Phased array antenna and calibration method

Abstract

To provide a wire-free phased array antenna that facilitates phase control in communications. [Solution] The phased array antenna comprises a plurality of first flying bodies arranged in an array on the same plane and at least one second flying body, each of which includes a first transceiver unit arranged along the same plane and a first adjustment mechanism that adjusts the relative position and attitude between the flying bodies, and the second flying body includes a second adjustment mechanism that adjusts the relative position and attitude between the flying bodies and is arranged along the arrangement of the first adjustment mechanisms of each of the plurality of first flying bodies, and a first communication unit that is spaced a predetermined distance from the second adjustment mechanism in a direction intersecting the same plane on the side of the first transceivers of the plurality of first flying bodies and has a fixed relative position with respect to the second adjustment mechanism, and which communicates with the first transceiver unit of at least one of the plurality of first flying bodies.

Description

[Technical Field]

[0001] The present invention relates to a phased array antenna and a calibration method. [Background technology]

[0002] It has been proposed to deploy a large number of small satellites in space, fly them in formation, and have these small satellites communicate wirelessly with each other, thereby functioning as a wire-free phased array antenna. For example, Patent Document 1 describes that a plurality of small satellites constitute a phased array antenna system, which relays communications between communication devices on the ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7416468 Summary of the Invention [Problem to be solved by the invention]

[0004] Even with such unconnected array antennas using small satellites, calibration and signal synthesis are required, just like with conventional wired array antennas.

[0005] However, in the unconnected array antenna disclosed in Patent Document 1, the antenna elements are not physically connected, and the relative positions of the antenna elements are not fixed due to disturbances on orbit, etc., which makes phase control in communication between each antenna element and other satellites that perform control, etc. complicated. Therefore, there is a problem in that it is difficult to simultaneously transmit signals from the controlling satellite to each antenna element and simultaneously receive signals from each antenna element.

[0006] Therefore, one object of the present disclosure is to provide a wire-free phased array antenna that allows easy phase control in communication. [Means for solving the problem]

[0007] A phased array antenna in one embodiment of the present disclosure comprises a plurality of first flying bodies arranged in an array on the same plane and at least one second flying body, each of which includes a first transceiver unit arranged along the same plane and a first adjustment mechanism that adjusts the relative position and attitude between the flying bodies, and the second flying body includes a second adjustment mechanism that adjusts the relative position and attitude between the flying bodies and is arranged along the arrangement of the first adjustment mechanisms of each of the plurality of first flying bodies, and a first communication unit that is spaced a predetermined distance from the second adjustment mechanism in a direction intersecting the same plane on the side of the first transceivers of the plurality of first flying bodies and has a fixed position relative to the second adjustment mechanism, and that communicates with the first transceiver unit of at least one of the plurality of first flying bodies. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a wire-free phased array antenna that facilitates phase control in communication. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a conceptual diagram for explaining an overview of a phased array antenna according to an embodiment of the present invention. [Figure 2] FIG. 1 is a plan view of a phased array antenna according to an embodiment of the present invention. [Figure 3] FIG. 1 is a schematic diagram of an array element satellite according to the present embodiment. [Figure 4] FIG. 1 is a block diagram showing the configuration of an array element satellite according to the present embodiment. [Figure 5] FIG. 2 is a schematic diagram of a control satellite according to the present embodiment. [Figure 6] FIG. 2 is a block diagram showing the configuration of a control satellite according to the present embodiment. [Figure 7] FIG. 10 is a sequence diagram illustrating a calibration process. DETAILED DESCRIPTION OF THE INVENTION

[0010] The configuration of a phased array antenna in this embodiment will be described with reference to Figures 1 to 6. Hereinafter, the drawings of the embodiment are merely examples, and the dimensions and shapes of each part are schematic, so the technical scope of the present invention should not be interpreted as being limited to this embodiment.

[0011] For convenience, each drawing may be accompanied by an orthogonal coordinate system consisting of an X-axis, a Y-axis, and a Z-axis. The directions parallel to the X-axis, Y-axis, and Z-axis are referred to as the X-axis, Y-axis, and Z-axis directions, respectively. The plane defined by the X-axis and Y-axis is referred to as the XY plane. For convenience, the positive direction of the Z-axis (the direction of the arrow) will be referred to as the sky side and up or upward, and the negative direction of the Z-axis (the direction opposite to the arrow) will be referred to as the ground side and down or downward.

[0012] (1) Overview of Phased Array Antenna 1 Fig. 1 is a conceptual diagram for explaining an overview of a phased array antenna 1 according to this embodiment. Fig. 2 is a plan view of the phased array antenna 1 according to this embodiment. The phased array antenna 1 includes a plurality of array element satellites 110 (an example of a first flying vehicle) and at least one control satellite 200 (an example of a second flying vehicle).

[0013] The multiple array element satellites 110 included in the phased array antenna 1 are arranged along the XY plane. At least some of the array element satellites 110 may be arranged in an array. The arrangement of the array element satellites 110 is not particularly limited, and may be, for example, linear, planar, lattice, or concentric circular. The control satellite 200 may be arranged in an array together with at least some of the array element satellites 110 included in the phased array antenna 1.

[0014] In this embodiment, a microsatellite is used as the array element satellite 110. The array element satellite 110 and the control satellite 200 may be collectively referred to as "satellite 100." For example, the size of one satellite 100 is several centimeters to several tens of centimeters. The total number N of satellites 100 constituting the phased array antenna 1 is not particularly limited. The total number N of satellites 100 may be several hundred, several thousand, or even tens of thousands or more. The distance between adjacent satellites 100 is, for example, several centimeters to several tens of centimeters. The distance between adjacent satellites 100 may be on the order of a wavelength or may be shorter than a wavelength (e.g., assumed frequency band = 0.8 GHz to 60 GHz). The altitude of each satellite 100 is, for example, several hundred kilometers to several thousand kilometers.

[0015] The multiple satellites 100 included in the phased array antenna 1 may fly on a predetermined circular orbit, thereby performing a formation flight (flying in formation) in a general circular orbit (GCO) or a record disc orbit. In the formation flight, the satellites 100 constituting the phased array antenna 1 may fly so that the arrangement of the satellites 100 rotates on an imaginary plane (plane of rotation) without changing their relative positions to each other.

[0016] At least some of the satellites 100 included in the phased array antenna 1 may constitute a receiving phased array antenna and receive signals transmitted from a transmitter. Furthermore, at least some of the satellites 100 included in the phased array antenna 1 may constitute a transmitting phased array antenna and transmit signals to a receiver. The phased array antenna 1 may relay communications between the transmitter and the receiver. That is, the transmitting phased array antenna may generate a signal based on a signal generated by the receiving phased array antenna receiving a signal from the transmitter, and transmit the signal to the receiver. Note that the phased array antenna 1 may include multiple receiving phased array antennas and / or multiple transmitting phased array antennas that may be formed by multiple satellites 100. These multiple receiving phased array antennas and / or multiple transmitting phased array antennas may each individually communicate with a ground station (a transmitter and / or a receiver grounded on the ground).

[0017] The transmitter and receiver are not particularly limited. For example, the transmitter and receiver may be mobile stations such as smartphones. In this case, at least some of the satellites 100 of the phased array antenna 1 may form a service link with the mobile stations (transmitters and / or receivers). Furthermore, for example, the transmitter and receiver may be base stations. In this case, at least some of the satellites 100 of the phased array antenna 1 may form a feeder link with the base station (transmitter and / or receivers). The transmitter and receiver may be integrated into one device.

[0018] (1-1) Array Element Satellite 110 The configuration of the array element satellite 110 will be described with reference to Figures 2 to 4. Figure 3 is a schematic diagram of the array element satellite 110 according to this embodiment. Figure 4 is a block diagram showing the configuration of the array element satellite 110 according to this embodiment. The array element satellite 110 comprises an adjustment mechanism 111, an antenna 112 (an example of a first transceiver), an antenna 113 (an example of a second transceiver), a transceiver circuit 115, and a control device 120. In this embodiment, the array element satellite 110 has a rectangular shape, but is not limited to this and may be spherical or cylindrical.

[0019] The adjustment mechanism 111 is a mechanism for adjusting the position and attitude of the array element satellite 110. The relative position and attitude of each array element satellite and the control satellite 200 are adjusted by the adjustment mechanism 111. In the case of a micro-array element satellite 110 that performs formation flight, the adjustment mechanism 111 may include an electromagnet. The electromagnet can adjust the relative positions of nearby satellites 100 using magnetic force, thereby maintaining a desired array shape. In this case, it is desirable that adjacent array element satellites 110 be positioned within a range where the magnetic fields of the electromagnets can influence each other. The magnetic field generated by the electromagnet acts on the adjustment mechanism 111 of the nearest array element satellite 110 but has almost no effect on satellites 100 positioned further away. This makes it possible to adjust the relative position and attitude of adjacent array element satellites 110. As described above, using an electromagnet for the adjustment mechanism 111 enables wireless coupling between satellites 100 with a simple configuration. This contributes to reducing the size, weight, and cost of the phased array antenna 1. The adjustment mechanism 111 is not limited to one that uses a driving force from an electromagnet, and may be, for example, a thruster or a propeller. In the embodiment illustrated in Fig. 3, one adjustment mechanism 111 is provided on each of four opposing faces in the X-axis direction and the Y-axis direction of the array element satellite 110, but this is not limiting. For example, multiple adjustment mechanisms 111 may be provided on one face, or an adjustment mechanism 111 may be provided on a face opposing the Z-axis direction, which is the up-down direction.

[0020] Antenna 112 and antenna 113 receive radio waves (an example of a signal) transmitted from a transmission source including control satellite 200, and output the radio waves to transmission / reception circuit 115. In addition, the radio waves generated by transmission / reception circuit 115 are output to the outside via antenna 112 and antenna 113.

[0021] The antenna 112 is provided on one surface of the array element satellite 110. The antennas 112 of the multiple array element satellites 110 are arranged along the same plane to form one large antenna surface. In this embodiment, as shown in Fig. 2, the antenna 112 is provided on one surface on the sky side / positive Z-axis direction side of each array element satellite 110, forming an antenna surface 300A on the XY plane. The directivity of the antenna surface 300A is determined by the excitation weight of each antenna 112.

[0022] The antenna 113 is provided on the surface of the array element satellite 110 opposite to the surface on which the antenna 112 is provided. In other words, the antennas 112 and 113 are located on opposite sides of the array element satellite 110. The antennas 113 of the multiple array element satellites 110 are arranged along the same plane to form one large antenna surface. In this embodiment, the antenna 113 is provided on one surface on the ground side / negative Z-axis direction side of each array element satellite 110, and forms an antenna surface 300B on the XY plane as shown in FIG. 2. In this way, the antenna surface 300B formed on the ground side receives signals from a transmitting source installed on the ground. The directivity of the antenna surface 300B is determined by the excitation weight of each antenna 113.

[0023] The transmission / reception circuit 115 includes a receiving unit 117, a transmitting unit 118, and a signal processing unit 119. The transmission / reception circuit 115 performs predetermined signal processing on a signal input from the antenna 112 or the antenna 113, and outputs the processed signal to the antenna 112 or the antenna 113.

[0024] The receiving unit 117 performs predetermined signal processing on the output signal from the antenna 112 or the antenna 113. The receiving unit 117 may be configured with, for example, a low noise amplifier, and may amplify the output signal from the antenna 112.

[0025] The transmitting unit 118 is configured with a power amplifier or the like, amplifies the output signal from the signal processing unit 119 , and outputs the amplified signal to the antenna 112 or the antenna 113 .

[0026] The signal processing unit 119 may have a function of, for example, performing signal phase shifting, modulation, demodulation, etc. As a result, the signal processing unit 119 controls the phase and amplitude of the signal in the transmission / reception circuit 115 so that the excitation weights of each of the antennas 112 and 113 become desired values. The desired values ​​may be calculated by the control device 120 or the signal processing unit 119, or may be obtained from other devices (other array element satellites 110, the control satellite 200, other satellites 100, a ground device, etc.). The signal processing unit 119 may control the transmission / reception circuit 115 to compensate for, for example, the phase difference between the received signals of each antenna 112 and each antenna 113 among the multiple array element satellites 110. The signal processing unit 119 may perform this control to compensate not only for the phase difference caused by the difference in the positions of the multiple array element satellites 110 but also for the phase difference caused by the variation of each individual array element satellite 110 (including information measured before the launch of the array element satellite 110, etc.). This makes it possible to control the directivity of the antenna surface 300A and the antenna surface 300B in a desired direction.

[0027] Furthermore, for example, as a phase shift process, the phase of the signal may be changed based at least on the distance between the control satellite 200 and the array element satellite 110. This makes it possible to control the directivity of the array element satellite 110 so that it points in the direction of the control satellite 200.

[0028] The control device 120 is a device that controls the overall operation of the array element satellite 110. Specifically, the control device 120 controls the position and attitude of the array element satellite 110 by controlling the adjustment mechanism 111. The control device 120 also controls communications between the array element satellite 110 and other devices (e.g., other array element satellites 110, the control satellite 200, other satellites 100, and ground stations). Furthermore, the control device 120 performs various signal processing and various information processing.

[0029] The control device 120 includes one or more processors 121 (hereinafter simply referred to as "processors 121") and one or more storage devices 122 (hereinafter simply referred to as "storage devices 122"). The processor 121 includes a CPU (Central Processing Unit) and performs various types of information processing. The storage device 122 stores various types of information required for processing by the processor 121. The storage device 122 stores a control program. The control program is a computer program executed by the processor 121, and the functions of the control device 120 are realized by cooperation between the processor 121 and the storage device 122. The control program may be recorded on a computer-readable recording medium.

[0030] (1-2) Control satellite 200 Next, the configuration of the control satellite 200 will be described with reference to Figures 5 and 6. Figure 5 is a schematic diagram of the control satellite 200 according to this embodiment. Figure 6 is a block diagram showing the configuration of the control satellite 200 according to this embodiment. The control satellite 200 has an adjustment unit 203, an antenna 201 (an example of a first communication unit), and an antenna 205 (an example of a second communication unit).

[0031] The adjustment unit 203 incorporates an adjustment mechanism 204 (an example of a second adjustment mechanism) and a control device 207. In this embodiment, the adjustment unit 203 has a rectangular shape, but is not limited to this and may be spherical or cylindrical. Furthermore, the adjustment unit 203 may be a part of the control satellite 200 which is integrally formed into a cylindrical or rectangular shape as a whole.

[0032] The adjustment mechanism 204 is a mechanism for adjusting the position and attitude of the control satellite 200, including the adjustment unit 203. The adjustment mechanism 204 can also adjust the relative position and relative attitude with respect to adjacent array element satellites 110. When the phased array antenna 1 is configured by satellites, as in this embodiment, the adjustment mechanism 204 may include an electromagnet. As shown in FIG. 2 , the adjustment unit 203 and the adjustment mechanism 204 are arranged along the plane on which the adjustment mechanisms 111 of the array element satellites 110 are arranged. The magnetic field generated by the electromagnet acts on the adjustment mechanism 111 of the nearest array element satellite 110, but has almost no effect on the adjustment mechanism 111 and adjustment mechanism 204 located further away. This makes it possible to adjust the relative position and relative attitude between the adjustment unit 203 and adjacent array element satellites 110. This allows fine adjustment of the relative position with respect to the array element satellite 110, thereby assisting in the formation of the array as a whole. That is, the phased array antenna 1 including the control satellite 200 and the array element satellite 110 can be configured without wires. In this case, the adjustment mechanism 204 of the adjustment unit 203 and the adjustment mechanism 111 of the array element satellite 110 do not need to be arranged exactly on the same plane, and may be arranged offset in the Z-axis direction as long as the magnetic fields of the electromagnets can influence each other. As described above, using an electromagnet for the adjustment mechanism 204 enables wireless coupling between the array element satellite 110 and the control satellite 200 to be achieved with a simple configuration. This contributes to reducing the size, weight, and cost of the phased array antenna 1. The adjustment mechanism 204 may be, for example, a thruster or a propeller. In the embodiment illustrated in FIG. 5, four surfaces facing each other in the X-axis and Y-axis directions are provided with one adjustment mechanism 204 each, but this is not limited to this. For example, multiple adjustment mechanisms 204 may be provided on one surface, or additional adjustment mechanisms 204 may be provided in the vertical direction.

[0033] The antenna 201 is a radio wave receiving unit in the control satellite 200 and a transmitting unit for radio waves transmitted from the control satellite 200. The antenna 201 is connected to a transmission / reception circuit 202. Radio waves generated by the transmission / reception circuit 202 are output to the outside via the antenna 201. Radio waves are also input to the transmission / reception circuit 202 from the outside via the antenna 201. The antenna 205 is also a radio wave receiving unit in the control satellite 200 and a transmitting unit for radio waves transmitted from the control satellite 200. The antenna 205 is connected to a transmission / reception circuit 206. Radio waves generated by the transmission / reception circuit 206 are output to the outside via the antenna 205.

[0034] The antennas 112, 113, 201, and 205 can each employ any configuration, such as a patch antenna, a horn antenna, or a dipole antenna, but it is desirable to use a shape that allows easy control of directivity (e.g., an array of patch antennas or an array of slot antennas) in order to achieve high gain as a phased array antenna formed by multiple array element satellites 110. At least some of the antennas 112, 113, 201, and 205 may be configured to be switchable between a receiving signal path and a transmitting signal path by a switch (not shown).

[0035] In this embodiment, the antenna 201 is connected to the adjustment unit 203 by a connecting unit 220 and is disposed a predetermined distance away from the adjustment unit 203 in the Z direction. Furthermore, the antenna 205 is disposed on the opposite side of the adjustment mechanism 204 from the antenna 201 in the Z direction. The antenna 205 is disposed a predetermined distance away from the adjustment unit 203 in the Z direction. The antennas 201 and 205 may be equipped with electromagnets, and their relative positions with the adjustment unit 203 may be maintained constant by magnetic force rather than a connecting unit. In the example shown in FIG. 3 , the antenna 201 is disposed on the sky side / positive side of the Z axis, and the antenna 205 is disposed on the ground side / negative side of the Z axis. Therefore, when communicating with the array element satellite 110, the antenna 201 preferably transmits and receives radio waves to and from the antenna 112 disposed above the array element satellite 110. Furthermore, the antenna 205 preferably transmits and receives radio waves to and from the antenna 113 disposed on the ground side of the array element satellite 110. As described above, the antenna 201 is disposed a predetermined distance from the antenna plane 300A in a direction intersecting with the antenna plane 300A. Furthermore, the antenna 205 is disposed a predetermined distance from the antenna plane 300B in a direction intersecting with the antenna plane 300B. This allows the control satellite 200 to communicate with multiple array element satellites 110 that are disposed on the same plane as the control satellite 200 without signal obstruction. Therefore, the control satellite 200 can broadcast radio waves to multiple array element satellites 110 and aggregate radio waves from multiple array element satellites 110. In this case, the greater the distance between the antenna 201 and the adjustment unit 203 and the antenna 205, the greater the number of array element satellites 110 that the control satellite 200 can communicate with. Furthermore, the distance between the antenna 201 and the adjustment unit 203 and the distance between the antenna 205 and the adjustment unit 203 may be the same or different.

[0036] In this embodiment, antenna 201 and antenna 205 are physically coupled to adjustment unit 203 by connectors 220 and 230, and the relative distance between antenna 201, adjustment unit 203, and antenna 205 is fixed. This allows antenna 201 and antenna 205 to be positioned in areas where a magnetic field does not reach. Therefore, compared to when antenna 201 and antenna 205 are maintained by electromagnets, antenna 201 and antenna 205 can be positioned farther away from adjustment unit 203. In this embodiment, antenna 201 is positioned in the sky and antenna 205 is positioned on the ground, but the up-down orientation may be reversed. Note that the external shape of control satellite 200 is not limited to the example in which rectangular bodies are connected by rod-shaped connectors as shown in FIG. 3, but may have an overall cylindrical, elliptical, or rectangular shape.

[0037] The control device 207 is a device that controls the overall operation of the control satellite 200. Specifically, the control device 207 controls the position and attitude of the control satellite 200 by controlling the adjustment mechanism 204. The control device 207 also controls communications between the control satellite 200 and other devices (e.g., the array element satellite 110, other satellites 100, and ground stations). Furthermore, the control device 207 performs various types of signal processing and various types of information processing.

[0038] The control device 207 includes one or more processors 208 (hereinafter simply referred to as "processor 208") and one or more storage devices 209 (hereinafter simply referred to as "storage device 209"). The processor 208 includes a CPU (Central Processing Unit) and performs various types of information processing. The storage device 209 stores various types of information required for processing by the processor 208. The storage device 209 stores a control program. The control program is a computer program executed by the processor 208, and the functions of the control device 207 are realized by cooperation between the processor 208 and the storage device 209. The control program may be recorded on a computer-readable recording medium.

[0039] (2) Functions of the control satellite 200 Next, we will explain an example of using the control satellite 200 in the phased array antenna 1. As described above, the control satellite 200 is capable of transmitting and receiving signals to and from a plurality of array element satellites 110, and therefore can perform a variety of functions.

[0040] At this time, the transmission / reception circuit 202 of the control satellite 200 may control the phase and amplitude of the signal generated by the transmission / reception circuit 202 so that the excitation weight of the antenna 201 becomes a desired value. Also, for example, the phase of the signal to be generated may be determined based at least on the distance between the antenna 201 and the antenna 112 of the array element satellite 110. This makes it possible to control the directivity of the antenna 201 so that it points toward the direction of the array element satellite 110. Also, the transmission / reception circuit 206 may control the phase and amplitude of the signal to be generated by the transmission / reception circuit 206 so that the excitation weight of the antenna 205 becomes a desired value. Also, for example, the phase of the signal to be generated may be determined based at least on the distance between the antenna 205 and the antenna 113 of the array element satellite 110. This makes it possible to control the directivity of the antenna 205 so that it points toward the direction of the array element satellite 110.

[0041] The distance between the antenna 201 and the antenna 112 of the array element satellite 110, and the distance between the antenna 205 and the antenna 113 of the array element satellite 110 may be calculated based on the relative positional relationship between the antenna 201, the array element satellite 110, and the antenna 205. In this calculation, for example, a ranging sensor (an example of ranging means) may be mounted on the array element satellite 110 or the control satellite 200, and the distance measured using the ranging sensor may be used. Alternatively, the relative positions between the array element satellite 110 and the control satellite 200 may be estimated by transmitting and receiving signals between them and measuring the strength of the signals. Furthermore, in this calculation, information on the absolute positions of the antenna 201, the array element satellite 110, and the antenna 205 may be used. For example, the array element satellite 110 or the control satellite 200 may acquire information on its own position and attitude in an absolute coordinate system using a well-known method. For example, the array element satellite 110 or the control satellite 200 may obtain information about its own position and attitude in an absolute coordinate system by using a camera to capture images of the sun, moon, earth, or stars.

[0042] At this time, it is desirable that the relative position between the adjustment unit 203 and the antenna 201 of the control satellite 200 be fixed by the connector 220. This allows the position of the antenna 201 of the control satellite 200 to be kept constant in a planar view of the antenna plane 300A. Furthermore, the angle of the antenna 201 with respect to the antenna plane 300A can be kept constant. In this way, since the relative position between the adjustment unit 203 and the antenna 201 is fixed by the connector 220, fluctuations in the distance between the adjustment unit 203 and the antenna 201 due to disturbances do not need to be taken into consideration. This makes it easy to grasp the distance and control the phase when controlling the directivity of the antenna 201 based on the distance from the array element satellite 110. The same applies to the antenna 205, the connector 230, and the antenna plane 300B.

[0043] (2-1) Calibration Using the control satellite 200, signal processing errors by each array element satellite 110 can be measured, and calibration can be performed using the measured errors. In conventional wired phased array antennas, calibration is performed to measure and correct phase errors due to array element placement errors and internal circuit variations. In wired phased array antennas, the array elements are physically connected, so calibration of phase errors due to array element placement errors can be performed at the time of manufacture. On the other hand, in unwired phased array antennas such as those of the present invention, the placement of the array element satellites 110 may shift due to disturbances on orbit. Therefore, there is a risk that the error measurement results will become invalid, making it difficult to continue using the calibration results obtained at the time of manufacture. Furthermore, while phase errors can also occur due to deterioration of internal circuits, it is difficult to perform real-time calibration during operation in wired phased array antennas. According to this embodiment, the phased array antenna 1 can be calibrated in real time during operation without using a dedicated calibration ground station or the like.

[0044] The error measurement is performed for two of the processes performed by the transmitter / receiver circuit 115 of the array element satellite 110: path R1, which processes the signal received by antenna 113 and outputs it to antenna 112, and path R2, which is the reverse path, which processes the signal received by antenna 112 and outputs it to antenna 113.

[0045] 2 and 7, the procedure for measuring the error of path R1, which processes a signal received by antenna 113 and outputs it to antenna 112, will be described. Error measurement for path R2 can be performed in almost the same way as error measurement for path R1, with the paths and transmitting and receiving antennas reversed, so a description thereof will be omitted.

[0046] The transmission / reception circuit 206 of the control satellite 200 outputs an adjustment reference signal 31 to the antenna 205. The antenna 205 transmits the adjustment reference signal 31 output from the transmission / reception circuit 206 toward the antenna 113 of the array element satellite 110 to be measured (S1). The antenna 113 outputs the adjustment reference signal 31 to the transmission / reception circuit 115. The transmission / reception circuit 115 performs predetermined signal processing on the adjustment reference signal 31 using the receiver 117, transmitter 118, and signal processor 119 to generate a test signal 32 (S2). The transmission / reception circuit 115 outputs the test signal 32 to the antenna 112. The antenna 112 transmits the input test signal 32 toward the antenna 201 of the control satellite 200 (S3). In this way, by separating the transmission / reception plane of the adjustment reference signal 31 and the transmission / reception plane of the test signal 32 above and below, it becomes easier to avoid a situation in which transmission and reception from the array element satellite 110 are coupled.

[0047] At this time, the storage device 209 of the control satellite 200 acquires adjustment time information t, which is information regarding the transmission time of the adjustment reference signal 31, from the transmission / reception circuit 206. The storage device 209 also stores a reference relative distance L1 between the antenna 205 and the antenna 113, and a reference relative distance L2 between the antenna 112 and the antenna 201. The storage device 209 also stores a reference correction value 33 for each array element satellite 110. The reference correction value 33 may include, for example, the transmission / reception characteristics of each array element satellite 110, the reference relative distances L1 and L2, and the adjustment time information t and wavelength λ of the adjustment reference signal 31. The transmission / reception characteristics may be, for example, errors in the length of the feed lines between each antenna of each array element satellite 110 and the transmission / reception circuit 115, measured during pre-shipment inspection of the phased array antenna 1, or losses due to the radome. The reference relative distances L1 and L2 are the relative distances between the satellites 100 measured during inspection of the phased array antenna 1 before shipping, for example.

[0048] The processor 208 of the control satellite 200 processes the adjustment reference signal 31 using the reference correction value 33 to generate a theoretical signal 34 (S4). The characteristic value of the theoretical signal 34 is the theoretical value when the adjustment reference signal 31 is transmitted from the antenna 205 to the antenna 113 of the array element satellite 110 to be measured, subjected to predetermined processing by the transmission / reception circuit 115, and then transmitted from the antenna 112 to the antenna 201 of the control satellite 200.

[0049] However, in reality, the actual relative distance between each array element satellite 110 and the control satellite 200 may deviate from the reference relative distances L1 and L2 due to disturbances during orbital operation. Furthermore, for example, the actual phase error may differ from the phase correction value calculated by the reference correction value 33 due to aging of the feeder line connecting the transmission / reception circuit 115 and the antennas 112 and 113. Therefore, an error may occur between the phase of the theoretical signal 34 and the phase of the test signal 32. The processor 208 of the control satellite 200 compares the phase of the theoretical signal 34 with the phase of the test signal 32 (S5). By comparing the theoretical signal 34 with the test signal 32, it is possible to measure the phase error occurring in the processing performed on the path R1 of the array element satellite 110 to be measured. From this phase error, it is possible to derive the alignment error and transmission / reception error occurring in the array element satellite 110 to be measured (S6). The processor 208 may also measure the amplitude error and frequency error occurring in the processing performed on the path R1.

[0050] Furthermore, the processor 208 of the control satellite 200 updates the reference correction value 33 based on the measured error. The control satellite 200 transmits the updated reference correction value 33 to the array element satellite 110 to be measured as a calibration signal (S7). The array element satellite 110 receives the updated reference correction value 33 and stores it in the storage device 122. In this way, it is possible to measure the error in the signal processing of the array element satellite 110 and perform calibration that reflects the error in real time.

[0051] Furthermore, since the phased array antenna 1 in this embodiment is unconnected, it is possible to freely adjust the position of each satellite 100. Therefore, by changing the position of the satellite 100 so as to compensate for the measured phase error, it is possible to perform real-time calibration while the phased array antenna 1 is operating in orbit (S8).

[0052] As described above, in the present invention, calibration of the array element satellite 110 can be performed under the same operating conditions (arrangement, attitude, frequency conditions, etc.) as when actually communicating with the ground.

[0053] The phased array antenna 1 may also include multiple control satellites 200, which may transmit adjustment reference radio waves to the array element satellite 110 being measured. Furthermore, the multiple control satellites 200 may be arranged in a mesh pattern at equal intervals on the XY plane. This allows adjustment reference radio waves to be transmitted to the same array element satellite 110 from different angles. This allows for more accurate characteristic evaluation. Furthermore, when the distance between the adjustment unit 203 and the antenna 201 and the distance between the adjustment unit 203 and the antenna 205 are both L, the control satellites 200 may be arranged at equal intervals of L / 2 or less on the XY plane. This allows the adjustment reference radio waves to be irradiated to the array element satellite 110 being measured from all angles that can actually occur, thereby enabling more accurate characteristic evaluation.

[0054] (2-2) Signal synthesis In a conventional wired phased array antenna, each array element receives a signal transmitted from a terrestrial transmitter. At this time, the received signals are phase-aligned and combined in each array element to amplify the weak signal transmitted from the ground. In the present invention, since each array element satellite 110 is not connected by electrical wiring, it is necessary to provide a method for combining signals without wiring.

[0055] In this embodiment, the control satellite 200 can combine signals transmitted from the array element satellites 110 of the phased array antenna 1. Here, a method for combining signals transmitted from the antenna 112 of each array element satellite 110 toward the antenna 201 of the control satellite 200 will be described, but the present invention is not limited to this. For example, signals transmitted from the antenna 113 of each array element satellite 110 toward the antenna 205 of the control satellite 200 can also be combined in a similar manner. When each array element satellite 110 combines signals from a terrestrial transmitter at the control satellite 200, it is desirable for communication to be performed between the antenna 112 and the antenna 201 located in the sky. This makes it possible to avoid coupling of signals transmitted from the ground and signals transmitted from each array element satellite 110 to the control satellite 200.

[0056] Each array element satellite 110 may determine the phase of the signal based at least on the distance between each antenna 112 and antenna 201. In particular, each array element satellite 110 may determine the phase of the signal so as to compensate for the difference in distance between antenna 201 and each of the antennas 112, for example. This makes it possible to control the directivity of antenna plane 300A to face the direction of antenna 201, and to make the signals transmitted from each of the antennas 112 have the same phase. In this case, the transmitted signal may be a signal received from an external device such as a terrestrial receiver that has been subjected to processing such as phase shifting, or may be a signal generated by each array element satellite 110.

[0057] Furthermore, the signals from each array element satellite 110 transmit information by amplitude modulation. As a result, the signals from each array element satellite 110 are combined in space before reaching the control satellite 200. This allows the antenna 201 of the control satellite 200 to receive a signal that is a combination of the signals from each array element satellite 110, and even with an unconnected phased array antenna, the signals transmitted by each array element satellite 110 can be combined.

[0058] (2-3) Signal transmission The control satellite 200 can broadcast a signal to each array element satellite 110 to be transmitted by each array element satellite 110. Based on the signal broadcast from the control satellite 200, each array element satellite 110 transmits a signal to a target receiver.

[0059] At this time, the control satellite 200 generates modulated radio waves by modulating a reference frequency signal, which is baseband information, and broadcasts them to each array element satellite 110. This has the advantage that synchronization of the timing of modulated wave transmission is not required, compared to when the reference frequency signal is broadcast from the control satellite 200 and then modulated radio waves are generated by each array element satellite 110. In addition, a local oscillator for each array element satellite 110 is also not required.

[0060] Each array element satellite 110 shifts the phase of the modulated radio wave based at least on the distance between the antenna of the control satellite 200 that transmitted the modulated radio wave and the antenna of the array element satellite 110 that received the modulated radio wave. This makes it possible to align the phase of the received modulated radio wave among all the array element satellites 110. Furthermore, each array element satellite 110 shifts the phase of the modulated radio wave based at least on the distance between the antenna of the array element satellite 110 that transmits the modulated radio wave and the receiver.

[0061] (4) Variations A description will be given of a modified example of the phased array antenna 1. In this modified example, light (visible light or laser) is used for signal communication between the antennas 113 of the multiple array element satellites 110 and the antenna 205 of the control satellite 200, rather than radio waves.

[0062] In the phased array antenna 1 according to this modification, the array element satellite 110 can be equipped with a light-emitting / receiving unit 153 (such as an LED for LiFi or a laser diode) instead of the conventional antenna 113. This allows the array element satellite 110 to communicate with the control satellite 200 using optical signals. The control satellite 200 is equipped with a light-emitting / receiving unit 255 instead of the antenna 205, thereby accurately receiving optical signals from the array element satellite 110.

[0063] In this modification, the use of optical communication increases the speed of signal transmission and reception by the phased array antenna 1. Optical signals have a higher frequency than radio waves and can transmit more data, making it possible to significantly improve overall communication capacity. In addition, the use of highly directional laser communication reduces unnecessary interference that occurs in radio wave communication, enabling more stable data transmission.

[0064] In this way, this modification utilizes optical communication technology, making it possible to provide a communication environment that is faster and less prone to interference than conventional radio wave communication.

[0065] (5) Other In the above-described embodiment, the phased array antenna 1 is configured to include a satellite 100 as an example of an air vehicle. However, the phased array antenna 1 is not limited to the satellite 100 flying in outer space, and may be configured by any air vehicle (such as an airplane or a drone) flying within the atmosphere.

[0066] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those illustrated and can be modified as appropriate. Furthermore, configurations shown in different embodiments can be partially substituted or combined with each other.

[0067] (Appendix 1) a plurality of first flying bodies arranged in an array on the same plane; at least one second vehicle; Equipped with Each of the plurality of first aircraft is a first transceiver disposed along the same plane; a first adjustment mechanism that adjusts the relative positions and attitudes of the aircraft; Including, The second aircraft a second adjustment mechanism that adjusts the relative positions and attitudes between the aircraft and is arranged along the arrangement of the first adjustment mechanisms of each of the multiple first aircraft; a first communication unit located on the side of the first transceiver units of the first flying bodies, spaced a predetermined distance from the second adjustment mechanism in a direction intersecting the same plane, and whose relative position with the second adjustment mechanism is fixed, and which communicates with the first transceiver unit of at least one of the first flying bodies among the first flying bodies; Including, Phased array antenna.

[0068] (Appendix 2) The plurality of first flying vehicles further including a second transceiver located on the opposite side of the first transceiver; The second aircraft The second communication unit is located at a predetermined distance from the second adjustment mechanism in a direction intersecting the same plane on the side of the second transceiver units of the first flying bodies, and has a fixed relative position with respect to the second adjustment mechanism, and further includes a second communication unit that communicates with the second transceiver units of at least one of the first flying bodies among the first flying bodies. 1. A phased array antenna as defined in claim 1.

[0069] (Appendix 3) the first transmitting / receiving units in the first aircraft constitute a first transmitting / receiving surface facing the first communication unit; The second transceivers in the first aircraft constitute second transceiver surfaces facing the second communication unit. 1. The phased array antenna of claim 2 or 3.

[0070] (Appendix 4) One of the first transmitting / receiving surface and the second transmitting / receiving surface is located facing the ground. 1. A phased array antenna as described in Appendix 3.

[0071] (Appendix 5) the at least one second flying vehicle is a plurality of second flying vehicles; The second adjustment mechanisms of the second aircraft are arranged so that they are spaced equally apart in a direction along the same plane. 5. The phased array antenna of any one of Supplementary Note 1 to Supplementary Note 4.

[0072] (Appendix 6) The distance between the second adjustment mechanisms of the plurality of second aircraft is equal to or less than half the distance between the first communication unit and the same plane. 6. The phased array antenna of claim 5.

[0073] (Appendix 7) The second flying vehicle has a distance measuring means. 10. The phased array antenna of claim 1 through claim 6.

[0074] (Appendix 8) The first and second aircraft communicate via radio waves. 8. The phased array antenna of any one of Supplementary Notes 1 to 7.

[0075] (Appendix 9) The first and second aircraft communicate with each other using optical signals. 8. The phased array antenna of any one of Supplementary Notes 1 to 7.

[0076] (Appendix 10) At least one first flying object of the plurality of first flying objects, further including a transceiver circuit for inputting and outputting signals via the first transceiver and the second transceiver; The second aircraft further comprising error measurement means for measuring a phase error of the signal for at least one first flying vehicle; the second flying object transmits a calibration reference signal to the at least one first flying object; At least one first flying object transmits a test signal generated based on the adjustment reference signal to a second flying object; the error measuring means measures a positioning error of the first flying object and an error of the transmitting / receiving circuit based on the test signal received from at least one first flying object; 10. The phased array antenna of any one of Supplementary Notes 2 to 9.

[0077] (Appendix 11) the second flying object performs calibration with respect to the at least one first flying object based on the error measured by the error measuring means; 11. The phased array antenna of claim 10.

[0078] (Appendix 12) the second aircraft transmits an adjustment reference signal from one of the first communication unit and the second communication unit, and receives a test signal from the other of the first communication unit and the second communication unit; 12. The phased array antenna of claim 10 or 11.

[0079] (Appendix 13) a plurality of first flying bodies arranged in an array on the same plane; at least one second vehicle; A method for calibrating a phased array antenna, comprising: The second flying object transmits an adjustment reference signal to at least one first flying object of the plurality of first flying objects; transmitting a test signal generated by at least one first air vehicle based on the calibration reference signal to a second air vehicle; measuring a position error and a transceiver circuit error of the first air vehicle based on the test signal received by the second air vehicle from at least one first air vehicle; the second flight vehicle calibrating the at least one first flight vehicle based on the measured error; A calibration method including: [Explanation of symbols]

[0080] 1...phased array antenna, 110...array element satellite, 200...control satellite, 100...satellite, 111...adjustment mechanism, 112...antenna, 113...antenna, 115...transmitting / receiving circuit, 120...control device, 300A, 300B...antenna surface, 117...receiving unit, 118...transmitting unit, 119...signal processing unit, 121...processor, 122...storage device, 201...antenna, 203...adjustment unit, 205...antenna, 204...adjustment mechanism, 207...control device, 202...transmitting / receiving circuit, 206...transmitting / receiving circuit, 208...processor, 209...storage device, 31...reference signal for adjustment, 32...test signal, 33...reference correction value, 153...light-emitting / receiving unit, 255...light-emitting / receiving unit, L1, L2...reference relative distance

Claims

1. a plurality of first flying bodies arranged in an array on the same plane; at least one second air vehicle; Equipped with Each of the plurality of first flying bodies is a first transceiver disposed along the same plane; a second transceiver located on the opposite side of the first transceiver; a first adjustment mechanism that adjusts the relative positions and attitudes of the aircraft; Including, The second flying vehicle, a second adjustment mechanism that adjusts the relative positions and attitudes between the flying bodies and is arranged along the arrangement of the first adjustment mechanisms of each of the plurality of first flying bodies; a first communication unit located on the side of the first transceiver unit of the plurality of first flying bodies, spaced a predetermined distance from the second adjustment mechanism in a direction intersecting the same plane, and whose relative position with respect to the second adjustment mechanism is fixed, the first communication unit wirelessly communicating with the first transceiver unit of at least one first flying body among the plurality of first flying bodies; a second communication unit located on the second transceiver side of the plurality of first flying bodies, spaced a predetermined distance from the second adjustment mechanism in a direction intersecting the same plane, and whose relative position with respect to the second adjustment mechanism is fixed, the second communication unit wirelessly communicating with the second transceiver of at least one first flying body among the plurality of first flying bodies; Including, Phased array antenna.

2. The first transceivers in the first aircraft constitute a first transceiver surface facing the first communication unit, The second transceivers in the first aircraft constitute a second transceiver surface facing the second communication unit.

10. The phased array antenna according to claim 1.

3. One of the first transmitting / receiving surface and the second transmitting / receiving surface is positioned facing the ground.

3. The phased array antenna according to claim 2.

4. the at least one second flying vehicle is a plurality of second flying vehicles; The second adjustment mechanisms of the plurality of second flying bodies are arranged so that they are equally spaced apart in a direction along the same plane.

10. The phased array antenna according to claim 1.

5. The distance between the second adjustment mechanisms of the plurality of second flying bodies is equal to or less than half the distance between the first communication unit and the same plane.

5. The phased array antenna according to claim 4.

6. The second aircraft has a distance measuring means.

10. The phased array antenna according to claim 1.

7. The first flying body and the second flying body communicate with each other via radio waves.

10. The phased array antenna according to claim 1.

8. The first flying body and the second flying body communicate with each other using optical signals.

10. The phased array antenna according to claim 1.

9. The second flying vehicle, further comprising error measurement means for measuring an error relating to the at least one first flying vehicle; the second flying vehicle transmits a reference signal for adjustment to the at least one first flying vehicle; The at least one first flying vehicle transmits a test signal generated based on the adjustment reference signal to the second flying vehicle; the error measurement means measures an error related to the at least one first flying vehicle based on the test signal received from the at least one first flying vehicle; the error related to the at least one first flying vehicle is an error in at least one of a phase, an amplitude, and a frequency of the test signal relative to a reference value based on the adjustment reference signal; 10. The phased array antenna according to claim 1.

10. The second flying vehicle performs calibration for the at least one first flying vehicle based on the error measured by the error measuring means. The phased array antenna according to claim 9.

11. The second aircraft transmits the adjustment reference signal from one of the first communication unit and the second communication unit, and receives the test signal from the other of the first communication unit and the second communication unit.

11. The phased array antenna according to claim 9 or 10.

12. a plurality of first flying bodies arranged in an array on the same plane; at least one second air vehicle; A method for calibrating a phased array antenna, comprising: The second air vehicle transmits an adjustment reference signal to at least one first air vehicle of the plurality of first air vehicles; transmitting a test signal generated by the at least one first air vehicle based on the adjustment reference signal to the second air vehicle; measuring an error associated with the at least one first air vehicle based on the test signal received by the second air vehicle from the at least one first air vehicle; the second air vehicle calibrating the at least one first air vehicle based on the measured error; Including, the error related to the at least one first flying vehicle is an error in at least one of a phase, an amplitude, and a frequency of the test signal relative to a reference value based on the adjustment reference signal; Calibration method.

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