Artificial satellite

Abstract

In an artificial satellite equipped with an optical communication device, after being released into space, it will have an antenna capable of transmitting and receiving radio waves in the same direction as the input and output of laser light from the optical communication device, enabling real-time communication of position and direction information with the optical communication partner. [Solution] The artificial satellite (1) comprises a structure (2) having multiple surfaces, an optical communication device (6) mounted on the structure, a deployable antenna (8) capable of transmitting and receiving radio waves, and a hinge part (18) that rotatably connects the deployable antenna to the structure. The laser light input / output surface (6A) of the optical communication device is located on the first surface (14) of the multiple surfaces of the structure. The hinge part is positioned in a way that allows the deployable antenna to be deployed from a folded state, where the deployable antenna is positioned along a second surface (16) adjacent to the first surface of the multiple surfaces of the structure, to a deployed state, where the direction of the deployable antenna substantially coincides with the direction of the optical axis (L) of the laser light from the optical communication device. The hinge part also connects the end of the deployed antenna on the first surface side in the folded state to the structure.

Description

Technical Field

[0001] The present invention relates to artificial satellites, and particularly to artificial satellites equipped with optical communication devices.

Background Art

[0002] Artificial satellites are equipped with antenna devices for communicating with ground stations and other artificial satellites via radio waves. In conventional artificial satellites, for example, a parabolic antenna constituting the antenna device is attached to the satellite body via a hinge mechanism (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, the development of small satellites capable of supporting various missions while achieving short delivery times and low costs has been underway. For example, in order to realize high-speed and high-capacity satellite communication while miniaturizing communication equipment mounted on satellites, it has been considered to mount an optical communication device using laser light on small satellites.

[0005] Because the spread of laser light transmitted and received via optical communication is extremely narrow (for example, a spread angle of less than 1 degree), when performing optical communication between satellites and the ground, or between satellites, over very long distances, the transmitters and receivers must be aligned with each other with extremely high precision. Therefore, with the optical communication transceiver pointed towards the target ground station or satellite, it is necessary to use a separate communication device to exchange information about each other's position and direction with the other ground station or satellite, while aligning the satellite's attitude and the direction of the laser light. Thus, it is required to position an antenna capable of transmitting and receiving radio waves in the same direction as the transmission and reception of laser light by the optical communication device, enabling real-time communication of position and direction information with the optical communication partner.

[0006] However, due to space limitations for equipment placement in small satellites, it is difficult to place other equipment such as antennas on the same plane as the laser light input / output surface of the optical communication device.

[0007] This invention has been made in view of the above problems, and aims to provide an artificial satellite equipped with an optical communication device that has an antenna capable of transmitting and receiving radio waves in the same direction as the input and output directions of laser light from the optical communication device after being released into space, and that can communicate information about position and direction with the optical communication partner in real time. [Means for solving the problem]

[0008] According to one aspect of the present invention, an artificial satellite comprising a structure having a plurality of surfaces, an optical communication device mounted on the structure, a deployable antenna capable of transmitting and receiving radio waves, and a hinge portion that rotatably connects the deployable antenna to the structure, Camera and, The optical communication device has a first surface among a plurality of surfaces of the structure, and the hinge portion is positioned so that the deployable antenna can be deployed from a folded state in which the deployable antenna is positioned along a second surface adjacent to the first surface among the plurality of surfaces of the structure to a deployed state in which the direction of the deployable antenna substantially coincides with the direction of the optical axis of the laser beam from the optical communication device, and the end of the deployed antenna on the first surface side in the folded state is connected to the structure. The second surface is positioned closer to the first surface than the folded unfolded antenna, and the camera is positioned further from the first surface than the folded unfolded antenna on the second surface, and is positioned to keep the unfolded unfolded antenna within its field of view.Artificial satellites will be provided.

[0009] According to one aspect of the present invention, the structure is a hexahedron having a longitudinal direction and a transverse direction, and the first face is a face parallel to the transverse direction.

[0010] According to one aspect of the present invention, the second surface is a surface parallel to the longitudinal direction, and on the second surface, Microstrip The antenna is positioned adjacent to the unfolded antenna in its folded state. According to one aspect of the present invention, the satellite is equipped with downlink / uplink antennas for transmitting and receiving signals between the satellite and a ground station, wherein the downlink / uplink antennas are positioned on a second plane at a location further from the first plane than a folded, deployed antenna, and the camera is positioned on the second plane at a location further from the first plane than the downlink / uplink antennas.

[0011] According to one aspect of the present invention ,mosquito The optical axis of the laser is tilted away from the structure relative to the optical axis of the laser beam of the optical communication device.

[0012] According to one aspect of the present invention, the hinge portion includes a spring that biases the deployable antenna from a folded state to an deployed state, and a stopper that holds the deployable antenna in the deployed state against the biasing force of the spring. [Effects of the Invention]

[0013] According to the present invention, an artificial satellite equipped with an optical communication device has an antenna capable of transmitting and receiving radio waves in the same direction as the input and output directions of the laser light emitted by the optical communication device after being released into space, enabling real-time communication of position and direction information with the optical communication partner. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing the state of a satellite after it has been placed into orbit using one embodiment of the present invention. [Figure 2] This is a schematic plan view showing the layout of the structure and mounted equipment according to one embodiment of the present invention. [Figure 3] This is an enlarged perspective view showing a deployable antenna according to one embodiment of the present invention. [Figure 4] This is a perspective view showing a structure and a folded antenna according to one embodiment of the present invention. [Figure 5]A perspective view showing a structure and a deployed antenna in a deployed state according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0015] Hereinafter, a satellite according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0016] First, referring to FIG. 1, the overall configuration of the satellite according to the present embodiment will be described. FIG. 1 is a perspective view showing the state of the satellite according to an embodiment of the present invention after orbit injection.

[0017] As shown in FIG. 1, the satellite 1 of the present embodiment includes a structure 2, a solar cell paddle 4 (SAP: Solar Array Paddle), an optical communication device 6, a deployable antenna 8, a camera 10, and a downlink / uplink antenna 12 different from the deployable antenna 8.

[0018] The structure 2 has a rectangular parallelepiped outer shape having a longitudinal direction and a lateral direction, and various devices such as a power supply system, an attitude control system, and a communication system of the satellite 1 are mounted inside. In the following description, the upper surface of the structure 2 shown in FIG. 1 is referred to as the +X plane, the lower surface as the -X plane, the right side surface as the +Y plane, the left side surface as the -Y plane, the surface on the back side of the paper as the +Z plane, and the surface on the front side of the paper as the -Z plane. Also, in the present embodiment, the Z direction is the longitudinal direction of the structure 2, and the X direction and the Y direction are the lateral directions of the structure 2.

[0019] In the satellite 1 of the present embodiment, a laser light input / output surface 6A (lens) of the optical communication device 6 is disposed on the -Z plane (optical communication surface 14, first surface) parallel to the lateral direction of the structure 2, and a deployable antenna 8, a camera 10, and a downlink / uplink antenna 12 different from the deployable antenna 8 are mounted on the +Y plane (antenna mounting surface 16, second surface) parallel to the longitudinal direction of the structure 2 and adjacent to the optical communication surface 14, and solar cell paddles 4 are mounted on the +X plane and the -X plane of the structure 2.

[0020] The solar panel 4 converts sunlight into electricity in space and supplies it to the onboard equipment of the satellite 1. The solar panel 4 is connected to the structure 2 via a hinge mechanism 4A provided at the +Z side end of the structure 2 on the +X and -X planes. This hinge mechanism 4A allows the solar panel 4 to be folded along the +X and -X planes when the satellite 1 is stored or mounted on a rocket, and when the satellite 1 is released into space, it is unfolded to be approximately coplane with the +Z plane, as shown in Figure 1.

[0021] Next, with reference to Figure 2, the arrangement of the onboard equipment of the satellite 1 according to this embodiment will be described. Figure 2 is a schematic plan view showing the layout of the structure 2 and the onboard equipment according to this embodiment.

[0022] The optical communication device 6 is a communication device that uses laser light to communicate with ground stations and other artificial satellites, and a known satellite optical communication device can be used. As shown in Figures 1 and 2, in this embodiment, the optical communication device 6 is positioned such that the laser light input / output surface 6A (lens) is located on the -Z plane (optical communication surface 14) of the structure 2. That is, the optical communication device 6 is positioned such that the optical axis L of the laser light input and output from the optical communication device 6 is parallel to the Z axis direction of the structure 2.

[0023] The deployable antenna 8 is an antenna capable of transmitting and receiving radio waves for communication, separate from optical communication by the optical communication device 6. In this embodiment, the deployable antenna 8 is rotatably connected to the -Z side end of the +Y plane (antenna mounting surface 16) of the structure 2 via a hinge portion 18. By using this deployable antenna 8 to communicate information about each other's positions and directions in real time with optical communication partners such as ground stations and other satellites, it becomes possible to control the attitude of the structure 2 so that the optical communication device 6 transmits laser light toward the partner's position or continues to capture laser light from the partner. Details of the deployable antenna 8 will be described later.

[0024] Camera 10 is mounted on the same +Y plane (antenna mounting surface 16) as the deployable antenna 8, but on the +Z side (farther from the optical communication surface 14) than the deployed antenna 8 in its folded state, for purposes such as photographing the Earth and confirming the deployment state of the deployable antenna 8. The optical axis C of camera 10 is inclined away from the structure 2 with respect to the optical axis L (i.e., Z axis) of the laser beam of the optical communication device 6, so that the deployed antenna 8 in its deployed state can be captured in the field of view of camera 10 while capturing a wide area in the direction of the Earth. In particular, in order to ensure the field of view of camera 10 even after the deployable antenna 8 is deployed, it is desirable to position camera 10 as far away as possible on the +Z side from the deployed antenna 8. The distance between the deployed antenna 8 and camera 10 is preferably 1 / 2 or more of the Z-axis length of the structure 2, and more preferably 2 / 3 or more of the Z-axis length of the structure 2.

[0025] The downlink / uplink antenna 12 is an antenna for transmitting and receiving signals between the satellite 1 and the ground station, and includes, for example, an S-band antenna and an X-band antenna. In this embodiment, the downlink / uplink antenna 12 has two substantially square, flat microstrip antennas and is positioned on the same +Y plane (antenna mounting surface 16) as the deployable antenna 8, adjacent to the deployed antenna 8 in its folded state, and between the deployable antenna 8 and the camera 10. By positioning the downlink / uplink antenna 12 on the same antenna mounting surface 16 as the deployable antenna 8 and adjacent to the deployable antenna 8 in this way, the wiring connecting the deployable antenna 8 and the downlink / uplink antenna 12 to the communication equipment 20 inside the structure 2 can be simplified, improving ease of assembly and reliability.

[0026] Furthermore, the structure 2 also houses the attitude control unit 22, the electrical box 24, and the battery 26, making maximum use of the equipment housing space within the structure 2.

[0027] Next, the configuration of the deployable antenna 8 according to this embodiment will be described with reference to Figures 3 to 5. Figure 3 is an enlarged perspective view showing the deployable antenna 8 according to this embodiment, Figure 4 is a perspective view showing the structure 2 and the deployable antenna 8 in a folded state according to this embodiment, and Figure 5 is a perspective view showing the structure 2 and the deployable antenna 8 in an deployed state according to this embodiment.

[0028] As shown in Figure 3, the deployable antenna 8 according to this embodiment is rotatably connected to the +Y plane (antenna mounting surface 16) of the structure 2 via the hinge portion 18.

[0029] The deployable antenna 8 comprises a flat antenna body 8A with a roughly square outer shape and a frame 8B that holds the antenna body 8A. The antenna body 8A is, for example, a microstrip antenna. In this embodiment, the deployable antenna 8 only needs to be able to communicate information about the position and orientation of the artificial satellite 1 and the optical communication partner, so the required communication speed and capacity are not high. Therefore, the antenna body 8A can be configured as an antenna for a low-power wide-area (LPWA) wireless communication system such as LoRa.

[0030] In order to prevent the antenna gain of the deployable antenna 8 from being obstructed by the structure 2 when deployed, and to minimize the effect of shielding by the deployable antenna 8 on the downlink / uplink antennas 12, it is desirable that the deployable antenna 8 be positioned as close as possible to the -Z plane of the structure 2 when deployed. Therefore, the hinge portion 18 is provided at the -Z side end of the +Y plane (antenna mounting surface 16) of the structure 2 so as to connect the -Z plane (optical communication surface 14) side end of the folded deployable antenna 8 to the vicinity of the -Z side end of the structure 2. The hinge portion 18 in this embodiment includes two hinges 18A and 18B, and one wing of each hinge 18A and 18B is fixed to the structure 2, and the other wing is fixed to the side edge of the frame 8B of the deployable antenna 8 on the structure 2 side, so that the rotation axis H of each hinge 18A and 18B is aligned in a straight line parallel to the X axis of the structure 2. As a result, the deployable antenna 8 can be deployed around the pivot axis H of the hinge portion 18 from a folded state (shown by dashed lines in Figure 2) positioned along the +Y plane (antenna mounting surface 16) of the structure 2, to a deployed state (shown by solid lines in Figure 2) where the antenna surface of the deployable antenna 8 approximately coincides with the -Z plane, and the direction of the deployable antenna 8 (i.e., the direction perpendicular to the antenna surface of the deployable antenna 8) approximately coincides with the direction of the optical axis L of the laser light from the optical communication device 6 (i.e., the Z-axis direction).

[0031] Each hinge 18A and 18B of the hinge portion 18 is provided with a spring 18C that applies a biasing force in the direction of opening the hinges 18A and 18B. This biasing force of the spring 18C biases the deployable antenna 8 from the folded state to the deployed state. Furthermore, the hinge portion 18 includes a stopper 18D that holds the deployable antenna 8 in the deployed state against the biasing force of the spring 18C.

[0032] The stopper 18D is formed at the -Z side end of the +Y plane (antenna mounting surface 16) of the structure 2, and has a planar portion (receiving surface 18E) facing the +Z direction. The receiving surface 18E of the stopper 18D is positioned at an angle such that it makes surface contact with the -Z side surface (contact surface 8C) of the side edge of the frame 8B of the deployable antenna 8 on the structure 2 side when the deployable antenna 8 is in the deployed state, that is, when the direction of the deployable antenna 8 (i.e., the direction perpendicular to the antenna surface of the deployable antenna 8) is approximately the same as the direction of the optical axis L of the laser light from the optical communication device 6 (i.e., the Z axis direction). As a result, when the deployable antenna 8 is deployed to the deployed state by the biasing force of the spring 18C of the hinges 18A and 18B, the contact surface 8C of the frame 8B of the deployable antenna 8 comes into contact with the receiving surface 18E of the stopper 18D at that position, and the deployable antenna 8 is held by the stopper 18D in the deployed position and angle.

[0033] Furthermore, the +Y plane (antenna mounting surface 16) of the structure 2 is provided with a holding and releasing mechanism 28 that holds the deployable antenna 8 in a folded state when the artificial satellite 1 is stored or mounted on a rocket, and releases the deployable antenna 8 to the deployed state when the artificial satellite 1 is released into space.

[0034] In this embodiment, a retaining plate 8D is attached to the side edge of the frame 8B of the deployable antenna 8 on the tip side (opposite the hinge portion 18), and is held in the folded state by a retaining release mechanism 28. In the folded state, the fishing line of the retaining release mechanism 28 is passed through an engagement hole provided on the surface of the retaining plate 8D facing the structure 2, thereby holding the deployable antenna 8 in the folded position. When the artificial satellite 1 is released into space, for example, when the power of the artificial satellite 1 is turned on, the fishing line of the retaining release mechanism 28 is burned out by the heating element, releasing the retaining plate 8D from the retaining release mechanism 28. As a result, the deployable antenna 8 is deployed to the deployed state by the biasing force of the springs 18C of the hinges 18A and 18B.

[0035] <Variation> In the embodiment described above, the hinge portion 18 is provided at the -Z side end of the +Y plane (antenna mounting surface 16) of the structure 2, but it may be positioned closer to the +Z plane than the position illustrated in the attached drawings. The further the position of the hinge portion 18 moves in the +Z direction, the greater the shielding effect of the structure 2 on the deployed antenna 8 in the deployed state, but it is possible to move the hinge portion 18 away from the -Z side end as long as the antenna gain necessary for communication with the optical communication partner can be obtained. In addition, the wings of the hinge portion 18 on the structure 2 side may be provided on the -Z plane (optical communication surface 14).

[0036] Furthermore, in the embodiment described above, it was explained that a downlink / uplink antenna 12 separate from the deployable antenna 8 is mounted on the same +Y plane (antenna mounting surface 16) as the deployable antenna 8. However, antennas for purposes other than downlink / uplink (for example, antennas for inter-satellite communication or radar antennas) may also be mounted on the same +Y plane (antenna mounting surface 16) as the deployable antenna 8.

[0037] Furthermore, although the above-described embodiment states that the structure 2 has a rectangular parallelepiped shape with a longitudinal direction and a transverse direction, it may also be a hexahedron having a longitudinal direction and a transverse direction other than a rectangular parallelepiped, or a polyhedron other than a hexahedron.

[0038] <Effects and Effects> Next, the effects and advantages of this embodiment described above will be explained.

[0039] According to this embodiment, in an artificial satellite 1 equipped with an optical communication device 6, the hinge portion 18 that rotatably connects the deployable antenna 8 to the structure 2 is positioned in a way that allows the deployable antenna 8 to be deployed from a folded state, where the deployable antenna 8 is positioned along the antenna mounting surface 16 adjacent to the optical communication surface 14, to a deployed state, where the directional direction of the deployable antenna 8 substantially coincides with the direction of the optical axis L of the laser light from the optical communication device 6, and connects the end of the deployed antenna 8 on the optical communication surface 14 side in the folded state to the structure 2. As a result, even in a small satellite that does not have space to mount an antenna for sending and receiving location information etc. with the optical communication partner on the optical communication surface 14, it is possible to mount the deployable antenna 8 on a surface other than the optical communication surface 14, and after the artificial satellite 1 is released into space, the deployable antenna 8 can be deployed to send and receive location information etc. with the optical communication partner in real time.

[0040] Furthermore, according to this embodiment, the structure 2 is a hexahedron having a longitudinal direction and a transverse direction, and the optical communication surface 14 is a surface parallel to the transverse direction. This makes it possible to mount the optical communication device 6, which has a long depth, in accordance with the shape of the structure 2, while also mounting the deployable antenna 8 on a surface adjacent to the optical communication surface 14.

[0041] Furthermore, according to this embodiment, the antenna mounting surface 16 is a surface parallel to the longitudinal direction, and a downlink / uplink antenna 12, separate from the deployable antenna 8, is provided on the antenna mounting surface 16 adjacent to the deployed antenna 8 in its folded state. This simplifies the wiring connecting the deployed antenna 8 and the downlink / uplink antenna 12 to the communication device 20 inside the structure 2, improving ease of assembly and reliability.

[0042] Furthermore, according to this embodiment, the antenna mounting surface 16 is equipped with a camera 10 positioned further from the optical communication surface 14 than the folded deployed antenna 8, and the optical axis C of the camera 10 is inclined away from the structure 2 with respect to the optical axis L of the laser beam of the optical communication device 6. This allows the deployed antenna 8 to be kept within the field of view of the camera 10 while a wide area of ​​the direction of the optical communication surface 14 (for example, towards the Earth) can be photographed, thus enabling both confirmation of the state of the deployed antenna 8 and photography of the Earth, etc.

[0043] Furthermore, according to this embodiment, the hinge portion 18 includes a spring 18C that biases the deployable antenna 8 from a folded state to a deployed state, and a stopper 18D that holds the deployable antenna 8 in the deployed state against the biasing force of the spring 18C. As a result, the deployable antenna 8 can be reliably deployed by the biasing force of the spring 18C after the artificial satellite 1 is released into space, and the deployable antenna 8 can be reliably held in a deployed state that allows communication with the optical communication partner by the stopper 18D. [Explanation of Symbols]

[0044] 1 satellite 2 Structure 4 solar panels 4A Hinge Mechanism 6 Optical communication device 6A Inlet / Outlet Radiation Surface 8 Planar antennas 8A Antenna Body 8B Frame 8C contact surface 8D retaining plate 10 Cameras 12 Downlink / Uplink Antennas 14 Optical communication surface 16 Antenna mounting surface 18. Hinge section 18A, 18B hinges 18C Spring 18D Stopper 18E Receiving surface 20 Communications devices 22 Attitude control unit 24 Electrical Box 26 batteries 28 Holding and releasing mechanism L Laser beam optical axis C Camera optical axis H hinge pivot axis

Claims

1. It is an artificial satellite, A structure having multiple surfaces, The optical communication device mounted on the aforementioned structure, A deployable antenna capable of transmitting and receiving radio waves, A hinge portion that rotatably connects the deployable antenna to the structure, Equipped with a camera, The laser light input and output surfaces of the optical communication device are located on the first surface among the plurality of surfaces of the structure. The aforementioned hinge portion is, The deployable antenna is positioned in a manner that allows it to be deployed from a folded state, where it is positioned along a second surface adjacent to the first surface among the multiple surfaces of the structure, to a deployed state, where the directional direction of the deployable antenna substantially coincides with the direction of the optical axis of the laser beam from the optical communication device, and The end on the first side of the unfolded antenna in the folded state is connected to the structure. On the second surface, it is provided at a position closer to the first surface than the folded unfolded antenna, The camera is positioned on the second surface at a location further from the first surface than the folded unfolded antenna, and is arranged to keep the unfolded antenna within its field of view. artificial satellite.

2. The aforementioned structure is a hexahedron having a longitudinal direction and a transverse direction. The first surface is a surface parallel to the shorter direction. The artificial satellite according to claim 1.

3. The second surface is a surface parallel to the longitudinal direction, On the second surface, a microstrip antenna is provided adjacent to the folded unfolded antenna. The artificial satellite according to claim 2.

4. The satellite is equipped with downlink / uplink antennas for transmitting and receiving signals between the satellite and a ground station, The downlink / uplink antenna is positioned on the second surface at a location further from the first surface than the folded unfolded antenna. The camera is positioned on the second surface at a location further from the first surface than the downlink / uplink antenna. The artificial satellite according to claim 1.

5. The optical axis of the camera is inclined toward the side away from the structure with respect to the optical axis of the laser beam of the optical communication device. The artificial satellite according to claim 1.

6. The aforementioned hinge portion is, A spring that biases the deployable antenna from the folded state to the deployed state, The antenna comprises a stopper that holds the deployable antenna in the deployed state against the biasing force of the spring, The artificial satellite according to claim 1 or 2.

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