JP2000065911A - Method for detecting arrival azimuth of radio wave and apparatus for detecting arrival azimuth of radio wave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect in time sequence azimuths of radio waves coming from horizontal and vertical directions by incorporating switches to RF output terminals of antennas arranged in the horizontal direction and antennas arranged in the vertical direction and changing the switches at every constant time. SOLUTION: A first switch 8a outputs either one of RF signals from directive antennas 1a and 1d under the control of a first control circuit 101. Similarly, a second switch 8b outputs either one of RF signals from directive antennas 1b and 1e under the control of the control circuit 101. A third switch 9 outputs either one of phase data output from a first memory circuit 51 and a second memory circuit 52 according to the control of the control circuit 101. An output circuit 72 outputs horizontal azimuth data and vertical azimuth data output from an arithmetic circuit 61 at every constant time as one set of data to an external apparatus according to the control of the control circuit 101. One kind of a circuit can process data to detect arrival azimuths in the horizontal direction and vertical directions although two kinds of circuits have been used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accurately detecting the direction of arrival of radio waves radiated from a vehicle-mounted wireless device, for example, in order to determine whether or not a vehicle-mounted wireless device for a toll road automatic toll collection system is mounted. The present invention relates to a radio wave arrival direction detection method and a radio wave arrival direction detection device.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing an embodiment of the prior art. Conventionally, this type of radio wave arrival direction detection apparatus arranges antennas in the horizontal and vertical directions as shown in FIG. 6 to detect the horizontal arrival direction angle and the vertical arrival direction angle of the arrival radio wave. And has two similar devices, a horizontal direction detecting device 201 and a vertical direction detecting device 202, which are operated in parallel to detect the incoming azimuth angles in the horizontal direction and the vertical direction.

Here, the horizontal azimuth θa and the vertical azimuth θe are defined as shown in FIG. First, the configuration will be described. Antennas 1a and 1b receive incoming radio waves,
An RF signal is output to the first phase comparison circuit 41a. Similarly, the antennas 1d and 1e receive incoming radio waves and output RF signals to the second phase comparison circuit 41b. The antenna 1c receives an incoming radio wave and outputs an RF signal to the distributor 2. The splitter 2 splits the RF signal output from the directional antenna 1c into two.

A first phase comparison circuit 41a detects a phase difference between the antennas 1a and 1b and the RF signal output from the distributor 2, and outputs the same to a first arithmetic circuit 61a. Similarly, the second phase comparison circuit 41b detects the phase difference between the antennas 1d and 1e and the RF signal output from the distributor 2, and the second arithmetic circuit 6
1b. As shown in FIG. 7, the storage circuit 51 previously stores data on the phase difference measured at the input terminal of the first phase comparison circuit 41a. Arrival azimuth angle θa (0 °
≤ θa ≤ 180 °), the phase difference between the RF signals output from the antennas 1a and 1c is Rac (θa), and the phase difference between the RF signals output from the antennas 1c and 1b is Rcb (θa
), And the phase difference between the RF signals output from the antennas 1b and 1a is Rba (θa).

Similarly, the first storage circuit 52 stores the first
The data of the phase difference measured at the input end of the phase comparison circuit 41b is stored. Arrival azimuth angle θe (0 °
When ≦ θe ≦ 180 °), the phase difference between the RF signals output from the antennas 1d and 1c is Rdc (θe), and the phase difference between the RF signals output from the antennas 1c and 1e is Rce (θ).
e) Let the phase difference between the RF signals output from the antennas 1e and 1d be Red (θe).

The first arithmetic circuit 61a calculates a horizontal direction of arrival of an incoming radio wave based on the phase difference data output from the first phase comparison circuit 41a and the horizontal phase difference data output from the first storage circuit 51. The angle is calculated and output to the output circuit 71. Similarly, the arithmetic circuit 61b calculates the vertical azimuth of arrival of the arriving radio wave from the phase difference data output from the first phase comparison circuit 41b and the vertical phase difference data output from the second storage circuit 52. Then, the signal is output to the output circuit 71. The output circuit 71 outputs the two input data as one set.

Next, the operation will be described. Antenna 1a,
1b, 1c, 1d, and 1e receive the radio waves of the same arriving wavefront. The phase difference between the RF signals output from the antennas 1a, 1c and 1b arranged in the horizontal direction is detected by a phase comparison circuit 41a. The phase difference between the RF signals output from the antennas 1a and 1c is Xac, the phase difference between the RF signals output from the directional antennas 1c and 1b is Xcb, and the phase difference between the RF signals output from the antennas 1b and 1a is Xba. I do. (Xa
c, Xcb, Xba) as a set of data
1a.

The antennas 1d, 1c,
The phase difference of the RF signal output from 1e is detected by the phase comparison circuit 41b. The phase difference between the RF signals output from the antennas 1d, 1c and 1e is detected by the phase comparison circuit 41b. The phase difference between the RF signals output from the antennas 1d and 1c is Xce, and the phase difference between the RF signals output from the antennas 1e and 1d is Xed. (Xdc, Xce, Xed) are output to the second arithmetic circuit 61b as a set of data.

The first arithmetic circuit 61a changes the value of θa from 0 ° to 180 ° and sets Rac (θa) and Rcb at that time.
(Θa) and Rba (θa) are read from the first storage circuit 51 and the following calculation is performed.
Is detected.

[0010]

(Equation 1)

Similarly, the second arithmetic circuit 61b performs the following operation to detect θe at which the value of P (θe) becomes maximum.

[0012]

(Equation 2)

Θa and θe are output to an output circuit 71,
The output circuit 71 outputs this to the external device as a set of data.

[0014]

The conventional radio wave arrival direction detecting device of this type has two devices which are substantially equivalent to the horizontal direction detection and the vertical direction detection of the incoming radio wave, so that the device structure is However, it is disadvantageous in terms of cost. An object of the present invention is to compare with a conventional radio wave arrival direction detecting device,
An object of the present invention is to provide a radio wave arrival direction detection method and a radio wave arrival direction detection device having a small, lightweight, and inexpensive device.

[0015]

In order to solve the above-mentioned problems, the present invention firstly incorporates a switch at the RF output terminals of a horizontally arranged antenna and a vertically arranged antenna. The azimuths of radio waves arriving from the horizontal direction and the vertical direction are detected in time series by switching at regular intervals.

Second, switches are incorporated at the RF output terminals of the antennas arranged in the horizontal direction and the antennas arranged in the vertical direction, and the switching operation of the switches is switched at regular intervals by a control signal of a control circuit. The RF signals output from the antennas arranged in the horizontal direction and the RF signals output from the antennas arranged in the vertical direction are alternately output to the arithmetic circuit via the phase comparison circuit, and the horizontal arrival azimuth and the vertical Direction arrival azimuth is detected alternately.

Third, a plurality of antennas arranged in the horizontal direction and the vertical direction, switches incorporated in the RF output terminals of the respective antennas, and control for switching these switches at regular intervals. And a radio wave arrival azimuth detector for alternately detecting a horizontal arrival azimuth and a vertical arrival azimuth from RF signals output from the antennas arranged in the horizontal direction and the vertical direction.

Fourth, a radio wave arrival azimuth detector for alternately detecting a horizontal arrival azimuth and a vertical arrival azimuth from RF signals output from the horizontal and vertical antennas is provided. , A phase comparison circuit, an arithmetic circuit, a horizontal data storage circuit and a vertical data storage circuit. Fifth, the arrival direction of the RF signal for each antenna in the arithmetic circuit is input to a phase comparison circuit via a predetermined switch, and is processed as phase difference data for each antenna by the phase comparison circuit, and is calculated. The value is determined by changing the value from 0 ° to 180 ° in the circuit and obtaining the maximum value in each of the horizontal direction and the vertical direction between the data read from the horizontal and vertical storage circuits.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration will be described with reference to the block diagram of FIG. The first switch 8a is a directional antenna 1
Either a or 1 d of the RF signal output is output under the control of the first control circuit 101. Similarly, the second switch 8b outputs one of the outputs of the RF signals from the directional antennas 1b and 1e under the control of the control circuit 101.

The third switch 9 outputs one of the phase data output from the first storage circuit 51 and the second storage circuit 52 under the control of the control circuit 101. Output circuit 7
The control circuit 101 converts horizontal angle data and vertical angle data output from the arithmetic circuit 61 at regular intervals into a control circuit 101.
And outputs it to the external device as a set of data.

The other components are the same as those of the prior art. The operation will be described with reference to the block diagram of FIG. First, the switches 8a, 8b, 9 are all switched to the S1 side by the control signal of the control circuit 101, and the output circuit 72 is in a state of receiving the horizontal angle data θa.

The antennas 1a, 1b, 1c, 1d and 1e are:
Receives incoming radio waves. The antennas 1a, 1b and 1c output the respective RF signals to the phase comparison circuit 41. The phase comparison circuit 41 calculates the phase difference Xac between the RF signals output from the antennas 1a and 1c and the RF signal output from the antennas 1c and 1b.
The phase difference Xcb of the signal and the phase difference Xba of the RF signals output from the antennas 1b and 1a are represented by a set of data (Xac, Xac).
cb, Xba) to the arithmetic circuit 61.

The arithmetic circuit 61 sets θa from 0 ° to 180 °
Rac (θa), Rcb (θ
a), Rba (θa) is read from the first storage circuit 51, and the following operation is performed to detect θa at which the value of P (θa) becomes maximum.

[0024]

(Equation 3)

Θa is output to the output circuit 72. The output circuit 72 stores the input θa as horizontal arrival azimuth data. After a certain period of time, the control circuit 101 outputs a control signal, the switches 8a, 8b, and 9 all switch to the S2 side, and the output circuit 72 enters a state of receiving the vertical arrival azimuth data θe.

The directional antennas 1c, 1d and 1e output their respective RF signals to the phase comparator 41. The phase comparison circuit 41 outputs a set of data (Xcd, Xde,
Xec) is output to the arithmetic circuit 61. The arithmetic circuit 61 also performs Rcd (θe), Rde (θe), Rec
(Θe) is read from the storage circuit 52, and the following calculation is performed to detect θe that maximizes the value of P (θe).

[0027]

(Equation 4)

Θe is output to the output circuit 72. After the θe input to the output circuit 72 is stored as vertical arrival azimuth data, (θa, θe) is output to an external device as a set of data. In the first embodiment of the present invention described above, the number of the antennas 1 arranged in the horizontal direction and the vertical direction is three each, but in the second embodiment, the number of the antennas 1 is three in the horizontal direction and the vertical direction. The number of arranged antennas 1 is five each.

First, the configuration will be described with reference to FIG. As shown in FIG. 3, five antennas 1 are arranged in the horizontal direction and five in the vertical direction. The antenna 1c is arranged at the center. The phase comparison circuit 42 includes switches 8a, 8b, 8c, 8
The phase difference between d and the RF signal output from the directional antenna 1c is detected and output to the arithmetic circuit 62.

As shown in FIG. 4, the first storage circuit 53 stores phase difference data of the incoming radio wave with respect to the horizontal arrival azimuth θa and data of the phase difference with respect to the vertical arrival azimuth θe, as shown in FIG. Have been. Arrival azimuth θa
, The phase difference of the RF signals output from the directional antennas 1a and 1b at the input end of the second phase comparison circuit 42 is represented by Rab
(Θa). Similarly, Rba (θa), Rcd (θ
a), Rde (θa), Rac (θa), Rce (θ
a) and Rbd (θa) are defined. Second storage circuit 54
Also, as shown in FIG. 4, data of the phase difference with respect to the vertical arrival angle θe of the arriving radio wave measured in advance is stored. At the arrival direction θe, the phase difference between the RF signals output from the directional antennas 1f and 1g at the input terminal of the second phase comparison circuit 42 is Rfg (θe). Similarly, Rgc (θ
e), Rch (θe), Rhi (θe), Rfc (θ
e), Rci (θe) and Rgh (θe) are defined.

The arithmetic circuit 62 stores the phase difference data output from the phase comparison circuit 42 and the first storage circuit 53 or the second
Is calculated from the phase difference data output from the storage circuit 54. The control circuit 102 includes a switch 8a,
8b, 8c, 8d, 9 and a switching signal are output to the output circuit 72 at regular time intervals.

Next, the operation will be described. First, the switches 8a, 8b, 8c,
8d and 9 are all switched to the S1 side, and the output circuit 72 enters a state of receiving the horizontal angle data θa. Antennas 1a, 1b, 1c, 1d, 1e, 1f, 1
g, 1h, and 1i receive incoming radio waves. Antenna 1
a, 1b, 1d, 1e, and 1c output the respective RF signals to the phase comparison circuit 42.

The phase comparison circuit 42 calculates the phase difference Xab between the RF signals output from the antennas 1a and 1b and the antennas 1b and 1b.
c and the phase difference Xbc of the RF signal output from the antenna 1c
And 1d, the phase difference Xcd between the RF signals output from the antennas 1d and 1e, the phase difference Xde between the RF signals output from the antennas 1d and 1e, and the phase difference Xac between the RF signals output from the antennas 1a and 1c.
And the phase difference X between the RF signals output from the antennas 1c and 1e
The phase difference Xbd between ce and the RF signals output from the antennas 1b and 1d is detected. These data are converted into a set of data (Xab, Xbc, Xcd, Xde, Xac, Xce,
Xbd) is output to the arithmetic circuit 62.

The arithmetic circuit 62 sets θa from 0 ° to 180 °
Rab (θa) and Rbc (θ
a), Rcd (θa), Rde (θa), Rac (θ
a), Rce (θa), and Rbd (θa) are read from the first storage circuit 53 and the following calculation is performed to detect θa at which the value of P (θa) becomes maximum.

[0035]

(Equation 5)

The detected θa is output to the output circuit 72. After a predetermined time, the control circuit 102 outputs the next control signal and switches the switches 8a, 8b, 8c, 8d, 9 to the S2 side. The antennas 1f, 1g, 1h, 1i, and 1c output their RF signals to the phase comparison circuit 42. The phase comparison circuit 42 detects the phase difference between the RF signals in the same manner as described above, and converts the data into a set of data (Xfg, Xfc,
Xch, Xhi, Xfc, Xci, Xgh) are output to the arithmetic circuit 62.

The arithmetic circuit 62 sets θe from 0 ° to 180 °
Rfg (θe), Rgc (θ
e), Rch (θe), Rhi (θe), Rfc (θ
e), Rci (θe), and Rgh (θe) are read from the second storage circuit 54 and the following calculation is performed to detect θe at which the value of P (θe) becomes maximum.

[0038]

(Equation 6)

The detected θe is output to the output circuit 72. The output circuit 72 outputs θa and θe as a set of data to an external device when θe is input.

[0040]

As described above, according to the present invention, in order to detect a horizontal arrival azimuth and a vertical arrival azimuth, two circuits equivalent to those conventionally processed by one circuit are used. In this case, the hardware scale is reduced to half that of the conventional product, and an inexpensive, compact and lightweight device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a radio wave arrival direction detecting device according to the present invention.

FIG. 2 is a block diagram showing another embodiment of the radio wave arrival direction detecting device according to the present invention.

FIG. 3 is an antenna array diagram of another embodiment of the radio wave arrival direction detecting device according to the present invention.

FIGS. 4A and 4B are explanatory diagrams of a phase difference detecting method of the radio wave arrival direction detecting device according to the present invention.

FIG. 5 is a block diagram of a conventional radio wave arrival direction detection device.

FIG. 6 is a 5-element antenna array diagram of the radio wave arrival direction detecting device.

FIGS. 7A and 7B are diagrams for explaining a phase difference detection method of a conventional radio wave arrival direction detection device.

[Explanation of symbols]

 1a-1i Antenna 2 Distributor 41-41b Phase Comparison Circuit 51 Storage Circuit 52 Storage Circuit 53 Storage Circuit 54 Storage Circuit 61-61b Arithmetic Circuit 71 Output Circuit 72 Output Circuit 8a-8d Switch 9 Switch 101 Control Circuit 102 Control Circuit 201 Horizontal direction detection device 202 Vertical direction detection device

Claims (5)

[Claims] 1. An azimuth angle of radio waves arriving from the horizontal direction and the vertical direction is obtained by installing a switch at an RF output terminal of an antenna arranged in a horizontal direction and an RF output terminal of an antenna arranged in a vertical direction and switching them at predetermined time intervals. A radio wave arrival direction detection method characterized by detecting in time series. 2. A switching device is incorporated at the RF output terminals of the antennas arranged in the horizontal direction and the antennas arranged in the vertical direction, and the switching operation of the switching device is switched at regular intervals by a control signal of a control circuit. The RF signal output from the antenna arranged in the direction and the RF signal output from the antenna arranged in the vertical direction are alternately output to the arithmetic circuit through the phase comparison circuit, and the horizontal arrival azimuth and the vertical arrival A radio wave arrival direction detection method characterized by alternately detecting an azimuth angle. 3. A plurality of antennas arranged in a horizontal direction and a vertical direction, a switch incorporated in an RF output terminal of each of the antennas, and a control circuit for controlling switching of each of the switches at regular intervals. And a radio wave arrival azimuth detector for alternately detecting a horizontal arrival azimuth and a vertical arrival azimuth from an RF signal output from the antenna arranged in the horizontal direction and the vertical direction. Characteristic radio wave arrival direction detection device. 4. A radio wave arrival azimuth detector for alternately detecting a horizontal arrival azimuth and a vertical arrival azimuth from an RF signal output from an antenna disposed in the horizontal direction and the vertical direction, 4. The radio wave arrival direction detecting device according to claim 3, wherein the comparing circuit, the arithmetic circuit, the horizontal data storage circuit and the vertical data storage circuit are configured. 5. An arrival direction of an RF signal for each antenna in the arithmetic circuit is input to a phase comparison circuit via a predetermined switch, and is processed as phase difference data for each antenna by the phase comparison circuit. The arithmetic circuit changes the value from 0 ° to 180 ° and determines the maximum value in each of the horizontal and vertical directions between the data read from the horizontal and vertical storage circuits. The radio wave arrival direction detecting device according to claim 4, characterized in that: