Pointing direction control device and method, optical communication terminal and system

Abstract

The pointing direction control device (11) comprises: a pointing direction control information acquisition unit (13) which acquires pointing direction control information, wherein the pointing direction control information is used to control the pointing direction of light transmission and reception performed by a first optical communication terminal (101) as a first transceiver; and a capture tracking control unit (17) as a pointing direction control unit which controls the pointing direction of light or radio wave transmission and reception performed by a second optical communication terminal (102) as a second transceiver based on the pointing direction control information acquired by the pointing direction control information acquisition unit (13).

Description

Technical Field

[0001] The present disclosure relates to a directional control device for controlling the directional direction of transmitting and receiving light or radio waves. Background Art

[0002] In the technology of receiving and transmitting light or radio waves in a satellite, interference from the satellite itself becomes a problem due to the high directivity of the light or radio waves received and transmitted by the transceiver installed on the satellite. For example, in the event of interference of a micro-radian level that the satellite cannot suppress, the direction in which the transceiver transmits and receives light or radio waves will shift. In addition, the direction may also shift due to other reasons. Moreover, in the event that the direction of the transceiver shifts, the communication quality may deteriorate. Therefore, the transceiver installed on the satellite corrects the deviation of the direction based on light such as beacon light received from the transceiver installed on a satellite other than the satellite, thereby having the performance of maintaining the accuracy of the direction (for example, refer to non-patent document 1).

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-patent document 1: Optical inter-satellite communication technology ~ Construction of future space communications ~ (Laser Research January 2011 Shiro Yamakawa, Takashi Jono Aerospace Research and Development Institute) Summary of the invention

[0006] Problem that the invention aims to solve

[0007] For example, when a satellite relays a signal, the satellite is provided with a plurality of transceivers to communicate with a plurality of other satellites or to observe the earth while communicating with other satellites. In such a satellite, in order to improve the communication quality, it is necessary to improve the performance of maintaining the above-mentioned pointing direction accuracy for all transceivers. Therefore, there is a problem that high-performance sensors and other equipment need to be provided for all transceivers.

[0008] The present disclosure is made to solve the above-mentioned problems, and its purpose is to provide a technology that maintains the accuracy of the pointing direction of at least one of a plurality of transceivers installed on a satellite without installing high-performance sensors or other equipment.

[0009] Means used to solve problems

[0010] The pointing direction control device disclosed in the present invention controls the pointing direction of the light or radio wave transmission and reception by the second transceiver device in a satellite provided with a first transceiver device for transmitting and receiving light and a second transceiver device for transmitting and receiving light or radio waves, wherein the pointing direction control device comprises: a pointing direction control information acquisition unit, which acquires pointing direction control information, and the pointing direction control information is used to control the pointing direction of the light transmission and reception by the first transceiver device; and a pointing direction control unit, which controls the pointing direction of the light or radio wave transmission and reception by the second transceiver device based on the pointing direction control information acquired by the pointing direction control information acquisition unit.

[0011] The first transceiver is a first optical communication terminal that performs optical communication via a first optical link, the second transceiver is a second optical communication terminal that performs optical communication via a second optical link, the pointing direction control information obtained by the pointing direction control information acquisition unit includes a first error in a pointing angle of the first optical communication terminal that performs optical communication via the first optical link, and the pointing direction control unit is a capture and tracking control unit that controls the pointing direction of the second optical communication terminal that performs optical communication via the second optical link based on the first error obtained by the pointing direction control information acquisition unit, thereby controlling the capture and tracking for maintaining the second optical link.

[0012] Effects of the Invention

[0013] According to the present disclosure, it is possible to maintain the accuracy of the pointing direction of at least one of a plurality of transceivers installed in a satellite without installing equipment such as a high-performance sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram showing a situation in which the optical communication system according to Embodiment 1 performs optical communication.

[0015] Figure 2 This is a block diagram showing the structure of the optical communication system according to Embodiment 1.

[0016] Figure 3 This is a flowchart showing the directional direction control method executed by the directional direction control device according to the first embodiment.

[0017] Figure 4 This is a flowchart showing the directional direction control method executed by the directional direction control device according to the first embodiment.

[0018] Figure 5A It is a block diagram showing a hardware structure for realizing the functions of the pointing direction control device. Figure 5B : is a block diagram showing the hardware structure for executing software that realizes the functions of the pointing direction control device.

[0019] Figure 6This is a schematic diagram for explaining a specific example of the error value estimation method performed by the pointing direction control device according to the first embodiment.

[0020] Figure 7 This is a block diagram showing a specific example of the directional control method according to the first embodiment.

[0021] Figure 8 This is a schematic diagram showing a situation in which the optical communication system according to the first variation of the first embodiment performs optical communication and observation.

[0022] Fig. 9 This is a block diagram showing the structure of an optical communication system according to a second variation of embodiment 1.

[0023] Fig.10 This is a schematic diagram showing a situation in which the optical communication system according to Embodiment 2 performs optical communication.

[0024] Fig.11 This is a block diagram showing the structure of an optical communication system according to Embodiment 2.

[0025] Fig.12 This is a flowchart showing a directional direction control method executed by the directional direction control device of the second embodiment.

[0026] Fig.13 This is a diagram for explaining the effect of the directional direction control method performed by the directional direction control device of embodiment 2. DETAILED DESCRIPTION

[0027] Hereinafter, in order to explain the present disclosure in more detail, the mode for implementing the present disclosure will be described with reference to the drawings.

[0028] Implementation method 1.

[0029] Figure 1 FIG. 1 is a schematic diagram showing a situation in which an optical communication system 100 according to Embodiment 1 performs optical communication. The optical communication system 100 includes a first transceiver that performs optical transmission and reception and a second transceiver that performs optical or radio wave transmission and reception. Figure 1 As shown, the optical communication system 100 includes a first optical communication terminal 101 and a second optical communication terminal 102. In addition, in Embodiment 1, the structure in which the optical communication system 100 includes two transceivers, namely, the first optical communication terminal 101 as a first transceiver and the second optical communication terminal 102 as a second transceiver, is described, but the number of transceivers included in the optical communication system 100 is not particularly limited.

[0030] The first optical communication terminal 101 and the second optical communication terminal 102 are respectively installed in the LEO satellite A. The first optical communication terminal 101 performs optical communication with the third optical communication terminal D installed in the GEO satellite C via the first optical link B. In addition, the second optical communication terminal 102 performs optical communication with the fourth optical communication terminal G installed in the LEO satellite F via the second optical link E.

[0031] In this specification, satellite refers to an artificial satellite. In addition, optical communication refers to communication by sending and receiving optical signals to which data is assigned. In addition, LEO (Low Earth Orbit) of LEO satellite refers to low earth orbit, and GEO (Geostationary Earth Orbit) of GEO satellite refers to geostationary orbit. In embodiment 1, GEO satellite C is a low-interference and stable satellite compared to LEO satellite A and LEO satellite F, and LEO satellite A and LEO satellite F are satellites with large interference compared to GEO satellite C.

[0032] In addition, in the first embodiment, the role of the GEO satellite C is to provide a line that is not easily affected by interference. Therefore, instead of the GEO satellite C, the third optical communication terminal D mentioned above may be set in a low-interference LEO, MEO (medium earth orbit) or ground station. In this case, the first optical communication terminal 101 performs optical communication with the third optical communication terminal D set in the LEO, MEO or ground station via the first optical link B. Alternatively, the structure of the first optical communication terminal 101 may be replaced by the following structure instead of the structure for performing optical communication with the third optical communication terminal D: light is sent to a prism or a reflector set in a place (for example, a planet, etc.) with less interference and more stability than the LEO satellite A, and the reflected light is received. In this case, the term "optical communication" used in the following description is replaced with optical transmission and reception.

[0033] Figure 2 1 is a block diagram showing the structure of the optical communication system 100 according to Embodiment 1. Figure 2 As shown, the optical communication system 100 includes a first optical communication terminal 101 and a second optical communication terminal 102 .

[0034] The first optical communication terminal 101 includes a transceiver 1, a directivity control device 2, and a capture and tracking mechanism 3. The directivity control device 2 includes a reception direction information acquisition unit 4, an error detection unit 5, and a capture and tracking control unit 6.

[0035] The transceiver 1 receives light via the first optical link B, thereby detecting reception direction information related to the direction in which the light is received via the first optical link B. The transceiver 1 outputs the detected reception direction information to the pointing direction control device 2. More specifically, the reception direction information detected by the transceiver 1 is, for example, the direction in which the light transmitted by the third optical communication terminal D of the GEO satellite C mentioned above is incident on the transceiver 1. In addition, the reception direction information may also include information related to the position at which the transceiver 1 receives the light via the first optical link B. In this case, the reception direction information is, for example, the position at which the light transmitted by the third optical communication terminal D of the GEO satellite C mentioned above is incident on the transceiver 1.

[0036] The reception direction information acquisition unit 4 acquires the reception direction information detected by the transmission and reception unit 1. The reception direction information acquisition unit 4 outputs the acquired reception direction information to the error detection unit 5.

[0037] The error detection unit 5 refers to the receiving direction information acquired by the receiving direction information acquisition unit 4 to detect a first error in the directional angle of the first optical communication terminal 101 performing optical communication via the first optical link B. More specifically, the error detection unit 5 refers to the receiving direction information acquired by the receiving direction information acquisition unit 4 to detect a first error in the directional angle of the transceiver unit 1 of the first optical communication terminal 101 performing optical communication via the first optical link B. The error detection unit 5 outputs the detected first error to the capture tracking control unit 6 and the directional direction control device 11 of the second optical communication terminal 102 described later.

[0038] In addition, the error detected by the error detection unit 5 is, for example, the difference between the directional angle at which the transceiver unit 1 performs optical communication via the first optical link B and the target directional angle used in the control by the capture tracking control unit 6 described later. In addition, when the reception direction information includes information related to the position at which the transceiver unit 1 receives light via the first optical link B, the error detection unit 5 may refer to the reception direction information acquired by the reception direction information acquisition unit 4 to further detect the error of the position at which the transceiver unit 1 performs optical communication via the first optical link B. In this case, the error of the position detected by the error detection unit 5 is, for example, the difference between the position at which the transceiver unit 1 performs optical communication via the first optical link B and the target position used in the control by the capture tracking control unit 6 described later.

[0039] The capture tracking control unit 6 controls the directional direction of the optical communication performed by the first optical communication terminal 101 via the first optical link B based on the first error detected by the error detection unit 5, thereby controlling the capture tracking for maintaining the first optical link B. More specifically, in Embodiment 1, the capture tracking control unit 6 controls the directional direction of the optical communication performed by the transceiver 1 of the first optical communication terminal 101 via the first optical link B based on the first error detected by the error detection unit 5, thereby controlling the capture tracking for maintaining the first optical link B. For example, when the directional angle of the transceiver 1 is controlled to be the target directional angle, the capture tracking control unit 6 adjusts the control amount by an amount corresponding to the first error. In addition, when the error detection unit 5 detects the error of the position as described above, the capture tracking control unit 6 may also control the position of the transceiver 1 for optical communication via the first optical link B based on the error of the position detected by the error detection unit 5, thereby controlling the capture tracking for maintaining the first optical link B.

[0040] The capture and tracking mechanism 3 changes the pointing direction of the transceiver 1 based on the control of the capture and tracking control unit 6, thereby performing capture and tracking for maintaining the first optical link B. In addition, when the capture and tracking control unit 6 controls the position of the transceiver 1 based on the position error as described above, the capture and tracking mechanism 3 may further change the position of the transceiver 1 based on the control of the capture and tracking control unit 6, thereby performing capture and tracking for maintaining the first optical link B. As an example of the capture and tracking mechanism 3, a piezoelectric actuator or the like is cited.

[0041] The second optical communication terminal 102 includes a transceiver 10, a directional control device 11, and a capture tracking mechanism 12. The directional control device 11 includes a directional control information acquisition unit 13, an error value estimation calculation unit 14, a reception direction information acquisition unit 15, an error detection unit 16, and a capture tracking control unit 17.

[0042] In addition, regarding the capture tracking of the second optical communication terminal 102 for maintaining the second optical link E, it is assumed that only rough capture is established. Rough capture refers to the following state: the state in which the second optical communication terminal 102 can track the fourth optical communication terminal G described above using beacon light, etc., or the state in which the second optical communication terminal 102 can be captured by the tracking sensor of the transceiver 10 but cannot always be captured by the communication sensor of the transceiver 10. As a reason why the second optical communication terminal 102 cannot perform fine capture, for example, it is considered that the resolution of the tracking sensor of the transceiver 10 is insufficient or the control is delayed due to satellite interference of the LEO satellite A, thereby causing oscillation of the capture tracking mechanism 12 that receives feedback.

[0043] The transceiver 10 receives light via the second optical link E, thereby detecting reception direction information related to the direction in which the light is received via the second optical link E. The transceiver 10 outputs the received reception direction information to the reception direction information acquisition unit 15. More specifically, the reception direction information is, for example, the direction in which the light transmitted by the fourth optical communication terminal G of the LEO satellite F mentioned above is incident on the transceiver 10. In addition, the reception direction information may also include information related to the position at which the transceiver 10 receives the light via the second optical link E. In this case, the reception direction information is, for example, the position at which the light transmitted by the fourth optical communication terminal G of the LEO satellite F mentioned above is incident on the transceiver 10.

[0044] The directional control information acquisition unit 13 acquires directional control information for controlling the directional direction of light transmission and reception by the first optical communication terminal 101. More specifically, in the first embodiment, the directional control information acquisition unit 13 acquires the directional control information including the first error of the directional angle of the optical communication performed by the transceiver unit 1 of the first optical communication terminal 101 via the first optical link B from the error detection unit 5 of the directional control device 2 of the first optical communication terminal 101. The directional control information acquisition unit 13 outputs the acquired directional control information to the error value estimation calculation unit 14.

[0045] In addition, the directional control information acquired by the directional control information acquisition unit 13 may also include an error in the position where the transceiver unit 1 of the first optical communication terminal 101 performs optical communication via the first optical link B. In addition, the directional control information acquisition unit 13 may further acquire at least one directional control information from at least one optical communication terminal (not shown) that is different from the first optical communication terminal 101 and the second optical communication terminal 102 and is installed on the LEO satellite A.

[0046] The error value estimation operation unit 14 estimates the second error of the directional angle at which the second optical communication terminal 102 performs optical communication via the second optical link E based on the first error obtained by the directional direction control information acquisition unit 13. More specifically, the error value estimation operation unit 14 estimates the second error of the directional angle at which the transceiver unit 10 of the second optical communication terminal 102 performs optical communication via the second optical link E based on the first error obtained by the directional direction control information acquisition unit 13. At this time, the error value estimation operation unit 14 may convert the first error obtained by the directional direction control information acquisition unit 13 into an interference value indicating the degree of interference with the LEO satellite A, and estimate the second error of the directional angle at which the transceiver unit 10 of the second optical communication terminal 102 performs optical communication via the second optical link E based on the converted interference value.

[0047] In addition, when the directional control information acquired by the directional control information acquisition unit 13 includes a position error as described above, the error value estimation operation unit 14 may estimate the error of the position at which the transceiver unit 10 of the second optical communication terminal 102 performs optical communication via the second optical link E based on the position error acquired by the directional control information acquisition unit 13. In addition, when the directional control information acquisition unit 13 acquires at least one directional control information from at least one other optical communication terminal, the error value estimation operation unit 14 may further estimate the second error of the directional angle at which the second optical communication terminal 102 performs optical communication via the second optical link E based on the error of the directional angle of at least one other optical communication terminal included in the at least one directional control information acquired by the directional control information acquisition unit 13.

[0048] The receiving direction information acquisition unit 15 acquires the receiving direction information related to the direction in which the second optical communication terminal 102 receives light via the second optical link E. More specifically, in Embodiment 1, the receiving direction information acquisition unit 15 acquires the receiving direction information related to the direction in which the transceiver 10 of the second optical communication terminal 102 receives light via the second optical link E. The receiving direction information acquisition unit 15 outputs the acquired receiving direction information to the error detection unit 16.

[0049] The error detection unit 16 refers to the receiving direction information acquired by the receiving direction information acquisition unit 15 to detect the third error of the directional angle of the second optical communication terminal 102 for optical communication via the second optical link E. More specifically, in Embodiment 1, the error detection unit 16 refers to the receiving direction information acquired by the receiving direction information acquisition unit 15 to detect the third error of the directional angle of the transceiver unit 10 of the second optical communication terminal 102 for optical communication via the second optical link E. The error detection unit 16 outputs the detected third error to the error value estimation operation unit 14. The error value estimation operation unit 14 may directly output the estimated second error and the acquired third error to the capture tracking control unit 17, or may calculate an error with higher accuracy than these errors based on the second error and the third error, and output the error to the capture tracking control unit 17.

[0050] In addition, the error detected by the error detection unit 16 is, for example, the difference between the directional angle at which the transceiver unit 10 performs optical communication via the second optical link E and the target directional angle used in the control by the capture tracking control unit 17 described later. In addition, when the reception direction information includes information related to the position at which the transceiver unit 10 receives light via the second optical link E, the error detection unit 16 may refer to the reception direction information acquired by the reception direction information acquisition unit 15 to further detect the error of the position at which the transceiver unit 10 performs optical communication via the second optical link E. In this case, the error of the position detected by the error detection unit 16 is, for example, the difference between the position at which the transceiver unit 10 performs optical communication via the second optical link E and the target position used in the control by the capture tracking control unit 17 described later.

[0051] The capture tracking control unit 17 is a directional control unit that controls the directional direction of the second optical communication terminal 102 as the second transceiver for transmitting and receiving light or radio waves based on the directional control information acquired by the directional control information acquisition unit 13. More specifically, in Embodiment 1, the capture tracking control unit 17 controls the directional direction of the transceiver 10 of the second optical communication terminal 102 for optical communication via the second optical link E based on the first error acquired by the directional control information acquisition unit 13, thereby controlling the capture tracking for maintaining the second optical link E. More specifically, the capture tracking control unit 17 controls the directional direction of the transceiver 10 of the second optical communication terminal 102 for optical communication via the second optical link E based on the second error estimated by the error value estimation operation unit 14 based on the first error, thereby controlling the capture tracking for maintaining the second optical link E. For example, when the directional angle of the transceiver 10 is to be controlled to the target directional angle, the capture tracking control unit 17 adjusts the control amount by an amount corresponding to the second error.

[0052] In more detail, the capture tracking control unit 17 controls the direction of the optical communication performed by the transceiver unit 10 of the second optical communication terminal 102 via the second optical link E based on the third error detected by the error detection unit 16, thereby controlling the capture tracking for maintaining the second optical link E. In this case, the capture tracking control unit 17 may also use the second error as a feedforward amount and the third error as a feedback amount, for example, to control the direction of the optical communication performed by the transceiver unit 10 via the second optical link E. As a result, the capture tracking capability of the second optical communication terminal 102 for maintaining the second optical link E is improved. This can improve the fine capture accuracy even when the second optical communication terminal 102 performs fine capture, and is not limited to the case where the second optical communication terminal 102 performs rough capture without performing fine capture. As an effect of the improvement in fine capture accuracy, an improvement in the received optical power can be expected.

[0053] In addition, when the error detection unit 16 detects the position error as described above, the capture tracking control unit 17 may also control the position of the transceiver 10 for optical communication via the second optical link E based on the position error detected by the error detection unit 16, thereby controlling the capture tracking for maintaining the second optical link E. In addition, when the error value estimation operation unit 14 further estimates the second error based on the error of the directional angle of at least one other optical communication terminal, the capture tracking control unit 17 may also control the directional direction of the transceiver 10 of the second optical communication terminal 102 for optical communication via the second optical link E based on the second error, thereby controlling the capture tracking for maintaining the second optical link E.

[0054] The capture tracking mechanism 12 changes the pointing direction of the transceiver 10 based on the control of the capture tracking control unit 17, thereby performing capture tracking for maintaining the second optical link E. In addition, when the capture tracking control unit 17 controls the position of the transceiver 10 based on the position error as described above, the capture tracking mechanism 12 may further change the position of the transceiver 10 based on the control of the capture tracking control unit 17, thereby performing capture tracking for maintaining the second optical link E. As an example of the capture tracking mechanism 12, a piezoelectric actuator or the like is cited.

[0055] Next, the operation of the directivity control device 2 of the first optical communication terminal 101 according to the first embodiment will be described with reference to the drawings. Figure 3 2 is a flowchart showing a directional control method executed by the directional control device 2. It is assumed that before the following directional control method is implemented, the transceiver 1 receives light via the first optical link B, thereby detecting reception direction information related to the direction of light received via the first optical link B.

[0056] like Figure 3 As shown in FIG. 1 , the reception direction information acquisition unit 4 acquires the reception direction information detected by the transmission and reception unit 1 (step ST1 ). The reception direction information acquisition unit 4 outputs the acquired reception direction information to the error detection unit 5 .

[0057] Next, the error detection unit 5 refers to the receiving direction information acquired by the receiving direction information acquisition unit 4 to detect a first error in the directional angle of the optical communication performed by the transceiver unit 1 via the first optical link B (step ST2). The error detection unit 5 outputs the detected first error to the capture tracking control unit 6 and the directional direction control information acquisition unit 13 of the directional direction control device 11 of the second optical communication terminal 102.

[0058] Next, the capture and tracking control unit 6 controls the direction of the optical communication performed by the transceiver 1 via the first optical link B based on the first error detected by the error detection unit 5, thereby controlling the capture and tracking for maintaining the first optical link B (step ST3).

[0059] The capture tracking mechanism 3 changes the pointing direction of the transceiver 1 based on the control performed by the capture tracking control unit 6 in step ST3, thereby performing capture tracking for maintaining the first optical link B. The transceiver 1 whose pointing direction has been changed by the capture tracking mechanism 3 receives light again via the first optical link B, thereby detecting the receiving direction information related to the direction of the light received via the first optical link B. The pointing direction control device 2 performs the above-mentioned steps ST1 to ST3 again based on the receiving direction information detected again by the transceiver 1. The first optical communication terminal 101 performs capture tracking for maintaining the first optical link B by repeating the above-mentioned actions.

[0060] Next, the operation of the directivity control device 11 of the second optical communication terminal 102 according to the first embodiment will be described with reference to the drawings. Figure 4 1 is a flowchart showing a directional control method executed by the directional control device 11. It is also assumed that before the following directional control method is implemented, the transceiver 10 receives light via the second optical link E, thereby detecting reception direction information related to the direction in which the light is received via the second optical link E.

[0061] like Figure 4 As shown, the directional control information acquisition unit 13 acquires the directional control information from the error detection unit 5 of the directional control device 2 of the first optical communication terminal 101, the directional control information including the first error of the directional angle at which the transceiver unit 1 of the first optical communication terminal 101 performs optical communication via the first optical link B (step ST10). The directional control information acquisition unit 13 outputs the acquired directional control information to the error value estimation calculation unit 14.

[0062] Next, the error value estimation calculation unit 14 estimates a second error in the directivity angle of the optical communication performed by the transceiver unit 10 via the second optical link E based on the first error acquired by the directivity control information acquisition unit 13 (step ST11 ).

[0063] Next, the reception direction information acquisition unit 15 acquires reception direction information about the direction in which the transmission / reception unit 10 receives light via the second optical link E (step ST12 ). The reception direction information acquisition unit 15 outputs the acquired reception direction information to the error detection unit 16 .

[0064] Next, the error detection unit 16 refers to the receiving direction information acquired by the receiving direction information acquisition unit 15 to detect the third error of the directional angle of the optical communication performed by the transceiver unit 10 via the second optical link E (step ST13). The error detection unit 16 outputs the detected third error to the error value estimation operation unit 14. The error value estimation operation unit 14 outputs the second error estimated in step ST11 and the acquired third error to the capture tracking control unit 17.

[0065] The capture tracking control unit 17 controls the direction of optical communication performed by the transceiver unit 10 via the second optical link E based on the second error estimated by the error value estimation operation unit 14 according to the first error in step ST11 and the third error detected by the error detection unit 16 in step ST13, thereby controlling the capture tracking for maintaining the second optical link E (step ST14).

[0066] The capture tracking mechanism 12 changes the pointing direction of the transceiver 10 based on the control performed by the capture tracking control unit 17 in step ST14, thereby performing capture tracking for maintaining the second optical link E. The transceiver 10 whose pointing direction has been changed by the capture tracking mechanism 12 receives light again via the second optical link E, thereby detecting the receiving direction information related to the direction of the light received via the second optical link E. Then, the pointing direction control device 11 performs the above-mentioned steps ST10 to ST14 again. The second optical communication terminal 102 performs capture tracking for maintaining the second optical link E by repeating the above-mentioned actions.

[0067] The functions of the receiving direction information acquisition unit 4, the error detection unit 5 and the capture tracking control unit 6 in the directional control device 2 are realized by the processing circuit. Figure 3 The processing circuit for the processes of step ST1 to step ST3 shown in the figure may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in a memory.

[0068] In addition, the functions of the directional control information acquisition unit 13, the error value estimation calculation unit 14, the reception direction information acquisition unit 15, the error detection unit 16 and the capture tracking control unit 17 in the directional control device 11 are realized by the processing circuit. Figure 4 The processing circuit for the processes of step ST10 to step ST14 shown in the figure may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in a memory.

[0069] Figure 5A It is a block diagram showing a hardware configuration for realizing the functions of the directional control device 2 or the directional control device 11. Figure 5B 1 is a block diagram showing a hardware configuration for executing software that realizes the functions of the pointing direction control device 2 or the pointing direction control device 11. Figure 5A and Figure 5B The transceiver device 21 shown respectively performs the function of the above-mentioned transceiver unit 1 or the function of the above-mentioned transceiver unit 10. Figure 5A and Figure 5B The capture and tracking mechanism 22 shown respectively performs the function of the capture and tracking mechanism unit 3 described above or the function of the capture and tracking mechanism unit 12 described above.

[0070] In the above processing circuit is Figure 5A In the case of the dedicated hardware processing circuit 20 shown, the processing circuit 20 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0071] The functions of the receiving direction information acquisition unit 4, the error detection unit 5, and the capture tracking control unit 6 in the pointing direction control device 2 may be realized by different processing circuits, or their functions may be realized by one processing circuit. In addition, the functions of the pointing direction control information acquisition unit 13, the error value estimation operation unit 14, the receiving direction information acquisition unit 15, the error detection unit 16, and the capture tracking control unit 17 in the pointing direction control device 11 may be realized by different processing circuits, or their functions may be realized by one processing circuit.

[0072] In the above processing circuit is Figure 5B In the case of the processor 23 shown in FIG. 1 , the functions of the receiving direction information acquisition unit 4, the error detection unit 5 and the capture tracking control unit 6 in the pointing direction control device 2 are respectively implemented by software, firmware or a combination of software and firmware. Alternatively, in the case where the processing circuit is Figure 5B In the case of the processor 23 shown, the functions of the pointing direction control information acquisition unit 13, the error value estimation operation unit 14, the receiving direction information acquisition unit 15, the error detection unit 16 and the capture and tracking control unit 17 in the pointing direction control device 11 are respectively implemented by software, firmware or a combination of software and firmware.

[0073] In addition, the software or firmware is described in the form of a program and stored in the memory 24 .

[0074] The processor 23 realizes the functions of the receiving direction information acquisition unit 4, the error detection unit 5 and the capture and tracking control unit 6 in the pointing direction control device 2 by reading and executing the program stored in the memory 24. That is, the pointing direction control device 2 includes the memory 24, which is used to store the program executed by the processor 23. Figure 3 Alternatively, the processor 23 realizes the functions of the pointing direction control information acquisition unit 13, the error value estimation calculation unit 14, the receiving direction information acquisition unit 15, the error detection unit 16, and the capture tracking control unit 17 in the pointing direction control device 11 by reading and executing the program stored in the memory 24. That is, the pointing direction control device 11 has a memory 24, which is used to store the results of the execution when the processor 23 executes the program. Figure 4 The procedure of the processing from step ST10 to step ST14 is shown.

[0075] These programs cause the computer to execute the steps or methods of the receiving direction information acquisition unit 4, the error detection unit 5, and the capture tracking control unit 6 in the pointing direction control device 2. The memory 24 may also be a computer-readable storage medium storing a program for causing the computer to function as the receiving direction information acquisition unit 4, the error detection unit 5, and the capture tracking control unit 6 in the pointing direction control device 2. Alternatively, these programs cause the computer to execute the steps or methods of the pointing direction control information acquisition unit 13, the error value estimation operation unit 14, the receiving direction information acquisition unit 15, the error detection unit 16, and the capture tracking control unit 17 in the pointing direction control device 11. The memory 24 may also be a computer-readable storage medium storing a program for causing the computer to function as the pointing direction control information acquisition unit 13, the error value estimation operation unit 14, the receiving direction information acquisition unit 15, the error detection unit 16, and the capture tracking control unit 17 in the pointing direction control device 11.

[0076] The memory 24 includes, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically-EPROM), and other non-volatile or volatile semiconductor memories, magnetic disks, floppy disks, optical disks, high-density disks, mini disks, DVDs, and the like.

[0077] The functions of the reception direction information acquisition unit 4, the error detection unit 5, and the capture and tracking control unit 6 in the pointing direction control device 2 may be partially realized by dedicated hardware and partially realized by software or firmware.

[0078] For example, the reception direction information acquisition unit 4 and the error detection unit 5 are implemented by a processing circuit as dedicated hardware. The capture and tracking control unit 6 may be implemented by the processor 23 reading and executing a program stored in the memory 24 .

[0079] Alternatively, the respective functions of the pointing direction control information acquisition unit 13, the error value estimation operation unit 14, the receiving direction information acquisition unit 15, the error detection unit 16 and the capture and tracking control unit 17 in the pointing direction control device 11 can also be partially implemented by dedicated hardware and partially implemented by software or firmware.

[0080] For example, the pointing direction control information acquisition unit 13 and the error value estimation calculation unit 14 are implemented by a processing circuit as dedicated hardware. The reception direction information acquisition unit 15, the error detection unit 16 and the acquisition tracking control unit 17 can also be implemented by the processor 23 reading and executing a program stored in the memory 24.

[0081] In this way, the processing circuit can implement the above functions through hardware, software, firmware or a combination thereof.

[0082] Next, a specific example of the error value estimation method of step ST11 in the directional control method executed by the directional control device 11 of the second optical communication terminal 102 according to the first embodiment will be described with reference to the drawings. Figure 6 is a schematic diagram for explaining a specific example of the error value estimation method performed by the pointing direction control device 11. Figure 6 , the two-dimensional positional relationship of the above-mentioned satellites is shown.

[0083] exist Figure 6 In , the angle formed by the line connecting LEO satellite A and GEO satellite C (first optical link B) and the line connecting LEO satellite A and LEO satellite F (second optical link E) is θ. In addition, it is assumed that fine capture between LEO satellite A and GEO satellite C is established.

[0084] First, in the above-mentioned step ST2, the error detection unit 5 of the directional control device 2 of the first optical communication terminal 101 detects the first error Δθ of the directional angle of the optical communication performed by the transceiver 1 via the first optical link B during a certain time interval Δt. Next, the directional control information acquisition unit 13 acquires the first error Δθ in the above-mentioned step ST10.

[0085] In addition, since the interference of GEO satellite C is smaller than that of LEO satellite A, the angle variation caused by the interference of LEO satellite A, which is the cause of the first error Δθ, is much larger than the angle variation caused by the interference of GEO satellite C, which is the cause of the first error Δθ. Therefore, in this specific example, in the above-mentioned step ST11, the error value estimation operation unit 14 of the second optical communication terminal 102 estimates that the second error of the directional angle at which the transceiver unit 10 performs optical communication via the second optical link E is the same value as the first error Δθ of the directional angle at which the transceiver unit 1 of the first optical communication terminal 101 performs optical communication via the first optical link B. The second error Δθ estimated by the error value estimation operation unit 14 is used for the control of the directional direction by the capture and tracking control unit 17 in the above-mentioned step ST14, thereby stabilizing the second optical link E between the LEO satellite A and the LEO satellite F.

[0086] Next, specific examples of the directional control method executed by the directional control device 2 of the first optical communication terminal 101 and the directional control method executed by the directional control device 11 of the second optical communication terminal 102 according to Embodiment 1 will be described with reference to the block diagram. Figure 7 This is a block diagram showing a specific example of the directional control method according to the first embodiment.

[0087] First, in the first optical communication terminal 101, in the above-mentioned step ST3, the capture tracking control unit 6 sets the pointing angle ( Figure 7 The capture tracking mechanism 3 takes the first error obtained in advance from the error detection unit 5 as input, and calculates the control amount for the capture tracking mechanism 3 using G11 as a transfer function, thereby controlling the direction in which the transceiver 1 performs optical communication via the first optical link B. Then, the capture tracking mechanism 3 changes the direction of the transceiver 1 based on the control performed by the capture tracking control unit 6 in step ST3, thereby performing capture tracking for maintaining the first optical link B. The transceiver 1 whose direction has been changed by the capture tracking mechanism 3 receives light via the first optical link B, thereby detecting the receiving direction information related to the direction in which the light is received via the first optical link B.

[0088] Then, the pointing direction control method is executed again by the pointing direction control device 2, and in the above-mentioned step ST1, the receiving direction information acquisition unit 4 acquires the receiving direction information detected by the transceiver 1. Next, in the above-mentioned step ST2, the error detection unit 5 uses the receiving direction information acquired by the receiving direction information acquisition unit 4 as input and G12 as a transfer function to calculate the first error of the pointing angle of the transceiver 1 performing optical communication via the first optical link B.

[0089] Next, in the above-mentioned step ST3, the capture and tracking control unit 6 takes the directional angle of the target and the first error calculated by the error detection unit 5 as inputs, uses G11 as a transfer function, and calculates the control amount for the capture and tracking mechanism unit 3 again, thereby controlling the directional direction of the optical communication performed by the transceiver unit 1 via the first optical link B. That is, in this specific example, the control performed by the capture and tracking control unit 6 is feedback control using the first error as a feedback amount.

[0090] On the other hand, in the second optical communication terminal 102, in the above-mentioned step ST14, the capture tracking control unit 17 takes the directional angle of the target, the second error obtained in advance from the error value estimation operation unit 14, and the third error obtained in advance from the error detection unit 16 as input, and uses G21 as a transfer function to calculate the control amount for the capture tracking mechanism unit 12, and controls the directional direction of the transceiver unit 10 to perform optical communication via the second optical link E, thereby controlling the capture tracking for maintaining the second optical link E. Then, the capture tracking mechanism unit 12 changes the directional direction of the transceiver unit 10 based on the control performed by the capture tracking control unit 17 in step ST14, thereby performing capture tracking for maintaining the second optical link E. The transceiver unit 10 whose directional direction is changed by the capture tracking mechanism unit 12 receives light via the second optical link E, thereby detecting the receiving direction information related to the direction of the light received via the second optical link E.

[0091] Then, the directional control method is executed again by the directional control device 11, and in the above-mentioned step ST10, the directional control information acquisition unit 13 acquires the directional control information including the first error calculated by the error detection unit 5 in the above-mentioned step ST2. Next, in the above-mentioned step ST11, the error value estimation calculation unit 14 uses the first error obtained by the directional control information acquisition unit 13 as input and the transfer function as G13 to calculate the second error of the directional angle of the transceiver unit 10 for optical communication via the second optical link E.

[0092] Next, in the above-mentioned step ST12, the receiving direction information acquisition unit 15 acquires the receiving direction information related to the direction in which the transceiver unit 10 receives light via the second optical link E. Next, in the above-mentioned step ST13, the error detection unit 16 uses the receiving direction information acquired by the receiving direction information acquisition unit 15 as input and G22 as a transfer function to calculate the third error of the directional angle of the optical communication performed by the transceiver unit 10 via the second optical link E.

[0093] Next, in the above-mentioned step ST14, the capture and tracking control unit 17 takes the directional angle of the target, the second error calculated by the error value estimation operation unit 14 in step ST11, and the third error calculated by the error detection unit 16 in step ST13 as input, and uses G21 as a transfer function to calculate the control amount for the capture and tracking mechanism unit 12, and controls the directional direction of the optical communication performed by the transceiver unit 10 via the second optical link E, thereby controlling the capture and tracking for maintaining the second optical link E. That is, in this specific example, the control performed by the capture and tracking control unit 6 is a control that uses both feedback control using the third error as a feedback amount and feedforward control using the second error as a feedforward amount.

[0094] Next, a first variation of the first embodiment will be described with reference to the accompanying drawings. In the above description, a configuration in which the first optical communication terminal 101 and the second optical communication terminal 102 are installed in the LEO satellite A is described. In the first variation of the first embodiment, a configuration in which an observation terminal is installed in the LEO satellite A instead of the second optical communication terminal 102 is described.

[0095] Figure 8 FIG. 1 is a schematic diagram showing a situation in which the optical communication system 103 of the first variant of the first embodiment performs optical communication and observation. Figure 8 As shown, the optical communication system 103 includes a first optical communication terminal 101 and an observation terminal 104. In addition, the structure of the first optical communication terminal 101 of the first modification example is the same as that of the first modification example. Figure 2 The structure of the first optical communication terminal 101 shown in FIG. 1 is the same as that of the first optical communication terminal 101. Figure 2 The second optical communication terminal 102 shown has a partially different structure.

[0096] The observation terminal 104 observes the earth by transmitting and receiving light or radio waves. Examples of the observation terminal 104 include an observation terminal having an optical element for ground imaging, an observation terminal having a radio wave processing device for ground imaging, or an observation terminal having a measuring device for measuring atmospheric conditions. When the observation terminal 104 is one of these observation terminals, the transceiver unit in the observation terminal 104 that is equivalent to the transceiver unit 10 of the second optical communication terminal 102 includes an optical element for ground imaging, a radio wave processing device for ground imaging, or a measuring device for measuring atmospheric conditions. The transceiver unit may also detect the receiving direction information related to the direction in which the light or radio wave is received by the same method as the above-mentioned method in which the transceiver unit 10 of the second optical communication terminal 102 detects the receiving direction information. Alternatively, the transceiver unit may also send light or radio waves toward the earth and receive the reflected light or radio waves, thereby detecting the receiving direction information related to the direction in which the light or radio wave is received.

[0097] The directional control unit in the observation terminal 104, which corresponds to the capture tracking control unit 17 of the second optical communication terminal 102, controls the directional direction in which the above-mentioned transceiver of the observation terminal 104 transmits and receives light or radio waves based on the first error acquired by the directional control information acquisition unit 13. More specifically, the directional control unit controls the directional direction in which the above-mentioned transceiver of the observation terminal 104 transmits and receives light or radio waves based on the second error estimated by the error value estimation calculation unit 14 based on the first error. More specifically, the directional control unit also controls the directional direction in which the above-mentioned transceiver of the observation terminal 104 transmits and receives light or radio waves based on the third error detected by the error detection unit 16.

[0098] Furthermore, the mechanism unit corresponding to the capture and tracking mechanism unit 12 of the second optical communication terminal 102 in the observation terminal 104 changes the directional direction of the transmission and reception unit 10 based on the control by the directional direction control unit described above, thereby adjusting the observation direction.

[0099] As described above, the directional control device 11 according to the first embodiment can also be applied to the observation terminal 104 by changing a part of the structure.

[0100] Next, a second variation of Embodiment 1 is described with reference to the accompanying drawings. In Embodiment 1, a configuration is described in which the pointing direction control device 11 of the second optical communication terminal 102 controls the pointing direction based on the first error obtained from the pointing direction control device 2 of the first optical communication terminal 101. In the second variation, an example in which the pointing direction control device 2 of the first optical communication terminal 101 has the same configuration as this configuration is also described.

[0101] Fig. 9 1 is a block diagram showing the structure of an optical communication system 105 according to a second variant of the first embodiment. Fig. 9 As shown, the directivity control device 30 of the first optical communication terminal 106 of the second modified example further includes a directivity control information acquisition unit 31 and an error value estimation calculation unit 32 compared to the above-mentioned directivity control device 2 .

[0102] The directivity control information acquisition unit 31 acquires the third error detected by the error detection unit 16 of the second optical communication terminal 102. The error value estimation operation unit 32 estimates a fourth error in the directivity angle of the optical communication performed by the transceiver 1 via the first optical link B based on the third error acquired by the directivity control information acquisition unit 31.

[0103] The capture and tracking control unit 6 of the second modification further controls the directional direction of the optical communication performed by the transceiver 1 via the first optical link B based on the fourth error estimated by the error value estimation calculation unit 32 from the third error, thereby controlling the capture and tracking for maintaining the first optical link B.

[0104] According to the configuration of the second modified example, the tracking capability of the first optical communication terminal 101 for maintaining the first optical link B is improved.

[0105] As described above, the pointing direction control device 11 of embodiment 1 controls the pointing direction of the second transceiver for transmitting or receiving light or radio waves in a satellite provided with the first optical communication terminal 101 as the first transceiver for transmitting or receiving light and the second optical communication terminal 102 as the second transceiver for transmitting or receiving light or radio waves, wherein the pointing direction control device 11 comprises: a pointing direction control information acquisition unit 13, which acquires pointing direction control information for controlling the pointing direction of the first transceiver for transmitting or receiving light; and a capture and tracking control unit 17 as a pointing direction control unit, which controls the pointing direction of the second transceiver for transmitting or receiving light or radio waves based on the pointing direction control information acquired by the pointing direction control information acquisition unit 13.

[0106] The first transceiver and the second transceiver are arranged in the same satellite, so the pointing direction of the first transceiver and the pointing direction of the second transceiver are correlated. Therefore, according to the above-mentioned structure, by controlling the pointing direction of the second transceiver for receiving and transmitting light or radio waves based on the pointing direction control information of the first transceiver, the accuracy of the pointing direction of the second transceiver can be maintained. In addition, for example, in other transceivers other than the first transceiver and the second transceiver, the pointing direction of the other transceivers for receiving and transmitting light or radio waves can also be controlled based on the pointing direction control information of the first transceiver. That is, for at least one of the multiple transceivers arranged on the satellite, the accuracy of the pointing direction can be maintained without the need to set up high-performance sensors and other equipment. In addition, the cost consumed by the equipment of the transceiver can be reduced thereby.

[0107] In addition, in the pointing direction control device 11 of embodiment 1, the first transceiver is the first optical communication terminal 101 that performs optical communication via the first optical link B, the second transceiver is the second optical communication terminal 102 that performs optical communication via the second optical link E, the pointing direction control information obtained by the pointing direction control information acquisition unit 13 includes the first error of the pointing angle of the first optical communication terminal 101 performing optical communication via the first optical link B, and the pointing direction control unit is the following capture tracking control unit 17, which controls the pointing direction of the second optical communication terminal 102 performing optical communication via the second optical link E based on the first error obtained by the pointing direction control information acquisition unit 13, thereby controlling the capture tracking for maintaining the second optical link E.

[0108] According to the above configuration, by controlling the pointing direction of the second optical communication terminal 102 based on the first error of the pointing angle of the first optical communication terminal 101, it is possible to correct the deviation of the pointing direction of the second optical communication terminal 102 caused by interference from the LEO satellite A, etc., and maintain the accuracy of the pointing direction of the second optical communication terminal 102. That is, for at least one of the plurality of optical communication terminals installed on the satellite, the accuracy of the pointing direction can be maintained without installing a high-performance sensor or other equipment.

[0109] In addition, the pointing direction control device 11 of embodiment 1 also has an error value estimation operation unit 14, which estimates the second error of the pointing angle of the second optical communication terminal 102 performing optical communication via the second optical link E based on the first error obtained by the pointing direction control information acquisition unit 13, and the capture and tracking control unit 17 controls the pointing direction of the second optical communication terminal 102 performing optical communication via the second optical link E based on the second error estimated by the error value estimation operation unit 14 based on the first error, thereby controlling the capture and tracking for maintaining the second optical link E.

[0110] According to the above configuration, the second error of the directional angle of the second optical communication terminal 102 is estimated based on the first error of the directional angle of the first optical communication terminal 101, and the directional direction of the second optical communication terminal 102 is controlled based on the second error. Thus, the directional direction of the second optical communication terminal 102 can be appropriately controlled.

[0111] In addition, the pointing direction control device 11 of embodiment 1 also includes: a receiving direction information acquisition unit 15, which acquires receiving direction information related to the direction in which the second optical communication terminal 102 receives light via the second optical link E; and an error detection unit 16, which refers to the receiving direction information acquired by the receiving direction information acquisition unit 15, and detects the third error of the pointing angle of the second optical communication terminal 102 performing optical communication via the second optical link E. The capture and tracking control unit 17 also controls the pointing direction of the second optical communication terminal 102 performing optical communication via the second optical link E based on the third error detected by the error detection unit 16, thereby controlling the capture and tracking for maintaining the second optical link E.

[0112] According to the above configuration, the directional direction of the second optical communication terminal 102 is controlled based on the third error in the directional direction of the second optical communication terminal 102. As a result, the accuracy of the directional direction of the second optical communication terminal 102 can be appropriately maintained.

[0113] In addition, in the pointing direction control device 11 of embodiment 1, the first transceiver is the first optical communication terminal 101 that performs optical communication via the first optical link B, the second transceiver is the observation terminal 104 that observes the earth by transmitting and receiving light or radio waves, the pointing direction control information obtained by the pointing direction control information acquisition unit 13 is the error of the pointing angle of the first optical communication terminal 101 performing optical communication via the first optical link B, and the capture and tracking control unit 17 serving as the pointing direction control unit controls the pointing direction of the observation terminal 104 for transmitting and receiving light or radio waves based on the error obtained by the pointing direction control information acquisition unit 13.

[0114] According to the above configuration, the directional direction of the observation terminal 104 is controlled based on the first error in the directional angle of the first optical communication terminal 101, thereby maintaining the accuracy of the directional direction of the observation terminal 104 without installing high-performance sensors or other equipment.

[0115] In addition, the second optical communication terminal 102 of embodiment 1 includes: the above-mentioned pointing direction control device 11; a transceiver unit 10 (second optical communication terminal transceiver unit), which receives light via the second optical link E, thereby detecting the receiving direction information of the second optical communication terminal 102; and a capture and tracking mechanism unit 12 (second optical communication terminal capture and tracking mechanism unit), which changes the pointing direction of the transceiver unit 10 based on the control of the capture and tracking control unit 17, thereby performing capture and tracking for maintaining the second optical link E.

[0116] According to the above configuration, the third error of the directional angle of the second optical communication terminal 102 for optical communication via the second optical link E can be detected with reference to the receiving direction information detected by the transceiver 10. Furthermore, the capture and tracking mechanism 12 changes the directional direction of the transceiver 10 through the control of the capture and tracking control unit 17 based on the third error, thereby appropriately maintaining the accuracy of the directional direction of the second optical communication terminal 102.

[0117] In addition, the optical communication system 100 of embodiment 1 includes the above-mentioned second optical communication terminal 102 and the first optical communication terminal 101, and the first optical communication terminal 101 has: a transceiver unit 1 (first optical communication terminal transceiver unit), which receives light via the first optical link B, thereby detecting the receiving direction information related to the direction of the light received via the first optical link B; a receiving direction information acquisition unit 4 (first optical communication terminal receiving direction information acquisition unit), which acquires the receiving direction information detected by the transceiver unit 1; an error detection unit 5 (first optical communication terminal error detection unit), which refers to the receiving direction information acquired by the receiving direction information acquisition unit 4. information, to detect the first error in the directional angle of the first optical communication terminal 101 performing optical communication via the first optical link B; a capture and tracking control unit 6 (first optical communication terminal capture and tracking control unit), which controls the directional direction of the first optical communication terminal 101 performing optical communication via the first optical link B based on the first error detected by the error detection unit 5, thereby controlling the capture and tracking for maintaining the first optical link B; and a capture and tracking mechanism unit 3 (first optical communication terminal capture and tracking mechanism unit), which changes the directional direction of the transceiver unit 1 based on the control of the capture and tracking control unit 6, thereby performing capture and tracking for maintaining the first optical link B.

[0118] According to the above-mentioned structure, by controlling the pointing direction of the second optical communication terminal 102 based on the first error detected by the error detection unit 5 of the first optical communication terminal 101, the accuracy of the pointing direction of the second optical communication terminal 102 can be appropriately maintained. In addition, by controlling the pointing direction of the transceiver unit 1 of the first optical communication terminal 101 based on the first error detected by the error detection unit 5, the first optical communication terminal 101 can appropriately maintain the accuracy of the pointing direction.

[0119] In addition, the first optical communication terminal 106 in the optical communication system 105 of embodiment 1 also includes: a pointing direction control information acquisition unit 31 (first optical communication terminal pointing direction control information acquisition unit), which acquires the third error detected by the error detection unit 16 of the second optical communication terminal 102; and an error value estimation operation unit 32 (first optical communication terminal error value estimation operation unit), which estimates the fourth error of the pointing angle of the transceiver 1 performing optical communication via the first optical link B based on the third error acquired by the pointing direction control information acquisition unit 31. The capture and tracking control unit 6 also controls the pointing direction of the transceiver 1 performing optical communication via the first optical link B based on the fourth error estimated by the error value estimation operation unit 32 according to the third error, thereby controlling the capture and tracking for maintaining the first optical link B.

[0120] According to the above configuration, the directional direction of the transceiver 1 of the first optical communication terminal 101 is controlled based on the third error of the directional angle of the second optical communication terminal 102, thereby maintaining the accuracy of the directional direction of the first optical communication terminal 101 without installing high-performance sensors or other equipment.

[0121] In addition, the pointing direction control method of embodiment 1 controls the pointing direction of the second transceiver for transmitting or receiving light or radio waves in a satellite provided with a first optical communication terminal 101 as a first transceiver for transmitting or receiving light and a second optical communication terminal 102 as a second transceiver for transmitting or receiving light or radio waves, wherein the pointing direction control method includes: a pointing direction control information acquisition step of acquiring pointing direction control information for controlling the pointing direction of the first transceiver for transmitting or receiving light; and a pointing direction control step of controlling the pointing direction of the second transceiver for transmitting or receiving light or radio waves based on the pointing direction control information acquired in the pointing direction control information acquisition step.

[0122] According to the above-mentioned structure, the same effect as that achieved by the directional control device 11 of the first embodiment can be achieved.

[0123] Implementation method 2.

[0124] As represented by the LEO constellation, there are uses in which the optical communication terminal of a single satellite communicates with each optical communication terminal of multiple satellites and switches the communication object (such as the Starlink plan of SPACE X). In such uses, the communication between the optical communication terminals is cut off during the time required for the capture when the optical communication terminal switches the communication object, which becomes the main reason for reducing the operation rate of the optical communication terminal. Therefore, being able to shorten the switching time of the communication object means that the communication volume between satellites can be increased.

[0125] In the optical communication between satellites, as a method for the optical communication terminal to capture signals, there is a spiral scanning method (for example, refer to the optical communication technology of space, Optics, Vol. 35, No. 9 (2006) by Yoshitoku Ben, URL: https: / / annex.jsap.or.jp / photonics / kogaku / public / 35-09-kaisetsu3.pdf). This method is the following method: the optical communication terminal set on the satellite of one party fixes the pointing direction, and the optical communication terminal set on the satellite of the other party scans the pointing direction in a spiral shape, thereby gradually making the pointing directions of each other consistent based on the pointing directions captured at the moment in the communication field of view. In such a method, the optical communication terminal changes the scanning range according to the degree to which the direction of the communication object satellite can be determined. Narrowing the scanning range involves shortening the time required for capture. In embodiment 2, the pointing direction control device of one party controls the pointing direction based on the pointing angle used by the pointing direction control device of the other party on the basis of the structure of embodiment 1, thereby shortening the time required for capture.

[0126] Embodiment 2 will be described below with reference to the drawings. Note that components having the same functions as those described in Embodiment 1 are denoted by the same reference numerals, and description thereof will be omitted.

[0127] Fig.10 1 is a schematic diagram showing a situation where the optical communication system 107 of Embodiment 2 performs optical communication. Fig.10 As shown, the optical communication system 107 includes a first optical communication terminal 101 and a second optical communication terminal 108 .

[0128] The first optical communication terminal 101 and the second optical communication terminal 108 are respectively installed in the LEO satellite A. As described above, the first optical communication terminal 101 performs optical communication with the third optical communication terminal D installed in the GEO satellite C via the first optical link B. In addition, the second optical communication terminal 108 performs optical communication with the fourth optical communication terminal G installed in the LEO satellite F via the second optical link E. In addition, as described above, the GEO satellite C is a low-interference and stable satellite compared to the LEO satellite A and the LEO satellite F. In addition, the fifth optical communication terminal H is installed in the GEO satellite C, and the sixth optical communication terminal I is installed in the LEO satellite F. The fifth optical communication terminal H and the sixth optical communication terminal I perform optical communication with each other via the third optical link J.

[0129] Fig.111 is a block diagram showing the structure of the optical communication system 107 according to Embodiment 2. Compared with the optical communication system 100 according to Embodiment 1, the optical communication system 107 includes a second optical communication terminal 108 instead of the second optical communication terminal 102. Compared with the second optical communication terminal 102 according to Embodiment 1, the directional direction control device 40 of the second optical communication terminal 108 further includes a directional angle conversion unit 41.

[0130] The directional control information acquisition unit 13 of the second embodiment further acquires, as the directional control information, a first directional angle for control used to control the directional direction of the optical communication performed by the first optical communication terminal 101 via the first optical link B. More specifically, the directional control information acquisition unit 13 further acquires, as the directional control information, a first directional angle for control used to control the directional direction of the optical communication performed by the first optical communication terminal 101 via the first optical link B from the capture tracking control unit 6 of the directional control device 2 of the first optical communication terminal 101. The directional control information acquisition unit 13 outputs the acquired first directional angle to the directional angle conversion unit 41.

[0131] The directional angle converter 41 converts the first directional angle obtained by the directional direction control information acquisition unit 13 into a second directional angle for controlling the directional direction of the second optical communication terminal 108 performing optical communication via the second optical link E, and outputs the converted second directional angle to the capture and tracking control unit 17.

[0132] The capture tracking control unit 17 of the second embodiment further controls the directional direction of the optical communication performed by the second optical communication terminal 108 via the second optical link E based on the first directional angle obtained by the directional direction control information acquisition unit 13, thereby controlling the capture tracking for maintaining the second optical link E. More specifically, in the second embodiment, the capture tracking control unit 17 further controls the directional direction of the optical communication performed by the transceiver unit 10 via the second optical link E based on the second directional angle converted by the directional angle conversion unit 41 according to the first directional angle, thereby controlling the capture tracking for maintaining the second optical link E.

[0133] The capture tracking control unit 17 of the second embodiment may also estimate the position of the second optical communication terminal 108 based on the second pointing angle converted by the pointing angle conversion unit 41 based on the first pointing angle and the orbit information related to the orbit of the LEO satellite A. In this case, the capture tracking control unit 17 may also control the position at which the transceiver unit 10 performs optical communication via the second optical link E based on the estimated position, thereby controlling the capture tracking for maintaining the second optical link E.

[0134] Next, the operation of the pointing direction control device 40 of the second optical communication terminal 108 of the second embodiment will be described with reference to the drawings. In addition, in the operation of the pointing direction control device 2 of the first optical communication terminal 101 of the second embodiment, except that the capture tracking control unit 6 outputs the first pointing angle for control used to control the pointing direction of the first optical communication terminal 101 for optical communication via the first optical link B to the pointing direction control information acquisition unit 13 of the pointing direction control device 40 of the second optical communication terminal 108, the operation is the same as that of the pointing direction control device 2 described in the first embodiment. Therefore, the description of the operation of the pointing direction control device 2 of the first optical communication terminal 101 of the second embodiment is omitted.

[0135] Fig.12 4 is a flowchart showing a directional control method executed by the directional control device 40. In addition, it is assumed that before the following directional control method is implemented, the transceiver 10 receives light via the second optical link E, thereby detecting reception direction information related to the direction in which the light is received via the second optical link E.

[0136] like Fig.12 As shown, the directional control information acquisition unit 13 acquires the directional control information from the error detection unit 5 of the directional control device 2 of the first optical communication terminal 101, the directional control information including the first error of the directional angle at which the transceiver unit 1 of the first optical communication terminal 101 performs optical communication via the first optical link B (step ST20). The directional control information acquisition unit 13 outputs the acquired directional control information to the error value estimation calculation unit 14.

[0137] Next, the error value estimation calculation unit 14 estimates a second error in the directivity angle of the optical communication performed by the transceiver unit 10 via the second optical link E based on the first error acquired by the directivity control information acquisition unit 13 (step ST21 ).

[0138] Next, the directional control information acquisition unit 13 also acquires the first directional angle for control used to control the directional direction of the optical communication performed by the first optical communication terminal 101 via the first optical link B from the capture tracking control unit 6 of the directional control device 2 of the first optical communication terminal 101 as directional control information (step ST22). The directional control information acquisition unit 13 outputs the acquired first directional angle to the directional angle conversion unit 41.

[0139] Next, the directional angle conversion unit 41 converts the first directional angle acquired by the directional direction control information acquisition unit 13 into a second directional angle for control used to control the directional direction of the second optical communication terminal 108 for optical communication via the second optical link E (step ST23). The directional angle conversion unit 41 outputs the converted second directional angle to the capture and tracking control unit 17.

[0140] Next, the reception direction information acquisition unit 15 acquires reception direction information about the direction in which the transmission / reception unit 10 receives light via the second optical link E (step ST24 ). The reception direction information acquisition unit 15 outputs the acquired reception direction information to the error detection unit 16 .

[0141] Next, the error detection unit 16 refers to the receiving direction information acquired by the receiving direction information acquisition unit 15 to detect the third error of the directional angle of the optical communication performed by the transceiver unit 10 via the second optical link E (step ST25). The error detection unit 16 outputs the detected third error to the error value estimation operation unit 14. The error value estimation operation unit 14 outputs the second error estimated in step ST21 and the third error acquired from the error detection unit 16 to the capture tracking control unit 17.

[0142] The capture and tracking control unit 17 controls the directional direction of the optical communication performed by the transceiver unit 10 via the second optical link E based on the second error estimated by the error value estimation operation unit 14 according to the first error in step ST21, the second directional angle converted by the directional angle conversion unit 41 in step ST23, and the third error detected by the error detection unit 16 in step ST25, thereby controlling the capture and tracking for maintaining the second optical link E (step ST26).

[0143] The capture tracking mechanism 12 changes the pointing direction of the transceiver 10 based on the control of the capture tracking control unit 17 in step ST26, thereby performing capture tracking for maintaining the second optical link E. The transceiver 10 whose pointing direction has been changed by the capture tracking mechanism 12 receives light again via the second optical link E, thereby detecting the receiving direction information related to the direction of the light received via the second optical link E. Then, the pointing direction control device 40 performs the above-mentioned steps ST20 to ST26 again. The second optical communication terminal 108 performs capture tracking for maintaining the second optical link E by repeating the above-mentioned actions.

[0144] In addition, the functions of the directional control information acquisition unit 13, the error value estimation calculation unit 14, the reception direction information acquisition unit 15, the error detection unit 16, the capture tracking control unit 17, and the directional angle conversion unit 41 in the directional control device 40 of the second embodiment are realized by the processing circuit. Fig.12The processing circuit for the processing of steps ST20 to ST26 shown in the figure may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in a memory. The hardware structure for realizing the functions of the pointing direction control device 40 of the second embodiment is similar to the hardware structure for realizing the functions of the pointing direction control device 40 of the second embodiment. Figure 5A In addition, the hardware structure of the software that executes the functions of the pointing direction control device 40 of the second embodiment is the same as that of the hardware structure of the second embodiment. Figure 5B The hardware structure shown is the same.

[0145] Next, the effects of the directional direction control method executed by the directional direction control device 40 according to the second embodiment will be described with reference to the drawings. Fig.13 This is a diagram for explaining the effects of the directional direction control method executed by the directional direction control device 40 .

[0146] In the above-mentioned step ST26, first, the capture and tracking control unit 17 controls the pointing direction of the optical communication performed by the transceiver unit 10 via the second optical link E based on the second error estimated by the error value estimation calculation unit 14 based on the first error in step ST21, thereby controlling the capture and tracking for maintaining the second optical link E. As a result, the influence of the interference caused by the LEO satellite A is suppressed, and the error range of the pointing angle is narrowed ( Fig.13 Therefore, the scanning range of the second optical communication terminal 108 when performing spiral scanning etc. is narrowed.

[0147] On the other hand, there is a problem that the pointing direction of the second optical communication terminal 108 is shifted not only by the interference of the LEO satellite A but also by the attitude error of the LEO satellite A. Therefore, in the above-mentioned step ST26, the capture tracking control unit 17 controls the pointing direction of the optical communication performed by the transceiver unit 10 via the second optical link E based on the second pointing angle converted by the pointing angle conversion unit 41 in step ST23, thereby controlling the capture tracking for maintaining the second optical link E. As a result, the deviation of the pointing direction of the second optical communication terminal 102 caused by the attitude error of the LEO satellite A can be corrected, and thus, the capture tracking can be performed as shown in FIG. Fig.13 The scan range is narrowed as shown in the solid line.

[0148] The above structure can also be applied to the LEO satellite F. In addition, it is also effective when the LEO satellite A has more than three optical communication terminals. For example, the LEO satellite A establishes links with multiple low-interference satellites, and the pointing direction control device 40 controls the pointing direction based on the pointing angle used to control the pointing direction of each optical communication terminal (not shown) that has established links with the multiple low-interference satellites for optical communication, thereby further narrowing the estimation range after the attitude error correction. Therefore, it is effective to shorten the time required for capture.

[0149] As described above, in the pointing direction control device 40 of embodiment 2, the pointing direction control information obtained by the pointing direction control information acquisition unit 13 also includes the first pointing angle for control used to control the pointing direction of the first optical communication terminal 101 for optical communication via the first optical link B, and the capture and tracking control unit 17 also controls the pointing direction of the second optical communication terminal 108 for optical communication via the second optical link E based on the first pointing angle obtained by the pointing direction control information acquisition unit 13, thereby controlling the capture and tracking for maintaining the second optical link E.

[0150] According to the above-mentioned structure, the pointing direction of the optical communication performed by the second optical communication terminal 108 via the second optical link E is controlled based on the first pointing angle for control in the first optical communication terminal 101, thereby being able to correct the deviation of the pointing direction of the second optical communication terminal 108 caused by the attitude error of the LEO satellite A, and maintaining the accuracy of the pointing direction of the second optical communication terminal 108. In addition, the scanning range of the second optical communication terminal 108 when performing spiral scanning or the like is narrowed.

[0151] In addition, the pointing direction control device 40 of embodiment 2 also has a pointing angle conversion unit 41, which converts the first pointing angle obtained by the pointing direction control information acquisition unit 13 into a second pointing angle for control used to control the pointing direction of the second optical communication terminal 108 for optical communication via the second optical link E. The capture and tracking control unit 17 also controls the pointing direction of the second optical communication terminal 108 for optical communication via the second optical link E based on the second pointing angle converted by the pointing angle conversion unit 41 according to the first pointing angle, thereby controlling the capture and tracking for maintaining the second optical link E.

[0152] According to the above-mentioned structure, the pointing direction of the second optical communication terminal 108 for optical communication via the second optical link E is also controlled based on the converted second pointing angle, thereby being able to correct the deviation of the pointing direction of the second optical communication terminal 108 caused by the attitude error of the LEO satellite A, and being able to appropriately maintain the accuracy of the pointing direction of the second optical communication terminal 108.

[0153] In addition, the embodiments may be freely combined or arbitrary components of the embodiments may be modified, or arbitrary components may be omitted in the embodiments.

[0154] Industrial Applicability

[0155] The pointing direction control device disclosed in the present invention can maintain the accuracy of the pointing direction of at least one of a plurality of transceivers installed in a satellite without installing high-performance sensors or other equipment, and can therefore be used in an optical communication system.

[0156] Description of Reference Numerals

[0157] 1 transceiver, 2 pointing direction control device, 3 capture tracking mechanism, 4 receiving direction information acquisition unit, 5 error detection unit, 6 capture tracking control unit, 10 transceiver, 11 pointing direction control device, 12 capture tracking mechanism, 13 pointing direction control information acquisition unit, 14 error value estimation operation unit, 15 receiving direction information acquisition unit, 16 error detection unit, 17 capture tracking control unit, 20 processing circuit, 21 transceiver, 22 capture tracking mechanism, 23 processor, 24 memory, 30 pointing direction control device, 31 pointing direction control information acquisition unit, 32 error value estimation operation unit, 40 pointing direction control device, 41 pointing angle conversion unit, 100 optical communication system, 101 first optical communication terminal, 102 second optical communication terminal, 103 optical communication system, 104 observation terminal, 105 optical communication system, 106 first optical communication terminal, 107 optical communication system, 108 second optical communication terminal.

Claims

1. A pointing direction control device, which controls the pointing direction of the second transceiver for transmitting or receiving light or radio waves in a satellite provided with a first transceiver for transmitting or receiving light and a second transceiver for transmitting or receiving light or radio waves, characterized in that: The pointing direction control device comprises: a directional control information acquisition unit, which acquires directional control information for controlling the directional direction in which the first transceiver performs transmission and reception of light; and a directional control unit that controls the directional direction of the second transceiver for transmitting and receiving light or radio waves based on the directional control information acquired by the directional control information acquisition unit, The first transceiver is a first optical communication terminal that performs optical communication via a first optical link. The second transceiver is a second optical communication terminal that performs optical communication via a second optical link. The directional control information acquired by the directional control information acquisition unit includes a first error in a directional angle of the first optical communication terminal for optical communication via the first optical link. The pointing direction control unit is a capture tracking control unit that controls the pointing direction of the second optical communication terminal for optical communication via the second optical link based on the first error acquired by the pointing direction control information acquisition unit, thereby controlling the capture tracking for maintaining the second optical link; The directional control device further includes an error value estimation operation unit, which estimates a second error of a directional angle of the second optical communication terminal for optical communication via the second optical link based on the first error acquired by the directional control information acquisition unit. The capture tracking control unit controls the directional direction of the optical communication performed by the second optical communication terminal via the second optical link based on the second error estimated by the error value estimation calculation unit from the first error, thereby controlling the capture tracking for maintaining the second optical link.

2. The pointing direction control device according to claim 1, characterized in that: The pointing direction control device also has: a reception direction information acquisition unit that acquires reception direction information related to a direction in which the second optical communication terminal receives light via the second optical link; and an error detection unit for detecting a third error in a directional angle of optical communication performed by the second optical communication terminal via the second optical link with reference to the reception direction information acquired by the reception direction information acquisition unit, The capture and tracking control unit further controls the capture and tracking for maintaining the second optical link by controlling the directional direction of the optical communication performed by the second optical communication terminal via the second optical link based on the third error detected by the error detection unit.

3. The pointing direction control device according to claim 1, characterized in that: The directional direction control information acquired by the directional direction control information acquisition unit further includes a first directional angle for control used to control the directional direction of the optical communication performed by the first optical communication terminal via the first optical link. The capture tracking control unit further controls the capture tracking for maintaining the second optical link by controlling the directional direction in which the second optical communication terminal performs optical communication via the second optical link based on the first directional angle acquired by the directional direction control information acquisition unit.

4. The pointing direction control device according to claim 3, characterized in that: The directional direction control device further includes a directional angle conversion unit, which converts the first directional angle obtained by the directional direction control information acquisition unit into a second directional angle for controlling the directional direction of the second optical communication terminal for optical communication via the second optical link. The capture tracking control unit further controls the capture tracking for maintaining the second optical link by controlling the directional direction of the second optical communication terminal for optical communication via the second optical link based on the second directional angle converted by the directional angle conversion unit from the first directional angle.

5. A pointing direction control device, which controls the pointing direction of the second transceiver for transmitting or receiving light or radio waves in a satellite provided with a first transceiver for transmitting or receiving light and a second transceiver for transmitting or receiving light or radio waves, characterized in that: The pointing direction control device comprises: a directional control information acquisition unit, which acquires directional control information for controlling the directional direction in which the first transceiver performs transmission and reception of light; and a directional control unit that controls the directional direction of the second transceiver for transmitting and receiving light or radio waves based on the directional control information acquired by the directional control information acquisition unit, The first transceiver is an optical communication terminal that performs optical communication via an optical link. The second transceiver is an observation terminal for observing the earth by transmitting and receiving light or radio waves. The directional direction control information acquired by the directional direction control information acquisition unit is a first error in a directional angle of the optical communication terminal for performing optical communication via the optical link. The directional direction control unit controls the directional direction in which the observation terminal transmits and receives light or radio waves based on the first error acquired by the directional direction control information acquisition unit; The pointing direction control device further comprises an error value estimation operation unit, which estimates a second error of the pointing angle of the earth observed by the observation terminal by transmitting and receiving light or radio waves based on the first error obtained by the pointing direction control information acquisition unit, and A capture and tracking control unit controls the observation terminal to observe the direction of the earth by transmitting and receiving light or radio waves based on the second error estimated by the error value estimation operation unit based on the first error, thereby controlling the capture and tracking for maintaining the observation of the earth.

6. An optical communication terminal, characterized in that: The optical communication terminal comprises the pointing direction control device according to claim 2, the optical communication terminal operates as the second optical communication terminal, The optical communication terminal further comprises: a second optical communication terminal transceiver that receives light via the second optical link to thereby detect the receiving direction information of the second optical communication terminal; and A second optical communication terminal capture and tracking mechanism changes the directional direction of the second optical communication terminal transceiver based on the control by the capture and tracking control unit, thereby performing capture and tracking for maintaining the second optical link.

7. An optical communication system, characterized in that: The optical communication system includes the optical communication terminal as the second optical communication terminal according to claim 6, and the first optical communication terminal. The first optical communication terminal comprises: a first optical communication terminal transceiver unit that receives light via the first optical link, thereby detecting reception direction information related to a direction in which the light is received via the first optical link; a first optical communication terminal receiving direction information acquiring unit, which acquires the receiving direction information detected by the first optical communication terminal transceiver; a first optical communication terminal error detection unit for detecting the first error in the directional angle of the optical communication performed by the first optical communication terminal via the first optical link, with reference to the reception direction information acquired by the first optical communication terminal reception direction information acquisition unit; a first optical communication terminal capture tracking control unit, which controls the direction of the optical communication performed by the first optical communication terminal via the first optical link based on the first error detected by the first optical communication terminal error detection unit, thereby controlling the capture tracking for maintaining the first optical link; as well as A first optical communication terminal capture and tracking mechanism changes the directional direction of the first optical communication terminal transceiver based on the control of the first optical communication terminal capture and tracking control unit, thereby performing capture and tracking for maintaining the first optical link.

8. The optical communication system according to claim 7, characterized in that: The first optical communication terminal further comprises: a first optical communication terminal pointing direction control information acquisition unit that acquires a third error detected by the error detection unit of the second optical communication terminal; and a first optical communication terminal error value estimation calculation unit, which estimates a fourth error of a directional angle of optical communication performed by the first optical communication terminal transceiver via the first optical link based on a third error acquired by the first optical communication terminal directional direction control information acquisition unit, The first optical communication terminal capture and tracking control unit also controls the direction of the optical communication performed by the first optical communication terminal transceiver via the first optical link based on the fourth error estimated by the first optical communication terminal error value estimation operation unit according to the third error, thereby controlling the capture and tracking for maintaining the first optical link.

9. A directional control method, in which, in a satellite provided with a first transceiver for transmitting and receiving light and a second transceiver for transmitting and receiving light or radio waves, the directional control method controls the directional control method of the second transceiver for transmitting and receiving light or radio waves, characterized in that: The pointing direction control method comprises: a directional control information acquisition step of acquiring directional control information for controlling the directional direction of light transmission and reception by the first transceiver; and a directional control step of controlling the directional direction of the light or radio wave transmission and reception by the second transceiver based on the directional control information acquired in the directional control information acquisition step, The first transceiver is a first optical communication terminal that performs optical communication via a first optical link. The second transceiver is a second optical communication terminal that performs optical communication via a second optical link. The directional control information acquired in the directional control information acquisition step includes a first error in a directional angle of the first optical communication terminal for optical communication via the first optical link. The pointing direction control step is a capture tracking control step in which the pointing direction of the second optical communication terminal for optical communication via the second optical link is controlled based on the first error obtained in the pointing direction control information acquisition step, thereby controlling the capture tracking for maintaining the second optical link; The directional control step further comprises an error value estimation calculation step, which estimates a second error of a directional angle of the second optical communication terminal for optical communication via the second optical link based on the first error obtained by the directional control information acquisition step. The tracking control step controls the direction of the optical communication performed by the second optical communication terminal via the second optical link based on the second error estimated from the first error in the error value estimation calculation step, thereby controlling the tracking for maintaining the second optical link.

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