenna of a transmission station as a reception signal; a signal recording device 13 for recording data of a reception signal; an array response output device 15 for outputting an array response vector based on zenith angle prior information θprior that is an assumed value of a zenith angle in an arrival direction of a transmission signal; an angle spectrum estimation section 21 for estimating an azimuth angle spectrum S(φ) of a transmission signal from data of the array response vector and a reception signal; and an arrival direction estimation section 22 for estimating an azimuth angle of each peak included in the azimuth angle spectrum S(φ) estimated by the angle spectrum estimation section 21 as an azimuth angle of an arrival direction of a transmission signal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an estimation device and an estimation method for estimating the direction of arrival of radio waves.

Background Art

[0002] Estimation of the direction of arrival of radio waves can be applied to various fields such as position estimation of wireless communication terminals, identification of illegal radio wave oscillation sources, and beam management, and high-resolution estimation methods using array antennas have been studied. As shown in FIG. 14, the conventional estimation method uses the array response when it is assumed that the zenith angle θ of the direction of arrival of the signal incident on the receiving antenna Rx of the receiving device 100 from the transmitting antenna of the transmitting station is 90 deg to estimate the azimuth angle φ of the direction of arrival.

[0003] For example, Patent Document 1 and Non-Patent Document 1 disclose an estimation method based on Multiple Signal Classification (MUSIC) using eigenvalue decomposition of the correlation matrix of received signals. Further, Non-Patent Document 2 discloses an estimation method based on compressive sensing focusing on the sparsity of the angular space.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, the fifth-generation mobile communication system has been in operation as a mobile communication system, and the corresponding wireless communication terminals are also increasing. Among them, millimeter waves with high frequencies that enable ultra-high-speed communication are also being used. Millimeter-wave radio waves are characterized by strong straight-line propagation, weakness to shielding, and large distance attenuation.

[0007] That is, since communication using millimeter waves is assumed to have a relatively narrow coverage area and a short transmission and reception distance, the transmission antenna for millimeter waves is installed at a high position to ensure visibility. For this reason, as shown in FIGS. 14 and 15, due to the difference in antenna height between the transmitter and the receiver, the actual zenith angle θ of the arrival direction of the transmission signal from the transmission antenna Tx of the transmitting station becomes an angle other than 90°.

[0008] For example, when the receiving device 100 is installed on the ground and the transmission antenna Tx of the transmitting station is installed on the rooftop of a building or the like, the zenith angle θ becomes smaller than 90°. Also, when the receiving device 100 is mounted on a drone and arranged at a higher altitude than the transmission antenna Tx, the zenith angle θ becomes larger than 90°.

[0009] However, since the conventional methods disclosed in Patent Document 1, Non-Patent Document 1, and Non-Patent Document 2 used the array response assuming that the zenith angle θ was 90 deg, there was a problem that the accuracy of arrival direction estimation deteriorated when the antenna heights between the transmitter and receiver were different.

[0010] The present invention has been made to solve such conventional problems, and an object thereof is to provide an estimation device and an estimation method capable of accurately estimating the azimuth angle of the signal arrival direction even in an environment where the antenna heights between the transmitter and receiver are different.

Means for Solving the Problems

[0011] To solve the above problems, an estimation device according to the present invention includes a receiving device (10) having a plurality of antenna elements (Rx_0 to Rx_N-1) that receive a transmission signal transmitted from a transmission antenna of a transmission station as a reception signal, a signal recording device (13) that records data of the reception signal, an array response output device (15) that outputs an array response vector based on zenith angle prior information that is an assumed value of the zenith angle of the arrival direction of the transmission signal, an angle spectrum estimation unit (21) that estimates the azimuth angle spectrum of the transmission signal from the array response vector and the data of the reception signal, and an arrival direction estimation unit (22) that estimates the azimuth angle of each peak included in the azimuth angle spectrum estimated by the angle spectrum estimation unit as the azimuth angle of the arrival direction of the transmission signal.

[0012] With this configuration, the estimation device according to the present invention can accurately estimate the azimuth angle of the arrival direction of the transmission signal even in an environment where the antenna heights between the transmitter and receiver are different, that is, even when the zenith angle of the arrival direction of the transmission signal is an angle other than 90 deg.

[0013] Further, the estimation device according to the present invention may further include an elevation angle measurement device (40) that measures the elevation angle of the transmission antenna as seen from the center position of the plurality of antenna elements, and the zenith angle prior information may be a value of the elevation angle measured by the elevation angle measurement device.

[0014] With this configuration, even in a multipath situation where both the direct wave and the reflected wave of the transmission signal are incident on a plurality of antenna elements, the estimation device according to the present invention can accurately estimate the azimuth angles of the arrival directions of the direct wave and the reflected wave of the transmission signal.

[0015] Further, the estimation method according to the present invention includes a step (S3) of receiving, by a plurality of antenna elements (Rx_0 to Rx_N-1), a transmission signal transmitted from a transmission antenna of a transmission station as a reception signal, a step (S4) of recording data of the reception signal, a step (S5) of outputting an array response vector based on zenith angle prior information which is an assumed value of the zenith angle of the arrival direction of the transmission signal, an angle spectrum estimation step (S6) of estimating an azimuth angle spectrum of the transmission signal from the array response vector and the data of the reception signal, and a step (S7) of estimating, as the azimuth angle of the arrival direction of the transmission signal, the azimuth angle of each peak included in the azimuth angle spectrum estimated by the angle spectrum estimation step.

Effects of the Invention

[0016] The present invention provides an estimation device and an estimation method capable of accurately estimating the azimuth angle of the arrival direction of a signal even in an environment where the antenna heights between a transmitter and a receiver are different.

Brief Description of the Drawings

[0017]

Figure 1

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Embodiments for Carrying Out the Invention

[0018] (First Embodiment) First, embodiments of the estimation device and the estimation method according to the first embodiment of the present invention will be described with reference to the drawings.

[0019] As shown in FIG. 1, the estimation device 1 of the present embodiment includes a receiving device 10, a signal recording device 13, an operating device 14, an array response output device 15, a signal processing device 20, and a display device 30. Each device is connected to each other by wireless communication or wired communication.

[0020] The receiving device 10 includes a plurality of N antenna elements Rx_0 to Rx_N-1 that receive a transmission signal transmitted from a transmission antenna of a transmission station (not shown) as a reception signal, and a plurality of N reception units 11_0 to 11_N-1 that are the same number as the plurality of N antenna elements Rx_0 to Rx_N-1. Hereinafter, the plurality of N antenna elements Rx_0 to Rx_N-1 may also be collectively described simply as "reception antenna Rx".

[0021] Each of the antenna elements Rx_0 to Rx_N-1 is, for example, a planar antenna such as a microstrip antenna, and constitutes, for example, a Uniform Circular Array (UCA) antenna. That is, when the number N of the antenna elements Rx_0 to Rx_N-1 is 4, the four antenna elements Rx_0 to Rx_3 each have directivity in the directions of 0 deg, 90 deg, 180 deg, and 270 deg in the horizontal plane.

[0022] Each of the reception units 11_0 to 11_N-1 is configured to perform reception processing such as amplification, frequency conversion, and analog-to-digital conversion on the reception signal (radio signal) received by the corresponding antenna element Rx_0 to Rx_N-1. The number of the reception units 11_0 to 11_N-1 may be less than the number of the antenna elements Rx_0 to Rx_N-1. In that case, a configuration in which the antenna elements Rx_0 to Rx_N-1 can be switched by a switch or the like and connected to each of the reception units 11_0 to 11_N-1 is sufficient.

[0023] FIGS. 2(a) and (b) are schematic diagrams showing a configuration example of the receiving device 10. In the examples of FIGS. 2(a) and (b), N = 4, and four antenna elements Rx_0 to Rx_3 are provided at a height h on four side surfaces of a quadrangular prism-shaped column 12.

[0024] As shown in Fig. 2(b), the four antenna elements Rx_0 to Rx_3 are arranged such that the center positions of adjacent antenna elements are separated from each other by 0.5λ in the horizontal direction. Here, λ is the wavelength of the transmission signal of the millimeter wave transmitted from the transmission antenna of the transmitting station.

[0025] Note that the receiving device 10 may be installed at a ground measurement point, or may be mounted on a drone or the like and arranged at a measurement point above the transmitting station.

[0026] The signal recording device 13 is a device provided with a storage for recording data of the received signal received and processed by the receiving device 10.

[0027] The operation device 14 is for receiving an operation input by the user, and is configured by, for example, a touch panel including a touch sensor for detecting a contact position by a contact operation on an input surface corresponding to the display screen of the display device 30. Alternatively, the operation device 14 may be configured to include an input device such as a keyboard or a mouse.

[0028] The operation device 14 sets the zenith angle prior information θ prior associated with the radio environment scenario selected by the operation input from the user to the subsequent array response output device 15. That is, the user can indirectly select the zenith angle prior information θ prior by selecting a radio environment scenario using the operation device 14. In the present embodiment, the zenith angle prior information θ prior is an assumed value of the zenith angle of the arrival direction of the transmission signal from the transmission antenna of the transmitting station when the center position of the arrangement of the plurality of antenna elements Rx_0 to Rx_N-1 is taken as the origin.

[0029] Examples of radio environment scenarios include Dense Urban Macro, Dense Urban Micro, Rural, Indoor Hotspot, Dense Urban Macro (Drone), Dense Urban Micro (Drone), and Rural (Drone).

[0030] Dense Urban Macro is a wireless environment scenario assuming an urban environment with a high user density and a high traffic load centered on pedestrians and vehicles. The area covered by one transmitter is relatively large, about several hundred meters in radius.

[0031] Dense Urban Micro is a wireless environment scenario assuming an urban environment with a high user density and a high traffic load centered on pedestrians and vehicles. The area covered by one transmitter is relatively small, about several tens of meters in radius.

[0032] Rural is a wireless environment scenario that covers a wider and continuous wide area to support users of pedestrians, vehicles, and high-speed vehicles.

[0033] Indoor Hotspot is a wireless environment scenario in an isolated indoor environment such as an office or a shopping mall, with a very high user density and based on stationary users and pedestrians.

[0034] The above Dense Urban Macro, Dense Urban Micro, Rural, and Indoor Hotspot are all wireless environment scenarios assuming that the receiving device 10 is installed at a ground measurement point.

[0035] Dense Urban Macro (Drone) is a wireless environment scenario assuming that in the above Dense Urban Macro, the receiving device 10 is loaded on a drone and placed at an aerial measurement point.

[0036] Dense Urban Micro (Drone) is a wireless environment scenario assuming that in the above Dense Urban Micro, the receiving device 10 is loaded on a drone and placed at an aerial measurement point.

[0037] Rural (Drone) is a wireless environment scenario assuming that in the above-mentioned Rural, the receiving device 10 is mounted on a drone and placed at a measurement point in the air.

[0038] Figure 3 shows, for each of Dense Urban Macro, Dense Urban Micro, and Indoor Hotspot in the above wireless environment scenario, the zenith angle prior information θ such that the estimation error of the arrival direction becomes small by computer simulation described later. prior For example, when the user selects Dense Urban Micro in the wireless environment scenario via the operating device 14, 70 deg is set as the zenith angle prior information θ prior for the array response output device 15 in the subsequent stage.

[0039] The array response output device 15 outputs an array response vector a (bold) prior (φ) based on the zenith angle prior information θ θprior as shown in the following equation (1). Here, φ is the azimuth angle of the arrival direction of the transmission signal when the center position of the arrangement of the plurality of antenna elements Rx_0 to Rx_N-1 is the origin. For example, the array response output device 15 has a storage for storing array response vectors determined for each value that can be a candidate for the zenith angle prior information θ prior and may call the array response vector corresponding to the zenith angle prior information θ prior selected by the operating device 14.

[0040]

Equation

[0041] Each element of the array response vector a (bold) θprior (φ) is represented by the following equation (2).

[0042]

Equation

[0043] Here, n is an integer from 0 to N - 1. G n (θ, φ) is the antenna gain [dBi] corresponding to the zenith angle θ and the azimuth angle φ, and can be obtained by previously measuring the radiation patterns of the actual antenna elements Rx_0 to Rx_N - 1. λ is the wavelength of the transmission signal. r (bold) n is the position vector of each antenna element when the center position of the arrangement of the plurality of antenna elements Rx_0 to Rx_N - 1 is taken as the origin. d (bold)(θ, φ) is, as shown in FIG. 4, the arrival direction of the transmission signal when the center position of the arrangement of the plurality of antenna elements Rx_0 to Rx_N - 1 is taken as the origin, that is, a unit vector indicating the direction determined by the zenith angle θ and the azimuth angle φ.

[0044] The position vectors r (bold) of each antenna element Rx_0 to Rx_N - 1 n is represented by the following equation (3) in the case of a UCA antenna.

[0045]

Equation

[0046] Here, R is the array radius, and is usually set such that the center positions of adjacent antenna elements are 0.5λ apart from each other in the horizontal direction.

[0047] The unit vector d (bold)(θ, φ) indicating the arrival direction of the transmission signal is represented by the following equation (4).

[0048]

Equation

[0049] The signal processing device 20 includes an angle spectrum estimation unit 21 and an arrival direction estimation unit 22. The signal processing device 20 is composed of a control device such as a computer including, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an FPGA (Field Programmable Gate Array), a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), and the like. For example, the signal processing device 20 can be configured software-wise for at least a part of the angle spectrum estimation unit 21 and the arrival direction estimation unit 22 by executing a predetermined program by the CPU or the GPU.

[0050] Note that the above program is stored in advance in the ROM or the HDD. Alternatively, the above program may be provided or distributed in a state recorded on a computer-readable recording medium such as a compact disk or a DVD in an installable format or an executable format. Alternatively, the above program may be stored in a computer connected to a network such as the Internet and provided or distributed by downloading via the network.

[0051] The angle spectrum estimation unit 21 estimates an azimuth angle spectrum including information on the azimuth angle of the arrival direction of the transmission signal from the array response vector a (bold) θprior (φ) output from the array response output device 15 and the vector data of the received signal (hereinafter also simply referred to as "received signal vector") y (bold)(t) received and processed by the receiving device 10 and recorded in the signal recording device 13.

[0052] The received signal vector y (bold)(t) is a vector having, as elements, the time waveform data y n (t) of the received signal at the antenna element Rx_n. However, n is an integer from 0 to N - 1.

[0053] [Number]

[0054] For example, the angle spectrum estimation unit 21 may estimate the azimuth angle spectrum of the transmission signal by using a known beamforming method, MUSIC method, or arrival direction estimation algorithm such as FISTA (Fast Iterative Shrinkage-Thresholding Algorithm).

[0055] Hereinafter, the estimation process of the azimuth angle spectrum when the angle spectrum estimation unit 21 uses FISTA, which is one of the compressive sensing algorithms, will be described.

[0056] As shown in FIG. 5, the angle space is divided into M small regions (bins), and the situation where the transmission signal passes through the m-th bin (corresponding to the azimuth angle φ m and is incident on each antenna element Rx_0 to Rx_N-1 is considered. Assuming that the transmission signal arrives from the direction of the zenith angle prior information θ prior , the received signal vector y (bold) (t) is given by the following equation (6).

[0057] [Number]

[0058] Here, A (bold) θprior is an array response matrix consisting of M columns, and each column is an array response vector a (bold) m corresponding to the azimuth angle φ from 0 to M-1 θprior (φ m ). x (bold) (t) is the transmission signal vector, and its element x m (t) is the time waveform data of the transmission signal arriving via the m-th bin #m. z (bold) (t) is the noise vector, and its element z0(t) is the time waveform data of the noise.

[0059] Normally, since it is considered that the transmission signal is incident only on a part of the M bins, the transmission signal vector **x**(t) is assumed to be a sparse vector with many zeros in its elements. Therefore, the angle spectrum estimation unit 21 can estimate the transmission signal vector **x**(t) by applying compressive sensing such as FISTA to the received signal vector **y**(t).

[0060] Furthermore, the angle spectrum estimation unit 21 calculates the power value of the transmission signal from the estimated transmission signal vector **x**(t) for each azimuth angle φ m to estimate the azimuth angle spectrum S(φ). FIG. 6 is a graph schematically showing the azimuth angle spectrum S(φ) estimated by the angle spectrum estimation unit 21 when the number of arrival waves of the transmission signal is two waves.

[0061] The arrival direction estimation unit 22 detects the peak included in the azimuth angle spectrum S(φ) estimated by the angle spectrum estimation unit 21, and estimates the azimuth angle of the detected peak as the azimuth angle of the arrival direction of the transmission signal.

[0062] The arrival direction estimation unit 22 estimates that the azimuth angle of the arrival direction of the transmission signal is φ m when the power value of the peak of the m-th transmission signal x m (t) is equal to or greater than a specified value. For example, in the example of FIG. 6, if the specified value is -40 dB, the arrival direction estimation unit 22 estimates 162 deg and 273 deg as the azimuth angle φ of the arrival direction of the transmission signal, and if the specified value is -30 dB, the arrival direction estimation unit 22 estimates 162 deg as the azimuth angle φ of the arrival direction of the transmission signal. This specified value can be set to an arbitrary value, for example, by an operation input to the operation device 14 by the user.

[0063] The display device 30 is composed of a display device such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube). The display device 30 displays, for example, as shown in FIG. 6, the azimuth angle spectrum S(φ) estimated by the angle spectrum estimation unit 21 and the azimuth angle φ of the peak of the azimuth angle spectrum S(φ) estimated by the arrival direction estimation unit 22 in accordance with the display control signal from the signal processing device 20.

[0064] Hereinafter, the effect of the estimation device 1 according to the present embodiment will be confirmed by computer simulation. In this computer simulation, Dense Urban Macro, Dense Urban Micro, and Indoor Hotspot described in Report ITU-R M.2412-0 are used as the radio environment scenario. Also, in this computer simulation, a carrier frequency of 28.0 GHz is assumed, and FISTA is adopted as the arrival direction estimation algorithm.

[0065] FIG. 7 is a graph showing the antenna element radiation pattern in the horizontal plane of a UCA antenna composed of four antenna elements #0 to #3 used as the receiving antenna Rx in this computer simulation. The four antenna elements #0 to #3 each have directivity in the directions of 0 deg, 90 deg, 180 deg, and 270 deg in the horizontal plane. Based on Report ITU-R M.2412-0, the maximum directivity gain of each antenna element #0 to #3 is 5 dBi, and the beam widths in both the vertical and horizontal directions are 90 deg.

[0066] FIG. 8 is a table showing the parameters used in this computer simulation. "Cell radius" represents the horizontal distance between the transmitting antenna of the transmitting station and the center positions of the four antenna elements #0 to #3. "Tx antenna height" represents the height of the transmitting antenna of the transmitting station. "Rx antenna height" represents the height of the four antenna elements #0 to #3.

[0067] Therefore, the actual zenith angle θ of the transmitting antenna as seen from the center positions of the four antenna elements #0 to #3 is 80.0 deg in Dense Urban Macro, 73.6 deg in Dense Urban Micro, and 84.3 deg in Indoor Hotspot at the cell edge.

[0068] In this computer simulation, a known received signal vector y (bold) (t) based on the transmission signal from a transmitting antenna at a known position is prepared for each of the above three radio environment scenarios. That is, this computer simulation simulates the process in which the known received signal vector y (bold) (t) is input to the signal processing device 20 of the estimation device 1 of the present embodiment, and the signal processing device 20 estimates the azimuth angle of the known arrival direction of the transmission signal.

[0069] FIG. 9 is a graph showing the root mean squared error (RMSE) between the azimuth angle estimated by the above computer simulation and the actual known azimuth angle for each radio environment scenario when the zenith angle prior information θ prior is 10 deg, 20 deg, 30 deg, 40 deg, 50 deg, 60 deg, 70 deg, 80 deg, and 90 deg. That is, FIG. 9 shows the estimation error of the azimuth angle obtained by the computer simulation. This RMSE is calculated according to the following formula (7), where T is the total number of trials of the computer simulation, φ is the actual known azimuth angle in the t-th trial, and φ^ t is the azimuth angle estimated in the t-th trial. t

[0070]

Equation

[0071] According to the graph of FIG. 9, in Dense Urban Macro / Micro, which are outdoor scenarios, the zenith angle prior information θ prior ​It can be seen that the RMSE is best when it is 70deg. On the other hand, in the Indoor Hotspot which is an indoor scenario, when the zenith angle prior information θ prior is 90deg, it can be seen that the RMSE is best. The zenith angle prior information θ prior shown in FIG. 3 already given above is the zenith angle prior information θ prior that gives the best RMSE in this computer simulation.

[0072] FIG. 10 is a graph showing, for each of the above wireless environment scenarios, the estimation error when the zenith angle prior information θ prior is 90deg among the azimuth estimation errors shown in FIG. 9 and the estimation error at the zenith angle prior information θ prior at which the RMSE shown in FIG. 3 is best. That is, the estimation error when the zenith angle prior information θ prior is 90deg corresponds to the estimation error of the conventional method using the array response vector assuming that the zenith angle of the arrival direction of the transmission signal is 90deg. On the other hand, the estimation error when the zenith angle prior information θ prior is the value shown in FIG. 3 corresponds to the estimation error of the estimation method of the present invention.

[0073] In environments such as Dense Urban Macro and Dense Urban Micro, since the difference between the height of the transmission antenna of the transmitting station and the height of the receiving antenna Rx of the receiving device 10 is relatively large with respect to the horizontal distance between the transmission antenna and the receiving antenna Rx, the zenith angle of the arrival direction of the transmission signal tends to be smaller than 90deg. From the results shown in FIG. 10, it was confirmed that the estimation accuracy of the zenith angle of the arrival direction of the transmission signal can be improved in an environment where the zenith angle of the arrival direction of the transmission signal is smaller than 90deg by the estimation device 1 of the present embodiment.

[0074] Hereinafter, an example of the processing of the estimation method using the estimation device 1 according to the present embodiment will be described with reference to the flowchart of FIG. 11. Note that descriptions overlapping with the description of the configuration of the above-described estimation device 1 will be omitted as appropriate.

[0075] First, the receiving device 10 is arranged at a measurement point on the ground or in the air (step S1).

[0076] Next, a radio environment scenario is selected by an operation input to the operation device 14 by the user (step S2).

[0077] Next, the receiving device 10 receives the transmission signal transmitted from the transmission antenna of the transmitting station as a received signal by a plurality of antenna elements Rx_0 to Rx_N-1, and performs reception processing such as amplification, frequency conversion, and analog-digital conversion on the received signal (step S3).

[0078] Next, the signal recording device 13 records the data of the received signal received by the reception processing in step S3 (step S4).

[0079] Next, the array response output device 15 outputs an array response vector a (bold) prior based on the zenith angle prior information θ θprior (φ) associated with the radio environment scenario selected in step S2 (step S5).

[0080] Next, the angle spectrum estimation unit 21 estimates the azimuth angle spectrum S(φ) of the transmission signal from the array response vector a (bold) θprior (φ) output from the array response output device 15 and the data of the received signal recorded in the signal recording device 13 (angle spectrum estimation step S6).

[0081] Next, the arrival direction estimation unit 22 estimates the azimuth angle of each peak included in the azimuth angle spectrum S(φ) estimated in the angle spectrum estimation step S6 as the azimuth angle of the arrival direction of the transmission signal (step S7).

[0082] Next, the display device 30 displays the azimuth angle spectrum S(φ) estimated in the angle spectrum estimation step S6 and the azimuth angle of the peak of the azimuth angle spectrum S(φ) estimated in step S7 (step S8).

[0083] As described above, the estimation device 1 according to the present embodiment can switch and use the zenith angle prior information θ, which is an assumed value of the zenith angle of the arrival direction of the transmission signal, according to the radio environment scenario selected by the user. prior Furthermore, the estimation device 1 according to the present embodiment uses the array response vector a (bold) prior (φ) based on the selected zenith angle prior information θ θprior to estimate the azimuth angle of the arrival direction of the transmission signal.

[0084] Thereby, the estimation device 1 according to the present embodiment can accurately estimate the azimuth angle of the arrival direction of the transmission signal even in an environment where the antenna heights between the transmitter and the receiver are different, that is, even when the zenith angle of the arrival direction of the transmission signal is an angle other than 90°.

[0085] In addition, the estimation device 1 according to the present embodiment can accurately estimate the azimuth angle of the arrival direction of the transmission signal even when the position of the transmission antenna of the transmitting station is unknown by appropriately selecting a radio environment scenario by the user.

[0086] (Second Embodiment) Subsequently, the estimation device 2 according to the second embodiment of the present invention will be described with reference to the drawings. Regarding the same configuration as that of the first embodiment, the same reference numerals are given and the description will be omitted as appropriate, and mainly the differences from the first embodiment will be described.

[0087] The estimation device 1 of the first embodiment is configured to select the zenith angle prior information θ associated with the radio environment scenario by the user selecting the radio environment scenario via the operation device 14. prior

[0088] As shown in FIG. 12, the estimation device 2 of the second embodiment includes an elevation angle measurement device 40 that sets the zenith angle prior information θ prior to the array response output device 15 instead of the operation device 14.

[0089] The elevation angle measuring device 40 is composed of, for example, a level with a laser or a finder, and measures the elevation angle of the transmission antenna of the transmitting station as seen from the center positions of the plurality of antenna elements Rx_0 to Rx_N-1, that is, the elevation angle of the transmission antenna of the transmitting station located on the line of sight from the center positions of the plurality of antenna elements Rx_0 to Rx_N-1. Further, the elevation angle measuring device 40 sets the measured elevation angle value as the zenith angle pre-information θ prior to the array response output device 15.

[0090] In the present embodiment, the array response output device 15 outputs an array response vector a (boldface) prior (φ) based on the zenith angle pre-information θ θprior set by the elevation angle measuring device 40. The subsequent processing of the estimation device 2 in the present embodiment is the same as that of the estimation device 1 in the first embodiment.

[0091] Furthermore, as shown in FIG. 13, the estimation device 2 in the present embodiment can estimate not only the direct wave (solid arrow) but also the arrival direction of the reflected wave (dashed arrow) of the transmission signal from the transmission antenna Tx of the transmitting station when the direct wave and the reflected wave of the transmission signal from the transmission antenna Tx of the transmitting station enter the reception antenna Rx. This is because it is considered that the direct wave and the reflected wave from the same transmission antenna Tx have a high correlation in the arrival direction, so the array response vector a (boldface) prior based on the same zenith angle pre-information θ θprior (φ) can be used.

[0092] As described above, the estimation device 2 according to the present embodiment uses the elevation angle value of the transmission antenna Tx measured by the elevation angle measuring device 40 as the zenith angle pre-information θ prior .

[0093] Thereby, the estimation device 2 according to the present embodiment can accurately estimate the azimuth angles of the arrival directions of the direct wave and the reflected wave of the transmission signal even in a so-called multipath situation where both the direct wave and the reflected wave of the transmission signal enter the reception antenna Rx.

Explanation of Reference Numerals

[0094] 1,2 Estimation Device 10 Receiver 11_0 to 11_N-1 Receiving Section 13 Signal Recording Device 14 Operating Device 15 Array Response Output Device 20 Signal Processing Device 21 Angle Spectrum Estimation Section 22 Direction-of-Arrival Estimation Section 30 Display Device 40 Elevation Measurement Device Tx Transmitting Antenna Rx Receiving Antenna Rx_0 to Rx_N-1 Antenna Elements

Claims

1. A receiving device (10) having a plurality of antenna elements (Rx_0 to Rx_N-1) that receive a transmission signal transmitted from a transmission antenna of a transmitting station as a reception signal, A signal recording device (13) that records data of the reception signal, An array response output device (15) that outputs an array response vector based on zenith angle prior information, which is an assumed value of the zenith angle of the arrival direction of the transmission signal, An angle spectrum estimation unit (21) that estimates the azimuth angle spectrum of the transmission signal from the array response vector and the data of the reception signal, An arrival direction estimation unit (22) that estimates the azimuth angle of each peak included in the azimuth angle spectrum estimated by the angle spectrum estimation unit as the azimuth angle of the arrival direction of the transmission signal, comprising an estimation device.

2. Further comprising an elevation angle measurement device (40) that measures the elevation angle of the transmission antenna as viewed from the center position of the plurality of antenna elements, The zenith angle prior information is the value of the elevation angle measured by the elevation angle measurement device, and the estimation device according to claim 1.

3. Receiving, by a plurality of antenna elements (Rx_0 to Rx_N-1), a transmission signal transmitted from a transmission antenna of a transmitting station as a reception signal (S3); Recording data of the reception signal (S4); Outputting an array response vector based on zenith angle prior information, which is an assumed value of the zenith angle of the arrival direction of the transmission signal (S5); An angle spectrum estimation step (S6) of estimating the azimuth angle spectrum of the transmission signal from the array response vector and the data of the reception signal; Estimating, as the azimuth angle of the arrival direction of the transmission signal, the azimuth angle of each peak included in the azimuth angle spectrum estimated by the angle spectrum estimation step (S7), comprising an estimation method.

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