Radio Wave Arrival Direction Estimation Device and Radio Wave Arrival Direction Estimation Method

Abstract

A radio wave direction-of-arrival estimation device according to one embodiment is characterized by having: a radio wave absorbent body which extends in the vertical direction; a plurality of non-directional antennas which are positioned around the radio wave absorbent body so as to extend in the same direction as does the radio wave absorbent body; a measurement unit for measuring the C / N value or the received power of each radio wave received by the plurality of non-directional antennas; an estimation unit for estimating the direction of arrival of the radio waves on the basis of each C / N value or received power measured by the measurement unit; and an output unit for outputting information which expresses the direction of arrival of the radio waves which was estimated by the estimation unit.

Description

Technical Field

[0001] The present invention relates to a radio wave arrival direction estimation apparatus and a radio wave arrival direction estimation method.

Background Art

[0002] Conventionally, many methods have been proposed for estimating the arrival direction of radio waves in wireless communication. For example, a method using the phase difference of radio waves based on the difference in the positions of antennas, the MUSIC (Multiple Signal Classification) method, etc. are promising, and there are methods that enable estimating the arrival direction of radio waves in the horizontal plane by changing the direction of the main lobe or null point of the antenna pattern (see, for example, Non-Patent Document 1).

[0003] In the prior art, radio waves arriving from each direction in three dimensions are not assumed, and the arrival direction of radio waves is estimated based on the correlation matrix obtained using an array antenna. That is, conventionally, the planar arrival direction has been estimated.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the prior art has problems in that a plurality of antenna elements and highly directional antennas are required, and the accuracy does not improve in the low frequency band.

[0006] Also, in a low-frequency band such as the VHF band, since the antenna element size is large and arrays and other antennas become large-scale, installation may be difficult.

[0007] The present invention has been made in view of the above-described problems, and an object thereof is to provide a radio wave arrival direction estimation device and a radio wave arrival direction estimation method capable of estimating the radio wave arrival direction with a simple configuration without using a highly directional antenna.

Means for Solving the Problems

[0008] A radio wave arrival direction estimation device according to an embodiment of the present invention includes a radio wave absorber extending in the vertical direction, a plurality of omnidirectional antennas arranged around the radio wave absorber so as to extend in the same direction as the radio wave absorber, a measurement unit that measures the received power or C / N value of the radio waves received by the plurality of omnidirectional antennas, respectively, an estimation unit that estimates the radio wave arrival direction based on each of the received power or C / N value measured by the measurement unit, and an output unit that outputs information indicating the radio wave arrival direction estimated by the estimation unit. Moreover, the radio wave absorber is formed so as to separately partition each of the plurality of omnidirectional antennas while releasing one direction on a straight line passing through the center of the radio wave absorber and the center of the omnidirectional antenna. It is characterized by this.

[0009] Further, a radio wave arrival direction estimation method according to an embodiment of the present invention is a radio wave arrival direction estimation method for estimating the radio wave arrival direction using a radio wave absorber extending in the vertical direction and a plurality of omnidirectional antennas arranged around the radio wave absorber so as to extend in the same direction as the radio wave absorber, and includes a measurement step of measuring the received power or C / N value of the radio waves received by the plurality of omnidirectional antennas, respectively, an estimation step of estimating the radio wave arrival direction based on each of the measured received power or C / N value, and an output step of outputting information indicating the estimated radio wave arrival direction. including Moreover, the radio wave absorber is formed so as to separately partition each of the plurality of omnidirectional antennas while releasing one direction on a straight line passing through the center of the radio wave absorber and the center of the omnidirectional antenna. It is characterized by this.

Effects of the Invention

[0010] According to the present invention, the radio wave arrival direction can be estimated with a simple configuration without using a highly directional antenna.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0012] Hereinafter, a configuration example of a radio wave arrival direction estimation device 1 according to an embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration example of the arrival direction estimation device 1 according to an embodiment.

[0013] As shown in FIG. 1, the arrival direction estimation device 1 according to an embodiment includes, for example, an antenna unit 2, a measurement unit 10, an estimation unit 12, and an output unit 14.

[0014] The antenna unit 2 includes a radio wave absorber 20 extending in the vertical direction and a plurality of omnidirectional antennas 22 arranged around the radio wave absorber 20 so as to extend in the same direction as the radio wave absorber 20, and outputs the received power of the radio waves received by each of the plurality of omnidirectional antennas 22 to the measurement unit 10. The omnidirectional antenna 22 is, for example, a whip antenna in which the horizontal direction is omnidirectional.

[0015] For example, the plurality of omnidirectional antennas 22 are arranged at equal intervals on a circumference centered on an axis extending in the vertical direction passing through the center of the radio wave absorber 20.

[0016] The measurement unit 10 measures the received power or C / N value of the radio waves received by each of the plurality of omnidirectional antennas 22 and outputs it to the estimation unit 12.

[0017] Based on the received power or C / N value measured by the measurement unit 10, the estimation unit 12 estimates the arrival direction of the radio wave and outputs information indicating the estimated arrival direction to the output unit 14.

[0018] The output unit 14 outputs the information indicating the arrival direction of the radio wave estimated by the estimation unit 12, for example, by displaying it.

[0019] Next, the antenna unit 2 will be described in more detail. FIG. 2 is a diagram showing a specific example of the configuration of the antenna unit 2. FIG. 2(a) is a view of the antenna unit 2 seen from above. FIG. 2(b) is a perspective view of the antenna unit 2.

[0020] As shown in FIG. 2, a plurality of omnidirectional antennas 22 are attached around the radio wave absorber 20 in the antenna unit 2. Here, eight omnidirectional antennas 22 from A to H are arranged around the radio wave absorber 20 at intervals of 45°. The more omnidirectional antennas 22 there are, the higher the estimation accuracy of the arrival direction of the radio wave by the arrival direction estimation device 1.

[0021] FIG. 3 is a diagram illustrating the arrival direction of the radio wave with respect to the antenna unit 2. As shown in FIG. 3, for example, it is assumed that the radio wave is arriving between the omnidirectional antennas 22 of F and E.

[0022] At this time, high-level radio waves will be received by the omnidirectional antennas 22 of D, E, F, and G. Therefore, the estimation unit 12 can estimate the arrival direction of the radio wave based on the magnitudes of the received powers of the radio waves received by the omnidirectional antennas 22 of D, E, F, and G.

[0023] When the radio wave arrives from the direction of the omnidirectional antenna 22 of F, high-level radio waves will be received by the omnidirectional antennas 22 of D, E, F, G, and H. However, since the received power of the omnidirectional antenna 22 of F is the maximum, the omnidirectional antenna 22 can estimate that the radio wave is arriving from the direction of F.

[0024] Figure 4 is a flowchart showing an operation example of the arrival direction estimation device 1. As shown in Figure 4, in step 100 (S100), the measurement unit 10 measures the received power or C / N value of the radio wave respectively.

[0025] In step 102 (S102), the estimation unit 12 estimates the arrival direction of the radio wave.

[0026] In step 104 (S104), the output unit 14 outputs by displaying information indicating the arrival direction of the radio wave.

[0027] Figure 5 is a diagram showing a modified example (antenna unit 2a) of the antenna unit 2. As shown in Figure 5, in the antenna unit 2a, a plurality of omnidirectional antennas 22 may be arranged at positions where the side surface of the columnar radio wave absorber is recessed.

[0028] As described above, since the arrival direction estimation device 1 has the radio wave absorber 20 in which the antenna unit 2 extends in the vertical direction and a plurality of omnidirectional antennas 22 arranged around the radio wave absorber 20 so as to extend in the same direction as the radio wave absorber 20, it is possible to estimate the arrival direction of the radio wave with a simple configuration without using a highly directional antenna.

Description of Reference Numerals

[0029] 1... Arrival direction estimation device, 2, 2a... Antenna unit, 10... Measurement unit, 12... Estimation unit, 14... Output unit, 20, 20a... Radio wave absorber, 22... Omnidirectional antenna

Claims

1. A radio wave absorber extending in the vertical direction, a plurality of omnidirectional antennas arranged around the radio wave absorber so as to extend in the same direction as the radio wave absorber, a measuring unit that measures the received power or C / N value of the radio waves received by the plurality of omnidirectional antennas respectively, an estimating unit that estimates the arrival direction of the radio waves based on the received power or C / N value measured by the measuring unit respectively, and an output unit that outputs information indicating the arrival direction of the radio waves estimated by the estimating unit ; The radio wave absorber is formed so as to partition each of the plurality of omnidirectional antennas individually while releasing one direction on the straight line passing through the center of the radio wave absorber and the center of the omnidirectional antenna. A radio wave arrival direction estimation device characterized by this.

2. The plurality of omnidirectional antennas are arranged at equal intervals on a circumference centered on an axis extending in the vertical direction passing through the center of the radio wave absorber. The radio wave arrival direction estimation device according to Claim 1, characterized by this.

3. In a radio wave arrival direction estimation method for estimating the arrival direction of radio waves using a radio wave absorber extending in the vertical direction and a plurality of omnidirectional antennas arranged around the radio wave absorber so as to extend in the same direction as the radio wave absorber, a measuring step of measuring the received power or C / N value of the radio waves received by the plurality of omnidirectional antennas respectively, an estimating step of estimating the arrival direction of the radio waves based on the received power or C / N value measured respectively, and an output step of outputting information indicating the arrival direction of the radio waves estimated. ; The radio wave absorber is formed so as to partition each of the plurality of omnidirectional antennas individually while releasing one direction on the straight line passing through the center of the radio wave absorber and the center of the omnidirectional antenna. A radio wave arrival direction estimation method characterized by this.

4. The plurality of omnidirectional antennas are arranged at equal intervals on a circumference centered on an axis extending in the vertical direction passing through the center of the radio wave absorber. The radio wave arrival direction estimation method according to Claim 3, characterized by this.

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