JP2002314487A - Free-space optical communications unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in a conventional optical free-space optical communications unit that is not adequate to mount on a satellite because the conventional unit requires a large space and has difficulty in downsizing and weight reduction as the entire unit, that has had possibility of interference between a control system for an optical reflecting mirror and a transmission lens control system because they are independent, and that deteriorates a control arithmetic operation speed because a plurality of the control systems exist and result in increasing the control arithmetic quantity. SOLUTION: The free-space optical space communications unit of this invention is provided with a rough tracking mechanism that roughly directs a light receiving section of a transmission/reception telescope to the opposite station to roughly capture a transmission light from the opposite station, a fine tracking mechanism that precisely captures the light roughly captured by the rough tracking mechanism, and a rough tracking compensation device and a fine tracking compensation device that calculates a correction amount of a gimbal angle given respectively to the rough tracking mechanism and the fine tracking mechanism at capturing, at tracking and at communication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical communication using space propagation between space vehicles such as artificial satellites, space stations, space shuttles, or between space vehicles and ground stations. The present invention relates to an optical space communication device to which the present invention is applied.

[0002]

2. Description of the Related Art Generally, an optical communication system employs an optical fiber system in which communication stations are connected by an optical fiber cable and optical communication is performed between the communication stations using the optical fiber cable as a transmission line. . In such an optical communication system, it is possible to dramatically increase the communication capacity as compared with conventional RF communication. By the way, in the field of recent space development, communication such as inter-satellite communication has been diversified, and an increase in communication capacity has been demanded. Therefore, in the field of space development, construct an optical communication system between a ground station and a spacecraft or between spacecrafts to increase the communication capacity and achieve diversification of communication. There is a plan. For example, a plurality of artificial satellites (hereinafter, referred to as satellites) launched from the earth into a relatively low-altitude spatial orbit are arranged at predetermined intervals, and a low-orbit intersatellite link connecting these satellites by communication is formed. Have been Until now, low-orbit satellite-to-satellite links have been provided by radio communication, but optical communication using laser light has been studied instead.

As an optical communication device used for this type of optical communication, for example, there is an optical communication device described in Japanese Patent Application Laid-Open No. 2000-180652, which is shown in FIG. In the figure, 110 is an optical antenna, 111 is a directivity adjustment mechanism, 1
12 is a collimator lens, 113 is a beam splitter,
114 is a condenser lens, 115 is a light detection unit, and 116 is an optical antenna pointing control unit. 117 is a reflecting mirror for adjusting the optical axis,
118 is an imaging lens, 119 is a beam splitter, 12
0 is an angle adjusting mechanism, 121 is a beam splitter, 122
Denotes a light detection unit, and 123 denotes a reflecting mirror angle control unit. 124
Is a transmission lens, 125 is a beam splitter, 126 is an optical axis adjusting mechanism, 127 is an optical axis controller, 128 is a light detector, and 129 is an optical fiber cable. 130 is an optical signal processing unit, 131 is a transmitting unit, 132 is a reflecting mirror, 133 is a lens, 201 is a main reflecting mirror, 202 is a sub reflecting mirror, 203
Is a pointing member.

[0004] The optical communication apparatus shown in FIG. 8 includes an angle adjustment mechanism 1 on an optical path of communication light received by an optical antenna 110 provided to be able to adjust the direction of transmission and reception of communication light with a communication partner station.
The reflecting mirror 117 whose optical axis can be adjusted via the optical axis 20 and the transmission lens 1 whose optical axis can be adjusted via the optical axis adjusting mechanism 126
24 are arranged in order, and first, the angle of the optical axis of the communication light is aligned and adjusted by controlling the drive of the angle adjusting mechanism 120,
The optical axis adjusting mechanism 126 is drive-controlled to similarly perform alignment adjustment, and the communication light after the alignment adjustment is optically coupled to one end of the optical fiber cable 129. As a result, the spatial propagation distance can be easily increased, and the optical signal processing can be performed simply and with high accuracy.

Further, there is a conventional optical communication device described in Japanese Patent Application Laid-Open No. 8-79184, and the configuration is shown in FIG. In the drawing, reference numerals 301 to 304 denote light receiving units and reference numerals 305 to 3
08 is an optical fiber, 309 to 312 are optical amplifiers, 313
Reference numerals 316 are photodiodes, and 317 is an arithmetic processing unit.

The optical communication apparatus shown in FIG. 9 guides laser light received by four light-receiving sections 301 to 304 comprising optical systems to optical amplifiers 309 to 312 by optical fibers 305 to 308, and is amplified by the optical amplifiers 309 to 312. The respective optical signals are detected by a four-quadrant photodetector composed of photodiodes 313 to 316, and an arithmetic processing unit 317 detects light signals from light receiving units 301 to 30 based on detection signals from the photodiodes 313 to 316.
4 is calculated, and a part (for example, 316) of the photodiodes 313 to 316 is also used as a communication light receiving element. As a result, an amplified detection output similar to that of a four-division avalanche photodiode can be obtained using a general photodiode, and can also be used as a communication light receiving element.

[0007]

Since the conventional optical communication apparatus is configured as described above, there are the following problems in realizing directional control that requires high accuracy and high reliability. there were.

The optical communication device shown in FIG. 8 is a combination of a reflecting mirror 117 having an adjustable optical axis, an angle adjusting mechanism 120, a transmission lens 124 having an adjustable optical axis, an optical axis adjusting mechanism 126, and the like. Therefore, the installation space and the installation space for the device for driving them are large, and it is difficult to reduce the size and weight of the entire device, and it is not suitable for mounting on a satellite. In addition, since the control system of the reflecting mirror 117 whose optical axis is adjustable and the control system of the transmission lens 124 whose optical axis is adjustable are independent, interference between the control systems may occur. Further, since there are a plurality of control systems, there is a problem that the amount of control calculation increases and the control calculation speed decreases.

On the other hand, the optical communication device shown in FIG. 9 also uses a part of the four photodiodes 313 to 316 as a communication light receiving element. The amount of light to the light receiving element for use may decrease, and communication may not be sufficiently performed with weak received light. When the optical axis is adjusted so that the optical axis is incident on the center of the communication light receiving element so that the amount of light received by the communication light receiving element is maximized, the received light cannot be incident on all the remaining three photodiodes. There is a problem that the function as a quadrant sensor is impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and enables communication even with a weak reception light, and provides a degree of freedom in the installation place of the receiver by reducing the size and weight. It is an object of the present invention to obtain an optical space communication device capable of performing the following.

The present invention relates to an optical space communication apparatus capable of quickly switching to the communication mode and shortening the communication cutoff time even when the received light deviates from the field of view of the light receiving fiber coupler due to disturbance or the like and cannot be guided to the receiver. The purpose is to obtain.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical space communication device capable of guiding received light to a receiver even when received light on a light receiving fiber coupler cannot enter the entire optical position detecting function.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical space communication apparatus which can guide a reception light to a receiver even when a reception light beam intensity pattern is complicated.

According to the present invention, there is provided an optical space communication apparatus capable of simplifying a control system configuration without performing coordinate conversion on each sensor by canceling rotation of received light in an internal optical system due to rotation of a coarse capturing and tracking mechanism. The purpose is to.

[0015]

SUMMARY OF THE INVENTION An optical space communication apparatus according to the present invention performs gimbal driving in an elevation direction and an azimuth direction so that a light receiving section of a transmission / reception telescope is roughly directed to a partner station and transmitted from the partner station. A coarse capturing and tracking mechanism that roughly captures light, a fine capturing and tracking mechanism that precisely captures the received light roughly captured by the coarse capturing and tracking mechanism by driving the two-axis gimbal, and a gimbal angle of the coarse capturing and tracking mechanism is detected. A coarse capture and tracking mechanism gimbal angle sensor, a fine capture and tracking mechanism gimbal angle sensor for detecting the gimbal angle of the fine capture and tracking mechanism, a pointing sensor for detecting a relative angle error with a partner station in a wide range, and the pointing sensor An adder that adds the relative angle error detected by the gimbal angle sensor and the gimbal angle detected by the coarse capturing and tracking mechanism gimbal angle sensor; A tracking sensor that detects an angular error with higher precision and higher frequency than the pointing sensor, a trajectory predicted value that predicts and sets a relative angle of the partner station with respect to its own station from trajectory information, and forms a precise capture and tracking control system during capture A command value at the time of capturing set in advance as a target value for tracking, a command value at the time of tracking preset as a target value for forming a precise capturing and tracking control system during tracking, and a precise capturing and tracking control system during communication A communication command value preset as a target value for, and a light-receiving fiber coupler optically coupled to a receiver that has a function of detecting an ultra-high-precision light position from the received light and demodulates the received light into an electric signal, At the time of tracking and communication from the detection output of the precise capture tracking mechanism gimbal angle sensor, the received light angle deviation amount detector that calculates the angle deviation amount of the received light on the light receiving fiber coupler A fine-coarse / coarse compensator for obtaining a control target value for driving the coarse-capture-tracking control mechanism such that the gimbal angle is set near the origin; and an output of the adder and the trajectory prediction at the time of capturing. From the value and the feedback amount of the output of the coarse capturing and tracking mechanism gimbal angle sensor, a correction amount of the gimbal angle given to the coarse capturing and tracking mechanism is calculated, and the control target value from the fine / coarse cooperative compensator during tracking and communication. A coarse capture and tracking compensator that calculates a correction amount of a gimbal angle to be applied to the coarse capture and tracking mechanism from the trajectory predicted value and the feedback amount of the output of the coarse capture and tracking mechanism gimbal angle sensor, and the capture command value during capture. The gimbal angle correction amount of the precise capture and tracking mechanism is calculated from the feedback amount of the output of the fine capture and tracking mechanism gimbal angle sensor, and the tracking command value and the From the feedback amount of the output of the racking sensor and calculate the correction amount of the gimbal angle given to the fine capture and tracking mechanism,
A precise capturing and tracking compensator that calculates a gimbal angle correction amount to be applied to the fine capturing and tracking mechanism from the communication time command value and the feedback amount of the output of the received light angle deviation amount detector during communication; And control mode switching means for setting each control mode at the time of communication.

In the optical space communication apparatus according to the present invention, a gimbal drive is performed in the elevation direction and the azimuth direction so that the light receiving portion of the transmission / reception telescope is roughly directed to the partner station, and the transmission light from the partner station is roughly captured. A capturing and tracking mechanism, and a fine capturing and tracking mechanism that precisely captures the received light roughly captured by the coarse capturing and tracking mechanism by driving the two-axis gimbal;
A coarse capturing and tracking mechanism gimbal angle sensor for detecting the gimbal angle of the coarse capturing and tracking mechanism; a fine capturing and tracking mechanism gimbal angle sensor for detecting the gimbal angle of the fine capturing and tracking mechanism; A pointing sensor, an adder that adds the relative angle error detected by the pointing sensor and the gimbal angle detected by the coarse capturing and tracking mechanism gimbal angle sensor, and a relative angle error with the partner station by the pointing sensor. A tracking sensor that detects with high accuracy and high frequency, a trajectory prediction value that predicts and sets the relative angle of the partner station with respect to the own station from trajectory information, and a target value that is set in advance as a target value for forming a precise capture tracking control system at the time of capture The command value at the time of capture and the command at the time of tracking preset as the target value for forming the precise capture tracking control system at the time of tracking And a light-receiving fiber coupler that has a function of detecting an ultra-high-precision light position from the received light and optically couples to a receiver that demodulates the received light into an electric signal, and calculates a light angle deviation amount of reception on the light-receiving fiber coupler. A received light angle shift amount detector, a received light offset calculator for calculating an offset amount given to a precise capture and tracking control system during communication from an output of the received light angle shift amount detector, and the fine capture and tracking mechanism gimbal angle A fine / coarse coordinator for obtaining a control target value for driving the coarse capture / tracking control mechanism such that the fine capture / tracking mechanism gimbal angle is set near the origin at the time of tracking and communication from a detection output of a sensor; Sometimes, a gimbal angle correction amount given to the coarse capturing and tracking mechanism is calculated from the output of the adder, the trajectory prediction value, and the feedback amount of the output of the coarse capturing and tracking mechanism gimbal angle sensor. The amount of gimbal angle correction given to the coarse capturing and tracking mechanism from the control target value from the fine and coarse cooperative compensator, the orbit predicted value, and the feedback amount of the output of the coarse capturing and tracking mechanism gimbal angle sensor during tracking and communication. Calculates the gimbal angle correction amount given to the fine capture tracking mechanism from the capture command value and the feedback amount of the output of the fine capture tracking mechanism gimbal angle sensor at the time of capture, and performs tracking. At the time, the tracking time command value and the feedback amount of the output of the tracking sensor are used to calculate the gimbal angle correction amount given to the precise capture and tracking mechanism, and the output offset amount of the reception light offset calculator and the tracking sensor of the tracking sensor during communication. A precise capture and tracking compensator that calculates a correction amount given to the gimbal angle of the fine capture and tracking mechanism from the output feedback amount Control mode switching means for setting each control mode at the time of capturing, tracking and communication.

In the optical space communication apparatus according to the present invention, instead of the received light offset calculator, an offset amount generating means for extracting a fixed offset amount when the output of the received light angle deviation amount detector is larger than a threshold during communication. A fine tracking and compensating device that calculates a gimbal angle correction amount given to the fine capturing and tracking mechanism from the feedback amount of the output of the tracking sensor and the fixed offset amount during communication. .

In the optical space communication apparatus according to the present invention, the control mode switching means determines the incident light angle from the detection output of the tracking sensor, and determines the incident light angle on the light receiving fiber coupler from the output of the received light angle deviation detector. By judging the angle shift, each control mode at the time of capturing, tracking and communication is switched and set.

In the optical space communication apparatus according to the present invention, the control mode switching means includes: a first switch for switching and setting a control mode between communication and tracking in the coarse acquisition and tracking control system; A second switch for switching and setting a control mode at the time of tracking and communication, and determining an incident light angle from a detection output of the tracking sensor to set the first switch to one of a control mode at the time of communication and tracking. A tracking sensor angle determiner, and a received light angle shift amount determiner that determines the angle shift of the received light on the light receiving fiber coupler from the output of the received light angle shift amount detector and extracts a determination output that determines tracking time and communication time; In response to both outputs of the tracking sensor angle determiner and the received light angle deviation amount determiner, the second switch is captured, tracked, or communicated. Those having a switch automatic switch to be set to the control mode.

In the optical space communication apparatus according to the present invention, the pointing sensor is constituted by a two-dimensional CCD, the tracking sensor is constituted by a four-quadrant detector, and the light receiving fiber coupler optically couples the received light to the receiver. And a multi-mode fiber arranged around the single mode fiber for detecting the position of the received light.

In the optical space communication apparatus according to the present invention, a gimbal drive is performed in the elevation direction and the azimuth direction so that the light receiving section of the transmission / reception telescope is roughly directed to the partner station to roughly supplement the transmission light from the partner station. A capturing and tracking mechanism, and a fine capturing and tracking mechanism that precisely captures the received light roughly captured by the coarse capturing and tracking mechanism by driving the two-axis gimbal;
A coarse capturing and tracking mechanism gimbal angle sensor for detecting the gimbal angle of the coarse capturing and tracking mechanism; a fine capturing and tracking mechanism gimbal angle sensor for detecting the gimbal angle of the fine capturing and tracking mechanism; A pointing sensor, a adder that adds the relative angle error detected by the pointing sensor and the gimbal angle detected by the coarse capturing and tracking mechanism gimbal angle sensor, and predicts the relative angle of the partner station to the own station from the trajectory information. The set trajectory prediction value, the command value at the time of capture set in advance as a target value for forming the fine capture tracking control system at the time of capture, and the target value for forming the fine capture tracking control system at the time of communication are set in advance. A light receiving filter that has the function of detecting the ultra-high-precision light position from the received light and the communication time command value and optically couples to a receiver that demodulates the received light into an electric signal. A coupler, a received light angle shift amount detector for calculating an angle shift amount of the received light on the light receiving fiber coupler, and the fine capture and tracking mechanism gimbal during tracking and communication based on a detection output of the fine capture and tracking mechanism gimbal angle sensor. A coarse / coarse coordinator for obtaining a control target value for driving the coarse capturing / tracking control mechanism so that an angle is set near the origin; and an output of the adder, the trajectory predicted value, and the coarse capturing / tracking during capturing. A gimbal angle correction amount given to the coarse capturing and tracking mechanism is calculated from a feedback amount of an output of a mechanism gimbal angle sensor, and a control target value, the trajectory predicted value, and the coarse capturing and tracking value from the fine / coarse coordinator during communication are calculated. A coarse capture tracking compensator that calculates a gimbal angle correction amount to be applied to the coarse capture tracking mechanism from a feedback amount of an output of a mechanism gimbal angle sensor; From the value and the feedback amount of the output of the precise capture and tracking mechanism gimbal angle sensor, a correction amount of the gimbal angle given to the precise capture and tracking mechanism is calculated, and at the time of communication, the communication command value and the reception light angle deviation amount detector are used. A precise capture and tracking compensator that calculates a gimbal angle correction amount to be applied to the fine capture and tracking mechanism from an output feedback amount, and a control mode switching unit that sets a control mode during capture and during communication. .

In the optical space communication apparatus according to the present invention, the control mode switching means determines the incident light angle from the detection output of the tracking sensor, and determines the incident light angle on the light receiving fiber coupler from the output of the received light angle deviation detector. The control mode at the time of capturing and at the time of communication is switched and set by determining the angle shift.

In the optical free-space communication apparatus according to the present invention, the adder retains the previous output value at the time of light reception when the pointing sensor cannot obtain a detection output when the pointing sensor is not receiving light.

Further, the optical space communication apparatus according to the present invention comprises an image rotation detector for detecting a rotation angle of the received light generated in the internal optical system by rotation of the coarse capturing and tracking mechanism, and rotating the internal optical system. And a rotation mechanism control circuit that drives and controls the rotation mechanism so as to cancel the image rotation generated in the internal optical system in response to the detection output of the image rotation detector.

In the optical space communication apparatus according to the present invention, the light receiving section is roughly directed to the partner station by the coarse capturing and tracking mechanism driven by the gimbal, and the light receiving section is accurately transferred to the partner station by the fine capturing and tracking mechanism driven by the gimbal. In an optical space communication device that controls to direct light, an image rotation detector that detects a rotation angle of received light generated in an internal optical system by rotation of the coarse capturing and tracking mechanism, and a rotation mechanism that rotates the internal optical system And a rotation mechanism control circuit that drives and controls the rotation mechanism so as to cancel the image rotation generated in the internal optical system in response to the detection output of the image rotation detector.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a schematic configuration of an optical space communication apparatus according to the present invention. In the figure, reference numeral 101 denotes transmission light from a partner station, 102 receives this transmission light 101, and transmits transmission light of its own station. Transmitting and receiving telescope to launch,
103 is the light receiving unit. 1 is a secondary mirror of the transmission / reception telescope 102, and 2 is a primary mirror for capturing the transmission light 102. 3 is 3
The component of the transmission light 102 reflected by the primary mirror 2 at the secondary mirror, that is, the received light is guided through the secondary mirror 1 into the elevation axis. Reference numeral 4 denotes a quaternary mirror for guiding the received light passing through the tertiary mirror 3 into the azimuth axis. Reference numeral 5 denotes a coarse capturing and tracking mechanism that gimbal-drives the transmission / reception telescope 102 in the elevation direction, roughly directs the light receiving unit 103 of the transmission / reception telescope 102 to the partner station, and captures the transmission light 101 from the partner station.
Reference numeral 6 denotes a coarse capturing and tracking mechanism that gimbal-drives the transmitting and receiving telescope 102 in the azimuth direction, and roughly moves the light receiving unit 103 of the transmitting and receiving telescope 102 to the partner station together with the coarse capturing and tracking mechanism 5 to capture the transmitted light. Reference numeral 7 denotes a gantry for installing the coarse capturing and tracking mechanism 6, 8 denotes a column for connecting the gantry 7 to an installation surface, and 9 denotes an internal optical system on which sensors and an optical system are mounted. 1
Numeral 0 denotes a fine capturing and tracking mechanism including a reflecting mirror driven by a two-axis gimbal to further finely capture and track the received light roughly captured by the operation of the coarse capturing and tracking mechanisms 5 and 6.

Reference numerals 11 and 14 are beam splitters. 1
Reference numeral 2 denotes a pointing sensor which is used for coarse capturing and tracking and comprises a two-dimensional CCD or the like for detecting a relative angle error with a partner station from received light in a wide range. Reference numeral 13 denotes a dichroic mirror, and reference numeral 15 denotes a tracking sensor including a four-quadrant detector that is used for precise capturing and tracking and that can detect a relative angle error with respect to a partner station from received light with higher accuracy and higher frequency than the pointing sensor 12. 16 and 19 are reflecting mirrors,
Reference numeral 26 denotes a receiver for performing signal processing on received light and demodulating it into an electric signal. Reference numeral 17 denotes a light-receiving fiber coupler having an ultra-high-precision optical position detection function for guiding received light to the receiver 26, and has a structure described later with reference to FIG.

Reference numeral 18 denotes a biaxially drivable optical line difference correction mechanism for adjusting the optical line difference correction angle in the direction in which the own station transmits to the partner station. Reference numeral 20 denotes a transmitter for generating transmission light from the own station, and reference numeral 21 denotes an installation surface of the transmission / reception telescope 102. Reference numeral 22 denotes a coarse capturing and tracking mechanism control circuit that drives and controls the coarse capturing and tracking mechanisms 5 and 6. Reference numeral 23 denotes a reception light angle shift amount detector for calculating the reception light angle shift amount on the light receiving fiber coupler 17. Reference numeral 24 denotes a fine capture and tracking mechanism control circuit for driving and controlling the fine capture and tracking mechanism 10, and reference numeral 25 denotes an optical fiber for optically coupling light received from the light receiving fiber coupler 17 to a receiver 26. 33 is a control target value for driving the coarse capture and tracking control mechanisms 5 and 6 from the detection output of the fine capture and tracking mechanism gimbal angle sensor 36 so that the fine capture and tracking mechanism gimbal angle is set near the origin during tracking and communication. Is a fine and coarse cooperative compensator.

FIG. 2 is a block diagram showing a signal processing process of the free-space optical communication apparatus according to Embodiment 1 of the present invention. In FIG. Is a gimbal angle sensor for detecting a rough capturing and tracking mechanism. Reference numeral 27 denotes an adder for adding the output of the pointing sensor 12 and the output of the coarse capturing and tracking mechanism gimbal angle sensor 30 each time the output of the pointing sensor 12 is obtained during light reception. Reference numeral 28 denotes a coarse capturing and tracking compensator for calculating the amount of gimbal angle correction of the coarse capturing and tracking mechanisms 5 and 6 in each of the control modes during capturing, tracking and communication. Reference numeral 29 denotes a sampler that samples the output of the coarse capturing and tracking mechanism gimbal angle sensor 30 in accordance with the output cycle of the pointing sensor 12. Reference numeral 31 denotes a trajectory prediction value obtained by predicting and setting the relative angle of the partner station with respect to the own station from the trajectory information.

Reference numeral 32 denotes a first switch for switching the target value of the coarse capture tracking control system between capture and tracking. 36
Denotes a gimbal angle sensor configured with a displacement sensor and the like to detect the gimbal angle of the fine capturing and tracking mechanism 10. Numeral 34 denotes a capturing command value preset as a target value for forming a fine capture tracking control system at the time of capturing, and 35 denotes a tracking command value preset as a target value for forming a fine capturing / tracking control system at tracking. It is. Numeral 38 denotes a fine capture and tracking compensator that calculates the amount of correction of the gimbal angle of the fine capture and tracking mechanism 10 in each of the control modes during capture, tracking, and communication. Reference numeral 37 denotes a second switch for switching between control modes at the time of capturing, tracking, and communication of the input of the fine capture and tracking compensator 38.
The switch, together with the first switch 32, constitutes the control mode switching means of the present invention. A communication command value 39 is set in advance as a target value for forming a precise capture and tracking control system during communication.

FIG. 3 is a perspective view showing an example of the configuration of the light receiving fiber coupler 17. In FIG. 3, reference numeral 40 denotes a single mode fiber for optically coupling the received light to the receiver 26;
Reference numerals 1, 42, 43, and 44 denote multi-mode fibers disposed around the single-mode fiber 40 for detecting the position of the received light on the light-receiving fiber coupler 17.

Next, the operation will be described. The operation of the optical space communication apparatus includes a capture mode in which the light receiving unit 103 of the transmission / reception telescope 102 is roughly directed toward the partner station to roughly capture the transmission light from the partner station, and a tracking mode in which the coarsely captured received light is precisely captured. And a communication mode in which communication by the receiver 26 and the transmitter 20 is performed in a state where the target is determined for the partner station.

At the time of capturing, the first switch 32 and the second switch 37 in the circuit of FIG. 2 are respectively connected to the capturing mode side a. The pointing sensor 12 detects a relative angle error with respect to the partner station in a wide range. Therefore, the purpose of the coarse capture tracking control system is to perform control so that the detection output indicating the relative angle error of the pointing sensor 12 becomes zero. The pointing sensor 12 usually has a two-dimensional CCD
However, it takes time for detection, and an output is obtained only at intervals of several tens of milliseconds. Therefore, when the output of the pointing sensor 12 is obtained in order to increase the control band, the detection output representing the gimbal angle of the coarse capturing and tracking mechanism gimbal angle sensor 30 at that time is sampled by the sampler 29.
, And is added by the adder 27 to obtain a target value of the coarse capture and tracking control system.

The trajectory prediction value 31 is further added to the target value of the coarse capture and tracking control system. This is a prediction of the relative angle of the partner station from the orbital information of the own station and the orbital information of the partner station, assuming that the optical space communication device performs communication between artificial satellites. 12
Is not receiving light, the light receiving section 10 is controlled by the open loop control.
3. The coarse acquisition and tracking mechanism 5, so that 3 faces almost toward the partner station.
6 can be controlled. Using the sum of the output of the adder 27 and the predicted trajectory value 31 as a target value, the coarse capturing and tracking mechanism gimbal angle sensor 3
The coarse detection and tracking control system is formed by feeding back the 0 detection output. The deviation between the target value and the feedback amount is input to the coarse capture tracking compensator 28, and the coarse capture tracking compensator 28
ID (Proportional Integrato)
The coarse capturing and tracking mechanisms 5 and 6 are driven such that the deviation becomes zero by, for example, n and differential control.

Next, the operation of the adder 27 will be described. Here, for the sake of explanation, the effect of the trajectory prediction value 31 will be omitted, but the function is exactly the same when the trajectory prediction value 31 is included. The coarse capturing and tracking compensator 28 operates so that the output of the coarse capturing and tracking mechanism gimbal angle sensor 30 becomes equal to the detection output of the pointing sensor 12. However, due to the characteristics of the coarse supplementary tracking compensator 28 or the errors included in the pointing sensor 12, the operations of the coarse capturing and tracking mechanisms 5 and 6 are rarely completely directed to the partner station, and some errors remain. For this error,
It can be detected by the next signal of the pointing sensor 12. Since this error is relative to the state of the coarse capturing and tracking mechanisms 5 and 6 at that time, in order to give an absolute target value of the gimbal angle, the coarse capturing and tracking mechanism gimbal angle sensor 30 Needs to be added. This is the role of the adder 27.

The adder 27 operates so as to keep the previous output value at the time of light reception when the pointing sensor 12 does not receive light and no detection output is obtained. As a result, even if the movement of the partner station is fast and the error cannot be reduced to the level required for tracking by the coarse capture and tracking control system and the target station cannot be tracked, the coarse capture and tracking mechanisms 5 and 6 can be used next time. The transmission / reception telescope 102 can be directed toward the partner station until the partner station is captured. Therefore, at the time of the next light reception of the pointing sensor 12, the initial error is reduced, and the tracking can be reliably started.

Further, in order to control the gimbal angle of the precise capturing and tracking mechanism 10 to a neutral point, the detection output of the precise capturing and tracking mechanism gimbal angle sensor 36 is fed back to constitute a fine capturing and tracking control system. Although the capture command value 34 is 0, an offset can also be given. The command value at the time of capture 34
The deviation between the feedback amount and the feedback amount is input to the fine capture and tracking compensator 38, and the fine capture and tracking compensator 38 drives the fine capture and tracking mechanism 10 by PID control or the like so that the deviation becomes zero.

Next, at the time of tracking, that is, when the space optical communication apparatus enters a tracking stage of accurately capturing the partner station from the stage of capturing the partner station, the first switch 32 and the second switch 37 are respectively set to the tracking mode side b. Switch to At the time of tracking, higher pointing accuracy is required in order to aim at the partner station. Therefore, it is necessary to switch the sensor from the pointing sensor 12 such as a two-dimensional CCD to the tracking sensor 15 such as a four-quadrant detector. In addition, it is necessary to operate both the fine capture tracking control system and the coarse capture tracking control system cooperatively so as not to deviate from the driving range of the fine capture tracking mechanism 10.

In order to operate both the fine capture tracking control system and the coarse capture tracking control system cooperatively, the value of the fine capture tracking mechanism gimbal angle sensor 36 is used so that the coarse capture tracking is returned to the neutral point. The mechanisms 5 and 6 are driven. That is, first, the output of the fine capturing and tracking mechanism gimbal angle sensor 36 is input to the fine and coarse cooperative compensator 33, where, for example, integration control is performed, and the trajectory predicted value 31 is added to the target value of the coarse capturing and tracking compensator 28. And Therefore, the first switch 32 is switched to the tracking mode side b, and the target value of the coarse capture tracking control system is switched. In this case, the coarse capturing and tracking mechanisms 5 and 6 move so as to return the gimbal angle of the fine capturing and tracking mechanism 10 to the neutral point irrespective of the value of the pointing sensor 12, so that both control systems interfere with each other. The precise capture and tracking control system can achieve high-accuracy tracking accuracy without departing from the driving range of the fine capture and tracking mechanism 10.

At the time of tracking, in order to guide the received light to the origin of the tracking sensor 15, the tracking sensor 15
Is fed back to constitute a precise capture and tracking control system. The tracking command value 35 is 0, but an offset can also be given. The deviation between the tracking command value 35 and the feedback amount is input to the fine capture tracking compensator 38, and the fine capture tracking compensator 38 drives the fine capture tracking mechanism 10 by PID control or the like so that the deviation becomes zero. I do.

Next, at the time of communication, that is, when the space optical communication apparatus enters the stage of communicating with the partner station from the stage of tracking the partner station, the first switch 32 is in the tracking mode side b and the second switch 32 is in the tracking mode side b.
The switch 37 switches to the communication mode side c. During communication, higher directivity is required to guide the received light to the receiver 26. Therefore, the tracking switch 15 is switched from the light receiving fiber coupler 17 by the second switch 37.
Of the fine capture and tracking control system.

At the time of communication, in order to guide the received light to the center of the light receiving fiber coupler 17 shown in FIG. The input light beams 43 and 44 are optically coupled to the received light angle deviation amount detector 23, and the received light angle deviation amount on the light receiving fiber coupler 17 is calculated.
The received light angle deviation amount is fed back to form a precise capture and tracking control system. The communication command value 39 is 0,
An offset can also be given. This communication command value 3
The deviation between 9 and the feedback amount is precisely captured and tracked compensator 38.
, And the precise capture and tracking compensator 38 drives the fine capture and tracking mechanism 10 by PID control or the like so that the deviation becomes zero. As a result, the reception light is guided to the center of the single mode fiber 40, and sufficient reception light can be guided to the receiver 26.

The received light angle deviation amount detector 23 includes:
Photodiodes (not shown) for converting received light optically coupled from the multimode fibers 41, 42, 43, and 44 into electric signals are provided, and add and subtract outputs from the respective photodiodes. Then, the received light position shift amount is detected by the same method as that of the four-quadrant detector, and is converted into the drive angle amount of the fine capture and tracking mechanism 10. Similarly, the receiver 26 includes a photodiode (not shown) for converting received light optically coupled from the single mode fiber 40 into an electric signal.

By converting the received light optically coupled to the receiver 26 by the optical fiber 25 into an electric signal, the effect of electric noise can be suppressed, and communication can be performed even with weak light. In addition, since there is no restriction on the routing of the optical fiber 25, the degree of freedom of the installation location of the receiver 26 increases. Receiver 26
Single mode fiber 40 for guiding light to the surroundings and multimode fiber 4 for detecting the position of the light around the single mode fiber 40
By integrating 1, 42, 43, and 44, the size and weight of the sensor can be reduced and the space can be saved.

In the example described above, three control modes are assumed: capture, tracking, and communication. However, the installation error of the optical system such as the pointing sensor 12 and the light receiving fiber coupler 17 can be neglected. 12
When the angle can be detected with high accuracy, it is possible to immediately shift from the capture mode to the communication mode.
It is also possible to configure the space optical communication apparatus in various control modes. Therefore, in this case, the tracking sensor 15 and the tracking command value 35 can be omitted.

As described above, according to the first embodiment, acquisition and tracking can be performed only by the coarse acquisition and tracking control mechanisms 5 and 6 and the fine acquisition and tracking control mechanism 10, so that the optical space communication apparatus is small and lightweight. The effect that can be realized is obtained. Further, the light receiving unit 103 can capture and track the other station at high speed over a wide range and with high accuracy, and the mounting errors of the pointing sensor 12, the tracking sensor 15 and the light receiving fiber coupler 17 can be reduced by the coarse capturing and tracking mechanisms 5, 6, Since the canceling is performed by the control of the capturing and tracking mechanism 10, the effect of smoothly transitioning from the capturing mode to the tracking mode without causing interference between the coarse capturing and tracking control system and the fine capturing and tracking control system and reliably maintaining the tracking. Is obtained. Furthermore, after the pointing light from the partner station is highly accurately controlled in the tracking mode, the mode is shifted from the tracking mode to the communication mode,
The light receiving fiber coupler 17 with an ultra-high-precision optical position detection function is used to perform the pointing control with higher precision, so that the receiver 26
Since the received light is guided to the receiver, communication can be performed even if the received light is weak, and the effect of increasing the degree of freedom of the installation location of the receiver 26 can be obtained.

Embodiment 2 FIG. 4 is a block diagram showing a signal processing process of the free-space optical communication apparatus according to Embodiment 2 of the present invention. Portions corresponding to FIG. In the figure, reference numeral 45 denotes a tracking sensor angle determiner, which determines whether or not the received light is incident on the field of view of the tracking sensor 15, and whether or not the received light is incident on a certain high-precision directional angle, that is, The first switch 62 determines the incident light angle.
Is automatically set to one of the control modes during communication and during tracking. 46 is a received light angle deviation amount judging device,
This is to determine whether or not the received light on the light receiving fiber coupler 17 has entered the field of view of the light receiving fiber coupler 17, that is, to determine the angular deviation of the received light. Reference numeral 47 denotes an automatic switch for automatically switching the second switch 37 to one of the control modes of capturing, tracking, and communication in response to the outputs of the tracking sensor angle determiner 45 and the received light angle deviation amount determiner 46. It is something that switches.

Next, the operation will be described. At the time of initial capture, the tracking sensor 15 is in a non-light receiving state, and therefore the tracking sensor angle determiner 45 sets both the first switch 32 and the second switch 37 to the capture mode side a. When the received light enters the field of view of the tracking sensor 15, the tracking sensor angle determiner 45
Switches the first switch 32 to the tracking mode side b and also switches the second switch 37 to the tracking mode side b through the automatic switch 47. Further, when the received light is incident within a set high-accuracy directivity angle of the tracking sensor 15 during tracking, the tracking sensor angle determiner 45 switches the second switch 37 to the communication mode side c by the switch automatic switch 47. Here, the value of the high-precision directivity angle set by the tracking sensor 15 is given so that the received light enters the field of view of the light-receiving fiber coupler 17 if the value is within this set value. Therefore, at the time of communication, both outputs from the tracking sensor angle determiner 45 and the received light angle deviation amount determiner 46 are output so that the second switch 37 is set to the communication mode.

When the received light deviates from the field of view of the light receiving fiber coupler 17 due to disturbance or the like, the received light angle shift amount judging device 4
6 determines that communication is not possible, and switches the second switch 37 from the communication mode side c to the tracking mode side b by the automatic switch changer 47. At the time of this tracking, if the received light is incident within a certain set high-accuracy directivity angle of the tracking sensor 15, the tracking sensor angle determiner 45 switches the second switch 37 again by the automatic switch 47 to the communication mode side. c, but the tracking sensor 1
When the received light deviates from the field of view of 5, the determination output of the dragging sensor angle determiner 45 is given to the automatic switch changer 47, and the second switch 37 is switched from the tracking mode side b to the capture mode side a. At the same time, the first switch 32 also switches from the tracking mode side b to the capture mode side a.

In the example described above, three control modes are assumed: capture, tracking, and communication. However, the installation error of the optical system such as the pointing sensor 12 and the light receiving fiber coupler 17 can be neglected. 12
When the angle can be detected with high accuracy, it is possible to immediately shift from the capture mode to the communication mode.
It is also possible to configure the space optical communication apparatus in various control modes. Therefore, in that case, the tracking sensor 15 and the tracking command value 35 can be omitted,
Since the tracking mode can be omitted, the tracking sensor angle determiner 45 can be omitted as a configuration of the control mode switching means.

As described above, according to the second embodiment, the 17 capture mode, the tracking mode, and the communication mode are automatically switched and set using the detection output of the tracking sensor 15 and the light receiving fiber coupler. Even if the received light deviates from the field of view of the tracking sensor 15 due to disturbance or the like, it is possible to immediately shift to the tracking mode after shifting to the capture mode.
Even if the received light cannot be guided to the receiver 26 because it deviates from the field of view of 7, the mode can be shifted to the communication mode immediately after shifting to the tracking mode, and the effect of shortening the communication interruption time can be obtained.

Embodiment 3 FIG. FIG. 5 is a block diagram showing a signal processing process of the free-space optical communication apparatus according to Embodiment 3 of the present invention. Parts corresponding to FIG. 2 and FIG. . In the figure, 48
Is a reception light offset calculator for obtaining an output for offsetting the detection output of the tracking sensor 15 from the output of the reception light angle deviation amount detector 23. Reference numeral 49 denotes a third switch for switching a target value to the fine acquisition tracking control system in the tracking mode and the communication mode.

Next, the operation will be described. At the time of capturing, such as at the time of initial capturing, the tracking sensor 15 is in the non-light receiving state.
The switch 32 and the second switch 37 are set to the capture mode side a. In this case, the capture command value 34 is provided to the fine capture and tracking compensator 38 to constitute a fine capture and tracking control system. When the coarse capturing is performed and the received light enters the field of view of the tracking sensor 15, the tracking sensor angle determiner 45 switches the first switch 32, the second switch 37, and the third switch 49 from the capturing mode side a to the tracking mode. Switch to side b.

At the time of tracking, the tracking sensor 15
Tracking sensor 1 to guide the received light to the origin of the
5 is fed back to form a precise capture and tracking control system. The tracking command value 35 is 0, but an offset can also be given. The deviation between the tracking command value 35 and the feedback amount is input to the fine capture tracking compensator 38,
The fine capture and tracking compensator 38 has a deviation of 0 due to PID control or the like.
The precise capturing and tracking mechanism 10 is driven so that

Further, at the time of tracking, the tracking sensor 15
When the received light is incident within a set high-accuracy directivity angle, the tracking sensor angle determiner 45 switches the third switch 49 from the tracking mode side b to the communication mode side c by the automatic switch 47. Here, the value of the high-precision directivity angle set by the tracking sensor 15 is given so that the received light enters the field of view of the light-receiving fiber coupler 17 if the value is within this set value. At the time of communication, the output of the tracking sensor 15 is fed back so as to follow the output of the received light offset calculator 48 to form a fine acquisition tracking control system. The deviation between the output signal of the received light offset calculator 48 and the feedback amount is determined by the precise acquisition and tracking compensator 38.
, And the precise capture and tracking compensator 38 drives the fine capture and tracking mechanism 10 by PID control or the like so that the deviation becomes zero.

Next, the operation of the received light offset calculator 48 will be described. The multi-mode fibers 41, 42, 4 serving as a light position detecting function of the light receiving fiber coupler 17 of FIG.
The signal detected by any one of 3 and 44 is compared with the signal of the single mode fiber 40 for optically coupling the received light to the receiver 26, and is converted into the driving angle amount of the fine capturing and tracking mechanism 10. Is added to the output signal of the tracking sensor 15 as an offset amount. This offset allows the received light to be guided to the receiver 26. The received light is incident on the single mode fiber 40 of the light receiving fiber coupler 17, but the received light is not incident on all of the multimode fibers 41, 42, 43, and 44 for the optical position detection function, that is, the received light spot is Even if the received light has a certain intensity distribution, even when the received light is small, even if the received light angle fluctuates slightly, the change in the angle is detected by the received light angle deviation amount detector 23 and the photodiode provided in the receiver 26. It is possible to calculate the offset amount to the precise capture and tracking control system.

In communication, if the received light deviates from the field of view of the light receiving fiber coupler 17 due to disturbance or the like, the received light angle deviation determiner 46 determines that communication is not possible, and the third switch 49 is tracked by the automatic switch 47. Switch to mode b. In the state returned at the time of this tracking,
When the received light is incident within a set high-accuracy directivity angle of the tracking sensor 15, the determination output of the tracking sensor angle determiner 45 is given to the switch automatic switching device 47, and the third switch 49 is returned to the communication mode side c. When the received light deviates from the field of view of the tracking sensor 15, the tracking sensor angle determiner 45 switches the first switch 32 and the second switch 37 from the tracking mode side b to the capture mode side a.

As described above, according to the third embodiment, the capture mode, the tracking mode, and the communication mode can be automatically switched. In the case where the mode immediately shifts to the tracking mode after shifting to the capture mode and the received light deviates from the field of view of the light receiving fiber coupler 17 due to disturbance or the like, and the received light cannot be guided to the receiver 26, the mode immediately shifts to the tracking mode. To the communication mode
The effect of shortening the communication interruption time can be obtained. Further, by providing the reception light offset calculator 48, even when the reception light spot is small during communication and cannot enter all the optical position detection function units of the light receiving fiber coupler 17,
The effect of guiding the received light to the receiver 26 is obtained by the offset amount.

Embodiment 4 FIG. FIG. 6 is a block diagram showing a signal processing process of the free-space optical communication apparatus according to Embodiment 4 of the present invention. Portions corresponding to FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 50 denotes an offset amount generator for giving the output from the received light angle deviation amount detector 23 to the tracking sensor 15 as an offset, which is replaced by the received light offset calculator 48 of the third embodiment. Things.

Next, the operation will be described. In the capturing mode such as the initial capturing mode, the tracking sensor 15 is in the non-light receiving state, so that the tracking sensor angle determination unit 45
Sets the first switch 32 and the second switch 37 to the capture mode side a. In this case, the capture command value 34 is provided to the fine capture and tracking compensator 38 to constitute a fine capture and tracking control system. When the coarse capturing is performed and the received light enters the field of view of the tracking sensor 15, the tracking sensor angle determiner 45 switches the first switch 32, the second switch 37, and the third switch 49 from the capturing mode side a to the tracking mode. Switch to side b.

At the time of tracking, the tracking sensor 15
Tracking sensor 1 to guide the received light to the origin of the
5 is fed back to form a precise capture and tracking control system. The tracking command value 35 is 0, but an offset can also be given. The deviation between the tracking command value 35 and the feedback amount is input to the fine capture tracking compensator 38,
The fine capture and tracking compensator 38 has a deviation of 0 due to PID control or the like.
The precise capturing and tracking mechanism 10 is driven so that further,
When the received light is incident within a set high-accuracy directivity angle of the tracking sensor 15 during tracking, the tracking sensor angle determiner 45 switches the third switch 49 by the automatic switch 47 from the tracking mode side b to the communication mode side c. Switch to Here, the value of the high-precision directivity angle set by the tracking sensor 15 is given so that the received light enters the field of view of the light-receiving fiber coupler 17 if the value is within this set value.

At the time of communication, the output of the tracking sensor 15 is fed back so as to follow the output signal of the offset amount generator 50, thereby forming a precise capture and tracking control system.
The deviation between the output signal of the offset amount generator 50 and the feedback amount is input to the fine acquisition tracking compensator 38. Drive.

Next, the operation of the offset amount generator 50 will be described. A signal detected by one of the multi-mode fibers 41, 42, 43, and 44, which is a light position detecting function of the light-receiving fiber coupler 17, is compared with a set threshold for allowing the received light to enter the single-mode fiber 40. I do. Multimode fiber 4 above this threshold
When the signal detected by any one of 1, 42, 43, and 44 is larger, a certain offset amount converted to the driving angle amount of the fine capture and tracking mechanism 10 is output, and this is output to the tracking sensor 15. Add to output. Then, the multimode fibers 41, 42, 4 are set to be smaller than the set threshold value.
Until the signal detected from one of the signals 3 and 44 becomes smaller, a certain fixed amount of offset is continuously added.
That is, assuming that a certain offset amount is s, the output of the offset amount generator 50 in the first cycle is A (1) = s
The output of the offset amount generator 50 in the second cycle is A
(2) = s + s = 2 × A, and the output of the offset amount generator 50 at the n-th cycle is A (n) = s × n. The multimode fibers 41, 42, 4 are larger than the set threshold.
When the signal detected by one of the signals 3 and 44 becomes smaller, the offset amount generator 50 outputs 0. By this offset operation, the received light can be guided to the receiver 26.

The received light is incident on the single mode fiber 40 of the light receiving fiber coupler 17, but the received light is not incident on all of the multimode fibers 41, 42, 43, and 44 for the optical position detection function, that is, the reception is performed. Even in the case where the light spot is small, the received light has a certain intensity distribution. Even when the angle change is detected and the received light beam intensity pattern is complicated, the received light beam intensity can be binarized at a certain threshold value to guide the received light to the receiver 26.

Next, when the received light deviates from the field of view of the light receiving fiber coupler 17 due to disturbance or the like during communication, the received light angle deviation judging unit 46 judges that communication is impossible, and the automatic switch 47 switches the third switch 49 to communicate. The mode c is switched to the tracking mode b. Returning to tracking, when the received light is incident within a set high-accuracy directivity angle of the tracking sensor 15, the tracking sensor angle determiner 45 sets the third switch 49 to the communication mode side c by the automatic switch 47. When the received light deviates from the field of view of the tracking sensor 15, the tracking sensor angle determination unit 45 switches the first switch 32 and the second switch 37 from the tracking mode side b to the capture mode side a.

As described above, according to the fourth embodiment, the capture mode, the tracking mode, and the communication mode are automatically switched. Therefore, even if the received light deviates from the field of view of the tracking sensor 15 due to disturbance or the like, the capture mode is not changed. The mode immediately shifts to the tracking mode after the shift to, and the received light deviates from the field of view of the light receiving fiber coupler 17 due to disturbance or the like.
Even when the received light cannot be guided to the tracking mode, the mode immediately shifts to the communication mode after shifting to the tracking mode, so that the effect of shortening the communication cutoff time can be obtained. Further, by providing the offset amount generator 50, even when the received light spot is small and cannot enter all the optical position detection function units of the light receiving fiber coupler 17 during communication, the receiver 26 can be provided with a constant offset amount. As a result, the function of the receiver 26 can be prevented from being impaired even when the intensity pattern of the received light beam is complicated.

Embodiment 5 FIG. 7 is a configuration diagram showing a schematic configuration of an optical space communication apparatus according to Embodiment 5 of the present invention. In FIG. 7, parts corresponding to those in FIG. In the figure, 51 is a coarse capturing and tracking mechanism 5, 6
Is an image rotation detector for detecting the rotation angle of the received light generated by the rotation of the optical system, 53 is a rotation mechanism for rotating the internal optical system 9, and 52 is a response to a detection output from the image rotation detector 51. And a rotation mechanism control circuit for controlling the rotation of the rotation mechanism 53.

Next, the operation will be described. Capture mode,
In the tracking mode or the communication mode, the coarse capturing and tracking mechanisms 5 and 6 rotate to capture and track the transmission light 101 from the partner station. In the case of FIG. 1, at this time, the received light rotates in the internal optical system in accordance with the rotation of the coarse capturing / tracking mechanisms 5 and 6, and therefore, it is necessary to perform coordinate conversion on each sensor that receives the received light. In the configuration of the fifth embodiment, the influence is canceled by the rotation mechanism 53. When the rough capturing and tracking mechanisms 5 and 6 rotate, the image rotation angle in the internal optical system is calculated by the image rotation detector 51, and an output indicating the corresponding amount is extracted. Next, upon receiving an output corresponding to the calculated rotation angle, the rotation mechanism control circuit 52 calculates a rotation angle command value for the rotation mechanism 53 so as to cancel the image rotation generated in the internal optical system 9 and takes out the control output. . The rotation mechanism 53 is rotated by the control output from the rotation mechanism control circuit 52 to cancel the generated image rotation.

As described above, according to the fifth embodiment, the rotation of the received light in the internal optical system 9 due to the rotation of the coarse capturing and tracking mechanisms 5 and 6 can be canceled in the capturing mode, the tracking mode, and the communication mode. There is no need to perform coordinate conversion on each sensor, and the effect of simplifying the control system configuration is obtained.

[0070]

As described above, according to the present invention, the light receiving section of the transmission / reception telescope is roughly directed to the partner station by gimbal driving in the elevation direction and azimuth direction to roughly supplement the transmission light from the partner station. A coarse capture and tracking mechanism, a fine capture and tracking mechanism that precisely captures the received light roughly captured by the coarse capture and tracking mechanism by biaxial gimbal driving, and a coarse capture and tracking mechanism gimbal that detects the gimbal angle of the coarse capture and tracking mechanism An angle sensor, a precise capture and tracking mechanism gimbal angle sensor that detects the gimbal angle of the fine capture and tracking mechanism, a pointing sensor that detects a relative angle error with the partner station in a wide range,
An adder that adds the relative angle error detected by the pointing sensor and the gimbal angle detected by the coarse capturing and tracking mechanism gimbal angle sensor, and a tracking sensor that detects the relative angle error with the partner station with higher accuracy and higher frequency than the pointing sensor A trajectory prediction value that predicts and sets the relative angle of the partner station to its own station from the trajectory information, a capture command value that is set in advance as a target value for forming a precise capture tracking control system at the time of capture, and a precision command during tracking. A tracking command value preset as a target value for forming the acquisition tracking control system, a communication command value preset as a target value for forming the precise acquisition tracking control system during communication, and A light receiving fiber coupler that has the function of detecting the light position with ultra-high accuracy and optically couples to a receiver that demodulates the received light into an electric signal, and reception on the light receiving fiber coupler Received light angle deviation detector that calculates the amount of angular deviation of the target, and coarse capture and tracking so that the gimbal angle of the fine capture and tracking mechanism is set near the origin during tracking and communication based on the detection output of the fine capture and tracking mechanism gimbal angle sensor A fine and coarse cooperative compensator for obtaining a control target value for driving the control mechanism;
Calculates the gimbal angle correction amount given to the coarse capture tracking mechanism from the output of the adder, the predicted trajectory value, and the feedback amount of the output of the coarse capture tracking mechanism gimbal angle sensor during capturing. A coarse capture and tracking compensator that calculates the amount of gimbal angle correction to be applied to the coarse capture and tracking mechanism from the control target value, trajectory prediction value, and feedback amount of the output of the coarse capture and tracking mechanism gimbal angle sensor, The gimbal angle correction amount of the precise capture and tracking mechanism is calculated from the value and the feedback amount of the output of the gimbal angle sensor, and the precise capture and tracking mechanism is used based on the tracking command value and the feedback amount of the output of the tracking sensor during tracking. The amount of gimbal angle correction to be applied to the sensor is calculated, and during communication, the precise acquisition tracking is performed based on the communication command value and the feedback amount of the output of the received light angle deviation detector. A precise capture and tracking compensator that calculates the amount of gimbal angle correction given to the mechanism and control mode switching means for setting each control mode during capture, tracking, and communication. There is an effect that a station can be acquired and tracked at high speed over a wide range and with high accuracy. In addition, since the mounting errors of the pointing sensor, tracking sensor, and light receiving fiber coupler can be canceled out by controlling the coarse capturing and tracking mechanism and the capturing and tracking mechanism, capturing without causing interference between the coarse capturing and tracking control system and the fine capturing and tracking control system. There is an effect that the mode is smoothly shifted from the mode to the tracking mode and the tracking can be reliably maintained. Furthermore, after controlling the direction of the received light from the partner station with high accuracy in the tracking mode, the mode shifts from the tracking mode to the communication mode, and the light receiving fiber coupler with an ultra-high-precision optical position detection function is used to achieve higher accuracy. Since the received light is guided to the receiver by performing directivity control, the communication can be performed even if the received light is weak. In addition, since the received light is optically coupled to the receiver using a light-receiving fiber coupler, the degree of freedom can be given to the installation location of the receiver. In addition, the coarse capture and tracking control mechanism and the fine capture Since the acquisition and tracking can be performed only by the configuration of the tracking control mechanism, there is an effect of reducing the size and weight of the entire optical space communication apparatus.

According to the present invention, a coarse capturing and tracking mechanism for gimbal driving in the elevation direction and the azimuth direction to roughly direct the light receiving section of the transmission / reception telescope toward the partner station to roughly capture the transmission light from the partner station, A fine capture tracking mechanism that precisely captures the received light roughly captured by the coarse capture tracking mechanism by biaxial gimbal driving, a coarse capture tracking mechanism gimbal angle sensor that detects the gimbal angle of the coarse capture tracking mechanism, and a fine capture tracking A precision capture and tracking mechanism gimbal angle sensor that detects the gimbal angle of the mechanism, a pointing sensor that detects the relative angle error with the partner station in a wide range, and a relative angle error and a coarse capture and tracking mechanism that are detected by the pointing sensor An adder that adds the detected gimbal angle, and a relative angle error with the partner station that is higher in accuracy and frequency than the pointing sensor A tracking sensor to detect, a trajectory predicted value that predicts and sets the relative angle of the partner station to its own station from the trajectory information, and a capture command value that is set in advance as a target value for forming a precise capture tracking control system at the time of capture. , A tracking command value that is set in advance as a target value for forming a precise capture and tracking control system during tracking, and a reception that demodulates received light into an electric signal with a function of detecting an ultra-high-precision light position from received light. Optical fiber coupler that optically couples to the device, Received optical angle deviation detector that calculates the amount of optical angle deviation for reception on the optical fiber coupler, and precise tracking control during communication from the output of the received optical angle deviation detector The receiver optical offset calculator that calculates the amount of offset given to the system, and the precise capture and tracking mechanism gimbal angle is set near the origin during tracking and communication based on the detection output of the fine capture and tracking mechanism gimbal angle sensor. A coarse and coarse cooperative compensator that obtains a control target value for driving the coarse capture and tracking control mechanism so that the output of the adder, the trajectory prediction value, and the feedback amount of the coarse capture and tracking mechanism gimbal angle sensor output during capture Calculates the amount of gimbal angle correction to be given to the coarse tracking and tracking mechanism from the control target value and trajectory predicted value from the coarse and coarse cooperative compensator during tracking and communication, and the feedback amount of the output from the coarse capturing and tracking mechanism gimbal angle sensor. A coarse capture tracking compensator that calculates the amount of gimbal angle correction given to the coarse capture tracking mechanism, and a gimbal angle given to the fine capture tracking mechanism from the command value during capture and the feedback amount of the output of the fine capture tracking mechanism gimbal angle sensor during capture Calculate the amount of gimbal angle correction given to the precise capture tracking mechanism from the tracking command value and the feedback amount of the output of the tracking sensor during tracking. A precise capture and tracking compensator that calculates a correction amount to be applied to the gimbal angle of the fine capture and tracking mechanism from the output offset amount of the received light offset calculator and the feedback amount of the output of the tracking sensor during communication; Since the control mode switching means for setting each control mode at the time of communication is provided, there is an effect that the light receiving section can be captured and tracked with respect to the partner station at high speed over a wide range and with high accuracy. In addition, since the mounting errors of the pointing sensor, tracking sensor, and light receiving fiber coupler can be canceled out by controlling the coarse capturing and tracking mechanism and the capturing and tracking mechanism, capturing without causing interference between the coarse capturing and tracking control system and the fine capturing and tracking control system. There is an effect that the mode is smoothly shifted from the mode to the tracking mode and the tracking can be reliably maintained. Furthermore, after controlling the direction of the received light from the partner station with high accuracy in the tracking mode, the mode shifts from the tracking mode to the communication mode, and the light receiving fiber coupler with an ultra-high-precision optical position detection function is used to achieve higher accuracy. Since the received light is guided to the receiver by directing control to the receiver, communication is possible even if the received light is weak, and the received light on the light receiving fiber coupler is incident on the entire optical position detection function part Even in the case where it is impossible, there is an effect that the received light can be guided to the receiver. In addition, since the received light is optically coupled to the receiver using a light-receiving fiber coupler, the degree of freedom can be given to the installation location of the receiver. In addition, the coarse capture and tracking control mechanism and the fine capture Since the acquisition and tracking can be performed only by the configuration of the tracking control mechanism, there is an effect of reducing the size and weight of the entire optical space communication apparatus.

According to the present invention, instead of the received light offset calculator, there is provided an offset amount generator for taking out a fixed offset amount when the output of the received light angle deviation amount detector is larger than the threshold during communication, The precise capture and tracking compensator
Since the gimbal angle correction amount given to the precise acquisition tracking mechanism is calculated from the feedback amount of the output of the tracking sensor and a fixed offset amount during communication, the light receiving unit can be moved at high speed and with high accuracy to the partner station. Has the effect of being able to capture and track. In addition, since the mounting errors of the pointing sensor, tracking sensor, and light receiving fiber coupler can be canceled out by controlling the coarse capturing and tracking mechanism and the capturing and tracking mechanism, capturing without causing interference between the coarse capturing and tracking control system and the fine capturing and tracking control system. There is an effect that the mode is smoothly shifted from the mode to the tracking mode and the tracking can be reliably maintained. Furthermore, after controlling the direction of the received light from the partner station with high accuracy in the tracking mode, the mode shifts from the tracking mode to the communication mode, and the light receiving fiber coupler with an ultra-high-precision optical position detection function is used to achieve higher accuracy. Since the receiving light is guided to the receiver by controlling the pointing direction, it is possible to communicate even if the receiving light is weak,
Even if the received light spot on the receiving fiber coupler is too small to enter the entire optical position detection function unit, it is possible to guide the received light to the receiver by giving a fixed offset amount, and when the received light beam intensity pattern is complicated. This also has the effect of not impairing the function of the receiver. In addition, since the received light is optically coupled to the receiver using a light-receiving fiber coupler, the degree of freedom can be given to the installation location of the receiver. In addition, the coarse capture and tracking control mechanism and the fine capture Since the acquisition and tracking can be performed only by the configuration of the tracking control mechanism, there is an effect of reducing the size and weight of the entire optical space communication apparatus.

According to this invention, the control mode switching means determines the incident light angle from the detection output of the tracking sensor, and determines the angle deviation of the received light on the light receiving fiber coupler from the output of the received light angle deviation detector. The control mode is set to switch between the capture mode, the tracking mode, and the communication mode, thereby automatically switching between the capture mode, the tracking mode, and the communication mode. Even if the received light deviates from, the tracking mode can be shifted to the tracking mode immediately after the shift to the capture mode. It is possible to return to the communication mode immediately after switching to the mode, and there is an effect that the communication cutoff time can be reduced.

According to the present invention, the control mode switching means includes the first switch for switching and setting the control mode between the communication and the tracking of the coarse capture and tracking control system, and the control and control of the fine capture and tracking control system. A second switch for switching and setting a control mode during communication, and a tracking sensor angle determiner for determining an incident light angle from a detection output of the tracking sensor and setting the first switch to one of a communication mode and a tracking control mode A received light angle deviation amount determiner that determines the angular deviation of the received light on the light receiving fiber coupler from the output of the received light angle deviation amount detector and obtains a determination output that determines when to track and when to communicate, and a tracking sensor angle determiner Switch for setting the second switch to one of the control modes during capture, tracking, and communication in response to both outputs of the controller and the received light angle deviation amount determiner Since it is configured to have a dynamic switch, the capture mode one de, tracking mode and the communication mode can be automatically switched to, even when the received light deviates from the tracking sensor field of view due to a disturbance or the like,
The mode can be shifted to the tracking mode immediately after shifting to the capture mode. Even if the received light deviates from the field of view of the light receiving fiber coupler due to disturbances and the received light cannot be guided to the receiver, it immediately returns to the communication mode after shifting to the tracking mode. There is an effect that the transfer can be performed and the communication cutoff time can be reduced.

According to the present invention, the pointing sensor is composed of a two-dimensional CCD, the tracking sensor is composed of a four-quadrant detector, and the light receiving fiber coupler is a single mode fiber for optically coupling the received light to the receiver. A multi-mode fiber is installed around the fiber and used to detect the position of the received light.Accurate reception according to the functions of each control mode during capture, tracking, and communication Light detection can be performed, and there is an effect that control of the capturing and tracking mechanism is sufficiently maintained.

According to the present invention, a coarse capturing and tracking mechanism for gimbal driving in the elevation direction and azimuth direction to roughly direct the light receiving unit of the transmission / reception telescope toward the partner station to roughly capture the transmission light from the partner station, A fine capture tracking mechanism that precisely captures the received light roughly captured by the coarse capture tracking mechanism by biaxial gimbal driving, a coarse capture tracking mechanism gimbal angle sensor that detects the gimbal angle of the coarse capture tracking mechanism, and a fine capture tracking A precision capture and tracking mechanism gimbal angle sensor that detects the gimbal angle of the mechanism, a pointing sensor that detects the relative angle error with the partner station in a wide range, and a relative angle error and a coarse capture and tracking mechanism that are detected by the pointing sensor An adder that adds the detected gimbal angle, and an orbit prediction value that predicts and sets a relative angle of the partner station with respect to the own station from the orbit information, A capture command value preset as a target value for forming a fine capture tracking control system at the time of capture, a communication command value preset as a target value for forming a fine capture tracking control system at the time of communication, A light-receiving fiber coupler that has the function of detecting the position of light with ultra-high accuracy from light and optically couples to a receiver that demodulates the received light into an electric signal, and a received light angle that calculates the amount of angular deviation of the received light on the light-receiving fiber coupler Control target value for driving the coarse capture and tracking control mechanism so that the gimbal angle of the fine capture and tracking mechanism is set near the origin during tracking and communication based on the deviation amount detector and the detection output of the fine capture and tracking mechanism gimbal angle sensor And a coarse / coordinated compensator to obtain
The amount of gimbal angle correction to be applied to the coarse tracking and tracking mechanism is calculated from the output of the adder, the predicted trajectory value, and the feedback amount of the output of the coarse capturing and tracking mechanism gimbal angle sensor during capturing, and control from the fine and coarse cooperative compensator during communication. A coarse capture and tracking compensator that calculates the amount of gimbal angle correction to be applied to the coarse capture and tracking mechanism from the target value, predicted trajectory value, and the feedback amount of the output of the coarse capture and tracking mechanism gimbal angle sensor. The amount of gimbal angle correction given to the precise tracking mechanism is calculated from the feedback amount of the output of the capturing and tracking mechanism gimbal angle sensor, and the accuracy is calculated from the communication command value and the feedback amount of the output of the received light angle deviation detector during communication. A precise capture and tracking compensator that calculates a correction amount of the gimbal angle given to the capture and tracking mechanism; and a control mode switching unit that sets a control mode during capture and during communication. Since it is configured so that it can be used, the installation error of the optical system such as the pointing sensor and the light receiving fiber coupler can be ignored, and it can be applied when the pointing sensor that can detect the angle with high accuracy is used. Since the capture control of the optical space communication device can be performed in these two types of control modes, there is an effect that the device configuration can be further simplified.

According to the present invention, the control mode switching means determines the incident light angle from the detection output of the tracking sensor, and determines the angle deviation of the received light on the light receiving fiber coupler from the output of the received light angle deviation detector. The control mode is set to switch between the capture mode and the communication mode by changing the mode. In this case, the communication mode can be immediately shifted to the capture mode after the shift to the capture mode. The mode can be returned to the mode, and there is an effect that the communication cutoff time can be reduced.

According to the present invention, when the pointing sensor cannot obtain a detection output when no light is received, the adder is configured to hold the output value at the time of the previous light reception as it is. Even if the movement is fast and the error cannot be reduced to the level required for tracking or communication mode in the coarse capture tracking control system and it can not enter the partner station's tracking, the coarse capture tracking mechanism will not In the meantime, the transmission / reception telescope can be directed toward the partner station, so that the next time light is received by the pointing sensor, the initial error is reduced and the tracking or communication mode can be surely entered.

According to the present invention, the image rotation detector for detecting the rotation angle of the received light generated in the internal optical system by the rotation of the coarse capturing and tracking mechanism, the rotation mechanism for rotating the internal optical system, and the image rotation A rotation mechanism control circuit that drives and controls the rotation mechanism so as to cancel the image rotation generated in the internal optical system in response to the detection output of the detector, so that in the capture mode, the tracking mode, and the communication mode, The rotation of the received light in the internal optical system due to the rotation of the coarse capturing and tracking mechanism can be canceled, and there is no need to perform coordinate conversion on each sensor, which has the effect of simplifying the control system configuration.

According to the present invention, the light for controlling the light receiving section to be roughly directed to the partner station by the gimbal driven coarse capturing and tracking mechanism and for controlling the light receiving section to be directed to the partner station with high precision by the gimbal driven fine capturing and tracking mechanism. In a spatial communication device,
An image rotation detector that detects the rotation angle of the received light generated in the internal optical system by the rotation of the coarse capturing and tracking mechanism, a rotation mechanism that rotates the internal optical system, and in response to the detection output of the image rotation detector A rotation mechanism control circuit that drives and controls the rotation mechanism so as to cancel the image rotation generated by the internal optical system. The rotation of the received light in the system can be canceled, and there is no need to perform coordinate conversion on each sensor, which has the effect of simplifying the control system configuration.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a free-space optical communication apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a signal processing step of the free-space optical communication apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a perspective view showing a configuration example of a light receiving fiber coupler according to Embodiment 1 of the present invention.

FIG. 4 is a block diagram showing a signal processing step of the free-space optical communication apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a block diagram showing a signal processing step of the free-space optical communication apparatus according to Embodiment 3 of the present invention.

FIG. 6 is a block diagram showing a signal processing step of the free-space optical communication apparatus according to Embodiment 4 of the present invention.

FIG. 7 is a configuration diagram schematically showing a free-space optical communication apparatus according to Embodiment 5 of the present invention.

FIG. 8 is a configuration diagram illustrating an example of a conventional optical communication device.

FIG. 9 is a configuration diagram showing another example of a conventional optical communication device.

[Description of Signs] 1 secondary mirror, 2 primary mirror, 3rd mirror, 4th mirror, 5, 6
Rough capture and tracking mechanism, 7 frames, 8 columns, 9 internal optical system, 10 fine capture and tracking mechanism, 11, 14 beam splitter, 12 pointing sensor, 13 dichroic mirror, 15 tracking sensor, 16, 19
Reflection mirror, 17 receiving fiber coupler, 18 optical line difference correcting mechanism, 20 transmitter, 21 installation surface, 22 coarse capturing and tracking mechanism control circuit, 23 received light angle deviation detector, 24
Fine capture tracking mechanism control circuit, 25 optical fiber, 26 receiver, 27 adder, 28 coarse capture tracking compensator, 29 sampler, 30 coarse capture tracking mechanism gimbal angle sensor, 31
Orbit predicted value, 32 1st switch, 33 fine / coarse coordinator, 34 capture command value, 35 tracking command value, 36
Fine capture tracking mechanism gimbal angle sensor, 37 second switch, 38 fine capture tracking compensator, 39 communication command value, 4
0 Single mode fiber, 41, 42, 43, 44
Multi-mode fiber, 45 tracking sensor angle judgment device, 46 reception light angle deviation amount judgment device, 47 automatic switch switch, 48 reception light offset calculator,
49 third switch, 50 offset amount generator, 51
Image rotation detector, 52 rotation mechanism control circuit, 53 rotation mechanism, 101 transmission light, 102 transmission / reception telescope, 103
Light receiving unit, 110 Optical antenna, 111 Direction adjustment mechanism, 112 Collimator lens, 113 Beam splitter, 114 Condensing lens, 115 Light detector, 116
Optical antenna pointing controller, 117 optical axis adjusting reflector,
118 imaging lens, 119 beam splitter, 12
0 angle adjustment mechanism, 121 beam splitter, 122
Light detection unit, 123 Reflector mirror angle control unit, 124 Transmission lens, 125 Beam splitter, 126 Optical axis adjustment mechanism unit, 127 Optical axis control unit, 128 Light detection unit, 12
9 optical fiber cable, 130 optical signal processing unit, 131
Transmitting unit, 132 reflecting mirror, 133 lens, 201
Main reflecting mirror, 202 Sub-reflecting mirror, 203 Pointing member, 30
1-304 light receiving section, 305-308 optical fiber, 3
09 to 312 Optical amplifier, 313 to 316 Photodiode, 317 Operation processing unit.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuhide Kodachi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Within Mitsubishi Electric Corporation (72) Inventor Toshio Kashise 2-3-2 Marunouchi, Chiyoda-ku, Tokyo No. Mitsubishi Electric Corporation F-term (reference) 5K002 AA03 FA03 FA04

Claims (11)

[Claims] 1. A coarse capturing and tracking mechanism for performing gimbal driving in an elevation direction and an azimuth direction to roughly direct a light receiving unit of a transmission / reception telescope toward a partner station and roughly capture transmission light from the partner station; A fine capture tracking mechanism that precisely captures the received light roughly captured by the tracking mechanism by biaxial gimbal driving; a coarse capture tracking mechanism gimbal angle sensor that detects a gimbal angle of the coarse capture tracking mechanism; A precise capturing and tracking mechanism gimbal angle sensor for detecting a gimbal angle of the mechanism; a pointing sensor for detecting a relative angle error with a partner station in a wide range; a relative angle error detected by the pointing sensor and the coarse capturing and tracking mechanism gimbal angle. An adder for adding the gimbal angle detected by the sensor; Tracking sensor that detects at high frequency and high frequency, trajectory prediction value that predicts and sets the relative angle of the partner station to its own station from trajectory information, and target value that is set in advance as a target value for forming a precise capture tracking control system during capture The command value at the time of capture, the command value at the time of tracking preset as a target value for forming the precise capture and tracking control system at the time of tracking, and the preset value as the target value for forming the precise capture and tracking control system at the time of communication A communication command value, a light receiving fiber coupler optically coupled to a receiver having a function of detecting an ultra-high precision light position from the received light and demodulating the received light into an electric signal, and an angle of the received light on the light receiving fiber coupler A receiving light angle shift amount detector for calculating a shift amount, and the fine capture and tracking mechanism gimbal angle is set near the origin during tracking and communication based on the detection output of the fine capture and tracking mechanism gimbal angle sensor. A fine / coarse coordinator for obtaining a control target value for driving the coarse capture / tracking control mechanism so as to be determined; and an output of the adder, the trajectory predicted value, and the coarse capture / tracking mechanism gimbal angle sensor during capture. A gimbal angle correction amount given to the coarse capturing and tracking mechanism is calculated from the output feedback amount, and a control target value, the trajectory predicted value, and the coarse capturing and tracking mechanism gimbal from the fine and coarse cooperative compensator during tracking and communication. A coarse capture tracking compensator that calculates a gimbal angle correction amount given to the coarse capture tracking mechanism from a feedback amount of the output of the angle sensor, and a capture command value and a fine capture tracking mechanism gimbal angle sensor output during capture. The gimbal angle correction amount of the precise capturing and tracking mechanism is calculated from the feedback amount, and the tracking command value and the output of the tracking sensor are fed back during tracking. The gimbal angle to be given to the fine-acquisition tracking mechanism from the communication command value and the feedback amount of the output of the received light angle deviation amount detector at the time of communication is calculated. An optical space communication apparatus, comprising: a fine acquisition tracking compensator that calculates a correction amount of the above; and a control mode switching unit that sets each control mode during acquisition, tracking, and communication. 2. A coarse capturing and tracking mechanism for performing gimbal driving in an elevation direction and an azimuth direction to roughly point a light receiving unit of a transmission / reception telescope toward a partner station and roughly capture transmission light from the partner station; A fine-capture tracking mechanism that precisely captures the received light roughly captured by the tracking mechanism by biaxial gimbal driving; a coarse-capture tracking mechanism that detects a gimbal angle of the coarse capture tracking mechanism; and a fine-capture tracking. A precise capturing and tracking mechanism gimbal angle sensor for detecting a gimbal angle of the mechanism; a pointing sensor for detecting a relative angle error with a partner station in a wide range; a relative angle error detected by the pointing sensor and the coarse capturing and tracking mechanism gimbal angle. An adder for adding the gimbal angle detected by the sensor; Tracking sensor that detects at high frequency and high frequency, trajectory prediction value that predicts and sets the relative angle of the partner station to its own station from trajectory information, and target value that is set in advance as a target value for forming a precise capture tracking control system during capture It has a command value at the time of capture, a command value at the time of tracking set as a target value for forming a precise capture and tracking control system at the time of tracking, and a function of detecting an ultra-high-precision optical position from the received light, and electrically controls the received light. A light-receiving fiber coupler optically coupled to a receiver for demodulating the signal, a reception light angle deviation amount detector for calculating a light angle deviation amount of reception on the light reception fiber coupler, and an output of the reception light angle deviation amount detector A reception light offset calculator for calculating an offset amount to be applied to a precise capture and tracking control system during communication; and a fine capture and tracking during tracking and communication based on a detection output of the fine capture and tracking mechanism gimbal angle sensor. A fine and coarse cooperative compensator that obtains a control target value for driving the coarse capture and tracking control mechanism so that the capture and tracking mechanism gimbal angle is set near the origin; and an output of the adder and the trajectory prediction value during capturing. A gimbal angle correction amount to be given to the coarse capturing and tracking mechanism is calculated from the feedback amount of the output of the coarse capturing and tracking mechanism gimbal angle sensor, and a control target value from the fine and coarse cooperative compensator and the trajectory during tracking and communication. A coarse capture and tracking compensator that calculates a gimbal angle correction amount to be applied to the coarse capture and tracking mechanism from the predicted value and a feedback amount of the output of the coarse capture and tracking mechanism gimbal angle sensor; Calculate a gimbal angle correction amount to be applied to the fine tracking mechanism from the feedback amount of the output of the capturing tracking mechanism gimbal angle sensor, and when tracking, the tracking command value and the tracking command value are calculated. A gimbal angle correction amount to be applied to the fine capture and tracking mechanism is calculated from the feedback amount of the output of the racking sensor, and the precision is calculated from the output offset amount of the received light offset calculator and the feedback amount of the output of the tracking sensor during communication. An optical space comprising: a precise capture and tracking compensator for calculating a correction amount given to a gimbal angle of a capture and tracking mechanism; and control mode switching means for setting respective control modes during capture, tracking, and communication. Communication device. 3. An offset amount generator for taking out a constant offset amount when an output of a received light angle deviation amount detector is larger than a threshold value during communication, instead of a received light offset calculator, and precisely capturing and tracking compensation. 4. The optical space communication apparatus according to claim 3, wherein a compensator calculates a correction amount of a gimbal angle to be given to the precise capturing and tracking mechanism from a feedback amount of an output of the tracking sensor and the fixed offset amount during communication. . 4. The control mode switching means determines the incident light angle from the detection output of the tracking sensor, and determines the angle shift of the received light on the light receiving fiber coupler from the output of the received light angle shift amount detector. The optical space communication apparatus according to any one of claims 1 to 3, wherein each of the control modes at the time of tracking, tracking, and communication is switched and set. 5. A control mode switching means comprising: a first switch for switching and setting a control mode between communication and tracking in a coarse capture and tracking control system; and control during capture, tracking and communication in a fine capture and tracking control system. A second switch for switching and setting a mode; a tracking sensor angle determiner for determining an incident light angle from a detection output of the tracking sensor to set the first switch to a control mode for communication or tracking; A received light angle shift amount determiner that determines the angle shift of the received light on the light receiving fiber coupler from the output of the light angle shift amount detector and extracts a determination output that determines the tracking time and the communication time, the tracking sensor angle determiner, and A switch for setting the second switch to one of the control modes during capture, tracking, and communication in response to both outputs of the received light angle deviation amount determiner. Optical space communication apparatus according to claim 1, characterized in that having an automatic switch. 6. A pointing sensor is constituted by a two-dimensional CCD, a tracking sensor is constituted by a four-quadrant detector, a light-receiving fiber coupler is a single-mode fiber for optically coupling received light to a receiver, and the center of the single-mode fiber. The optical space communication apparatus according to any one of claims 1 to 5, further comprising a multi-mode fiber disposed around the multi-mode fiber for detecting a position of the reception light. 7. A coarse capturing and tracking mechanism for performing gimbal driving in an elevation direction and an azimuth direction to roughly direct a light receiving unit of the transmission / reception telescope toward a partner station and roughly capture transmission light from the partner station; A fine-capture tracking mechanism that precisely captures the received light roughly captured by the tracking mechanism by biaxial gimbal driving; a coarse-capture tracking mechanism that detects a gimbal angle of the coarse capture tracking mechanism; and a fine-capture tracking. A precise capturing and tracking mechanism gimbal angle sensor for detecting a gimbal angle of the mechanism; a pointing sensor for detecting a relative angle error with a partner station in a wide range; a relative angle error detected by the pointing sensor and the coarse capturing and tracking mechanism gimbal angle An adder that adds the gimbal angle detected by the sensor, and a trajectory that predicts and sets the relative angle of the partner station to its own station from trajectory information A predicted value, a command value at the time of capture set as a target value for forming the fine capture and tracking control system at the time of capture, and a communication time command preset as a target value for forming the fine capture and tracking control system at the time of communication A light receiving fiber coupler that has a function of detecting an ultra-high-precision light position from the received light and optically couples the light to a receiver that demodulates the received light into an electric signal; A receiving light angle deviation detector to be calculated; and the coarse capturing and tracking control mechanism so that the fine capture and tracking mechanism gimbal angle is set near the origin during tracking and communication based on the detection output of the fine capture and tracking mechanism gimbal angle sensor. A fine and coarse cooperative compensator for obtaining a control target value for driving the output of the adder, the trajectory prediction value, and the feedback amount of the output of the coarse capture and tracking mechanism gimbal angle sensor during capture. The gimbal angle correction amount to be given to the coarse capturing and tracking mechanism is calculated from the control target value and the trajectory predicted value from the fine and coarse cooperative compensator during communication and the feedback amount of the output of the coarse capturing and tracking mechanism gimbal angle sensor. A coarse capture tracking compensator that calculates the amount of gimbal angle correction to be applied to the coarse capture tracking mechanism, and the fine capture tracking based on the capture command value and the feedback amount of the output of the fine capture tracking mechanism gimbal angle sensor during capture. A gimbal angle correction amount given to the mechanism is calculated, and a gimbal angle correction amount given to the fine capture tracking mechanism is calculated from the communication command value and the output amount of the output of the received light angle deviation amount detector during communication. An optical space communication apparatus comprising: a fine-acquisition tracking compensator; and a control mode switching means for setting a control mode during capture and during communication. 8. A control mode switching means for detecting an incident light angle from a detection output of the tracking sensor and for determining an angle deviation of the reception light on the light receiving fiber coupler from an output of the reception light angle deviation detector. The optical space communication apparatus according to claim 7, wherein a control mode at the time of communication and a mode at the time of communication are switched and set. 9. The method according to claim 1, wherein the adder holds a previous output value at the time of light reception as it is when the pointing sensor cannot obtain a detection output during no light reception. An optical space communication device according to any one of the preceding claims. 10. An image rotation detector for detecting a rotation angle of received light generated in an internal optical system due to rotation of a coarse capturing and tracking mechanism, a rotation mechanism for rotating the internal optical system, and an image rotation detector. 10. A rotation mechanism control circuit for driving and controlling the rotation mechanism so as to cancel image rotation generated in the internal optical system in response to a detection output. An optical space communication device according to any one of the preceding claims. 11. Optical spatial communication in which a gimbal-driven coarse capturing / tracking mechanism roughly directs the light receiving unit to the partner station, and a gimbal-driven fine capturing / tracking mechanism controls the light receiving unit to point to the partner station with high precision. In the apparatus, an image rotation detector that detects a rotation angle of received light generated in an internal optical system by rotating the coarse capturing and tracking mechanism, a rotation mechanism that rotates the internal optical system, and an image rotation detector. An optical space communication device, comprising: a rotation mechanism control circuit that drives and controls the rotation mechanism so as to cancel the image rotation generated in the internal optical system in response to the detection output.