JP2007036521A - Receiver, transmitter and automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the enlargement and an increase in the cost of an automobile-loaded satellite-communication antenna by a constraint by an environmental resistance or the like because the satellite-communication antenna is installed outside an automobile for avoiding the effect of an automobile body. <P>SOLUTION: The whole of a receiver 200 and a transmitter 300 containing antennas 211, 221, 311 and 321 is installed in a compartment. Elliptically polarized waves are formed by a distortion by the oblique projection of the radio waves of circularly polarized waves to a glass, but receiving sections 210 and 220 separate linearly polarized wave components and receive them, and a synthetic section 230 optimally synthesizes the components. The previously compensated elliptically polarized waves are transmitted so as to form the circularly polarized waves after the reception of the distortion by the glass in the case of a transmission. Consequently, a transmission control computer 332 predicts the distortion on the basis of the synthetic ratio of the synthesizer 230, transmitters 310 and 320 transmit a transmission signal adjusted by a transmission adjuster 331 as the linearly polarized waves, and the radio waves of the elliptically polarized waves are radiated by the synthesis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for optimal reception and optimal transmission in a wireless communication system that transmits and receives circularly polarized radio waves when elliptical polarization occurs due to characteristics of a transmission path.

An antenna of a wireless communication device mounted on an automobile or the like is installed outside the vehicle, for example, on a roof, in order to prevent communication failure due to being behind the vehicle body.
However, when communicating with a satellite moving at a high elevation angle, a line of sight with the satellite can be secured even if the antenna is installed in the vehicle, for example, under the windshield.
Communication with a satellite moving at a high elevation angle uses circularly polarized waves that do not require tracking of the plane of polarization because the positional relationship with the satellites changes in a complex manner.
JP 2000-232312 A JP 2002-064321 A Japanese Patent Laid-Open No. 11-088216 Japanese Patent Laid-Open No. 08-023227 Japanese Patent Laid-Open No. 2000-091842 JP 2003-322668 A

When an antenna is installed in a vehicle, the electric wave is attenuated by refraction reflection when passing through the windshield.
Since the windshield has an inclination, radio waves do not enter the glass perpendicularly, but enter with a certain incident angle. The incident angle varies depending on the positional relationship between the satellite and the car, the direction of the car, etc., and is not constant.
It is known that when a radio wave is incident on a material having a different refractive index and dielectric constant and is refracted and reflected, the polarization component parallel to the incident surface and the polarization component perpendicular to the incident surface have different reflectances.
Therefore, when circularly polarized radio waves pass through the windshield, the longitudinal and lateral attenuation factors differ and become elliptically polarized waves.
At this time, since the incident angle is not constant, the axial ratio (flatness) of the elliptically polarized wave is unknown.
Furthermore, since the direction of the incident surface is not constant, the direction of the major axis of the elliptically polarized wave is also unknown.

  The present invention has been made, for example, in order to solve the above-described problems. In an apparatus for transmitting and receiving radio waves that are elliptically polarized due to the characteristics of the transmission line, etc., the axial ratio of the elliptically polarized wave and the long axis The purpose is to enable optimal transmission and reception even when the direction is unknown.

The receiving apparatus according to the present invention is
In a receiver that receives elliptically polarized radio waves,
A first receiving antenna that receives a linearly polarized component in a predetermined direction in an elliptically polarized radio wave, and serves as a first received signal;
Receiving a linearly polarized wave component in a predetermined direction different from the first receiving antenna in the elliptically polarized radio wave, and a second receiving antenna as a second received signal;
A first demodulator that receives the first received signal received by the first receiving antenna, demodulates the input first received signal, and sets the first demodulated signal;
A second demodulator that receives the second received signal received by the second receiving antenna, demodulates the input second received signal, and sets the second demodulated signal;
Combining the first demodulated signal demodulated by the first demodulator and the second demodulated signal demodulated by the second demodulator so that the quality of the signal is a predetermined quality, And a synthesis unit
It is characterized by having.

  According to the present invention, for example, a linearly polarized wave component in a predetermined direction in an elliptically polarized radio wave and a linearly polarized wave component in a different predetermined direction are separately demodulated, and then combined into a combined signal. When the axial ratio of the elliptically polarized wave is small, there is an effect that an optimum combined signal can be obtained even when the direction of the long axis is unknown.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

  FIG. 1 is a block configuration diagram showing an example of a block configuration of the receiving device 200 and the transmitting device 300 in this embodiment.

  In this embodiment, the receiving apparatus 200 will be described.

  The reception apparatus 200 includes a first reception unit 210 (first reception antenna 211 and first demodulation unit 212), a second reception unit 220 (second reception antenna 221 and second demodulation unit 222), a synthesis Section 230 (reception adjustment section 231 and reception control calculation section 232), and decoding reproduction section 240.

Both the first receiving antenna 211 and the second receiving antenna 221 are antennas that receive linearly polarized radio waves.
Note that each of the first receiving antenna 211 and the second receiving antenna 221 does not have to be a single antenna. For example, a plurality of antennas may be used to improve directivity.
The first receiving antenna 211 and the second receiving antenna 221 are arranged to receive linearly polarized waves that are spatially orthogonal to each other when viewed from the zenith direction.
Thereby, the linearly polarized wave component of each direction in the elliptically polarized wave received by the receiving device 200 is received.
Note that the first receiving antenna 211 and the second receiving antenna 221 are not necessarily physically separated antennas. By providing different feeding points on one antenna, two types of linearly polarized wave components can be obtained. The structure which can receive may be sufficient.
In addition, the first receiving antenna 211 and the second receiving antenna 221 do not necessarily need to receive orthogonal linearly polarized components that are orthogonal to each other, and only need to receive linearly polarized components having different directions.
The first reception antenna 211 and the second reception antenna 221 output the received radio waves as a first reception signal and a second reception signal, respectively.

The first demodulator 212 and the second demodulator 222 receive the first reception signal and the second reception signal received by the first reception antenna 211 and the second reception antenna 221 respectively, and perform frequency conversion. And demodulate to an intermediate frequency.
The first demodulator 212 and the second demodulator 222 output the demodulated signals as a first demodulated signal and a second demodulated signal, respectively.

In addition, as a configuration example of the first receiving unit 210 and the second receiving unit 220, the configuration of the receiving antenna and the demodulating unit is shown. However, a linearly polarized wave component having a different polarization direction is received and a corresponding signal is received. Any other known configuration may be used as long as the configuration is output.
Moreover, it is good also as a structure which receives not only the linearly polarized wave component of two polarization directions but three or more linearly polarized wave components, and outputs the 3 or more signal corresponding to it.

  The combining unit 230 combines the first demodulated signal and the second demodulated signal, and outputs a combined signal.

  The reception adjustment unit 231 adjusts the amplitude and phase of the first demodulated signal and the second demodulated signal based on the reception control signal from the reception control calculation unit 232, and adds the first demodulated signal and the first demodulated signal. And the second demodulated signal.

The reception control calculation unit 232 measures the quality of the combined signal output from the reception adjustment unit 231, obtains the combination ratio and the amount of phase shift so that the measured quality is the best, and outputs the corresponding reception control signal.
For example, the signal-to-noise ratio of the combined signal is measured. Alternatively, the output power of the combined signal may be measured.

  The decoding / reproducing unit 240 further demodulates the synthesized signal output from the synthesizing unit 230 and extracts a baseband signal. The extracted baseband signal is, for example, a signal or information for broadcasting / communication / positioning and used by an external device.

  The operation will be described below.

FIG. 2 is a diagram illustrating the relationship between the elliptically polarized radio wave received by the receiving apparatus 200 and the demodulated signal.
In general, when communication is performed using circularly polarized radio waves, the attenuation due to the transmission characteristics of the transmission path varies depending on the direction of the polarization component and becomes elliptically polarized.
Further, even when the receiving antenna is not correctly oriented in the transmission direction, it is received as an elliptically polarized wave.

In FIG. 2, the xy plane is a plane on which the receiving antenna is arranged, and receives radio waves from the normal direction of the xy plane.
The first receiving antenna 211 receives a linearly polarized component in the y-axis direction.
The second receiving antenna 221 receives a linearly polarized wave component in the x-axis direction.

The received elliptically polarized radio wave has three parameters a, b, and α.
a is an amplitude in the major axis direction, b is an amplitude in the minor axis direction, and α is a spatial angle of the major axis direction with respect to the x axis direction.

The amplitude of the first demodulated signal 512 is p, the amplitude of the second demodulated signal 522 is q, and the phase difference between the first demodulated signal 512 and the second demodulated signal 522 is β.
Since the first demodulator 212 and the second demodulator 222 only perform frequency conversion, the ratio between the amplitude p and the amplitude q and the phase difference β are the amplitudes of the first received signal and the second received signal. The ratio and phase difference are maintained.

  Here, for the sake of simplicity, it is assumed that the gain of the demodulation unit is 1.

For example, if α = 0, p = b, q = a, and β = π / 2.
here,

と置くと、一般に、

In general,

が成り立つ。

Holds.

The reception adjusting unit 231 uses a phase shifter to phase-shift one or both of the first demodulated signal and the second demodulated signal so that the phase difference β between the first demodulated signal and the second demodulated signal becomes zero. To do.
In addition, one or both of the first demodulated signal and the second demodulated signal are amplified or attenuated by an amplifier or an attenuator so that the amplitudes p and q of the first demodulated signal and the second demodulated signal are equal.
The reception adjusting unit 231 adds the demodulated signals having the same amplitude and phase with an adder to obtain a combined signal.

  The reception control calculation unit 232 measures the quality of the combined signal, generates a reception control signal for controlling the reception adjustment unit 231 based on the measurement result, and outputs the reception control signal.

In order to obtain the optimum amplification amount and phase shift amount, the reception control calculation unit 232 operates as follows, for example.
First, a reception control signal for controlling the reception adjustment unit 231 is output so as to synthesize a signal with an arbitrary amplification amount and phase shift amount (for example, amplification amount 1 and phase shift amount 0).
Based on this, the signal-to-noise ratio of the combined signal output from the reception adjustment unit 231 is measured and stored in the storage device.
Next, the reception control signal is changed to change the amplification amount and the phase shift amount of the reception adjustment unit 231.
Again, the signal-to-noise ratio of the combined signal is measured and stored in the storage device.
By repeating this, the relationship between the amplification amount and phase shift amount within a predetermined range and the signal-to-noise ratio is obtained, and the storage device stores the amplification amount and phase shift amount that have the best signal-to-noise ratio. Set the optimum amount of amplification and phase shift.

  In order to shorten the time required to obtain the optimum amplification amount and phase shift amount, for example, the step width for changing the amplification amount and phase shift amount is initially increased, and the range is gradually narrowed down. Also good.

  As described above, since the amplification amount and the phase shift amount of the reception adjustment unit 231 are controlled based on the quality of the combined signal, it is not necessary to measure the amplitude and phase of the reception signal or the demodulated signal, and it is optimal with a simpler configuration. There is an effect that the amount of amplification and the amount of phase shift can be obtained.

  In addition, according to this structure, theoretically, both right-handed circularly polarized wave and left-handed circularly polarized wave can be received. However, since 0 <β <π / 2 when receiving right-handed circularly polarized wave, and −π / 2 <β <0 when receiving left-handed circularly polarized wave, the two can be distinguished. Therefore, when a signal that is not a desired radio wave is received, interference can be avoided by taking measures such as cutting the output.

  FIG. 3 is a block diagram illustrating another example of a block configuration of the receiving device 200 and the transmitting device 300 in this embodiment.

  The receiving apparatus 200 and the transmitting apparatus 300 in this example are the same as those described with reference to FIG.

The reception control calculation unit 232 does not measure the quality of the combined signal, but measures the amplitudes p and q and the phase difference β of the first demodulated signal and the second demodulated signal.
The reception control calculation unit 232 obtains the optimum amplification amount and phase shift amount of the reception adjustment unit 231 based on the measured amplitudes p and q and the phase difference β, and generates a reception control signal.
The reception adjustment unit 231 amplifies and shifts the first demodulated signal and the second demodulated signal based on the reception control signal generated by the reception control calculation unit 232, and outputs a combined signal.

  As described above, since the optimum amplification amount and phase shift amount are obtained by directly measuring the amplitude and phase of the demodulated signal, there is an effect that there is no time loss due to feedback and the optimum reception can be performed quickly.

  FIG. 4 is a diagram showing an example of the automobile 100 equipped with the receiving device 200 and the transmitting device 300 in this embodiment.

The receiving apparatus 200 and the transmitting apparatus 300 in this embodiment are assumed to communicate with the communication satellite 400.
The communication satellite 400 is a satellite that moves at a high elevation angle (for example, an elevation angle of 70 degrees or more).
Therefore, as shown in FIG. 4, the reception device 200 and the transmission device 300 (the antenna thereof) can be mounted on the communication satellite 400 through the windshield 110 (an example of a protection portion and a cover portion) even when the reception device 200 and the transmission device 300 (the antenna thereof) are mounted in the vehicle interior. The prospect can be secured.

  Note that the receiving device 200 and the transmitting device 300 only need to be installed at a position where the line of sight with the communication satellite 400 can be ensured, so that the receiving device 200 and the transmitting device 300 may be installed not only on the windshield 110 but also on the rear glass or the sunroof.

  However, in general passenger cars, the windshield has a gentler inclination with respect to the horizontal plane than the rear glass. Therefore, it is preferable to install the windshield under the windshield because it is less affected by the glass.

  FIG. 5 is a schematic diagram showing a state in which radio waves communicated between the communication satellite 400, the receiving device 200, and the transmitting device 300 are transmitted through the windshield 110.

Radio waves from the communication satellite 400 enter the windshield 110.
Part of the radio wave is reflected by the surface of the windshield 110, and part of it is refracted and enters the windshield.
Similarly, even at the boundary surface between the windshield 110 and the vehicle interior, the light is reflected and refracted (the reflected wave is not shown), and the radio wave enters the vehicle interior, and is received by the receiving device 200.

  Similarly, when the radio wave transmitted by the transmission device 300 passes through the windshield 110, it is reflected and refracted and then travels toward the communication satellite 400.

  The reflectivity and transmissivity when radio waves are reflected and refracted vary depending on the incident angle. It also differs depending on the polarization direction.

FIG. 6 is a graph showing an example of the relationship between the incident angle θ and the radio wave transmittance.
Here, the “orthogonal polarization” is a linear polarization component in a direction perpendicular to an incident surface (a surface including an incident radio wave and a normal line of a boundary surface (for example, air and windshield)).
The “parallel polarization” is a linearly polarized component in a direction parallel to the incident surface.
In this figure, the transmittance is obtained by summing attenuation due to two refractions of the front glass surface and the back surface.

An elliptically polarized wave (including a circularly polarized wave) can be regarded as a combination of two linearly polarized waves.
If the radio wave transmitted by the communication satellite 400 is a clean circularly polarized wave, the linearly polarized wave component in any direction has the same magnitude.
However, in this embodiment, since the receiving device 200 (the antenna thereof) is in the vehicle interior, the radio waves attenuated as shown in FIG. 6 are received due to reflection / refraction when passing through the windshield 110.

  At this time, as shown in FIG. 6, the amount of attenuation differs depending on the spatial direction of the polarization component. Therefore, even if the original radio wave is completely circularly polarized, the radio wave received by the receiving device 200 is It becomes elliptical polarization.

  In this embodiment, even when the radio wave that has been elliptically polarized by being transmitted through the windshield 110 is received in this manner, the combining unit 230 combines the signals so that the quality of the combined signal is the best. Therefore, there is an effect that a good reception state can be maintained.

Thus, if the receiving apparatus 200 is premised on communication with a satellite with a high elevation angle, even if the receiving apparatus 200 is installed in the interior of the automobile 100, it is affected by shadowing due to the roof or shaft of the automobile. And the received power does not decrease.
Although the influence of attenuation due to transmission through the windshield 110 is unavoidable, the above-described configuration can compensate for this attenuation.
As a result, the receiving device 200 can be installed in the passenger compartment of the automobile 100, so that environmental resistance performance is not required as in the case of installing outside the vehicle, and there are no restrictions due to the mounting structure such as cable routing.
Thereby, the structure of the receiving apparatus 200 can be simplified and manufacturing cost can be kept low.

In the configuration example described above, the first demodulated signal and the second demodulated signal are added together with the same amplitude and phase to obtain a combined signal.
However, for example, a configuration may be adopted in which the signal-to-noise ratio of the first demodulated signal and the second demodulated signal is measured, and the one with the better reception state is selected to obtain a combined signal.
Alternatively, the signal-to-noise ratio of signals added with the same amplitude and phase may be measured, and a signal having the best reception state may be selected from the three to obtain a combined signal.
With such a configuration, since the best signal is always selected, the communication quality is improved.

  The receiving device 200 is most effective when used for communication with a satellite that moves at a high elevation angle. However, due to measures such as increasing the number of antennas, a general geostationary satellite or ground equipment is used. It can also be used for broadcasting, communication and positioning.

Embodiment 2. FIG.
A second embodiment will be described with reference to FIGS.

  FIG. 1 is a block configuration diagram showing an example of a block configuration of the receiving device 200 and the transmitting device 300 in this embodiment.

  In this embodiment, the transmission apparatus 300 will be described.

The transmission apparatus 300 includes a first transmission unit 310 (first transmission antenna 311 and first modulation unit 312), a second transmission unit 320 (second transmission antenna and second modulation unit 322), and a separation unit. 330 (transmission adjustment unit 331 and transmission control calculation unit 332) and signal generation unit 340 (an example of an input unit).
The combining unit 230 and the separation unit 330 are examples of the control unit 350.

Both the first transmission antenna 311 and the second transmission antenna 321 are antennas that transmit linearly polarized radio waves.
Note that each of the first transmission antenna 311 and the second transmission antenna 321 does not have to be a single antenna. For example, a plurality of antennas may be used to improve directivity.
The first transmission antenna 311 and the second transmission antenna 321 are arranged to transmit linearly polarized waves that are spatially orthogonal to each other in the zenith direction.
As a result, the radio wave radiated from the transmission apparatus 300 is combined with two linearly polarized waves to become elliptically polarized waves (including circularly polarized waves) as a whole.
Note that the first transmission antenna 311 and the second transmission antenna 321 do not necessarily need to be physically separated antennas. By providing different feeding points on one antenna, two types of linearly polarized radio waves are provided. May be configured to transmit.
Further, the first transmission antenna 311 and the second transmission antenna 321 do not necessarily need to transmit orthogonal linearly polarized waves, and may transmit linearly polarized waves having different directions.
The first transmission antenna 311 and the second transmission antenna 321 receive the first modulated signal and the second modulated signal, respectively, and transmit them.

  Note that the first transmission antenna 311 and the second transmission antenna 321 may be shared with the first reception antenna and the second reception antenna of the reception device 200.

  The first modulation unit 312 and the second modulation unit 322 receive the first transmission signal and the second transmission signal, perform frequency conversion to the transmission frequency, and use them as the first modulation signal and the second modulation signal. Output.

In addition, as a configuration example of the first transmission unit 310 and the second transmission unit 320, the configuration of the transmission antenna and the modulation unit has been shown. However, linearly polarized waves having different polarization directions corresponding to the input signals are shown. Any other known configuration may be used as long as it is configured to transmit radio waves and combine them into elliptically polarized waves.
Moreover, it is good also as a structure which becomes not only a linearly polarized wave of two polarization directions but an electromagnetic wave of three or more linearly polarized waves, and becomes an elliptically polarized wave by the combination.

  The separation unit 330 separates the original signal and outputs a first transmission signal and a second transmission signal.

  The transmission adjustment unit 331 separates the original signal based on the transmission control signal from the transmission control calculation unit 332, and adjusts the amplitude and phase of each as the first transmission signal and the second transmission signal.

  The transmission control calculation unit 332 generates and outputs a transmission control signal that controls the ratio by which the transmission adjustment unit 331 divides the original signal, the amount of amplification of the first transmission signal and the second transmission signal, and the amount of phase shift. .

  The signal generation unit 340 (an example of an input unit) receives a baseband signal, modulates the input baseband signal, and outputs it as an original signal. The baseband signal is input from an external device and is a signal or information for communication or the like.

  The operation will be described below.

  The transmission control calculation unit 332 is configured so that the elliptically polarized radio wave generated by combining the linearly polarized radio waves transmitted by the first transmission antenna 311 and the second transmission antenna 321 has a desired polarization characteristic. A transmission control signal for controlling the transmission adjustment unit 331 is generated.

  FIG. 7 is an explanatory diagram for explaining the relationship between the amount of attenuation of the received elliptically polarized wave and the polarization characteristic of the elliptically polarized wave to be transmitted.

The circularly polarized radio wave 501 transmitted by the communication satellite 400 is attenuated when passing through the windshield 110 and is received by the receiving apparatus 200 as an elliptically polarized radio wave 502.
At this time, the attenuation rate in the direction with the smallest attenuation (direction inclined by α with respect to the x axis) is a / c, and the attenuation rate in the direction with the largest attenuation is b / c.

Assuming that the attenuation rate when the radio wave transmitted by the transmission device 300 passes through the windshield 110 is the same as that at the time of reception, in order to be circularly polarized after passing through the windshield 110, c ′ = a It is only necessary to transmit radio waves such that “× (a / c), c ′ = b” × (b / c).
That is, adjustment is made so that a ′ = cc ′ / a and b ′ = cc ′ / b.
Here, when C = cc ′ / ab, a ′ = Cb and b ′ = Ca.

  The amplitude of the first transmission signal is p ′, the amplitude of the second transmission signal is q ′, and the phase difference between the first transmission signal and the second transmission signal is β ′.

  here,

After all,

であるから、ｐ’＝Ｃｑ、ｑ’＝Ｃｐ、γ’＝−γとすればよい。γ＝β−π／２、γ’＝β’−π／２であるから、β’＝π−βである。

Therefore, p ′ = Cq, q ′ = Cp, and γ ′ = − γ may be set. Since γ = β−π / 2 and γ ′ = β′−π / 2, β ′ = π−β.

  In order to realize this, the separation unit 330 operates as follows, for example.

  The transmission control calculation unit 332 receives the reception control signal output from the reception control calculation unit 232, obtains the amplification amount and the phase shift amount of the transmission adjustment unit 331 based on the input reception control signal, and determines the transmission control signal. Output.

  As described in Embodiment 1, the reception control signal is amplified so that the amplitudes p and q of the first demodulated signal and the second demodulated signal are equal, and phase-shifted so that the phase difference β is zero. Is a signal that instructs the reception adjustment unit 231.

  For example, if the amplification amount of the first demodulated signal in the reception adjustment unit 231 is r / p and the amplification amount of the second demodulated signal is r / q, the amplitudes of the two demodulated signals are equal.

The transmission adjustment unit 331 separates the original signal into two signals having the same amplitude. Here, let r ′ be the amplitude of the separated signal.
The transmission control calculation unit 332 directly uses the amplification amount instructed by the reception control calculation unit 232 as the amplification amount of the transmission signal. That is, the amplification amount of the first transmission signal is r / p, the amplification amount of the second transmission signal is r / q, and a transmission control signal indicating it is output.
Based on the transmission control signal, the transmission adjustment unit 331 amplifies one of the two separated signals by r / p to make a first transmission signal, and r / q amplifies the other to make a second transmission signal.
Here, if C = rr ′ / pq, the amplitude p ′ of the first transmission signal is p ′ = (r / p) × r ′ = Cq, and the amplitude q ′ of the second transmission signal is q ′ = (r / q) × r ′ = Cp.

  The reception adjustment unit 231 keeps the phase of the first demodulated signal as it is, delays the phase of the second demodulated signal by β (= γ + π / 2), and sets the phases of the first demodulated signal and the second demodulated signal. Align.

The transmission adjustment unit 331 separates the original signal into two signals whose phases are shifted by π.
The transmission control calculation unit 332 uses the phase shift amount instructed by the reception control calculation unit 232 as it is as the phase shift amount of the transmission signal. That is, the first transmission signal is not phase-shifted, the phase of the second transmission signal is delayed by β, and a transmission control signal indicating that is output.
Based on the transmission control signal, the transmission adjusting unit 331 uses one of the two separated signals as it is as the first transmission signal without shifting the phase, and delays the other phase by β as the second transmission signal.
Then, the phase difference β ′ between the first transmission signal and the second transmission signal is β ′ = π−β.

With the configuration described here, the reception control signal generated by the reception control calculation unit 232 can be used as it is as a transmission control signal. The transmission control calculation unit 332 may output the input reception control signal as it is as a transmission control signal.
Or in order to adjust transmission power, you may output the transmission control signal which controls the ratio of the amplification factor of a 1st transmission signal and a 2nd transmission signal, and amplifies and attenuates as a whole.

  As described above, the attenuation characteristic of the transmission path is predicted based on the received polarization state of the elliptically polarized wave, and the amplified radio wave is transmitted so as to compensate the predicted attenuation characteristic. A wave of waves arrives. Therefore, there is an effect that communication with good quality becomes possible.

As shown in FIG. 4, when the transmission device 300 (the antenna thereof) is installed in the passenger compartment of the automobile 100, the transmitted radio wave obliquely passes through the windshield 110 and reaches the communication partner (in this example, the communication satellite 400). To do.
As described in the first embodiment, the radio wave transmitted obliquely through the windshield 110 is attenuated by the catadioptric action at the time of transmission. The attenuation characteristic at this time varies depending on the polarization direction.

  The transmitting apparatus 300 predicts the attenuation characteristic of the radio wave to be transmitted from the attenuation characteristic of the radio wave received by the receiving apparatus 200, and transmits the radio wave compensated for it.

  The attenuation due to catadioptric refraction in the windshield 110 differs depending on the refractive index of the windshield 110. The refractive index varies depending on the frequency of the radio wave, but when the frequency of the transmitted radio wave is the same as or close to the frequency of the received radio wave, the refractive index may be considered to be substantially the same.

  Therefore, it can be considered that the attenuation characteristic of the transmitted radio wave predicted based on the attenuation characteristic of the received radio wave is equal to the actual attenuation characteristic if the reception frequency and the transmission frequency are close.

  Therefore, when the reception frequency and the transmission frequency are close, there is an effect that the attenuation characteristic of the transmission radio wave by the windshield 110 can be compensated with the above-described simple configuration.

When the reception frequency and the transmission frequency are far from each other, a difference in attenuation characteristic based on a difference in refractive index due to a frequency difference is stored in advance in a storage device, for example.
The transmission control calculation unit 332 reads the difference in attenuation characteristics from the storage device, and uses this to calculate the amplification amount / phase shift amount based on the transmission control signal from the amplification amount / phase shift amount based on the reception control signal.

  Thereby, even when the reception frequency and the transmission frequency are separated, there is an effect that the attenuation characteristic of the transmission radio wave by the windshield 110 can be compensated.

Thus, if the transmission device 300 is premised on communication with a satellite with a high elevation angle, even if the transmission device 300 is installed in the interior of the automobile 100, it is affected by shadowing due to the roof or shaft of the automobile. And transmission power does not decrease.
Although the influence of attenuation due to transmission through the windshield 110 is unavoidable, the above-described configuration can compensate for this attenuation.
As a result, the transmission device 300 can be installed in the vehicle interior of the automobile 100, so that environmental resistance is not required as in the case of installation outside the vehicle, and there are no restrictions due to the mounting structure such as cable routing.
Thereby, the structure of the transmission apparatus 300 can be simplified and manufacturing cost can be suppressed low.

Embodiment 3 FIG.
The third embodiment will be described with reference to FIG.

  FIG. 8 is a block configuration diagram showing an example of a block configuration of transmitting apparatus 300 in this embodiment.

  The transmitting apparatus 300 includes a first receiving unit 210 (first receiving antenna 211 and first demodulation unit 212), a second receiving unit 220 (second receiving antenna 221 and second demodulation unit 222), One transmission unit 310 (first transmission antenna 311 and first modulation unit 312), second transmission unit 320 (second transmission antenna 321 and second modulation unit 322), control unit 350 (transmission control calculation) Unit 332 and transmission adjustment unit 331), and a signal generation unit 340 (an example of an input unit).

Among these, the first receiving unit 210 and the second receiving unit 220 are the same as those of the receiving apparatus 200 described in the first embodiment, and thus description thereof is omitted here.
In addition, the first transmission unit 310, the second transmission unit 320, and the signal generation unit 340 are the same as those of the transmission device 300 described in the second embodiment, and thus description thereof is omitted here.

The control unit 350 divides the original signal input from the signal generation unit 340 into a first transmission signal and a second transmission signal and outputs them.
With the first transmission signal and the second transmission signal, the elliptically polarized radio wave transmitted by combining the linearly polarized radio waves transmitted by the first transmitter 310 and the second transmitter 320 is predetermined. The control unit 350 adjusts the amplitude and phase so as to have the above characteristics.

  That is, the control unit 350 is a block that performs the same function as the separation unit 330 described in the second embodiment.

The control unit 350 includes a transmission adjustment unit 331 and a transmission control calculation unit 332.
Among these, the transmission adjustment unit 331 is the same as that of the transmission apparatus 300 described in the second embodiment, and thus description thereof is omitted here.

The transmission control calculation unit 332 generates a transmission control signal that controls the transmission adjustment unit 331.
Based on the first demodulated signal and the second demodulated signal output from the first receiving unit 210 and the second receiving unit 220, the transmission control calculating unit 332 outputs the first transmission signal and the first transmission signal in the transmission adjusting unit 331. The amount of amplification / phase shift of the second transmission signal is obtained, and a transmission control signal indicating the amount is generated.

  As described in Embodiment 2, the amplification amount and phase shift amount in the transmission adjustment unit 331 can be obtained from the amplitude ratio and phase difference between the first demodulated signal and the second demodulated signal.

Depending on the form of communication, there is a case where transmission is unilaterally and reception is not necessary.
Even when reception is not necessary, if the attenuation characteristic of the transmission path is measured by receiving the signal from the communication partner in this way, the polarization characteristics of the radio wave to be transmitted are based on the measurement. It is possible to control the performance and to secure a good communication state.

  Summarizing what has been described above.

When an attempt is made to receive a signal from a satellite with an antenna installed in a car, the received power is reduced due to the influence of the glass or the body such as the roof. In order to avoid this, it is generally possible to avoid these effects by installing the antenna outside the vehicle, but mounting it outside the vehicle increases the restrictions on environmental resistance and mounting structure, and increases the size of the antenna. This is causing high prices.
However, in the case of a satellite moving at a high elevation angle, the signal is hardly affected by the vehicle body unless the angle of the windshield of the automobile is steep, and the signal can be received by compensating only for the attenuation of the windshield.
Taking advantage of this characteristic of high elevation satellites, circularly polarized signals are separated and received by orthogonal linearly polarized antennas, demodulated, and then optimally combined to configure the antenna for satellite installation in-house. The cost is reduced and simplified.
In addition, as an algorithm for optimal synthesis, the optimum synthesis is performed by switching the algorithm according to the reception state, such as those that optimize the noise-to-signal power ratio, those that optimize the signal level, and those that selectively receive. Adapt.
Furthermore, based on the composite distribution value obtained by reception, the transmission signal can be transmitted with weights applied to a plurality of antennas, and transmission / reception antennas can be configured. it can.

In mobile satellite communications, the direction of the satellite and the mobile body cannot be specified, so circularly polarized radio waves that do not require polarization tracking are often used. As a technique for miniaturizing a circularly polarized antenna for satellite communication used in such a system, there is a technique realized by providing feeding points with a phase difference of 90 degrees on a patch antenna. Such an antenna has a simple configuration, but if there is a difference in the power of the horizontally polarized wave component and the vertically polarized wave component of the received circularly polarized signal, the received power will change depending on the direction of the antenna and the signal quality will deteriorate. It is also conceivable that the message cannot be received.
Such a power difference for each polarization appears remarkably when radio waves pass obliquely through the glass. The component in which the glass tilt direction and the polarization direction coincide with each other is greatly attenuated, and the component perpendicular to the glass tilt direction and the polarization direction is not attenuated so much. Using these circularly polarized radio wave transmission characteristics of glass, linearly polarized antennas that are orthogonal to the zenith direction and orthogonal to each other are arranged in a specific direction with respect to the inclination of the windshield. By receiving signals with high attenuation and signals with low attenuation individually and combining them optimally, circularly polarized signals can be received efficiently, enabling the antenna to be mounted in the vehicle and reducing the antenna cost. It aims to simplify the structure.

In FIG. 9, a satellite station (communication satellite 400) outputs a circularly polarized signal for broadcasting, communication, positioning, etc. to a mobile station (receiving device 200 mounted on automobile 100).
As shown in FIG. 10, linearly polarized antennas are arranged at the lower part of the windshield so as to be orthogonal to the zenith direction.
In FIG. 11, linearly polarized antennas (first receiving antenna 211 and second receiving antenna 221) separate circularly polarized signals into horizontally polarized waves and vertically polarized waves and receive the signals.
The demodulator (the first demodulator 212 and the second demodulator 222) demodulates the signal from each antenna to generate a received signal (first demodulated signal, second demodulated signal).
The optimum synthesizer (synthesizer 230) synthesizes the demodulated signals of the antennas, weights the phase and amplitude of the signals from the antennas so that the noise-to-signal power ratio becomes maximum.
The decoding / playback unit (240) combines the output of the optimum combining unit and outputs signals and information for broadcasting, communication, positioning, etc. to the outside.

By using a satellite moving at a high elevation angle, the line of sight from the lower part of the windshield to the satellite is secured, and the attenuation that occurs when a circularly polarized signal passes through the glass differs between the vertically polarized wave and the horizontally polarized wave. Since it is smaller than the other attenuation, each is separated and received, and the quality of the signal can be maintained by optimally combining these signals. The number of antennas can be two or more as shown in FIG.
Further, as shown in FIGS. 13 to 15, the optimum synthesizer algorithm is not limited to the method of maximizing the noise-to-signal power ratio of the synthesized word, but also the method of maximizing the synthesized power and the respective noise-to-signal power ratio. There is a method of comparing and switching received power. Or it is good also as the method of selecting and switching these some algorithms. The quality of the line is improved by using an algorithm corresponding to each reception environment.

In FIG. 16, based on the phase / amplitude control information for each antenna obtained by reception, the weight for the phase / amplitude of the transmission signal is estimated (by the transmission control calculation unit 332) and transmitted before each antenna input (transmission). By performing weighting (adjustment unit 331), it is possible to optimize the circularly polarized signal from the mobile station (transmitting device 300 mounted on automobile 100).
As a result, communication transmission antennas (first transmission antenna 311 and second transmission antenna 321) can also be mounted in the vehicle, so that further cost reduction is expected.
As shown in FIG. 17, when the transmitting antenna and the receiving antenna are different antennas, transmission and reception can be realized simultaneously. This is effective when the transmission frequency and reception frequency are different.
Further, as shown in FIG. 16, the transmitting antenna and the receiving antenna may be shared.

FIG. 3 is a block configuration diagram illustrating an example of a block configuration of a receiving device 200 and a transmitting device 300 in Embodiment 1 and Embodiment 2. The figure which shows the relationship between the electromagnetic wave of the elliptical polarization which the receiver 200 receives, and a demodulation signal. FIG. 4 is a block diagram illustrating another example of a block configuration of the reception device 200 and the transmission device 300 in Embodiment 1. FIG. 3 is a diagram illustrating an example of an automobile 100 equipped with a receiving device 200 and a transmitting device 300 in Embodiment 1. The schematic diagram which shows a mode that the electromagnetic wave which the communication satellite 400 communicates with the receiver 200 and the transmitter 300 permeate | transmits the windshield 110. FIG. The graph which shows an example of the relationship between incident angle (theta) and the transmittance | permeability of an electromagnetic wave. Explanatory drawing for demonstrating the relationship between the attenuation amount of the received elliptically polarized wave, and the polarization characteristic of the elliptically polarized wave which should be transmitted. FIG. 10 is a block configuration diagram illustrating an example of a block configuration of a transmission apparatus 300 according to Embodiment 3. The figure which shows the relationship between the motor vehicle 100 and the communication satellite 400. FIG. FIG. 3 is a diagram illustrating an example of a position where a receiving device 200 and a transmitting device 300 are installed in an automobile 100. The figure which shows an example of the installation state of the antenna of the receiver 200. FIG. The figure which shows an example of the installation state of the antenna of the receiver 200. FIG. The block block diagram which shows an example of the block configuration of the synthetic | combination part 230. FIG. The block block diagram which shows an example of the block configuration of the synthetic | combination part 230. FIG. The block block diagram which shows an example of the block configuration of the synthetic | combination part 230. FIG. The figure which shows an example of the installation state of the antenna of the receiver 200 and the transmitter 300. The figure which shows an example of the installation state of the antenna of the receiver 200 and the transmitter 300.

Explanation of symbols

  100 automobile, 110 windshield, 200 receiving device, 210 first receiving unit, 211 first receiving antenna, 212 first demodulating unit, 220 second receiving unit, 221 second receiving antenna, 222 second receiving antenna Demodulation unit, 230 synthesis unit, 231 reception adjustment unit, 232 reception control calculation unit, 240 decoding reproduction unit, 300 transmission device, 310 first transmission unit, 311 first transmission antenna, 312 first modulation unit, 320 second Second transmission unit, 321 second transmission antenna, 322 second modulation unit, 330 separation unit, 331 transmission adjustment unit, 332 transmission control calculation unit, 340 signal generation unit, 400 communication satellite, 501 601 Radio wave 502, 602 Elliptical polarization radio wave, 512 first demodulated signal, 522 second demodulated signal.

Claims (11)

In a receiver that receives elliptically polarized radio waves,
A first receiving antenna that receives a linearly polarized component in a predetermined direction in an elliptically polarized radio wave, and serves as a first received signal;
Receiving a linearly polarized wave component in a predetermined direction different from the first receiving antenna in the elliptically polarized radio wave, and a second receiving antenna as a second received signal;
A first demodulator that receives the first received signal received by the first receiving antenna, demodulates the input first received signal, and sets the first demodulated signal;
A second demodulator that receives the second received signal received by the second receiving antenna, demodulates the input second received signal, and sets the second demodulated signal;
Combining the first demodulated signal demodulated by the first demodulator and the second demodulated signal demodulated by the second demodulator so that the quality of the signal becomes a predetermined quality, And a synthesis unit
A receiving apparatus comprising: The synthesis unit is
The first demodulated signal demodulated by the first demodulator, the second demodulated signal demodulated by the second demodulator, and the amplification of at least one of the first demodulated signal and the second demodulated signal A reception control signal for controlling at least one of an amount, an attenuation amount, and a phase shift amount, and based on the received reception control signal, at least one of the first demodulated signal and the second demodulated signal, A reception adjustment unit that adjusts by at least one of amplification, attenuation, and phase shift, and adds to a combined signal;
A reception control calculation unit for obtaining the reception control signal in which the quality of the combined signal is a predetermined quality;
The receiving apparatus according to claim 1, comprising: The receiving device is
A circularly polarized radio wave passes through a transmission line in which the attenuation amount of the linearly polarized wave component in a predetermined direction and the attenuation amount of the linearly polarized wave component in a predetermined direction different from the predetermined direction are elliptical polarized waves. The receiving apparatus according to claim 1, wherein the receiving apparatus is a receiving apparatus that receives a signal. The receiving device is
In the arrival direction of radio waves received by the first receiving antenna and the second receiving antenna, the receiving device is protected and has a protection unit that transmits radio waves,
When circularly polarized radio waves pass through the protection unit, the attenuation amount of the linear polarization component in a predetermined direction differs from the attenuation amount of the linear polarization component in a predetermined direction different from the predetermined direction, resulting in elliptical polarization. The receiving apparatus according to claim 1, wherein the receiving apparatus receives received radio waves.   An automobile having the receiving device according to claim 1 for receiving a radio wave transmitted through a cover portion covering the passenger compartment. In a transmitter that transmits elliptically polarized radio waves,
An input section for inputting the original signal;
A separation unit that separates the original signal input by the input unit into a first transmission signal and a second transmission signal;
A first modulation unit that modulates the first transmission signal separated by the separation unit into a first modulation signal;
A second modulation unit that modulates the second transmission signal separated by the separation unit into a second modulation signal; and
A first transmission antenna that transmits the first modulated signal modulated by the first modulator as a linearly polarized radio wave in a predetermined direction;
A second transmission antenna that transmits the second modulated signal modulated by the second modulation unit as a linearly polarized radio wave in a predetermined direction different from that of the first transmission antenna;
And transmitting an elliptically polarized radio wave by combining the radio waves transmitted by the first transmission antenna and the second transmission antenna. The separation part is
The original signal input by the input unit and a transmission control signal for controlling at least one of the amplification amount, attenuation amount, and phase shift amount of the signal obtained by dividing the original signal are input. The first divided signal and the second divided signal are divided and at least one of the first divided signal and the second divided signal is amplified, attenuated, and phase-shifted based on the input transmission control signal. A transmission adjusting unit that adjusts at least one of the first transmission signal and the second transmission signal;
A transmission control calculation unit for obtaining the transmission control signal in which elliptically polarized radio waves generated by combining the radio waves transmitted by the first transmission antenna and the second transmission antenna are circularly polarized after passing through a predetermined transmission path; ,
The transmission apparatus according to claim 6, further comprising: The transmitter is
An elliptically polarized radio wave is received, and at least one of an amplitude ratio and a phase difference between a linearly polarized component in a predetermined direction of the received elliptically polarized radio wave and a linearly polarized component in a predetermined direction other than the predetermined direction is determined. A receiving device that outputs the component ratio signal shown,
The transmission control calculation unit
Input the component ratio signal output by the receiver,
Based on the input component ratio signal, when the received elliptically polarized radio wave passes through the transmission line, the amount of attenuation of the linearly polarized component in a predetermined direction and the linearly polarized wave in a predetermined direction different from the predetermined direction The transmission apparatus according to claim 7, wherein an attenuation amount of a component is estimated, and the transmission control signal is obtained based on the estimated attenuation amount. The transmitter is
In the radiation direction of the radio wave transmitted by the first transmission antenna and the second transmission antenna, the transmission device is protected and has a protection unit that transmits the radio wave.
When the transmitted elliptically polarized radio wave passes through the protection unit, the attenuation amount of the linear polarization component in a predetermined direction differs from the attenuation amount of the linear polarization component in a predetermined direction different from the predetermined direction. The transmission device according to claim 6, wherein the transmission device is a wave.   An automobile comprising the transmission device according to claim 6 which transmits a transmitted radio wave through a cover portion covering the vehicle interior. In a transmitter that transmits elliptically polarized radio waves,
A first receiving unit that receives a linearly polarized component in a predetermined direction in an elliptically polarized radio wave and sets it as a first received signal;
A second receiving unit that receives a linearly polarized wave component in a predetermined direction different from the first receiving unit in the elliptically polarized radio wave, and sets the second received signal;
An input section for inputting the original signal;
A separation unit that separates the original signal input by the input unit into a first transmission signal and a second transmission signal;
The first reception signal received by the first reception antenna and the second reception signal received by the second reception antenna are input, and the first reception signal and the second reception signal that are input A component ratio signal indicating at least one of an amplitude ratio and a phase difference is generated, the first transmission signal and the second transmission signal separated by the separation unit are input, and based on the generated component ratio signal, the above A control unit that controls at least one of amplitude and phase of at least one of the first transmission signal and the second transmission signal;
A first transmitter for transmitting the first transmission signal as a linearly polarized radio wave in a predetermined direction;
A second transmitter that transmits the second transmission signal as a linearly polarized radio wave in a predetermined direction different from that of the first transmitter;
A transmission device comprising:

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