JPWO2020105143A1 - Optical space communication device and optical space communication method - Google Patents

Abstract

Optical signals are transmitted from an optical transceiver (2) that performs optical spatial communication of an optical signal including an identification signal and communication data, an RF transceiver (3) that performs RF spatial communication of an RF signal including communication data, and an optical transceiver (2). After being transmitted, it is determined whether or not the optical space communication is normal based on the time change of the signal intensity in the identification signal included in the backward scattered light of the optical signal received by the optical transceiver (2). If the optical space communication is abnormal, the optical space communication device is configured to include a determination unit (51) for determining the cause of the abnormality in the optical space communication based on the time change of the signal strength.

Description

The present invention relates to an optical space communication device and an optical space communication method for performing optical space communication of optical signals.

The following Patent Document 1 includes a hybrid communication station including an optical transceiver that performs data communication using an optical signal and an RF transceiver that performs data communication using a radio frequency (hereinafter referred to as "RF") signal. Is disclosed.
The hybrid communication station disclosed in Patent Document 1 monitors the optical power level of the optical signal transmitted from the communication partner. If the optical power level has not deteriorated, the optical transceiver uses the optical signal to perform data communication.
If the optical power level is degraded, the RF transceiver uses the RF signal for data communication.

Special Table 2003-520491

In the hybrid communication station disclosed in Patent Document 1, if the optical power level of the optical signal transmitted from the communication partner is deteriorated, the RF transceiver performs data communication using the RF signal. Therefore, the hybrid communication station can continue the data communication even if the communication quality of the optical signal deteriorates for some reason. The communication rate of RF signal data communication is lower than that of optical signal data communication, but the reliability of RF signal data communication is high because the communication quality of RF signals does not deteriorate due to fluctuations in weather conditions and the like.
However, since the hybrid communication station disclosed in Patent Document 1 merely monitors the optical power level of the optical signal, it is not possible to identify the cause of the deterioration of the communication quality of the optical signal. There was a challenge.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an optical space communication device and an optical space communication method capable of identifying an abnormal factor of optical space communication.

The optical space communication device according to the present invention includes an optical transceiver that performs optical space communication of an optical signal including an identification signal and communication data, a radio frequency transceiver that performs radio frequency space communication of a radio frequency signal including communication data, and an optical transceiver. After the optical signal is transmitted from, it is determined whether or not the optical space communication is normal based on the time change of the signal intensity in the identification signal included in the backward scattered light of the optical signal received by the optical transceiver. However, if the optical space communication is abnormal, a determination unit for determining the cause of the abnormality in the optical space communication is provided based on the time change of the signal strength.

According to the present invention, the determination unit determines based on the time change of the signal intensity in the identification signal included in the backward scattered light of the optical signal received by the optical transceiver after the optical signal is transmitted from the optical transceiver. An optical space communication device is configured so as to determine whether or not the optical space communication is normal, and if the optical space communication is abnormal, determine the cause of the abnormality in the optical space communication based on the time change of the signal strength. did. Therefore, the optical space communication device according to the present invention can identify an abnormal factor of optical space communication.

It is a block diagram which shows the optical space communication apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the time-series signal processing unit 34 of the optical space communication apparatus which concerns on Embodiment 1. FIG. It is a hardware block diagram which shows the hardware of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72. It is a hardware block diagram of the computer when a part of the time series signal processing unit 34 is realized by software, firmware, etc. It is a block diagram which shows the determination part 51 of the optical space communication apparatus which concerns on Embodiment 1. FIG. It is a hardware block diagram which shows the hardware of the determination part 51 and the control part 52 of the optical space communication apparatus which concerns on Embodiment 1. FIG. It is a hardware block diagram of the computer when the determination unit 51 and the control unit 52 are realized by software, firmware, or the like. It is explanatory drawing which shows the time-series signal output from a signal combiner 24, the light intensity-modulated by an optical intensity modulator 26, and the backscattered light received by an optical receiver 33. FIG. 9A is an explanatory diagram showing the spectrum of the optical signal during the period including the identification signal, and FIG. 9B is an explanatory diagram showing the spectrum of the optical signal during the period including the modulated signal of the communication data. It is explanatory drawing which shows the optical signal transmitted from the optical transceiver 2 and the backscattered light of an optical signal. FIG. 11A is an explanatory diagram showing the spectra of backscattered lights 101 and 102. FIG. 11B is an explanatory diagram showing a pass band of LPF65. FIG. 12A is _{an explanatory diagram showing the fast Fourier transform result at time t 0} , and FIG. 12B is an explanatory diagram showing the fast Fourier transform result at time t ₁ . It is explanatory drawing which shows the time change data which shows the time change of the signal strength of the identification signal corresponding to the distance range (0) to (N). FIG. 14A is an explanatory diagram showing time change data when the optical space communication is normal, and FIG. 14B is a case where the optical space communication is normal and the aerosol concentration in the optical space is reduced as compared with FIG. 14A. 14C is an explanatory diagram showing the time change data of FIG. 14C, which shows the time change data when the optical space communication device shown in FIG. 1 fails and the signal intensity of the optical signal output from the optical transceiver 2 decreases. 14D is an explanatory diagram showing time change data when the weather is rainfall or dense fog, and FIG. 14E is time change data when an optical axis shift occurs between the optical space communication device on the transmitting side and the receiving side. The explanatory diagram and FIG. 14F are explanatory views showing the time change data when a shield invades the transmission line in the optical space. It is a flowchart which shows the processing content of the determination unit 51.

Hereinafter, in order to explain the present invention in more detail, a mode for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.
FIG. 1 is a configuration diagram showing an optical space communication device according to the first embodiment.
In FIG. 1, the data interface unit 1 buffers the communication data for transmission, and the communication data received by the optical transceiver 2 or the communication received by the radio frequency (hereinafter referred to as “RF”) transceiver 3. Buffer the data.
The transmission buffer 11 is a memory for buffering communication data for transmission.
The reception buffer 12 is a memory for buffering the communication data received by the optical transceiver 2 or the communication data received by the RF transceiver 3.

The optical transceiver 2 carries out optical space communication of an optical signal including an identification signal and communication data.
The RF transceiver 3 carries out RF spatial communication of RF signals including communication data.

When the transmission switch 21 receives a control signal from the control unit 52 indicating that optical space communication is to be performed, the transmission switch 21 outputs the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. ..
When the transmission switch 21 receives a control signal from the control unit 52 indicating that RF spatial communication is to be performed, the transmission switch 21 transfers the transmission communication data buffered by the transmission buffer 11 to the transmission buffer 41 of the RF transceiver 3. Output to.

The data modulation drive circuit 22 modulates the communication data output from the transmission switch 21 and outputs the modulated signal of the communication data to the signal combiner 24.
The burst modulation drive circuit 23 periodically oscillates the trigger signal and outputs the trigger signal to the time-series signal processing unit 34.
Further, the burst modulation drive circuit 23 _{outputs an identification signal having a frequency of f 0} to the signal combiner 24 in synchronization with the trigger signal.
The signal combiner 24 combines a modulation signal (hereinafter, referred to as “modulation communication data”) including communication data output from the data modulation drive circuit 22 and an identification signal output from the burst modulation drive circuit 23. Then, a time-series signal, which is a combined wave signal of the modulated communication data and the identification signal, is output to the light intensity modulator 26.
In the signal combine processing by the signal combiner 24, the modulated communication data and the identification signal are combined so that the modulated communication data and the identification signal are arranged in chronological order.

The reference light source 25 is a light source that continuously oscillates light of a single frequency.
The wavelength of the light oscillated from the reference light source 25 is different from the wavelength of the light oscillated from the reference light source included in the optical space communication device of the communication partner (not shown). Here, it is assumed that the configuration of the optical space communication device of the communication partner (not shown) is the same as the configuration of the optical space communication device shown in FIG. However, the optical space communication device of the communication partner may be a device capable of performing optical space communication of optical signals and RF space communication of RF signals, and has exactly the same configuration as the optical space communication device shown in FIG. It doesn't have to be the same.

The optical intensity modulator 26 intensity-modulates the light oscillated by the reference light source 25 with the time-series signal output from the signal combiner 24, and outputs the optical signal obtained by the intensity modulation to the storage type optical amplifier 27. To do. The optical signal output from the light intensity modulator 26 is pulsed light.
In the storage type optical amplifier 27, among the optical signals output from the optical intensity modulator 26, the amplification factor during the period including the identification signal is larger than the amplification factor during the period containing the modulated communication data. , Amplifies the optical signal output from the optical intensity modulator 26.
The storage type optical amplifier 27 outputs the amplified optical signal to the optical circulator 28.

The optical circulator 28 outputs the optical signal output from the storage type optical amplifier 27 to the wavelength branch coupler 29, and outputs the backward scattered light of the optical signal output from the wavelength branch coupler 29 to the optical receiver 33.
The wavelength branch coupler 29 outputs the optical signal output from the optical circulator 28 to the telescope 30.
If the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner, the wavelength branch coupler 29 outputs the optical signal to the optical receiver 31 for data communication. To do.
If the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, the wavelength branch coupler 29 outputs the optical signal to the optical circulator 28. The optical signal is backscattered light of an optical signal transmitted from the telescope 30.
The telescope 30 outputs the optical signal output from the wavelength branching coupler 29 to the optical space, thereby transmitting the optical signal to the optical space communication device of the communication partner.
Further, the telescope 30 receives the optical signal transmitted from the optical space communication device of the communication partner, and also receives the backscattered light of the optical signal output to the optical space.

The data communication optical receiver 31 receives the optical signal output from the wavelength branch coupler 29, demodulates the communication data included in the optical signal, and outputs the communication data to the reception switch 32.
When the reception switch 32 receives a control signal from the control unit 52 indicating that optical space communication is to be performed, the reception switch 32 transmits the communication data output from the data communication optical receiver 31 to the reception buffer 12 of the data interface unit 1. Output.
When the reception switch 32 receives a control signal from the control unit 52 indicating that RF spatial communication is to be performed, the reception switch 32 receives the communication data buffered by the reception buffer 44 of the RF transceiver 3 for reception of the data interface unit 1. Output to buffer 12.

The optical receiver 33 receives the backscattered light output from the wavelength branch coupler 29 via the optical circulator 28, converts the backscattered light into an electric signal, and outputs the electric signal to the time-series signal processing unit 34. To do.
The time-series signal processing unit 34 uses the trigger signal output from the burst modulation drive circuit 23 to extract the identification signal contained in the backscattered light from the electric signal output from the optical receiver 33 for identification. Calculate the signal strength of the signal.
Each time the time-series signal processing unit 34 calculates the signal strength, the time-series signal processing unit 34 stores the signal strength in the monitor buffer 35 to generate time change data indicating the time change of the signal strength.
The monitor buffer 35 is a memory for buffering the time change data generated by the time series signal processing unit 34.

The transmission buffer 41 buffers the communication data output from the transmission switch 21 of the optical transceiver 2.
The transmitter / receiver 42 modulates the RF signal as a carrier with the communication data buffered by the transmission buffer 41, and outputs the RF signal to the transmission / reception antenna 43.
The transmitter / receiver 42 receives the RF signal output from the transmitter / receiver antenna 43, demodulates the RF signal, extracts communication data, and outputs the communication data to the reception buffer 44.
The transmission / reception antenna 43 transmits the RF signal to the optical space communication device of the communication partner by radiating the RF signal output from the transmitter / receiver 42 into space.
The transmission / reception antenna 43 receives the RF signal transmitted from the optical space communication device of the communication partner, and outputs the received RF signal to the transmitter / receiver 42.
The reception buffer 44 buffers the communication data output from the transmitter / receiver 42.

The determination unit 51 determines whether or not the optical space communication is normal based on the time change indicated by the time change data buffered by the monitor buffer 35, and if the optical space communication is abnormal, the time. Based on the time change indicated by the change data, the cause of the abnormality in the optical space communication is determined. The causes of abnormalities in optical space communication include optical axis deviation due to positional deviation between the optical space communication device on the transmitting side and the receiving side, fluctuations in weather conditions, failure of the optical space communication device, or sudden occurrence of the communication path. Invasion of shields, etc. is conceivable.
The determination unit 51 outputs a determination result indicating whether or not the optical space communication is normal to the control unit 52.
The control unit 52 is realized by, for example, the control circuit 88 shown in FIG. 6 described later.
If the determination unit 51 determines that the optical space communication is normal, the control unit 52 enables the optical space communication and invalidates the RF space communication. Therefore, the control unit 52 indicates that the optical space communication is performed. Is output to each of the transmission switch 21 and the reception switch 32.
If the determination unit 51 determines that the optical space communication is abnormal, the control unit 52 enables the RF space communication and invalidates the optical space communication. Therefore, the control unit 52 indicates that the RF space communication is performed. Is output to each of the transmission switch 21 and the reception switch 32.

FIG. 2 is a configuration diagram showing a time-series signal processing unit 34 of the optical space communication device according to the first embodiment.
In FIG. 2, the reception signal input unit 61 is a terminal for inputting an electric signal output from the optical receiver 33 as a reception signal of backscattered light.
The trigger signal input unit 62 is a terminal for inputting a trigger signal output from the burst modulation drive circuit 23.

The identification signal extraction unit 63 includes a clock generation unit 64, a low-pass filter LPF (Low Pass Filter) 65, an analog-to-digital converter ADC (Analog to Digital Converter) 66, a data buffer 67, and a data extraction unit 68. I have.
The identification signal extraction unit 63 blocks the passage of communication data contained in the backscattered light and extracts the identification signal contained in the backscattered light.

The clock generation unit 64 oscillates the clock signal and outputs the clock signal to the ADC 66.
When the LPF65 receives the received signal of the backscattered light from the received signal input unit 61, it blocks the passage of the communication data contained in the backscattered light and extracts the identification signal contained in the backscattered light. The extracted identification signal is output to the ADC 66.
The ADC 66 samples the identification signal output from the LPF 65 in synchronization with the clock signal output from the clock generation unit 64, and outputs the sampling data of the identification signal to the data buffer 67.
According to the sampling theorem, the frequency of the clock signal is set to be at least twice _{the frequency f 0 of the identification signal.}

The data buffer 67 is a memory for buffering the sampling data of the identification signal output from the ADC 66. The sampling data buffered by the data buffer 67 is associated with the elapsed time from the time when the trigger signal is input from the trigger signal input unit 62. The elapsed time from the time when the trigger signal is input corresponds to the distance from the telescope 30 to the position where the optical signal is scattered (hereinafter, referred to as “distance range”). Therefore, the data buffer 67 stores sampling data having different distance ranges.
The data extraction unit 68 is realized by, for example, the data extraction circuit 81 shown in FIG.
The data extraction unit 68 extracts sampling data of each distance range from the data buffer 67 as an identification signal corresponding to each distance range, and outputs the extracted sampling data to the Fourier transform unit 70 of the signal strength calculation unit 69. ..
FIG. 3 is a hardware configuration diagram showing the hardware of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72.

The signal strength calculation unit 69 includes a Fourier transform unit 70 and a signal strength calculation processing unit 71, and calculates the signal strength of the identification signal extracted by the identification signal extraction unit 63.
The Fourier transform unit 70 is realized by, for example, the Fourier transform circuit 82 shown in FIG.
The Fourier transform unit 70 performs high-speed Fourier transform on the sampling data of each distance range extracted by the data extraction unit 68, and outputs each high-speed Fourier transform result to the signal strength calculation processing unit 71.
The signal strength calculation processing unit 71 is realized by, for example, the signal strength calculation processing circuit 83 shown in FIG.
_{The signal strength calculation processing unit 71 outputs the component of the frequency f 0} indicated by each high-speed Fourier transform result of the Fourier transform unit 70 to the time change data generation unit 72 as the signal strength of the identification signal corresponding to each distance range. To do.

The time change data generation unit 72 is realized by, for example, the time change data generation circuit 84 shown in FIG.
The time change data generation unit 72 stores the signal strength of the identification signal corresponding to each distance range output from the signal strength calculation processing unit 71 in the monitor buffer 35, so that the time change indicating the time change of the signal strength is shown. Generate data.
The data output unit 73 is a terminal for outputting the signal strength calculated by the time change data generation unit 72 to the monitor buffer 35.

In FIG. 2, each of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72, which are a part of the components of the time series signal processing unit 34, is shown in FIG. It is assumed that it will be realized with dedicated hardware. That is, it is assumed that a part of the time series signal processing unit 34 is realized by the data extraction circuit 81, the Fourier transform circuit 82, the signal strength calculation processing circuit 83, and the time change data generation circuit 84.
Here, each of the data extraction circuit 81, the Fourier conversion circuit 82, the signal strength calculation processing circuit 83, and the time change data generation circuit 84 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, and the like. An ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof is applicable.

A part of the time-series signal processing unit 34 is not limited to that realized by dedicated hardware, and a part of the time-series signal processing unit 34 is realized by software, firmware, or a combination of software and firmware. It may be what is done.
The software or firmware is stored as a program in the memory of the computer. A computer means hardware for executing a program, and corresponds to, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, a computing device, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor). To do.

FIG. 4 is a hardware configuration diagram of a computer when a part of the time series signal processing unit 34 is realized by software, firmware, or the like.
When a part of the time-series signal processing unit 34 is realized by software or firmware, the processing procedures of the data extraction unit 68, the Fourier transform unit 70, the signal strength calculation processing unit 71, and the time change data generation unit 72 are executed on the computer. The program for making the data is stored in the memory 91. Then, the processor 92 of the computer executes the program stored in the memory 91.

FIG. 5 is a configuration diagram showing a determination unit 51 of the optical space communication device according to the first embodiment.
FIG. 6 is a hardware configuration diagram showing the hardware of the determination unit 51 and the control unit 52 of the optical space communication device according to the first embodiment.
In FIG. 5, the data acquisition unit 51a is realized by, for example, the data acquisition circuit 85 shown in FIG.
The data acquisition unit 51a acquires the time change data when the optical space communication is normal and the time change data buffered by the monitor buffer 35 (hereinafter, referred to as “monitoring time change data”).
The data acquisition unit 51a outputs each of the time change data and the monitoring time change data when the optical space communication is normal to the signal strength comparison unit 51b.
The time change data when the optical space communication is normal may be stored in the internal memory of the data acquisition unit 51a or may be given from the outside.

The signal strength comparison unit 51b is realized by, for example, the signal strength comparison circuit 86 shown in FIG.
The signal strength comparison unit 51b compares the signal strength of each distance region indicated by the time change data when the optical space communication is normal with the signal strength of each distance region indicated by the monitoring time change data, and compares the signal strength of each distance region. The signal strength comparison result is output to the determination processing unit 51c.
The determination processing unit 51c is realized by, for example, the determination processing circuit 87 shown in FIG.
The determination processing unit 51c determines whether or not the optical space communication is normal based on the comparison result of the signal strength output from the signal intensity comparison unit 51b, and controls the determination result indicating whether or not the optical space communication is normal. Output to unit 52.
If the optical space communication is abnormal, the determination processing unit 51c determines the cause of the abnormality in the optical space communication based on the comparison result of the signal strength output from the signal strength comparison unit 51b.

In FIG. 5, it is assumed that each of the data acquisition unit 51a, the signal strength comparison unit 51b, and the determination processing unit 51c, which are the components of the determination unit 51, is realized by the dedicated hardware as shown in FIG. There is. That is, it is assumed that the components of the determination unit 51 are realized by the data acquisition circuit 85, the signal strength comparison circuit 86, and the determination processing circuit 87.
Further, it is assumed that the control unit 52 is realized by the control circuit 88 as shown in FIG.
Here, each of the data acquisition circuit 85, the signal strength comparison circuit 86, the determination processing circuit 87, and the control circuit 88 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, and the like. Alternatively, a combination of these is applicable.

The determination unit 51 and the control unit 52 are not limited to those realized by dedicated hardware, and a part of the determination unit 51 and the control unit 52 is realized by software, firmware, or a combination of software and firmware. It may be one.
FIG. 7 is a hardware configuration diagram of a computer when the determination unit 51 and the control unit 52 are realized by software, firmware, or the like.
When the determination unit 51 and the control unit 52 are realized by software, firmware, or the like, a program for causing a computer to execute the processing procedures of the data acquisition unit 51a, the signal strength comparison unit 51b, the determination processing unit 51c, and the control unit 52 is provided. It is stored in the memory 93. Then, the processor 94 of the computer executes the program stored in the memory 93.

Next, the operation of the optical space communication device shown in FIG. 1 will be described.
In the initial stage, the optical space communication of the optical signal by the optical transceiver 2 will be described as normal.
The control unit 52 outputs a control signal instructing the output of communication data to the data interface unit 1, and outputs a control signal indicating that optical space communication is to be performed to each of the transmission switch 21 and the reception switch 32.
Further, the control unit 52 outputs a control signal instructing the output of the trigger signal and the identification signal to the burst modulation drive circuit 23.

When the transmission switch 21 receives a control signal from the control unit 52 indicating that optical space communication is to be performed, the transmission switch 21 outputs the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. ..
When the data modulation drive circuit 22 receives the communication data from the transmission switch 21, the data modulation drive circuit 22 modulates the communication data and outputs the modulated signal of the communication data to the signal combiner 24.

When the burst modulation drive circuit 23 receives a control signal instructing the output of the trigger signal and the identification signal from the control unit 52, the burst modulation drive circuit 23 repeatedly oscillates the trigger signal at a pulse repetition interval (PRI: Pulse Repetition Interval) [sec].
The burst modulation drive circuit 23 outputs the trigger signal to the time-series signal processing unit 34 each time the trigger signal is oscillated.
Further, each time the burst modulation drive circuit 23 oscillates the trigger signal, the burst modulation drive circuit 23 outputs an identification signal having a time width of _{t 0 to the signal combiner 24 in synchronization with the trigger signal.}

The signal combiner 24 combines the identification signal output from the burst modulation drive circuit 23 with the modulation signal of the communication data output from the data modulation drive circuit 22.
As shown in FIG. 8, the signal combiner 24 outputs a time-series signal, which is a combined signal of the identification signal and the modulated signal of the communication data, to the light intensity modulator 26.
FIG. 8 is an explanatory diagram showing a time-series signal output from the signal combiner 24, light intensity-modulated by the light intensity modulator 26, and backscattered light received by the optical receiver 33.

The reference light source 25 continuously oscillates light of a single frequency, and outputs the continuously oscillated light to the light intensity modulator 26.
The light intensity modulator 26 intensity-modulates the light oscillated by the reference light source 25 by the time-series signal output from the signal combiner 24.
The light intensity modulator 26 outputs an optical signal, which is intensity-modulated light as shown in FIG. 8, to the storage type optical amplifier 27.

In the storage type optical amplifier 27, among the optical signals output from the optical intensity modulator 26, the amplification factor during the period including the identification signal is larger than the amplification factor during the period including the modulation signal of the communication data. As described above, the optical signal output from the light intensity modulator 26 is amplified. By amplifying the optical signal by the storage type optical amplifier 27, the signal level of the optical signal during the period including the identification signal becomes higher than the signal level of the optical signal during the period including the modulated signal of the communication data.
The storage type optical amplifier 27 outputs the amplified optical signal to the optical circulator 28.

When the optical circulator 28 receives an optical signal from the storage type optical amplifier 27, the optical circulator 28 outputs the optical signal to the wavelength branching coupler 29.
When the wavelength branch coupler 29 receives an optical signal from the optical circulator 28, the wavelength branch coupler 29 outputs the optical signal to the telescope 30.
The telescope 30 outputs the optical signal output from the wavelength branching coupler 29 to the optical space, thereby transmitting the optical signal to the optical space communication device of the communication partner.

FIG. 9 is an explanatory diagram showing a spectrum of an optical signal transmitted from the optical transceiver 2.
FIG. 9A shows the spectrum of the optical signal during the period including the identification signal, and FIG. 9B shows the spectrum of the optical signal during the period including the modulated signal of the communication data.
The frequency of the identification signal is f ₀ , the frequency band of the modulated signal of the communication data is fcL to fcH, and the frequency of the modulated signal of the communication data is higher than _{the frequency f 0 of the identification signal.}
The period t including the identification signal is (i × PRI) <t <(i × PRI) + t ₀ .
The period t including the modulated signal of the communication data is (i × PRI) + t ₀ <t <((i + 1) × PRI). i = 0, 1, 2, ...

FIG. 10 is an explanatory diagram showing an optical signal transmitted from the optical transceiver 2 and backscattered light of the optical signal.
In FIG. 10, 2a is an optical transceiver 2 of the optical space communication device shown in FIG. 1, and in FIG. 10, it is described as an optical transceiver of its own station.
Reference numeral 2b is an optical transceiver 2 of the optical space communication device of the communication partner, and in FIG. 10, it is described as an optical transceiver of the partner station.
The backscattered light 101 is backscattered light scattered by a soft target such as an aerosol or raindrop existing in the optical space between the own station and the partner station. In FIG. 10, the backscattered light 101 is referred to as a short-distance backscattered light.
The backscattered light 102 is backscattered light scattered by a hard target such as the housing of the partner station or the telescope 30 of the partner station. In FIG. 10, the backscattered light 102 is referred to as a long-distance backscattered light.
The signal intensity of the backscattered light 101 increases due to rainfall, dense fog, or the like.
The signal intensity of the backscattered light 102 decreases due to an optical axis shift between the own station and the partner station, precipitation, dense fog, or the like.

The telescope 30 receives the optical signal transmitted from the optical space communication device of the communication partner, and also receives the backscattered light 101 and 102 of the optical signal output to the optical space.
From the telescope 30, the optical signal having the spectrum shown in FIG. 9A and the optical signal having the spectrum shown in FIG. 9B are alternately output to the optical space. Further, the backscattered light 101 is backscattered at a plurality of positions. Therefore, the backscattered light in which the plurality of backscattered light 101 having the spectrum shown in FIG. 9A and the backscattered light 102 having the spectrum shown in FIG. 9B are mixed is received by the telescope 30.

If the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner, the wavelength branch coupler 29 outputs the optical signal to the optical receiver 31 for data communication. To do.
When the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, the optical signal is backscattered light 101, 102. In this case, the wavelength branch coupler 29 outputs the backscattered lights 101 and 102 received by the telescope 30 to the optical circulator 28.

The data communication optical receiver 31 receives the optical signal output from the wavelength branch coupler 29 and demodulates the communication data contained in the optical signal.
The data communication optical receiver 31 outputs the demodulated communication data to the reception switch 32.
Since the reception switch 32 receives a control signal from the control unit 52 indicating that optical space communication is to be performed, the communication data output from the data communication optical receiver 31 is used as a reception buffer for the data interface unit 1. Output to 12.
The reception buffer 12 buffers the communication data transmitted from the reception switch 32 and notifies the control unit 52 that the communication data has been received.

When the optical circulator 28 receives the backscattered light 101 and 102 from the optical circulator 28, the optical circulator 28 outputs the backscattered light 101 and 102 to the optical receiver 33.
When the optical receiver 33 receives the backscattered light 101 and 102 from the optical circulator 28, it converts each of the backscattered light 101 and 102 into an electric signal and outputs each electric signal to the time series signal processing unit 34.

Each time the time-series signal processing unit 34 receives an electric signal from the optical receiver 33, the time-series signal processing unit 34 is included in the backscattered lights 101 and 102 from the electric signal by using the trigger signal output from the burst modulation drive circuit 23. Each identification signal is extracted, and the signal strength of each identification signal is calculated.
Each time the time-series signal processing unit 34 calculates the signal strength, the time-series signal processing unit 34 stores the signal strength in the monitor buffer 35 to generate time change data indicating the time change of the signal strength.
Hereinafter, the time-series signal processing unit 34 will specifically describe the time-varying data generation process.

The clock generation unit 64 oscillates the clock signal and outputs the clock signal to the ADC 66.
As shown in FIG. 11A, the reception signal input unit 61 receives an electric signal corresponding to each of the backscattered lights 101 and 102 from the optical receiver 33, and outputs each electric signal to the LPF 65.
FIG. 11A is an explanatory diagram showing the spectra of backscattered lights 101 and 102.
FIG. 11B is an explanatory diagram showing a pass band of LPF65. The cutoff frequency f _LPF of the LPF65 is in the range of _{f 0} <f _{LPF <fcL.}

When the LPF 65 receives each electric signal from the received signal input unit 61, as shown in FIG. 11B, the LPF 65 blocks the passage of communication data contained in the backscattered light 101,102, and the backscattered light 101,102 Each identification signal contained in is extracted.
The LPF65 outputs each extracted identification signal to the ADC 66.

When the ADC 66 receives the clock signal from the clock generation unit 64, the ADC 66 samples each identification signal output from the LPF 65 in synchronization with the clock signal, and outputs the sampling data of the identification signal to the data buffer 67.
The data buffer 67 buffers the sampling data of the identification signal output from the ADC 66. The sampling data buffered by the data buffer 67 is associated with the elapsed time from the time when the trigger signal is input from the trigger signal input unit 62. Further, the elapsed time from the time when the trigger signal is input corresponds to the distance range. Therefore, the data buffer 67 stores sampling data having different distance ranges.

The data extraction unit 68 extracts sampling data of each distance range from the data buffer 67 as an identification signal corresponding to each distance range.
For example, among the sampling data buffered by the data buffer 67, the sampling data in the distance range (0) in which the distance _{from the telescope 30 is L 0 has a period t (t 0} <t <t ₁ , t ₁ =). It corresponds to the sampling data of 2 × t _0).
L ₀ = (c × t ₀ ) / 2 [m], c is the speed of light.
Further, among the sampling data buffered by the data buffer 67, the sampling data in the distance range (1) in which the distance _{from the telescope 30 is L 1 has a period t (t 1} <t <t ₂ , t ₂ =). It corresponds to the sampling data of 3 × t _0).
L ₁ = (c × t ₁ ) / 2 [m]
Further, among the sampling data buffered by the data buffer 67, the sampling data in the distance range (N) in which the distance _{from the telescope 30 is L N has a period t (t N} <t <t _{N + 1} , t _N =). It corresponds to the sampling data of (N + 2) × t _0).
L _N = (c × t _N ) / 2 [m]

As shown in FIG. 12, the Fourier transform unit 70 performs a high-speed Fourier transform on the sampling data of each distance range extracted by the data extraction unit 68.
FIG. 12A is an explanatory diagram showing the fast Fourier transform result at _{time t 0} , and FIG. 12B is an explanatory diagram showing the fast Fourier transform result at _{time t 1.}
The LPF 65, since the modulated signal of the communication data contained by the backscattered light 101 and 102 has been removed, the fast Fourier transform result includes only the spectrum of the identification signal of the frequency f _{0.
The component of frequency f 0} shown in FIG. 12A is the signal strength of the identification signal corresponding to the distance range (0), and _{the component of frequency f 0} shown in FIG. 12B is the signal of the identification signal corresponding to the distance range (1). It is strength.

_{The signal strength calculation processing unit 71 uses the component of the frequency f 0} indicated by each of the fast Fourier transform results of the Fourier transform unit 70 as the signal strength of the identification signal corresponding to the distance range (0) to (N) as time change data. Output to the generation unit 72.
The time change data generation unit 72 stores the signal strength of the identification signal corresponding to the distance range (0) to (N) output from the signal strength calculation processing unit 71 via the data output unit 73 in the monitor buffer 35. By doing so, time change data indicating the time change of the signal strength is generated.
FIG. 13 is an explanatory diagram showing time change data showing the time change of the signal intensity of the identification signal corresponding to the distance range (0) to (N).
In FIG. 13, for example, _{the signal strength of the identification signal at t = t 0} is the signal strength of the identification signal corresponding to the distance range (0), and the signal strength of the identification signal at t = t ₁ is the distance range (1). ) Corresponds to the signal strength of the identification signal.
Further, the signal strength of the identification signal at t = t _N is the signal strength of the identification signal corresponding to the distance range (N).

Here, FIG. 14 is an explanatory diagram showing the relationship between the state of communication quality of the optical signal and the time change data.
FIG. 14A is an explanatory diagram showing time change data when optical space communication is normal.
In FIG. 14A, 111 is the signal strength of the identification signal included in the backscattered light 101 scattered by the soft target, and is the signal strength in the close range region when the optical space communication is normal. 111a is the signal strength in the extremely close distance region such as the distance range (0) among the signal strengths of the identification signals included in the backscattered light 101.
112 is the signal strength of the identification signal included in the backscattered light 102 scattered by the hard target, and is the signal strength in the long-distance region when the optical space communication is normal.

FIG. 14B is an explanatory diagram showing time change data when the optical space communication is normal and the aerosol concentration in the optical space is reduced as compared with FIG. 14A.
In FIG. 14B, 113 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target. Reference numeral 113a is the signal strength in the extremely close distance region such as the distance range (0) among the signal strengths of the identification signals included in the backscattered light 101.
The signal intensities 113 and 113a are lower than the signal intensities 111 and 111a, respectively, because the aerosol concentration in the optical space is reduced.
114 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal intensity 114 is the same value as the signal intensity 112 even if the aerosol concentration in the optical space is reduced.

FIG. 14C is an explanatory diagram showing time change data when the optical space communication device shown in FIG. 1 fails and the signal intensity of the optical signal output from the optical transceiver 2 decreases.
In FIG. 14C, 115 is the signal intensity of the identification signal included in the backscattered light 101 scattered by the soft target, and is a close range region when the signal level of the optical signal output from the optical transceiver 2 is lowered. The signal strength at. Reference numeral 115a is a signal strength in a very close distance region such as a distance range (0) among the signal strengths of the identification signals included in the backscattered light 101.
The signal intensities 115 and 115a are lower than the signal intensities 111 and 111a because the signal intensities of the optical signals output from the optical transceiver 2 are reduced.
116 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. Since the signal strength of the optical signal output from the optical transceiver 2 is lowered, the signal strength 116 is also lower than the signal strength 112.

FIG. 14D is an explanatory diagram showing time change data when the weather is rainfall or heavy fog.
In FIG. 14D, 117 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target. 117a is the signal strength in the extremely close distance region such as the distance range (0) among the signal strengths of the identification signals included in the backscattered light 101.
When the weather is rainfall or dense fog, the optical signal output from the optical transceiver 2 is scattered by raindrops and the like, so that the signal intensity 117a in the extremely close range such as the distance range (0) is higher than the signal intensity 111a. are doing.
However, even if the signal strength is 117 in the close range region, the signal strength 117 in the region closer to the hard target than the extremely close distance region tends to be lower than the signal strength 111.
118 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal strength 118 is also lower than the signal strength 112.

FIG. 14E is an explanatory diagram showing time change data when an optical axis shift occurs between the optical space communication device on the transmitting side and the receiving side.
In FIG. 14E, 119 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target. 119a is the signal strength of the identification signal included in the backscattered light 101 in the extremely close distance region such as the distance range (0). The signal strengths 119 and 119a of the identification signal are the same values as the signal strengths 111 and 111a even if the optical axis is deviated.
120 is the signal intensity of the identification signal contained in the backscattered light 102 scattered by the hard target. The signal strength 120 is lower than the signal strength 112 because the optical axis is deviated.

FIG. 14F is an explanatory diagram showing time change data when a shield invades the transmission path of the optical space.
In FIG. 14F, 121 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the soft target. 121a is the signal strength in the extremely close distance region such as the distance range (0) among the signal strengths of the identification signals included in the backscattered light 101. 122 is the signal intensity of the identification signal contained in the backscattered light 101 scattered by the shield in the transmission line. The optical signal output from the optical transceiver 2 is scattered by a shield to generate a peak. The signal strength 122 is the signal strength of the peak generated by being scattered by the shield, and is higher than the signal strength 111.
At a distance farther than the shield in the transmission line, the optical signal output from the optical transceiver 2 is shielded by the shield, so that the signal strength 123 is lower than the signal strengths 111 and 112.

The determination unit 51 acquires the time change data buffered by the monitor buffer 35.
The determination unit 51 determines whether or not the optical space communication is normal based on the time change indicated by the time change data, and outputs a determination result indicating whether or not the optical space communication is normal to the control unit 52.
If the optical space communication is abnormal, the determination unit 51 determines the abnormality factor of the optical space communication based on the time change indicated by the time change data, and outputs the determination result of the abnormality factor to the control unit 52.

FIG. 15 is a flowchart showing the processing contents of the determination unit 51.
Hereinafter, the processing content of the determination unit 51 will be specifically described with reference to FIG.
First, the data acquisition unit 51a acquires the time change data when the optical space communication as shown in FIG. 14A is normal (step ST1 in FIG. 15).
The data acquisition unit 51a outputs the time change data when the optical space communication is normal to the signal intensity comparison unit 51b.
The signal intensity comparison unit 51b recognizes the signal intensities 111, 111a, 112 of the identification signal in the normal state shown in FIG. 14A from the time change data when the optical space communication is normal.
Specifically, the signal strength comparison unit 51b has a signal strength having the largest distance range among one or more signal strengths in which peaks occur in the time change data when the optical space communication is normal. , Recognizes that the signal strength is 112 in the long distance region.
The signal strength comparison unit 51b recognizes that the signal strength having a smaller distance range than the distance range related to the signal strength 112 in the long distance region is the signal strength 111 in the short distance region.
The signal strength comparison unit 51b recognizes that, for example, the signal strength in the distance range (0) is the signal strength 111a in the extremely close distance region among the signal strength 111 in the close distance region.

The data acquisition unit 51a acquires the monitoring time change data, which is the time change data buffered by the monitor buffer 35 (step ST2 in FIG. 15).
The data acquisition unit 51a outputs the monitoring time change data to the signal strength comparison unit 51b.
The signal strength comparison unit 51b sets the signal strength S _N in the close range region, the signal strength S _Na in the extremely close distance region, and the signal strength S _{F in the long distance region included in the monitoring time change data.} recognize.
Specifically, in the monitoring time change data, the signal strength comparison unit 51b indicates that the signal strength having the largest distance range among the one or more signal strengths in which the peak occurs is the signal strength in the long distance region. It recognizes that the S _F.
The signal strength comparison unit 51b recognizes that than the distance range in accordance with the signal intensity S _F in the long range, the signal strength distance range is small, a signal strength S _N in a close-distance region.
The signal strength comparison unit 51b recognizes that, for example, the signal strength in the distance range (0) is the signal strength S _{Na in the extremely close distance region among the signal strength SN in the close distance region.}

In a situation where a shield has invaded the transmission line in the optical space, the distance range related to the signal strength at which the peak occurs is smaller than the distance range where the partner station is assumed to exist. .. Then, under such a situation, the signal strength having a larger distance range than the distance range related to the signal strength at which the peak is generated is uniformly lowered.
In the signal strength comparison unit 51b, the distance range related to the signal strength at which the peak is generated is smaller than the distance range where the partner station is assumed to exist, and the distance range related to the signal strength at which the peak is generated is small. than long as the distance range is greater signal strength decreases uniformly, recognizes that the signal strength has dropped uniformly is the signal strength S _F in the long range.
The distance range in which the partner station is assumed to exist may be stored in the internal memory of the signal strength comparison unit 51b or may be given from the outside.

The signal strength comparison unit 51b outputs the signal strength 111, the signal strength 111a, and the signal strength 112 in the normal state to the determination processing unit 51c.
Further, the signal strength comparison unit 51b outputs the signal strength S _{N in} the close range region, the signal strength S _Na in the extremely close distance region, and the signal strength S _F in the long distance region to the determination processing unit 51c.
_{The signal strength SN} in the close range region is a signal strength corresponding to the signal strength 113, the signal strength 115, the signal strength 117, the signal strength 119, or the signal strength 121.
_{The signal strength S Na} in the extremely close distance region is a signal strength corresponding to the signal strength 113a, the signal strength 115a, the signal strength 117a, the signal strength 119a, or the signal strength 121a.
Signal strength _{S F} in the long range, the signal strength 114, the signal strength 116, the signal strength 118, the corresponding signal strength of the signal strength 120 or signal strength 123.

The determination processing unit 51c compares the signal strength 112 in the long-distance region in the normal state with the signal strength S _F in the long-distance region (step ST3 in FIG. 15).
If the signal strength S _F is 112 or more (step ST3: YES in FIG. 15), the determination processing unit 51c has the signal strength 111 in the close-range range and the signal strength in the close-range range in the normal state. _{Compare with SN} (step ST4 in FIG. 15).
The determination processing unit 51c _{corresponds to the situation of FIG. 14A when the signal intensity SN} in the close distance region has a time zone of the signal intensity 111 or more (step ST4: NO in FIG. 15), and thus corresponds to the optical space. It is determined that the communication is normal (step ST5 in FIG. 15).
_{If the signal strength SN} in the close range region is smaller than the signal strength 111 over all the time (step ST4 of FIG. 15: YES), the determination processing unit 51c corresponds to the situation of FIG. 14B. Although the aerosol concentration in the optical space is decreasing, it is determined that the optical space communication is normal (step ST6 in FIG. 15).

Determination processing unit 51c, if the signal strength _{S F} is smaller than the signal strength 112 (step ST3 of FIG. 15: in the case of NO), the signal strength 111a in close proximity distance area in the normal, in close proximity length range The signal strength _{is compared with S Na} (step ST7 in FIG. 15).
_{If the signal intensity S Na} in the extremely close distance region is smaller than the signal intensity 111a (step ST7 in FIG. 15: when it is smaller), the determination processing unit 51c corresponds to the situation shown in FIG. 14C. Therefore, the optical space shown in FIG. It is determined that the optical space communication is abnormal due to the failure of the communication device (step ST8 in FIG. 15).

_{If the signal strength S Na} in the extremely close distance region is larger than the signal strength 111a (step ST7 in FIG. 15: when it is larger), the determination processing unit 51c corresponds to the situation shown in FIG. It is determined that the optical space communication is abnormal (step ST9 in FIG. 15).
_{When the signal strength S Na} in the extremely close distance region is the same value as the signal strength 111a (step ST7 in FIG. 15: the same case), the determination processing unit 51c determines that the signal strength 111 in the close distance region in the normal state and _{Compare with the signal strength SN} in the close range region (step ST10 in FIG. 15).
In the determination of whether or not the signal strength S _Na and the signal strength 111a are the same value, if _{the difference between the signal strength S Na} and the signal strength 111a is equal to or less than the threshold value, the determination processing unit 51c has the same value. It may be determined that. The threshold value may be stored in the internal memory of the determination processing unit 51c or may be given from the outside.

_{If the signal strength SN} in the close range region is the signal strength 111 or more over the entire time (step ST10: YES in FIG. 15), the determination processing unit 51c corresponds to the situation of FIG. 14E. , It is determined that the optical space communication is abnormal due to the optical axis deviation (step ST11 in FIG. 15).
The determination processing unit 51c _{corresponds to the situation of FIG. 14F when there is a time zone in which the signal intensity SN} in the close distance region is the signal intensity 111 or less (step ST10: NO in FIG. 15), and therefore is a shield. It is determined that the optical space communication is abnormal due to the intrusion of the light (step ST12 in FIG. 15). In the situation where the signal strength _SN is equal to or less than the signal strength 111, the signal strength 122 of the peak whose signal strength _{SN is smaller than the signal strength 111 and larger than the signal strength 111 for a part of time is} The situation is possible.

If the determination result output from the determination unit 51 indicates that the optical space communication is normal, the control unit 52 enables the optical space communication and invalidates the RF space communication, so that the optical space communication A control signal indicating that the above is to be performed is output to each of the transmission switch 21 and the reception switch 32.

When the transmission switch 21 receives a control signal from the control unit 52 indicating that optical space communication is to be performed, the transmission switch 21 subsequently transmits the transmission communication data buffered by the transmission buffer 11 to the data modulation drive circuit 22. Output.
However, in a situation where RF space communication is enabled and optical space communication is disabled, when a control signal indicating that optical space communication is to be performed is received from the control unit 52, the transmission switch 21 is set to RF space. Communication is switched so as to disable communication and enable optical space communication.
Specifically, the transmission switch 21 outputs the transmission communication data buffered by the transmission buffer 11 to the transmission buffer 41 of the RF transceiver 3, and then collects the transmission communication data. Switch to the situation of outputting to the modulation drive circuit 22.

When the reception switch 32 receives a control signal from the control unit 52 indicating that optical space communication is to be performed, the reception switch 32 subsequently receives the communication data output from the data communication optical receiver 31 as a reception buffer of the data interface unit 1. Output to 12.
However, in a situation where RF space communication is enabled and optical space communication is disabled, when a control signal indicating that optical space communication is to be performed is received from the control unit 52, the receiving switch 32 is set to RF space. Communication is switched so as to disable communication and enable optical space communication.
Specifically, the reception switch 32 outputs the communication data output from the data communication optical receiver 31 from the situation where the communication data buffered by the reception buffer 44 is output to the reception buffer 12. Switch to the situation of outputting to the reception buffer 12.

If the determination result output from the determination unit 51 indicates that the optical space communication is abnormal, the control unit 52 enables the RF space communication and invalidates the optical space communication, so that the RF space communication A control signal indicating that the above is to be performed is output to each of the transmission switch 21 and the reception switch 32.

When the transmission switch 21 receives a control signal from the control unit 52 indicating that RF spatial communication is to be performed, the transmission switch 21 transfers the transmission communication data buffered by the transmission buffer 11 to the transmission buffer 41 of the RF transceiver 3. Output to.
When the reception switch 32 receives a control signal from the control unit 52 indicating that RF spatial communication is to be performed, the reception switch 32 receives the communication data buffered by the reception buffer 44 of the RF transceiver 3 for reception of the data interface unit 1. Output to buffer 12.

In the first embodiment, the optical transceiver 2 that performs optical spatial communication of an optical signal including an identification signal and communication data, the RF transceiver 3 that performs RF spatial communication of an RF signal including communication data, and the optical transceiver 2 After the signal is transmitted, it is determined whether or not the optical space communication is normal based on the time change of the signal intensity in the identification signal included in the backward scattered light of the optical signal received by the optical transceiver 2. If the optical space communication is abnormal, the optical space communication device is configured to include a determination unit 51 for determining the cause of the abnormality in the optical space communication based on the time change of the signal strength. Therefore, the optical space communication device can identify the abnormal factor of the optical space communication.

Further, in the first embodiment, if the determination unit 51 determines that the optical space communication is normal, the optical space communication is enabled, the RF space communication is invalidated, and the optical space communication is abnormal by the determination unit 51. If it is determined to be present, the optical space communication device is configured to include a control unit 52 that enables RF space communication and disables optical space communication. Therefore, the optical space communication device can continue the transmission of communication data even when the optical space communication is abnormal.

Further, in the first embodiment, if the wavelength of the optical signal received by the telescope 30 is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner, the optical signal is used as the optical receiver 31 for data communication. If the wavelength of the optical signal output to the light and received by the telescope 30 is the wavelength of the optical signal transmitted from the telescope 30, light is provided so as to include a wavelength branching coupler 29 that outputs the optical signal to the optical circulator 28. A spatial communication device was configured. Therefore, in the optical space communication device, one telescope 30 can both receive the optical signal transmitted from the optical space communication device of the communication partner and receive the backscattered light of the optical signal transmitted from the telescope 30. it can.

In the present invention, it is possible to modify any component of the embodiment or omit any component of the embodiment within the scope of the invention.

The present invention is suitable for an optical space communication device and an optical space communication method for performing optical space communication of optical signals.

1 data interface, 2 optical transceiver, 3 RF transceiver, 11 transmission buffer, 12 reception buffer, 21 transmission switch, 22 data modulation drive circuit, 23 burst modulation drive circuit, 24 signal combiner, 25 reference light source, 26 optical intensity modulator, 27 storage optical amplifier, 28 optical circulator, 29 wavelength branch coupler, 30 telescope, 31 optical receiver for data communication, 32 receiver switch, 33 optical receiver, 34 time series signal processor, 35 Monitor buffer, 41 Transmission buffer, 42 Transmitter / receiver, 43 Transmission / reception antenna, 44 Reception buffer, 51 Judgment unit, 51a Data acquisition unit, 51b Signal strength comparison unit, 51c Judgment processing unit, 52 Control unit, 61 Received signal input Unit, 62 Trigger signal input unit, 63 Identification signal extraction unit, 64 Clock generation unit, 65 LPF, 66 ADC, 67 Data buffer, 68 Data extraction unit, 69 Signal strength calculation unit, 70 Fourier conversion unit, 71 Signal strength calculation processing Unit, 72 time change data generation part, 73 data output part, 81 data extraction circuit, 82 Fourier conversion circuit, 83 signal strength calculation processing circuit, 84 time change data generation circuit, 85 data acquisition circuit, 86 signal strength comparison circuit, 87 Judgment processing circuit, 88 control circuit, 91,93 memory, 92,94 processor, 101,102 backward scattered light, 111-123 signal strength, 111a, 113a, 115a, 117a, 119a, 121a signal strength.

The optical space communication device according to the present invention includes an optical transceiver that performs optical space communication of an optical signal including an identification signal and communication data, a radio frequency transceiver that performs radio frequency space communication of a radio frequency signal including communication data, and an optical transceiver. After the optical signal is transmitted from, it is determined whether or not the optical space communication is normal based on the time change of the signal intensity in the identification signal included in the backward scattered light of the optical signal received by the optical transceiver. However, if the optical space communication is abnormal, a determination unit for determining an abnormal factor of the optical space communication based on the time change of the signal strength is provided , and the frequency of the identification signal and the frequency band of the communication data are set. The optical transceiver is different from the identification signal extraction unit, which blocks the passage of communication data contained in the backward scattered light of the optical signal and extracts the identification signal contained in the backward scattered light, and the identification. By storing the signal strength each time the signal strength calculation unit calculates the signal strength of the identification signal extracted by the signal extraction unit and the signal strength calculation unit calculates the signal strength, the time of the signal strength is obtained. The determination unit includes a time change data generation unit that generates time change data indicating a change, and the determination unit normally performs the optical space communication based on the time change indicated by the time change data generated by the time change data generation unit. If the optical space communication is abnormal, the abnormality factor of the optical space communication is determined based on the time change indicated by the time change data.

Claims (6)

An optical transceiver that performs optical spatial communication of optical signals including identification signals and communication data,
A radio frequency transceiver that performs radio frequency space communication of a radio frequency signal including the communication data,
After the optical signal is transmitted from the optical transceiver, the optical space communication is normal based on the time change of the signal intensity in the identification signal included in the backward scattered light of the optical signal received by the optical transceiver. An optical space communication device including a determination unit that determines whether or not there is an abnormality, and if the optical space communication is abnormal, determines the cause of the abnormality in the optical space communication based on the time change of the signal strength. If the determination unit determines that the optical space communication is normal, the optical space communication is enabled, the radio frequency space communication is invalidated, and the determination unit determines that the optical space communication is abnormal. The optical space communication device according to claim 1, further comprising a control unit that enables the radio frequency space communication and disables the optical space communication. The frequency of the identification signal and the frequency band of the communication data are different.
The optical transceiver
An identification signal extraction unit that blocks the passage of communication data contained in the backscattered light of the optical signal and extracts the identification signal contained in the backscattered light.
A signal strength calculation unit that calculates the signal strength of the identification signal extracted by the identification signal extraction unit, and a signal strength calculation unit.
Each time the signal strength is calculated by the signal strength calculation unit, the signal strength is stored to provide a time change data generation unit that generates time change data indicating the time change of the signal strength.
The determination unit
Based on the time change indicated by the time change data generated by the time change data generation unit, it is determined whether or not the optical space communication is normal, and if the optical space communication is abnormal, the time change data. The optical space communication device according to claim 1, wherein an abnormality factor of the optical space communication is determined based on a time change indicated by. The determination unit compares the time change indicated by the time change data generated by the time change data generation unit with the time change of the signal strength when the optical space communication is normal, thereby performing the optical space communication. The optical space communication device according to claim 3, further comprising determining whether or not the data is normal and determining the cause of the abnormality. The wavelength of the optical signal transmitted from the optical transceiver is different from the wavelength of the optical signal transmitted from the optical space communication device of the communication partner.
The optical transceiver
A telescope that sends and receives optical signals,
If the wavelength of the optical signal received by the telescope is the wavelength of the optical signal transmitted from the optical space communication device of the communication partner, the optical signal is output to the optical receiver for data communication for demolishing the communication data. If the wavelength of the optical signal received by the telescope is the wavelength of the optical signal transmitted from the telescope, it is characterized by including a wavelength branch coupler that outputs the optical signal to the determination unit. The optical space communication device according to claim 1. An optical transceiver performs optical space communication of an optical signal including an identification signal and communication data,
The radio frequency transceiver performs radio frequency space communication of the radio frequency signal including the communication data.
After the optical signal is transmitted from the optical transceiver, the determination unit determines the optical space based on the time change of the signal intensity in the identification signal included in the backward scattered light of the optical signal received by the optical transceiver. An optical space communication method for determining whether or not communication is normal, and if the optical space communication is abnormal, determining the cause of the abnormality in the optical space communication based on the time change of the signal strength.

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