JPH0526996A - Beacon transmitting apparatus - Google Patents

Abstract

PURPOSE:To fabricate a system wherein errors are few in measurement and determination of position information with regard to a beacon transmitting apparatus in a road-vehicle information system. CONSTITUTION:A carrier wave signal 26 undergoes AM modulation with modulating signals 27 having the opposite phases, respectively. A radio beacon transmits the signals through two antennas 2 (2-1 and 2-2) having the mutually overlapped directivities in the directly downward directions. Meanwhile the positions of the antennas 2 (2-1 and 2-2) are determined based on the dip points of the demodulated signals of the modulated waves, which are received direcly beneath the antennas 2 (2-1 and 2-2). A receiving antenna 28 is provided directly beneath both antennas 2-1 and 2-2. An AM demodulating means 29 demodulates the received modulated waves. A phase comparing means 30 compares the phase of the demodulated signal with the phase of the modulating signal 27. Variable output power means 22-1 and 22-2 make it possible to vary the transmitting output powers of the modulated waves, which are transmitted from both natennas 2-1 and 2-2, based on the detected signal of the phase comparing means. This apparatus is constituted so as to provide these parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beacon transmitting device in a road-to-vehicle information system.

The road-to-vehicle information system receives beacon radio waves from a beacon transmitting device installed on the road to obtain the current position and traveling direction of an automobile that the driver drives, traffic congestion information on a road, destination guidance information on an intersection, etc. Is a system that can obtain.

The vehicle-mounted receiving device for receiving these pieces of information is
This is a mechanism for confirming and capturing the received information when passing under the beacon transmitting antenna.

By the way, there is a navigation system that determines the position of the vehicle using a map matching method and displays it on a map displayed on a CRT (Cathode Ray Tube). At that time, a road-vehicle information system is used. There is a system that corrects the position of the own vehicle from the received current position information when the own vehicle passes directly under the beacon transmission antenna.
In addition, this system has an advantage that the current position of the vehicle can be accurately measured and determined.

On the other hand, if the position directly below the beacon transmission antenna cannot be accurately determined, the system will have a large error.

However, the beacon radio wave propagates in a complicated manner under the influence of surrounding buildings and trees where transmission antennas are installed, parked vehicles on the road, and the like. Therefore, when the state around the transmitting antenna changes, the propagation state of the beacon radio wave also changes, and an error occurs when the vehicle-mounted receiving device measures and determines the position directly below the transmitting antenna.

Therefore, there is a demand for a transmitting device that can transmit beacon radio waves without being affected by changes in ambient conditions.

[0008]

2. Description of the Related Art (1) Overview of Road-to-Vehicle Information System FIG. 3 is a diagram for explaining the road-to-vehicle information system, (a) is a perspective view for explaining the installation state of radio beacons, and (b) is a communication area. It is a model figure explaining.

Transmitting device 1 for transmitting beacon radio waves
a, 1b, ... and transmitting antenna (combined beam antenna) 2a,
2b, ... are installed at intervals of several hundred meters at the key points of the road piece of road 3, and in general, street light poles 1a, 1b, ...
It is provided in facilities such as and pedestrian bridges.

The transmitting antenna 2 is composed of two antennas 2 _-1 , 2 _-2 whose directivity characteristics overlap directly below. Therefore, it is generally called a combined beam antenna 2.

The receivable area 7 of the beacon on the road is
The range obtained by combining the communication area -2 transmit antennas _2-2 and the communication area -1 transmit antennas 2 _-1, both the transmitting antenna 2
It is determined by the directivity of (2 _-1 , 2 _-2 ) and the transmission power.

Further, in the transmitted wave of the beacon illustrated in FIG. 3B, PM (Phase Modulation) modulation component 5 and AM (Amp
(Litude Modulation) modulation component is included, and each modulation component 5 and 6 has different information.

In the traveling directions of the automobile traveling on the road 3, the traveling direction 8 and the traveling direction 9 are opposite to each other.
There is.

(2) Transmitting device and received data FIG. 4 is a diagram for explaining the transmitting device and received data, (a) is a block diagram of the transmitting device and the transmitting antenna, and (b) is a diagram for explaining the received signal level. , (C) are diagrams for explaining the phase between the data frame and the clock.

1) Transmitting device (FIG. 3 (a)) The transmitting device of the beacon shown in FIG. 4 is a position directly below the transmitting antenna 2 (2 _-1 , 2 _-2 ) by PM modulation of traffic information such as traffic congestion information.
The information indicating 19 is transmitted by AM modulation.

That is, the data 10 is a carrier wave (for example,
f = 2.6 GHz) to GMSK (Gaussian Minimum Shift Keyin
g) Modulation is performed by the modulator 11. Further, information indicating the position directly under 19, a clock obtained in synchronism from the data 10 in the clock generator 12 (for example, f = 1 KHz) used as the modulation signal, two separate AM modulator 13 _-1, 13 _- Modulate by ₂ . And
The modulated waves modulated by both AM modulators 13 _-1 , 13 _-2 are separately transmitted and emitted from the transmission antenna 2 (2 _-1 , 2 _-2 ).

In the AM modulation, one modulation signal is inverted and modulated by the 180 ° phase shift circuit 14. As the carrier wave used for AM modulation, the modulated wave previously GMSK-modulated is used.

2) Received signal level (FIGS. 3 (a) and (b)) The transmitting antenna 2 (2 _{-1,2 -2} ) is composed of two antennas 2 _{-1,2 -2.}
Automotive directional characteristics are arranged to overlap at a position immediately below 19 thereof, and the antennas 2 _-1, 2 _-2 main lobe of, the both antenna 2 _-1, the position just below 19 _2-2 as a reference Are arranged symmetrically in the traveling direction of.

Therefore, the electric field strength of the received beacon becomes maximum at the position 19 directly below the transmitting antenna 2 (2 _-1 , 2 _-2 ), and gradually decreases at positions on both sides thereof. Therefore, the demodulated received signal level of the GMSK-modulated data modulation component 15 is the same as the electric field intensity distribution.

On the other hand, the demodulation reception signal level of the AM modulation component 16 which is AM-modulated by the clock of the opposite phase is the lowest (theoretically 0 at the position 19 immediately below the transmission antenna 2 (2 _-1 , 2 _-2 ). )
The maximum value is shown at both sides of the lowest point, and the value gradually decreases. That is, the dip point appears at the position directly below.

Then, the demodulated received signal obtained in the main lobe side of the antenna 2 _-1 , that is, in the communication area -1, and the antenna
Phase between the demodulated received signal obtained by 2 _-2 of the main lobe side or communication area -2 opposite phases. By the way, in the example shown in FIG. 3, the communication area-1 is the in-phase area and the clock is 180
° Communication area -2, which is phase-shifted, modulated and transmitted, is shown as the opposite phase area.

The position directly below the transmitting antenna 2 (2 _-1 , 2 _-2 ).
The reason why the dip point appears in the demodulated received signal of AM modulation component 16 in 19 is that the carrier waves emitted from both transmitting antennas 2 _-1 , 2 _-2 have the same phase, but their envelopes have the opposite phase and the same magnitude. Because it is.

3) Data frame and clock of demodulated received signal (FIG. 3 (c)) FIG. 3 (c) shows a communication area-1, that is, an in-phase area and a communication area-2.
That is, it shows the relationship between the data and the clock received in the reverse phase region. The data is typically transmitted in the frame structure, data portion 18 _-1 synchronization unit 17 to the head (18 _{-2) -1} (17 _-2) the provided data frame 20 _-1 (20 _-2 ) Is configured.

In the in-phase region, the clock 21 _-1 becomes "H" level in the synchronizing section 17 _-1 of the data frame 20 _-1 , and in the anti-phase region, the synchronization of the data frame 20 _-2 . In the section 17 _-2 , the clock 21 _-2 becomes "L" level.

Therefore, the clock obtained by receiving the beacon is
Lock 21_-1 ,twenty one_-2But the data frame 20_-1 , 20_-2Synchronization of
Part 17_-1 , 17_-2From "H" level to "L" level
Is it changed? Or conversely, from "L" level to "H"
Depending on whether the level has changed, the direction in which the vehicle is
You can know whether it is a direction or a down direction. Also,
Clock 21_-1 ,twenty one_-2From the dip point where the amplitude of
Transmit antenna 2 (2_-1, 2 _-2) Position, that is, the position of the vehicle
It can be measured and confirmed.

(3) Installation adjustment of beacon transmitting device When the transmitting antenna 2 (2 _-1 , 2 _-2 ) is installed in an infinite free space, the pointing of the antenna 2 (2 _-1 , 2 _-2 ) is performed. The characteristics and the electric field strength distribution show the characteristics according to the theory.

However, the transmitting antenna 2 on the actual road
When (2 _-1 , 2 _-2 ), is installed, the characteristics of the theory cannot be obtained due to the influence of surrounding objects such as buildings, trees and pedestrian bridges. Therefore, the clocks 21 _-1 , 21 _-2, that is, the dip points of the AM modulation component do not appear at the position 19 directly below the transmitting antenna 2 (2 _-1 , 2 _-2 ), and the communication area -1 or communication area -2 Appears by shifting to one of the areas.

FIG. 5 is a diagram for explaining an example of the influence of surrounding objects, showing the received signal level.

That is, the data modulation component 15 shown by the solid line
And the AM modulation component 16 show a theoretical distribution, and a dip point of the AM modulation component appears at the position 19 directly below the antenna, that is, at the coordinate d ₀ .

On the other hand, the data modulation component 15 shown by the alternate long and short dash line
A and AM modulation component 16A show the actual distribution example,
The dip point of the AM modulation component is the coordinate d _1, that is, the communication area-1
It is shifted to the side by Δd.

Therefore, an error occurs in the measurement and determination of the position 19 immediately below the transmitting antenna 2 (2 _-1 , 2 _-2 ), which is performed by the in-vehicle receiving device receiving the beacon.

Therefore, when the beacon transmission device and the transmission antenna 2 (2 _-1 , 2 _-2 ) are installed, the transmission antenna 2 (2
_-1, 2 at the position 19 immediately below _-2) as dip point of the AM modulation component appears, the transmission output power supplied to the communication area -1 side of the antenna 2 _-1 in the communication area -2 side of the antenna _2-2 Is being adjusted. That is, the balance of the transmission output power is adjusted.

[0033]

However, when there is an object that changes with time around the transmitting antenna 2 (2 _-1 , 2 _-2 ), the dip point of the AM modulation component shifts with time, As a result, the position 19 directly below cannot be measured and determined correctly.

For example, a tree repeats overgrowth and defoliation as the season changes. Further, the presence or absence of the vehicle and the position of the on-street parking vehicle change.

The technical problem of the present invention is to solve the above problems in the beacon transmitter of the road-to-vehicle information system and to make it possible to always distribute the dip point of the AM modulation component directly below the transmitting antenna. It is to build a system with less error by realizing. Another object is to facilitate installation and adjustment of the beacon transmission device.

[0036]

FIG. 1 is a block diagram of a transmitter, which is a diagram for explaining the principle of the present invention.

The present invention is characterized in that the transmission output power and the degree of modulation are automatically changed according to the surrounding conditions of the transmission antenna 2 (2 _-1 , 2 _-2 ).

And, basically, the radio beacon of the present invention
(Radio Beacon) is directly below, while facing different directions.
Antennas with directional characteristics that overlap each other in the direction
2 (2 _-1, 2_-2) From the
The wave signal 26 is AM-modulated and transmitted. On the other hand, the antenna
2 (2_-1, 2_-2), The modulated wave demodulation signal received immediately below
From the Dip point of the No._-1, 2_-2)
It is a system configuration for determining the position of.

(1) Automatically balance transmission output power
Beacon transmitter to adjust Transmit antenna 2 (2_-1, 2_-2), Which receives the modulated wave
Signal antenna 28 and the received signal received by the receiving antenna 28.
Means 29 for demodulating harmonics, and demodulated by the demodulating means 29
Means 30 for comparing the phase between the signal and the modulated signal 27, and
Dual antenna 2 _-1, 2_-2Transmission of modulated wave emitted from
Force power by the detection signal of the phase comparison means 30
Means for changing each 22_-1 ,twenty two_-2Beacon transmission with
It is a device.

Incidentally, the balance of the transmission output power is configured to be varied and controlled in the direction in which the modulation signal detected by the phase comparison means 30 becomes weak.

(2) Automatically adjusting the balance of modulation degree
Beacon transmitter Transmit antenna 2 (2_-1, 2_-2), Which receives the modulated wave
Signal antenna 28 and the received signal received by the receiving antenna 28.
Means 29 for demodulating harmonics, and demodulated by the demodulating means 29
Means 30 for comparing the phase between the signal and the modulated signal 27, and
Dual antenna 2 _-1, 2_-2Degree of modulation of modulated wave emitted from
, Respectively, according to the detection signal of the phase comparison means 30.
Means of change 23_-1 ,twenty three_-2With a beacon transmitter equipped with
is there.

The balance of the modulation degree is determined by the phase comparison means 30.
The modulation signal detected in step S1 is configured to be variably and controlled in the direction of decreasing.

(3) Transmit output power and modulation factor are automatically calculated
Beacon transmitter to adjust Transmit antenna 2 (2_-1, 2_-2), Which receives the modulated wave
Signal antenna 28 and the received signal received by the receiving antenna 28.
Means 29 for demodulating harmonics, and demodulated by the demodulating means 29
Means 30 for comparing the phase between the signal and the modulated signal 27, and
Dual antenna 2 _-1, 2_-2Transmission of modulated wave emitted from
Force power by the detection signal of the phase comparison means 30
Means for changing each 22_-1 ,twenty two_-2And both antennas 2_-1, 2
_-2The degree of modulation of the modulated wave emitted from
Means 23 for varying the detection signal from the stage 30_-1 ,twenty three
_-2And a beacon transmitting device.

That is, the beacon transmitting device has the features of the beacon transmitting device of (1) and the beacon transmitting device of (2).

[0045]

(1) Beacon transmission device for automatically adjusting the balance of transmission output power As shown in FIG. 1 (a), the modulated wave modulated by the AM modulation means 13a _-1 , 13a _-2 is output. It is supplied to the transmitting antenna 2 (2 _-1 , 2 _-2 ) via the power varying means 22 _-1 , 22 _-2 .

Therefore, it is possible to change the balance of the transmission output powers of the transmission antenna _2-1 and the transmission antenna _2-2 .

On the other hand, the receiving antenna 28 provided immediately below the transmitting antenna 2 (2 _-1 , 2 _-2 ) receives the composite wave of the modulated waves emitted from both antennas 2 _-1 , 2 _-2 , The demodulation means 29 extracts the envelope. But the transmitting antenna
Since the phase of the demodulated signal of the modulated wave emitted from 2 _-1 and the phase of the demodulated signal of the modulated wave emitted from transmitting antenna 2 _-2 are opposite phases, the electric field strength of either one of Only the demodulated signal of the strong modulated wave is obtained from the demodulation means 29.

If the electric field strengths of the two are the same, the demodulated signals cancel each other out to 0 (zero). That is, the transmitting antenna 2 (2 _-1, 2 _-2) dip point of the demodulated signal at just below the is obtained, the transmitting antenna 2 (2 _-1, 2 _-2) measuring the error in the determination of the position immediately below the Lost.

By the way, the phase comparison means 30
Based on 27, it is possible to detect whether the demodulated signals have the same phase or opposite phases.

Therefore, the transmitting antenna 2 _{-1 is set} so that the phase modulated wave obtained by the demodulating means 29 becomes relatively weak.
By varying the balance between the transmission output power of the transmission antenna 2 _{-2 and} the transmission output power of the transmission antenna 2 _-2 , the dip point of the demodulation signal can be obtained immediately below the transmission antenna 2 (2 _-1 , 2 _-2 ). it can.

(2) Beacon transmitter that automatically adjusts the balance of modulation degree In the beacon transmitter of (1), the magnitude of the demodulated signal of the modulated wave depends on its electric field strength. It was the configuration used.

On the other hand, the magnitude of the demodulated signal of the modulated wave also depends on its modulation degree. Therefore, the balance of the modulation degrees of the modulation degree varying means 23 _-1 , 23 _-2 is detected by the phase comparison means 30 so that the modulation degree of the modulated wave of the phase obtained by the demodulation means 29 becomes relatively small. By changing the
The dip point of the demodulated signal can be obtained immediately below the transmitting antenna 2 (2 _-1 , 2 _-2 ).

(3) Beacon transmitter which automatically adjusts the transmission output power and the modulation factor The features of the beacon transmitter of (1) and the beacon transmitter of (2) are combined, and the balance and modulation of the transmission output power are obtained. By simultaneously changing the degree balance, the applicable adjustment range can be further widened.

[0054]

EXAMPLES Next, examples of how the beacon transmission device according to the present invention can be embodied in practice will be described.

FIG. 2 is a diagram for explaining the embodiment, (a) is a block diagram of the transmitting device, and (b) is a diagram for explaining the installation state.

(1) Structure The beacon transmitting apparatus 1A of this embodiment includes a transmitting antenna 2
(2_-1, 2_-2) Of each antenna 2 _-1, 2_-2The transmission output power of
Bell adjustment part 22a_-1, 22a_-2The configuration is variable in FIG.
(a) Beacon transmission device, level adjustment unit 22a_-1, 22a_-2
Is added. By the way, the level adjuster 22
a_-1, 22a_-2Is an ATT (Attenuator) configuration, and LPF (L
ow pass filter) 34 output signal
It is changed and controlled.

The level adjuster 22a- ₁ is provided with the inversion buffer 24a.
Its attenuation is controlled via a, while the level adjuster
22a _-2 is directly controlled. This is because when the attenuation of one level adjuster 22a _-1 (22a _-2 ) is controlled to increase, the attenuation of the other level adjuster 22a _-2 (22a _-1 ) decreases. This is to control.

On the other hand, the receiving antenna 28a is arranged immediately below the transmitting antenna 2 (2 _{-1,2 -2} ), and its directional characteristics are oriented in the transmitting antenna 2 (2 _{-1,2 -2} ) direction. To install. (Fig. 2
(b))

Then, the modulated wave received by the receiving antenna 28 is amplified by the amplifying section 31 and demodulated by the AM demodulating section 32.
The phase comparison unit 33 compares the phase with the clock of the clock generation unit 12. Since the comparison result of the phase comparison unit 33 is a binary signal indicating in-phase or anti-phase, it is integrated and averaged by the LPF 34 to obtain a control signal having continuous analog values.

As a result of the above configuration, the level adjusting units 22a _-1 , 2
It is possible to continuously change and control the attenuation of 2a _-2 .

(2) The actuating receiving antenna 28a receives the modulated waves emitted from the transmitting antenna 2 _-1 and the transmitting antenna 2 _-2 . But,
The signal demodulated by the AM demodulation unit 32 is the signal on the side having the higher electric field strength. Therefore, the phase comparison unit 33
The comparison result of indicates that which of the transmitting antennas 2 _-1 and 2 _-2 has a higher electric field strength.

Therefore, the transmitting antenna on the side where the electric field strength is high
Transmit output power of 2 _-1 (2 _-2 ) to the other transmit antenna 2 _-2 (2
₋₁ ), the level control units 22a ₋₁ , 22a _{−2 are} controlled by the (control) signal obtained through the LPF 34 so as to decrease relatively.
Control the amount of attenuation. That is, to control the balance of the transmission output power of the transmitting antenna 2 _-1 and transmitting antenna _2-2.

As a result, at the position directly below the transmitting antenna 2 _-2 (2 _-1 ), it is automatically controlled so that the dip point of the clock signal can always be obtained.

(3) Other Embodiments Instead of varying the transmission output power of the transmission antenna 2 (2 _-1 , 2 _-2 ), modulated waves emitted from the transmission antenna 2 _-1 and the transmission antenna 2 _-2 Even if the modulation degree of the clock is changed, the same result as in the above embodiment can be obtained.

In this case, the balance of the modulation degree is controlled.
For that purpose, the clock generator 12 and the AM modulator 13 _-1
Between the 180 ° phase shift circuit 14 and the AM modulator 13 _-2 , a means for varying the level of the clock signal may be provided. That is, the ATT may be inserted. And LPF 34
The signal obtained via
It is sufficient to control the amount of attenuation of TT.

Of course, it is possible to control both the balance of the transmission output power and the balance of the modulation degree at the same time.

The AM modulation factor of the clock in the road-to-vehicle information system of this embodiment is specified to be 10%, and the allowable range of the deviation is also specified. Therefore, when varying / controlling the modulation factor, it is necessary to design so that the control range of the modulation factor is within the specified range. This is because the error rate increases when demodulating GMSK-modulated data when the AM modulation degree becomes too large.

In addition, it is possible to change / control the direction of the transmitting antenna 2 (2 _-1 , 2 _-2 ) and distribute the dip points of the AM modulation component at the position directly below it.
It has a disadvantage that the driving mechanism for changing the direction of (2 _-1 , 2 _-2 ) becomes complicated.

[0069]

As described above, according to the beacon transmitting apparatus of the present invention, even if there is an object that changes with time around the transmitting antenna, the dip point of the AM modulation component is always located directly below the transmitting antenna. Can be distributed.

Therefore, it is possible to construct a road-to-vehicle information system with a small error, and at the same time, it becomes unnecessary to adjust the installation of the beacon transmission device.

[Brief description of drawings]

FIG. 1 is a block diagram of a transmission device for explaining the principle of the present invention.

2A and 2B are diagrams illustrating an embodiment, FIG. 2A is a block diagram of a transmission device, and FIG. 2B is a diagram illustrating an installation state.

3A and 3B are diagrams illustrating a road-to-vehicle information system, in which FIG. 3A is a perspective view illustrating an installation state of a radio beacon, and FIG. 3B is a model diagram illustrating a communication area.

4A and 4B are diagrams for explaining a transmission device and reception data, FIG. 4A is a block diagram of the transmission device and a transmission antenna, FIG. 4B is a diagram for explaining a reception signal level, and FIG. 4C is a data frame and a clock. It is a figure explaining the phase between them.

FIG. 5 is a diagram for explaining an example of the influence of surrounding objects, and is a diagram showing received signal levels.

[Explanation of symbols]

1a, 1b, 1A Transmitter 2,2a, 2b, 2 _-1 ,, 2 _-2 Transmit antenna (combined beam antenna) 3 Road 4,4a, 4b Pole 5 PM (Phase Modulation) Modulation component 6 AM (Amplitude Modulation)
Modulation component 7 Communication area 8 Upward traveling direction 9 Downward traveling direction 10 Data (traffic information etc.) 11 GMSK (Gaussian Minimum)
Shift Keying) Modulator 12 Clock generator 13 _-1 , 13, _-2 , 13a _-1 ,, 13a _-2 AM Modulator 14,14a 180 ° Phase shift circuit 15,15A Data Modulation component 16,16A AM Modulation component 17 _-1 , 17 _-2 synchronization unit 18 _-1, 18 _-2 data unit 19 (transmitting antenna) directly below position 20 _-1, 20 _-2 data frame 21 _-1, 21 _-2 clock 22 _-1, 22 _-2, 22a _{- 1} , 22a _-2 Output power adjustment means (level adjustment section) 23 _-1 , 23 _-2 Modulation degree adjustment means 24,24a, 25 Inversion buffer 26 Carrier signal 27 Modulation signal 28,28a Receive antenna 29 AM modulation means 30 Phase comparison Means 31 Amplifier 32 AM demodulator 33 Phase comparator 34 LPF (Low Pass Filter)

Claims (3)

[Claims] 1. A direction directly below, while facing in different directions.
Two antennas with overlapping directional characteristics {2
(2_-1, 2_-2)}, Carry modulated signals (27) with opposite phases.
The transmitted signal (26) is AM-modulated and transmitted, while the antenna
Na {2 (2 (2_-1, 2 _-2)} The modulated wave received immediately below
From the dip point of the demodulated signal, the antenna {2 (2
_-1, 2_-2)} To determine the position of the radio beacon (Radio Bea
con), Both antennas (2_-1, 2_-2), Which receives the modulated wave
A signal antenna (28), Demodulates the modulated wave received by the receiving antenna (28)
Means (29), Of the signal demodulated by the demodulation means (29) and the modulated signal (27)
Means (30) for comparing the phases between, Both antennas (2_-1, 2_-2) Sends the modulated wave
Signal output power by the detection signal of the phase comparison means (30).
(22)_-1 ,twenty two_-2) When, Beacon transmission device characterized by comprising. 2. Directly downward direction while facing different directions
Two antennas with overlapping directional characteristics {2
(2_-1, 2_-2)}, Carry modulated signals (27) with opposite phases.
The transmitted signal (26) is AM-modulated and transmitted, while the antenna
Na {2 (2 (2_-1, 2 _-2)} The modulated wave received immediately below
From the dip point of the demodulated signal, the antenna {2 (2
_-1, 2_-2)} To determine the position of the radio beacon (Radio Bea
con), Both antennas (2_-1, 2_-2), Which receives the modulated wave
A signal antenna (28), Demodulates the modulated wave received by the receiving antenna (28)
Means (29), Of the signal demodulated by the demodulation means (29) and the modulated signal (27)
Means (30) for comparing the phases between, Both antennas (2_-1, 2_-2) Changes the modulated wave emitted from
The adjustment is made by the detection signal of the phase comparison means (30).
Means for changing each (23_-1 ,twenty three_-2) When, Beacon transmission device characterized by comprising. 3. Directly downward direction while facing different directions
Two antennas with overlapping directional characteristics {2
(2_-1, 2_-2)}, Carry modulated signals (27) with opposite phases.
The transmitted signal (26) is AM-modulated and transmitted, while the antenna
Na {2 (2 (2_-1, 2 _-2)} The modulated wave received immediately below
From the dip point of the demodulated signal, the antenna {2 (2
_-1, 2_-2)} To determine the position of the radio beacon (Radio Bea
con), Both antennas (2_-1, 2_-2), Which receives the modulated wave
A signal antenna (28), Demodulates the modulated wave received by the receiving antenna (28)
Means (29), Of the signal demodulated by the demodulation means (29) and the modulated signal (27)
Means (30) for comparing the phases between, Both antennas (2_-1, 2_-2) Sends the modulated wave
Signal output power by the detection signal of the phase comparison means (30).
(22)_-1 ,twenty two_-2) When, Both antennas (2_-1, 2_-2) Changes the modulated wave emitted from
The adjustment is made by the detection signal of the phase comparison means (30).
Means for changing each (23_-1 ,twenty three_-2) When, Beacon transmission device characterized by comprising.