JPH0728229B2 - Communication method and device using flexible structure antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] In a transmission system using an antenna having a structure for improving the radiation characteristic of an electromagnetic wave, the deformation state of the antenna is measured, and the time when the radiation characteristic improvement degree of this antenna electromagnetic wave is large. By detecting the band and performing communication during this time period, high-performance communication is possible even with a lightweight flexible structure antenna.

[Industrial application field]

The present invention relates to a communication system using a flexible structure antenna, and more particularly to a communication system requiring a lightweight structure antenna such as satellite communication.

When performing wireless communication with a moving body, a lightweight antenna is required to be mounted on the moving body. However,
In satellite communication, etc., there are restrictions such as long propagation distance of signals and inability to use elements with high transmission power in terms of available power or reliability. And an improved antenna gain is required.

[Conventional technology]

Parabolic antennas, antenna-mounted masts, and the like have been developed and used to improve radiation characteristics of electromagnetic waves such as antenna directivity and antenna gain.

However, the antenna-mounted mast vibrates due to wind or other external stress. For this reason, communication with a high directivity may cause communication interruption due to some vibration, and in reality, only a slightly dull directivity can be used.

The parabolic antenna also vibrates due to wind or other external stress. Therefore, in order to suppress this vibration, a solid (highly rigid) structure is required, and an increase in mass is unavoidable. Therefore, when it is necessary to drive the antenna to track the satellite, as in satellite communication, the driving climate becomes large and the driving force increases. Furthermore, the mass of the antenna mounted on the satellite is limited due to the launch capability of the rocket. Also,
Since the constant restraint force such as gravity on the ground does not work, once the vibration starts, the vibration continues for a long time.

[Problems to be solved by the invention]

As mentioned above, an antenna for mounting on a moving body,
It is desirable to use a lightweight antenna for satellite communication. However, if a lightweight and high-rigidity structure as in the past is used, a large antenna cannot be manufactured, so it is not possible to improve the radiation characteristics of electromagnetic waves. It is impossible to obtain sufficient performance in terms of directivity and antenna gain.

The present invention aims to solve such contradictory problems.

[Means for solving problems]

The above-mentioned problem is that the means for measuring the deformation state of the antenna and the means for detecting a time zone in which the radiation characteristic improvement degree of the electromagnetic wave of the antenna is large, based on the measurement result of the measuring means, It is solved by providing means for performing communication.

[Operation] By measuring the antenna deformation state, it is possible to know the period during which the antenna deformation is smallest. Then, by controlling the transmitting unit so as to perform communication within this period, it is possible to avoid communication in a state where the directivity and the antenna gain due to the deformation of the antenna are reduced, and it is possible to realize highly reliable communication.

〔Example〕

All structures have unique vibration modes. And
Even if deformations due to vibrations other than some of the low-order modes occur in this unique vibration mode, they are extremely small and disappear in a short period of time, so they can be ignored. Therefore, it is possible to grasp the state of vibration of the entire structure by appropriately selecting several observation points in the structure and observing the deformation of these points.

Therefore, the state of vibration of the entire antenna can be known by providing several observation points on the antenna and measuring the deformation at the observation points. Then, it is possible to detect a state in which the antenna directivity is the highest and the antenna gain is the highest. FIG. 4 is a diagram showing a configuration for observing the deformation of the antenna, in which 10 is a front view of the antenna, 1, 2, and 3 are two-dimensional laser scanning systems, 4, 5, and 6.
Is a light receiving device, 7, 8 and 9 are corner cubes, 11 is an antenna vibration state detection unit, 12 is a microprocessor, 21 and 2
Reference numerals 2 and 23 are beam splitters, and 24 is a laser scanning system control unit. The corner cubes 7, 8 and 9 are provided at the selected observation points in order to know the vibration of the entire antenna. Corner cube 7 installed at each observation point,
Reference numerals 8 and 9 reflect the laser beams output from the laser scanning systems 1, 2, and 3 by 180 degrees. Therefore, in FIG. 4, the beam splitters 21, 22, 23 are provided in the middle of the optical path so that the reflected light from the corner cubes 7, 8, 9 is separated and guided to the light receiving devices 4, 5, 6. Actually, the deviation between the incident light and the reflected light on the corner cube is several mm to several cm, and the beam splitter is not necessarily provided depending on the structure of the laser scanning system or the light receiving device. Although each observation point oscillates in three dimensions, it does not oscillate in any X, Y, or Z direction, but oscillates in correlation with each direction. Therefore, by expressing the position of each observation point at a specific time in a two-dimensional manner, it is possible to relatively represent the amount of variation from the specific state. Then, by scanning the vicinity of each observation point in a two-dimensional direction, the time during which the laser light is incident on the corner cubes 7, 8, 9 is specified within one scanning cycle of the laser according to the variation amount of the observation point. Therefore, it is necessary to know the position of the corner cubes 7, 8, 9 two-dimensionally by the detection time of the reflected light from the corner cubes 7, 8, 9 in each of the light receiving devices 4, 5, 6. Therefore, the relative variation amount from the position of the antenna in the ideal state can be calculated from the detected relative position.

In the example of FIG. 4, the number of corner cubes is the same as the number of laser scanning systems and light receiving devices, but if the scanning range of the laser scanning system is set appropriately, one laser scanning system and one laser scanning system will be used. It will be easily understood that the position of the plurality of corner cubes can be known by the light receiving device.

Next, a method for detecting the fluctuation amount at each observation point will be described with reference to FIGS.
A specific description will be given with reference to the drawings. FIG. 5 is a schematic diagram of the two-dimensional laser scanning system 1, 2, and 3 in FIG. 4, and FIG. 6 is a diagram for explaining the relationship between the laser scanning period and the variation amount at the observation point.

The laser light output from the semiconductor laser 25 is a rotating polygon mirror.
Reflected by 26. Since the rotary polygon mirror 26 is rotated in the direction of the arrow by the pulse motor 27, the reflected laser light is scanned in the horizontal direction. The light reflected by the rotary polygon mirror 26 is reflected by the other rotary polygon mirror 28. The rotary polygon mirror 28 is rotated by a pulse motor 29 in the direction of the arrow shown. Therefore, the laser light reflected by the rotary polygon mirror 28 is additionally scanned in the vertical direction, and as a result, the reflection side of this laser light (the corner cubes 7, 8 and 9 in FIG. 4).
Then, it is raster-scanned like a CRT display device.

FIG. 6 shows how the laser beam is scanned at the corner cubes 7, 8 and 9. When the horizontal scanning period is t _{X and the} vertical scanning period is 2 nt _X , the rotating polygon mirror 26 has a hexagonal shape, and therefore one rotation period is 6 t _X.
Further, since the rotary polygon mirror 28 is triangular, the cycle of one rotation is 3 × 2nt _X. In this way, the laser scanning controller 24 controls the rotations of the pulse motors 27 and 29. Of course, the pulse motors in the two-dimensional laser scanning systems 1, 2 and 3 are controlled to operate in synchronization.

As mentioned above, the scanning period in the two-dimensional direction is 2nt _X ,
Now, in an ideal state where the antenna is not deformed at all, the laser 1, the corner cube 7 and the beam splitter are
21 and the light receiving device 4, the laser 2, the corner cube 8, the beam splitter 22, the light receiving device 5, and the laser 3, the corner cube 9, the beam splitter 23, and the light receiving device 6 in the respective optical systems, the light receiving devices 4, 5, 6, The detection time of the input light at is within one scanning cycle, (nt _X + t
_X / 2). With such an adjustment, if the detection time of the input light in each of the light receiving devices 4, 5, and 6 in one scanning cycle is Y, then Y = At _X + B (A = 0,
It is expressed as 1,2, ... 2n, 0 <B <t _X ). Here, B and A represent the XY coordinates of each observation point in FIG. 6, and the detection time (nt _X + t at each observation point in the ideal state of the antenna).
( _X / 2) (t _X / 2, n) also represents the XY coordinate. Therefore, by measuring the above A and B, it is possible to calculate the variation amount X from the ideal state at the observation point using the coordinate system described above.

The variation X of the antenna is detected by the antenna state detecting unit 11 in FIG. 4 by the method described above, and its specific configuration will be described with reference to FIG. When the laser light is detected by the light receiving device 4, the comparison circuit 112 compares the output voltage of the light receiving device 4 with a predetermined reference value V ₀ . When the output voltage of the light receiving device 4 becomes higher than V ₀ , the comparison circuit 112 produces an output, which is input to the D terminal of the FF 115. Thus, comparing the output voltage of the light receiving device 4 with the reference value is
This is because erroneous detection is not caused by noise from the light receiving device 4.
FF115 operates with the reference clock from oscillator 111,
The timer 114 at t _X counts the reference clock from the oscillator 11. The n-ary counter 113 counts up to n carry signals output from the timer 114. Therefore, FF11
The outputs of the timer 114 and the n-ary counter 113 when the AND gates 116 and 117 are opened by 5 respectively represent the XY coordinates (B, A) of the corner cube 7 (observation point). Here table 119 shows each (B, A) and (t _X / 2,
n), that is, the variation amount X of the observation point is (B,
It is stored at the address determined by the value in A). Therefore, the decoder 118 decodes the input values of B and A to obtain the variation amount X of the observation point corresponding to (B, A) in the table 119.
Read from. And the X read from table 119
The value of is transferred to the microprocessor 12. The operation clocks of the timer 114 and the FF 115 are also input to the laser scanning control unit 24 and serve as a reference clock for driving the pulse motor in each of the laser scanning systems 1, 2 and 3. In addition, the light receiving device 5,
For 6 as well, with the same configuration, (B, A) and variation X
And to detect.

The microprocessor 12 obtains a temporal change in the variation amount X of each observation point input from the antenna state detection unit 11.
This temporal change is considered to be periodic. FIG. 8A shows how the variation X of each observation point detected by the microprocessor 12 changes with time. It is considered that each observation point does not vibrate arbitrarily, and the fluctuation period is almost equal. Here, in FIG. 8 (a), the fluctuation amount is 0 at time t ₀ t ₁ t ₂ t ₃ and the directivity and antenna gain at the time of antenna design are realized, that is, the most electromagnetic wave It can be said that the radiation characteristics are good. Therefore, by transmitting a signal at this time t ₀ t ₁ t ₂ t ₃ , any lightweight (flexible) antenna can transmit a signal based on the radiation characteristics of electromagnetic waves at the time of design. is there.

In reality, it is impossible to perform communication only at the time t ₀ t ₁ t ₂ t ₃ , so the allowable range X ₀ of the variation of the antenna 10
The signal may be transmitted in the time zone (the time width T in FIG. 8A) in which the fluctuation amount is X ₀ or less. Therefore, as shown in FIG. 8 (c), the time t ₀ t
_In the time width T near ₁ t ₂ t ₃ , data will be transmitted in bursts. In order to transmit data in bursts as shown in FIG. 8 (c), it is necessary to packetize the data in units of bytes.

FIG. 1 is a block diagram of an embodiment of a transmitter for realizing the present invention. The same parts as those in FIG. 4 are designated by the same reference numerals. The data to be transmitted is stored in the memory 16. The microprocessor 12 reads data from the memory 16 and buffers the read data in the FIFO 15. The read control unit 19 is instructed by the microprocessor 12 to read a predetermined amount of data from the memory 16, transfer the data to the FIFO 15, and store the address information notified when the data is written to the memory 16, Always memory 16
Recognize the amount of data stored in. The data read from the memory 16 is temporarily stored in the FIFO 15 according to the address from the write control unit 18. Then, under the control of the read control unit 17, the data accumulated in the FIFO 15 is read out by a predetermined byte and is packetized by the interface 14. The data packetized by the interface 14 is modulated by the transmitter 13 using the microwave as a carrier and transmitted from the antenna 10.

The control of the microprocessor 12 in the above configuration will be described with reference to the flowchart of FIG.

The microprocessor 12 receives the variation amount at each observation point from the antenna displacement state detection unit 11.

The microprocessor 12 knows the state of vibration of the entire antenna from the average value of the fluctuation amounts at the respective observation points received at, calculates the fluctuation amount X, and compares it with the above-mentioned allowable value X ₀ .

If X ₀ > X, the read control unit 17 is instructed to read a predetermined byte of data from the FIFO 15 and to transmit the data. If X ₀ <X, return to step.

After the transmission, the variation amount X of the entire antenna is calculated again from the data received from the antenna displacement state detection unit 11.

While X ₀ > X, the above steps are sequentially repeated.

When X ₀ <X, the reading control unit 17 is notified to stop reading the data from the FIFO 15, and the data transmission is interrupted. Then, when the FIFO 15 detects that the write area is exhausted by the read address from the read control unit 17 and the write address from the write control unit, the data from the memory 16 is sent to the read control unit 19. Stop reading. Then go back to the step.

As described above, the microprocessor 12 controls the transmission of data, but when it detects that a writing area is created in the FIFO 15, it reads the data to the reading control unit 19 and the writing control unit 18. , Instruct writing.

In the description of FIG. 2, the variation of the antenna 10 is constantly monitored and the data transmission is controlled. However, as described above, the variation X of the antenna 10 is as shown in FIG. In addition, it is considered to have periodicity. Therefore,
The data transmission time period can be predicted to some extent without constantly monitoring the variation amount X. The control of the microprocessor 12 in such a case will be described with reference to the flowchart of FIG.

The microprocessor 12 receives the variation amount at each observation point from the antenna displacement state detection unit 11. Then, the state of vibration of the entire antenna is known from the average value of the fluctuation amount at each observation point, the temporal change of the fluctuation amount X is recognized, and the period t ₀ of the fluctuation amount X is obtained.

The time zone T shown in FIGS. 8A and 8C is obtained from the allowable value X ₀ of the fluctuation amount, and the amount of data that can be transmitted in this time zone is obtained.

The start time of the time zone T is identified by the timer control, and at that time, the read control unit 17 is controlled so that the data amount set in the FIFO 15 is read from the FIFO 15.

Similar to the step of, the period t ₀ of the fluctuation amount X at the time of is calculated.

Determination of the difference between the current period t ₀ calculated in step with the period t ₀ calculated in step. Then, when the difference between the cycles of the fluctuation amount X is within the allowable value a, the next transmission time zone is determined based on the cycle t ₀ calculated in step,
Repeat steps ~.

If in the difference between the period t ₀ calculated in step with the period t ₀ of the variation amount X calculated allowable value a or more, the timer was stopped, with respect to out control unit 17 to read, the read data Instruct to cancel.

Then, the cycle t ₀ obtained in is set as the cycle of the fluctuation amount X, and the same processing is repeated thereafter.

As described above, the periodicity of the variation amount X of the antenna is used to predict the time zone in which the state of the antenna is suitable for transmission,
Transmission control can be performed. Further, since the time zone of the ideal state of the antenna can be predicted in this way, if the transmitting side transmits in advance using this time zone, the same effect as the receiving antenna can be obtained. Can be easily guessed.

Note that the transmission data is not required to be real-time as in the case of a telephone, and it is sufficient if a fixed amount of data can be obtained within a fixed time (when communication is regularly performed, such as observation data from meteorological satellites etc. ), The present invention is particularly effective.

〔The invention's effect〕

As described above in detail, according to the present invention, the communication is performed only in the best state of the antenna, so that even when a flexible structure (light weight) antenna is used, its radiation characteristics The degree of improvement of can be utilized. Therefore, it is possible to satisfy the strict antenna characteristics required for satellite communication and the like without using a high-rigidity antenna having a large mass.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining an embodiment of the present invention, FIGS. 2 and 3 are flowcharts for explaining a transmission timing control method in FIG. 1, and FIG. 4 is a displacement of an antenna. For explaining the observation system of FIG. 5, FIG. 5 is a view for explaining the configuration of the two-dimensional scanning system of laser light, and FIG. 6 shows the relationship between the scanning period of laser light and the variation amount of the antenna. FIG. 7 is a diagram for explaining, FIG. 7 is a block configuration diagram for detecting an antenna variation amount, and FIG. 8 is a diagram for explaining a relationship between an antenna vibration characteristic and a data transmission timing. In the figure, 10 is an antenna, 11 is an antenna displacement state detection unit, 12
Is a microprocessor, 15 is a FIFO, 17 is a FIFO read controller, and 18 is a FIFO write controller.

Claims (4)

[Claims] 1. A communication device using an antenna having a structure for improving radiation characteristics of electromagnetic waves, comprising means for measuring a deformed state of the antenna, and the antenna based on the measurement result of the measuring means. A communication device using a flexible structure antenna, comprising: a means for detecting a time zone in which the radiation characteristic improvement degree of electromagnetic waves is large; and a means for executing communication by the antenna in the time zone. 2. The measurement result indicates a vibration pattern of the antenna, and the detection means detects the time zone based on a vibration cycle of the antenna detected from the vibration pattern. A communication device using the flexible structure antenna according to item 1. 3. A communication device using a flexible structure antenna according to claim 1, wherein data is packetized and communicated in order to enable communication during the time zone. 4. A communication device using an antenna having a structure for improving radiation characteristics of electromagnetic waves, wherein a deformation state of the antenna is measured, and the radiation characteristics of the electromagnetic waves of the antenna are measured based on the measurement result. A communication method using a flexible structure antenna, characterized in that a time zone having a large degree of improvement is detected and communication is performed using the antenna in the time zone.