Transmitting phased array antenna system

Abstract

To improve the quality of communications in a phased array antenna system consisting of multiple satellites. [Solution] A transmitting phased array antenna system comprising a plurality of first flying bodies arranged in an array and a second flying body, wherein the second flying body comprises a modulation means for performing a modulation process to modulate a reference frequency signal with a predetermined signal, and a first transmission means for outputting a first transmission signal to each of the plurality of first flying bodies based on the output from the modulation means, and each first flying body comprises a first receiving means for receiving the first transmission signal transmitted from the second flying body, a demodulation means for performing a demodulation process corresponding to the modulation process on a first received signal generated based on the reception of the first transmission signal by the first receiving means, a phase shifting means for changing the phase of the output from the demodulation means based at least on the distance between the second flying body and the first flying body and the distance between the first flying body and a receiver, and a second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shifting means.

Description

[Technical Field]

[0001] The present disclosure relates to a transmitting phased array antenna system. [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] However, the small satellites that make up the phased array antenna system described above not only receive signals from ground-based equipment, but also receive and transmit signals between satellites, and it is desirable to prevent interference and crosstalk between these signals.

[0005] One object of the present disclosure is to improve the quality of communications in a phased array antenna system consisting of multiple satellites. [Means for solving the problem]

[0006] The transmitting phased array antenna system of the present disclosure is a transmitting phased array antenna system comprising a plurality of first flying bodies arranged in an array and a second flying body, wherein the second flying body comprises a modulation means for performing a modulation process to modulate a reference frequency signal with a predetermined signal, and a first transmitting means for outputting a first transmission signal to each of the plurality of first flying bodies based on the output from the modulation means, and each of the plurality of first flying bodies comprises a first receiving means for receiving the first transmission signal transmitted from the second flying body, a demodulation means for performing a demodulation process corresponding to the modulation process on a first received signal generated based on the reception of the first transmission signal by the first receiving means, a phase shifting means for changing the phase of the output from the demodulation means based at least on the distance between the second flying body and the first flying body and the distance between the first flying body and a receiver, and a second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shifting means. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to improve the quality of communication in a phased array antenna system configured with multiple satellites. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a conceptual diagram showing a schematic configuration of a satellite communication system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram illustrating an example of a functional configuration of a phased array antenna system. [Figure 3] FIG. 1 is a diagram illustrating the configuration of a receiving phased array antenna system. [Figure 4] FIG. 1 is a diagram illustrating a configuration of a transmitting phased array antenna system. [Figure 5] FIG. 1 is a diagram illustrating a first modified example of a phased array antenna system. [Figure 6] FIG. 10 is a diagram illustrating a second modified example of the phased array antenna system. [Figure 7]FIG. 10 is a diagram illustrating a third modified example of the phased array antenna system. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0010] (1) Overview of Satellite Communications System 1 1 is a conceptual diagram for explaining an overview of a satellite communication system 1 according to this embodiment. The satellite communication system 1 includes a phased array antenna system 2, a transmitter 3, and a receiver 4.

[0011] The phased array antenna system 2 includes a plurality of array element satellites 10 and at least one transmitting / receiving satellite 20. At least some of the plurality of array element satellites 10 included in the phased array antenna system 2 are arranged in an array. The arrangement of the array element satellites 10 is not particularly limited, and may be, for example, a linear, planar, lattice, or concentric arrangement. The transmitting / receiving satellite 20 may be arranged in an array together with at least some of the array element satellites 10 included in the phased array antenna system 2.

[0012] In this embodiment, microsatellites are used as the array element satellite 10 and / or the transmitting and receiving satellite 20. The array element satellite 10 and the transmitting and receiving satellite 20 may be collectively referred to as "satellites 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 system 2 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 wavelength or may be shorter than the 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.

[0013] The multiple satellites 100 included in the phased array antenna system 2 may fly on a predetermined circular orbit, thereby performing a formation flight (flying in formation) flying on a GCO (General Circular Orbit) or a record disc orbit. In the formation flight, the satellites 100 constituting the phased array antenna system 2 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.

[0014] At least some of the satellites 100 included in the phased array antenna system 2 may constitute a receiving phased array antenna system 2R (FIG. 3) and receive a transmission signal transmitted from the transmitter 3. At least some of the satellites 100 included in the phased array antenna system 2 may constitute a transmitting phased array antenna system 2S (FIG. 4) and transmit a transmission signal to the receiver 4. The phased array antenna system 2 may relay communication between the transmitter 3 and the receiver 4. That is, the transmitting phased array antenna system 2S may generate a transmission signal based on a signal generated by the receiving phased array antenna system 2R receiving the transmission signal from the transmitter 3, and transmit the generated transmission signal to the receiver 4. The phased array antenna system 2 may include a plurality of receiving phased array antenna systems 2R and / or a plurality of transmitting phased array antenna systems 2S, which may be constituted by a plurality of satellites 100. Each of the plurality of receiving phased array antenna systems 2R and / or the plurality of transmitting phased array antenna systems 2S may individually communicate with a ground station (the transmitter 3 and / or the receiver 4).

[0015] The transmitter 3 and the receiver 4 are not particularly limited. For example, the transmitter 3 and the receiver 4 may be mobile stations such as smartphones. In this case, at least some of the satellites 100 of the phased array antenna system 2 may form a service link with the mobile stations (the transmitter 3 and / or the receiver 4). Furthermore, for example, the transmitter 3 and the receiver 4 may be base stations. In this case, at least some of the satellites 100 of the phased array antenna system 2 may form a feeder link or a service link with the base station (the transmitter 3 and / or the receiver 4). The transmitter 3 and the receiver 4 may be provided together in one device.

[0016] (2) Configuration of Phased Array Antenna System 2 Fig. 2 is a block diagram showing an example of the functional configuration of a phased array antenna system 2 included in the satellite communication system 1. The phased array antenna system 2 includes a plurality of array element satellites 10 and a transmitting / receiving satellite 20. In the example of Fig. 2, the phased array antenna system 2 has a function as a receiving phased array antenna system 2R and a function as a transmitting phased array antenna system 2S. In the present disclosure, when distinguishing between individual array element satellites 10 or the configurations included in individual array element satellites 10, symbols such as "A" and "B" may be used.

[0017] (2-1) Array Element Satellite 10 The array element satellite 10 includes a receiving module 110 , an antenna 111 , an antenna 112 , a transmitting module 120 , an antenna 121 , an antenna 122 , a control device 130 , and an attitude control device 140 .

[0018] The antenna 111 receives a transmission signal (radio wave) transmitted from the transmitter 3 to generate a reception signal, which is then output to the reception module 110. Under the control of the control device 130, the reception module 110 performs predetermined signal processing, which will be described later, on the output signal from the antenna 111, and outputs the processed signal to the antenna 112. The antenna 112 transmits the transmission signal toward the transmission / reception satellite 20 based on the output signal from the reception module 110.

[0019] The antenna 121 generates a received signal by receiving a transmission signal (radio wave) transmitted from the transmitting / receiving satellite 20, and outputs the received signal to the transmitting module 120. Under the control of the control device 130, the transmitting module 120 performs predetermined signal processing on the output signal from the antenna 121, and outputs the processed signal to the antenna 122. The antenna 122 transmits the transmission signal to the receiver 4 based on the output signal from the transmitting module 120.

[0020] The antennas 111, 112, 121, and 122 can each be of any configuration, such as a patch antenna, a horn antenna, or a dipole antenna, but it is desirable to use a shape that makes it easy to control the 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 10. At least some of the antennas 111, 112, 121, and 122 may be configured as a single antenna that is physically or functionally integrated, and may be configured so that a switch (not shown) can switch between the signal path of the receiving phased array antenna system 2R and the signal path of the transmitting phased array antenna system 2S.

[0021] The control device 130 is a device that controls the overall operation of the array element satellite 10. Specifically, the control device 130 controls the position and attitude of the array element satellite 10 by controlling the attitude control device 140. The control device 130 also controls communications between the array element satellite 10 and other devices (e.g., other array element satellites 10, transmitting / receiving satellites 20, other satellites 100, and ground stations). Furthermore, the control device 130 performs various signal processing and various information processing.

[0022] The control device 130 includes one or more processors 131 (hereinafter simply referred to as "processors 131") and one or more storage devices 132 (hereinafter simply referred to as "storage devices 132"). The processor 131 includes a CPU (Central Processing Unit) and performs various types of information processing. The storage device 132 stores various types of information required for processing by the processor 131. The storage device 132 stores a control program. The control program is a computer program executed by the processor 131, and the functions of the control device 130 are realized by cooperation between the processor 131 and the storage device 132. The control program may be recorded on a computer-readable recording medium.

[0023] The attitude control device 140 is a mechanism for adjusting the position and attitude of the array element satellite 10. In the case of a micro-array element satellite 10 that performs formation flight, the attitude control device 140 may include an electromagnet 141. The electromagnet 141 adjusts the relative positions of adjacent satellites 100 using magnetic force, enabling control to maintain a desired array shape.

[0024] (2-2) Transmitting and receiving satellite 20 The transmitting / receiving satellite 20 includes a receiving module 210 , an antenna 211 , a transmitting module 220 , an antenna 221 , a control device 230 , and an attitude control device 240 .

[0025] The antenna 211 generates a received signal by receiving a transmission signal transmitted from each of the plurality of array element satellites 10, and outputs the received signal to the receiving module 210. Under the control of the control device 230, the receiving module 210 performs predetermined signal processing on the received signal generated by the antenna 211 receiving the transmission signals (radio waves) transmitted from the plurality of array element satellites 10. The content of the signal processing performed by the receiving module 210 is not particularly limited, and may include, for example, demodulation processing corresponding to modulation processing performed by the transmitter 3 or the like. For example, when the phased array antenna system 2 relays communication between the transmitter 3 and the receiver 4, the receiving module 210 may output the signal that has undergone signal processing to the transmitting module 220.

[0026] The transmitting module 220 performs predetermined signal processing on a predetermined signal under the control of the control device 230. The transmitting module 210 outputs the processed signal to the antenna 221. The antenna 221 transmits the transmission signal toward each of the multiple array element satellites 10 based on the output signal from the transmitting module 220.

[0027] The antennas 211 and 221 may each adopt any configuration such as a patch antenna, a horn antenna, or a dipole antenna, but may also have a shape that makes it easy to control the directivity (for example, an array of patch antennas or an array of slot antennas).The antennas 211 and 221 may be configured as a single antenna that is physically or functionally integrated, and may be configured so that a switch (not shown) can switch between the signal path of the receiving phased array antenna system 2R and the signal path of the transmitting phased array antenna system 2S.

[0028] The control device 230 controls the transmitting / receiving satellite 20. Specifically, the control device 230 controls the position and attitude of the transmitting / receiving satellite 20 by controlling the attitude control device 240. The control device 230 also controls communications between the transmitting / receiving satellite 20 and other devices (such as the array element satellite 10 and a ground station). Furthermore, the control device 230 performs various types of signal processing and various types of information processing.

[0029] The control device 230 includes one or more processors 231 (hereinafter simply referred to as "processor 231") and one or more storage devices 232 (hereinafter simply referred to as "storage device 232"). The processor 231 includes a CPU and the like, and performs various types of information processing. The storage device 232 stores various types of information required for processing by the processor 231. The storage device 232 stores a control program. The control program is a computer program executed by the processor 231, and the functions of the control device 230 are realized by cooperation between the processor 231 and the storage device 232. The control program may be recorded on a computer-readable recording medium.

[0030] The attitude control device 240 is a mechanism for adjusting the position and attitude of the transmitting / receiving satellite 20. In the case of a micro-satellite 20 that performs formation flight, the attitude control device 240 may include an electromagnet 241. This allows for fine adjustment of the relative position with the array element satellite 10, and assists in the formation of the array as a whole.

[0031] (3) Functions of Phased Array Antenna System 2 (3-1) Receiving phased array antenna system 2R 3 is a diagram illustrating a receiving phased array antenna system 2R. The receiving phased array antenna system 2R includes, for example, a receiving module 110, an antenna 111, and an antenna 112 provided in a plurality of array element satellites 10, and a receiving module 210 and an antenna 211 provided in a transmitting / receiving satellite 20.

[0032] The antennas 111 provided on the multiple array element satellites 10 are arranged in an array to form a phased array antenna 11. The directivity of the phased array antenna 11 is determined by the excitation weight of each antenna 111. The excitation weight of each antenna 111 is determined by signal processing in the receiving module 110. The control device 130 provided in each array element satellite 10 controls the phase and amplitude of the signal in the receiving module 110 so that the excitation weight of each antenna 111 becomes a desired value. The desired value may be calculated by the control device 130 or may be obtained from another device (another array element satellite 10, a transmitting / receiving satellite 20, another satellite 100, a ground device, etc.). The control device 130 may, for example, control the receiving module 110 so as to compensate for a phase difference in the received signals of each antenna 111 among the multiple array element satellites 10. The control device 130 may perform this control to compensate for not only the phase difference caused by the difference in the positions of the multiple array element satellites 10 but also the phase difference caused by the variance of each individual array element satellite 10 (including information measured before the launch of the array element satellite 10, etc.). This makes it possible to control the directivity of the phased array antenna 11 in the direction of the transmitter 3.

[0033] The antennas 112 provided on the multiple array element satellites 10 are arranged in an array to form a phased array antenna 12. The directivity of the phased array antenna 12 is determined by the excitation weight of each antenna 112. The excitation weight of each antenna 112 is determined by signal processing in the receiving module 110. The control device 130 provided in each array element satellite 10 controls the phase and amplitude of the signal in the receiving module 110 so that the excitation weight of each antenna 112 becomes a desired value. The desired value may be calculated by the control device 130 or may be obtained from another device (another array element satellite 10, a transmitting / receiving satellite 20, another satellite 100, a ground device, etc.). The control device 130 may, for example, control the receiving module 110 so as to compensate for a phase difference in the received signals of each antenna 112 among the multiple array element satellites 10. The control device 130 may perform this control to compensate for not only the phase difference caused by the difference in the positions of the multiple array element satellites 10 but also the phase difference caused by the variance of each individual array element satellite 10 (including information measured before the launch of the array element satellite 10, etc.). This makes it possible to control the directivity of the phased array antenna 12 in the direction of the transmitting / receiving satellite 20.

[0034] The receiving module 110 includes a receiving unit 113, a phase shifting unit 114, a modulating unit 115, a reference frequency signal generating unit 116, and a transmitting unit 117. These functional units included in the receiving module 110 control the phase and amplitude of the signal in the receiving module 110 under the control of the control device 130 so that the excitation weights of the antennas 111 and 112 each have a desired value.

[0035] The receiving unit 113 performs predetermined signal processing on the output signal from the antenna 111. The receiving unit 113 may be configured with, for example, a low noise amplifier, and may amplify the output signal from the antenna 111.

[0036] The phase shifting unit 114 performs a phase shifting process to change the phase of the output signal from the receiving unit 113 .

[0037] For example, as a phase shifting process, the phase shift unit 114 may change the phase of the signal based at least on the distance between the transmitter 3 and the array element satellite 10 including the phase shift unit 114. In particular, the phase shift unit 114 may change the phase of the signal so as to compensate for the difference in distance between the transmitter 3 and each of the multiple array element satellites 10. This makes it possible to control the directivity of the phased array antenna 11 to point in the direction of the transmitter 3.

[0038] For example, as a phase shifting process, the phase shift unit 114 may change the phase of the signal based at least on the distance between the transmitting / receiving satellite 20 and the array element satellite 10 including the phase shift unit 114. In particular, the phase shift unit 114 may change the phase of the signal so as to compensate for the difference in distance between the transmitting / receiving satellite 20 and each of the multiple array element satellites 10. This makes it possible to control the directivity of the phased array antenna 12 so as to point in the direction of the transmitting / receiving satellite 20.

[0039] The distance between the transmitter 3 and the array element satellite 10, and the distance between the array element satellite 10 and the transmitting / receiving satellite 20 may be calculated based on the relative positional relationships between the transmitter 3, the array element satellite 10, and the transmitting / receiving satellite 20. For example, a ranging sensor may be mounted on the array element satellite 10 or the transmitting / receiving satellite 20, and the distance measured using the ranging sensor may be used in this calculation. Alternatively, the relative positions between the array element satellite 10 and the transmitting / receiving satellite 20 may be estimated by transmitting and receiving signals between them and measuring the strength of the signals. Furthermore, the calculation may use absolute position information of the transmitter 3, the array element satellite 10, and the transmitting / receiving satellite 20. For example, the array element satellite 10 or the transmitting / receiving satellite 20 may obtain information about its own position and attitude in an absolute coordinate system using a well-known method. For example, the array element satellite 10 or the transmitting / receiving satellite 20 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.

[0040] The modulator 115 performs modulation processing to modulate the reference frequency signal generated by the reference frequency signal generator 116 with the output signal from the phase shifter 114. The reference frequency signal generator 116 may be configured as, for example, an oscillator circuit. The array element satellite 10 may acquire information (such as a reference frequency value) for generating a reference frequency signal from an external device (such as another satellite 100), and the reference frequency signal generator 116 may generate the reference frequency signal based on the information. The modulation method is not particularly limited, and may be, for example, amplitude modulation, frequency modulation, or phase modulation. As will be described later, a transmission signal (radio wave) is emitted from each antenna 112 provided on each of the multiple array element satellites 10. The emitted transmission signals are then combined in space so that their amplitudes are added together, and the transmitting / receiving satellite 20 receives the combined transmission signal. Therefore, when the modulation processing performed by the modulation unit 115 is amplitude modulation, the amplitude information of the signal on which the baseband information (output signal from the phase shift unit 114) is superimposed by the modulation processing can be transmitted more efficiently as a transmission signal synthesized in space to the transmitting / receiving satellite 20. It is desirable that the reference frequency signal generated by the reference frequency signal generation unit 116 has a frequency that is sufficiently higher (at least twice, for example, several times to several tens of times) than the reference frequency of the transmission signal transmitted from the transmitter 3.

[0041] The transmitting unit 117 is configured with a power amplifier or the like, and amplifies the output signal from the modulating unit 115 and outputs it to the antenna 112. Note that the transmitting unit 117 may superimpose a reference frequency signal generated by the reference frequency signal generating unit 116 on the output signal from the modulating unit 115 and output it to the antenna 112. The superimposed reference frequency signal may be used for demodulation processing by the demodulating unit 213 of the receiving module 210 provided in the transmitting / receiving satellite 20.

[0042] The antenna 112 emits a transmission signal based on the output signal from the transmitter 117 as radio waves. The transmission signals (radio waves) emitted from the antennas 112 provided on the multiple array element satellites 10 are combined in space and propagated toward the transmitting / receiving satellite 20 based on the directivity of the phased array antenna 12.

[0043] The transmitting unit 117 may perform signal processing on the output signal from the modulating unit 115 to direct the directivity of the phased array antenna 12 toward the transmitting / receiving satellite 20. The transmitting unit 117 may change the phase of the output signal from the modulating unit 115, for example, to compensate for the difference in distance between the transmitting / receiving satellite 20 and the array element satellite 10 included in each of the multiple array element satellites 10. The transmitting unit 117 may also perform time delay processing on the output signal from the modulating unit 115, for example, to compensate for the difference in distance between the transmitting / receiving satellite 20 and the array element satellite 10 included in each of the multiple array element satellites 10.

[0044] The antenna 211 provided on the transmitting / receiving satellite 20 receives the transmission signals (radio waves) that are transmitted from the antennas 112 of the multiple array element satellites 10 and combined in space.

[0045] The receiving module 210 includes a receiving section 212 and a demodulating section 213 , and performs predetermined signal processing on the output signal from the antenna 211 .

[0046] The receiving unit 212 performs predetermined signal processing on the output signal from the antenna 211. The receiving unit 212 may be configured with, for example, a low noise amplifier, and may amplify the output signal from the antenna 211.

[0047] The demodulation unit 213 performs demodulation processing on the output signal from the receiving unit 212, which corresponds to the modulation processing (amplitude modulation, frequency modulation, phase modulation, etc.) performed by the modulation unit 115 of the array element satellite 10. The demodulation unit 213 may, for example, extract a reference frequency signal superimposed by the transmitting unit 117 of the receiving module 110 provided in the array element satellite 10 from the output signal from the receiving unit 212, and then use the reference frequency signal for demodulation processing. Alternatively, the transmitting / receiving satellite 20 may obtain information (such as a reference frequency value) for generating a reference frequency signal from an external device (such as another satellite 100), and the demodulation unit 213 may generate a reference frequency signal based on the information, and then use the reference frequency signal for demodulation processing.

[0048] The receiving module 210 may further perform predetermined signal processing on the signal generated by the demodulation processing by the demodulation unit 213. The signal processing may include, for example, demodulation processing corresponding to modulation processing performed on the ground by the transmitter 3 or the like. This makes it possible to extract desired baseband information. Furthermore, the receiving module 210 may output the signal generated by the demodulation processing by the demodulation unit 213 to the transmitting module 220 included in the transmitting phased array antenna system 2S.

[0049] In the receiving phased array antenna system 2R, the modulators 115 provided in the multiple array element satellites 10 perform modulation processing to superimpose a reference frequency signal on the received signal. Therefore, the reference frequency signal of the signal received by the phased array antenna 11 from the transmitter 3 differs from the reference frequency signal transmitted by the phased array antenna 12 to the transmitting / receiving satellite 20. This allows the received signals and transmitted signals of the multiple array element satellites 10 to have different frequency bands, making it possible to prevent signal interference within the system.

[0050] (3-2) Transmitting phased array antenna system 2S 4 is a diagram illustrating a transmitting phased array antenna system 2S. The transmitting phased array antenna system 2S includes, for example, a transmitting module 220 and an antenna 212 provided in a transmitting / receiving satellite 20, and a transmitting module 120, an antenna 121, and an antenna 122 provided in a plurality of array element satellites 10.

[0051] The transmitting module 220 provided in the transmitting / receiving satellite 20 includes a modulation unit 222 , a reference frequency signal generation unit 223 , and a transmission unit 224 .

[0052] The modulator 222 performs modulation processing to modulate the reference frequency signal generated by the reference frequency signal generator 223 with a predetermined signal (baseband information). The reference frequency signal generator 223 may be configured as, for example, an oscillator circuit. The transmitting / receiving satellite 20 may obtain information (such as a reference frequency value) for generating a reference frequency signal from an external device (such as another satellite 100), and the reference frequency signal generator 223 may generate the reference frequency signal based on the information. The modulation method is not particularly limited, and may be, for example, amplitude modulation, frequency modulation, or phase modulation. It is desirable that the reference frequency signal generated by the reference frequency signal generator 223 has a frequency that is sufficiently higher (for example, twice, or several to several tens of times higher) than the reference frequency of the predetermined signal (baseband information).

[0053] The predetermined signal as baseband information to be modulated by the modulation unit 222 may be, for example, an output signal from the receiving module 210 included in the receiving phased array antenna system 2R, or may be any signal generated by the control device 230. The predetermined signal may also be a signal obtained by modulating a reference frequency signal for terrestrial transmission with the baseband information. It is desirable that the reference frequency signal generated by the reference frequency signal generation unit 223 has a frequency that is sufficiently higher (for example, about twice, or several to several tens of times) than the reference frequency of the predetermined signal.

[0054] The transmitting unit 224 is configured with a power amplifier or the like, and amplifies the output signal from the modulating unit 222 and outputs it to the antenna 221. Note that the transmitting unit 224 may superimpose a reference frequency signal generated by the reference frequency signal generating unit 223 on the output signal from the modulating unit 222 and output it to the antenna 221. The superimposed reference frequency signal may be used for demodulation processing by the demodulating unit 124 of the transmitting module 120 provided in the array element satellite 10.

[0055] The antenna 221 emits, as radio waves, a transmission signal based on an output signal from the transmitter 224. The transmission signal (radio wave) emitted from the antenna 221 propagates toward the plurality of array element satellites 10 based on the directivity of the antenna 221.

[0056] The antennas 121 provided on the multiple array element satellites 10 are arranged in an array to form a phased array antenna 13. The directivity of the phased array antenna 13 is determined by the excitation weight of each antenna 121. The excitation weight of each antenna 121 is determined by signal processing in the transmitting module 120. The control device 130 provided in each array element satellite 10 controls the phase and amplitude of the signal in the transmitting module 120 so that the excitation weight of each antenna 121 becomes a desired value. The desired value may be calculated by the control device 130 or may be obtained from another device (another array element satellite 10, a transmitting / receiving satellite 20, another satellite 100, a ground device, etc.). The control device 130 may, for example, control the transmitting module 120 so as to compensate for the phase difference of the received signals of each antenna 121 among the multiple array element satellites 10. This makes it possible to control the directivity of the phased array antenna 13 in the direction of the transmitting / receiving satellite 20.

[0057] The antennas 122 provided on the multiple array element satellites 10 are arranged in an array to form a phased array antenna 14. The directivity of the phased array antenna 14 is determined by the excitation weight of each antenna 122. The excitation weight of each antenna 122 is determined by signal processing in the transmitting module 120. The control device 130 provided in each array element satellite 10 controls the phase and amplitude of the signal in the transmitting module 120 so that the excitation weight of each antenna 122 becomes a desired value. The desired value may be calculated by the control device 130 or may be obtained from another device (another array element satellite 10, a transmitting / receiving satellite 20, another satellite 100, a ground device, etc.). The control device 130 may, for example, control the transmitting module 120 to compensate for a phase difference in the transmission signals of each antenna 122 among the multiple array element satellites 10. This makes it possible to control the directivity of the phased array antenna 14 in the direction of the receiver 4.

[0058] The transmitting module 120 includes a receiving unit 123, a demodulating unit 124, a phase shifting unit 125, and a transmitting unit 126. These functional units included in the transmitting module 120 control the phase and amplitude of the signal in the transmitting module 120 under the control of the control device 130 so that the excitation weights of the antennas 121 and 122 each have a desired value.

[0059] The receiving unit 123 performs predetermined signal processing on the output signal from the antenna 121. The receiving unit 123 may be configured with, for example, a low noise amplifier, and may amplify the output signal from the antenna 121.

[0060] The demodulation unit 124 performs demodulation processing on the output signal from the reception unit 123, corresponding to the modulation processing (amplitude modulation, frequency modulation, phase modulation, etc.) performed by the modulation unit 222 of the transmission / reception satellite 20. The demodulation unit 124 may, for example, extract a reference frequency signal superimposed by the transmission unit 224 of the transmission module 220 provided in the transmission / reception satellite 20 from the output signal from the reception unit 123, and then use the reference frequency signal for the demodulation processing. Alternatively, the array element satellite 10 may obtain information (such as a reference frequency value) for generating a reference frequency signal from an external device (such as another satellite 100), and the demodulation unit 124 may generate a reference frequency signal based on the information, and then use the reference frequency signal for the demodulation processing.

[0061] The phase shifter 125 performs a phase shift process to change the phase of the output signal from the demodulator 124 .

[0062] For example, as a phase shifting process, the phase shift unit 125 may change the phase of the signal based at least on the distance between the transmitting / receiving satellite 20 and the array element satellite 10. In particular, the phase shift unit 125 may change the phase of the signal so as to compensate for the difference in distance between the transmitting / receiving satellite 20 and each of the multiple array element satellites 10. This makes it possible to control the directivity of the phased array antenna 13 so that it points in the direction of the transmitting / receiving satellite 20.

[0063] For example, as a phase shifting process, the phase shifter 125 may change the phase of the signal based at least on the distance between the receiver 4 and the array element satellite 10. In particular, the phase shifter 125 may change the phase of the signal so as to compensate for the difference in distance between the receiver 4 and each of the multiple array element satellites 10. This makes it possible to control the directivity of the phased array antenna 14 so that it points in the direction of the receiver 4.

[0064] The distance between the receiver 4 and the array element satellite 10, and the distance between the array element satellite 10 and the transmitting / receiving satellite 20 may be calculated based on the relative positional relationships between the receiver 4, the array element satellite 10, and the transmitting / receiving satellite 20. For example, a ranging sensor may be mounted on the array element satellite 10 or the transmitting / receiving satellite 20, and the distance measured using the ranging sensor may be used in this calculation. Alternatively, the relative positions between the array element satellite 10 and the transmitting / receiving satellite 20 may be estimated by transmitting and receiving signals between them and measuring the strength of the signals. Furthermore, the calculation may use absolute position information of the receiver 4, the array element satellite 10, and the transmitting / receiving satellite 20. For example, the array element satellite 10 or the transmitting / receiving satellite 20 may obtain information about its own position and attitude in an absolute coordinate system using a well-known method. For example, the array element satellite 10 or the transmitting / receiving satellite 20 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.

[0065] The transmitting section 126 is configured with a power amplifier and the like, amplifies the output signal from the phase shifting section 125 , and outputs the amplified signal to the antenna 122 .

[0066] The antenna 122 emits a transmission signal as radio waves based on the output signal from the transmitter 126. The transmission signals (radio waves) emitted from the antennas 122 of the multiple array element satellites 10 are combined in space and propagated toward the receiver 4 based on the directivity of the phased array antenna 14.

[0067] In the transmitting phased array antenna system 2S, the reference frequency signal to be transmitted is modulated by the modulator 222 of the transmitting / receiving satellite 20, and then demodulated by the demodulators 124 of the multiple array element satellites 10. Therefore, the reference frequency signal of the signal received by the phased array antenna 13 from the transmitting / receiving satellite 20 differs from the reference frequency signal transmitted by the phased array antenna 14 to the receiver 4. This allows the received signals and transmitted signals of the multiple array element satellites 10 to have different frequency bands, making it possible to prevent signal interference within the system.

[0068] (4) Variations (4-1) First Modification 5 is a diagram illustrating a first modified example of the phased array antenna system 2. In this modified example, the phased array antenna system 2 additionally includes a third satellite 30. The third satellite 30 may be any of the satellites 100 included in the phased array antenna system 2.

[0069] The third satellite 30 includes an antenna 31 and a reference frequency signal generator 32 .

[0070] The reference frequency signal generating unit 32 may replace the reference frequency signal generating unit 116 included in the array element satellite 10. That is, the reference frequency signal generating unit 32 has a function of generating a reference frequency signal used for modulation processing by the modulator 115 of the array element satellite 10. The third satellite 30 may transmit the reference frequency signal generated by the reference frequency signal generating unit 32 to the array element satellite 10 via the antenna 31. Any antenna of the array element satellite 10 is capable of receiving the reference frequency signal from the third satellite 30. The modulator 115 of the transmitting module 120 included in the array element satellite 10 may modulate the received reference frequency signal with the output signal from the phase shifter 114 and output it to the transmitter 117. Note that the array element satellite 10 does not necessarily have to include the modulator 115.

[0071] The reference frequency signal generator 32 may replace the reference frequency signal generator 223 included in the transmitting / receiving satellite 20. In other words, the reference frequency signal generator 32 has a function of generating a reference frequency signal used for modulation processing by the modulator 222 of the transmitting / receiving satellite 20. The third satellite 30 may transmit the reference frequency signal generated by the reference frequency signal generator 32 to the transmitting / receiving satellite 20 via the antenna 31. Any antenna of the transmitting / receiving satellite 20 is capable of receiving the reference frequency signal from the third satellite 30. The modulator 222 of the transmitting module 220 included in the transmitting / receiving satellite 20 may modulate the received reference frequency signal with a predetermined signal as modulation processing, and output the modulated signal to the transmitting unit 224. Note that the transmitting / receiving satellite 20 does not necessarily have to be equipped with the modulator 222.

[0072] According to this modification, the third satellite 30 generates a reference frequency signal and provides it to the array element satellite 10 and the transmitting / receiving satellite 20, thereby reducing the need for a reference frequency signal generator in each satellite. As a result, the design of each satellite is simplified and energy consumption can be reduced. Furthermore, by centralizing the generation of the reference frequency signal, the signal accuracy and synchronization accuracy of the entire phased array antenna system 2 can be improved.

[0073] (4-2) Second Modification 6 is a diagram for explaining a second modified example of the phased array antenna system 2. In this modified example, light (visible light or laser) is used instead of radio waves for signal transmission from the multiple array element satellites 10 to the transmitting / receiving satellite 20.

[0074] In the phased array antenna system 2 according to the modified example, the array element satellite 10 can be equipped with a light projecting unit 151 (such as an LED for LiFi or a laser diode) instead of the conventional antenna 112. This allows the array element satellite 10 to transmit information to the transmitting / receiving satellite 20 using an optical signal. The transmitting / receiving satellite 20 can accurately receive the optical signal from the array element satellite 10 by being equipped with a light receiving unit 251 instead of the antenna 211.

[0075] Furthermore, in this modification, the transmitting / receiving satellite 20 can also be equipped with a light projecting unit 261 (such as an LED for LiFi or a laser diode) instead of the antenna 221. This allows the transmitting / receiving satellite 20 to transmit data to the array element satellite 10 using an optical signal. On the other hand, the array element satellite 10 receives an optical signal from the transmitting / receiving satellite 20 by being equipped with a light receiving unit 152 instead of the antenna 121.

[0076] In this modification, the use of optical communication increases the speed of signal transmission and reception in the phased array antenna system 2. Optical signals have a higher frequency than radio waves and can transmit more data, making it possible to significantly improve the communication capacity of the entire system. In addition, the use of highly directional laser communication reduces unnecessary interference that occurs in radio wave communication, enabling more stable data transmission.

[0077] 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.

[0078] (4-3) Third Modification 7 is a diagram for explaining a third modified example of the phased array antenna system 2. In this modified example, the receiving module 210 provided in the array element satellite 10 is configured to include multiple sets of antennas 111, receiving units 113, and phase shift units 114.

[0079] In this modification, the receiving module 210 includes an adder 118 after each pair and before the modulator 115. As a result, the transmission signal sent from the transmitter 3 is received by each of the multiple antennas 111, and signal processing is performed in the receiver 113 and phase shifter 114 at the subsequent stage. The output signal from each pair is added by the adder 118 and then output to the modulator 115.

[0080] This configuration makes it possible to amplify the transmission signal sent from the transmitter 3 inside one array element satellite 10. This makes it possible to reduce the number of array element satellites 10 in the phased array antenna system 2. In the conventional configuration, each array element satellite 10 processes the transmission signal individually, but in this modified example, multiple received signals are integrated in the adder 118, thereby improving signal strength and making the reception processing more efficient.

[0081] Furthermore, by combining the signals by the adder 118, the phase of the received signal is appropriately adjusted before being input to the modulator 115. This is expected to improve transmission and reception efficiency and communication quality. This modification makes it possible to maintain the functionality of the phased array antenna system 2 with fewer array element satellites 10, leading to overall system cost reduction and improved operational efficiency.

[0082] (4-4) Other In the above-described embodiment, the phased array antenna system 2 is configured to include a satellite 100 as an example of an air vehicle. However, the phased array antenna system 2 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.

[0083] 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.

[0084] (Appendix 1) A transmitting phased array antenna system including a plurality of first flying vehicles and a second flying vehicle arranged in an array, The second flying vehicle, a modulation means for performing a modulation process to modulate a reference frequency signal with a predetermined signal; a first transmitting means for outputting a first transmission signal to each of the first flying bodies of the plurality of first flying bodies based on the output from the modulating means; Each of the plurality of first aircraft is a first receiving means for receiving the first transmission signal transmitted from the second aircraft; demodulation means for performing demodulation processing corresponding to the modulation processing on a first received signal generated based on reception of the first transmitted signal by the first receiving means; phase shifting means for varying the phase of the output from the demodulation means based at least on the distance between the second air vehicle and the first air vehicle and the distance between the first air vehicle and a receiver; and second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shifting means. Transmitting phased array antenna system. (Appendix 2) Modulation is amplitude modulation the modulation means amplitude-modulates the reference frequency signal with the predetermined signal as the modulation processing; 2. The transmitting phased array antenna system of claim 1. (Appendix 3) The second aircraft further includes a reference frequency signal generating means for generating the reference frequency signal. 2. The transmitting phased array antenna system of claim 1. (Appendix 4) The second flying vehicle further includes a second receiving means for receiving the reference frequency signal. 2. The transmitting phased array antenna system of claim 1. (Appendix 5) the transmitting phased array antenna system further comprises a third air vehicle; The third aircraft includes a reference frequency signal generating means for generating the reference frequency signal. 5. The transmitting phased array antenna system of claim 4. (Appendix 6) the first transmission signal is a radio wave, the first transmitting means is a transmitting antenna unit that transmits the first transmission signal, which is a radio wave; The first receiving means is a receiving antenna unit that receives the first transmission signal, which is a radio wave. 2. The transmitting phased array antenna system of claim 1. (Appendix 7) the first transmission signal is an optical signal; the first transmitting means is a light projecting unit that projects the first transmission signal, which is an optical signal; the first receiving means is a light receiving unit that receives the first transmission signal, which is an optical signal; 2. The transmitting phased array antenna system of claim 1. (Appendix 8) A first flying vehicle constituting a plurality of first flying vehicles arranged in an array provided in a transmitting phased array antenna system, The second flying vehicle provided with the transmitting phased array antenna system, a modulation means for performing a modulation process to modulate a reference frequency signal with a predetermined signal; a first transmitting means for outputting a first transmission signal to each of the first flying bodies of the plurality of first flying bodies based on the output from the modulating means; Each of the plurality of first aircraft is a first receiving means for receiving the first transmission signal transmitted from the second aircraft; demodulation means for performing demodulation processing corresponding to the modulation processing on a first received signal generated based on reception of the first transmitted signal by the first receiving means; phase shifting means for varying the phase of the output from the demodulation means based at least on the distance between the second air vehicle and the first air vehicle and the distance between the first air vehicle and a receiver; and second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shifting means. 1st flight vehicle. (Appendix 9) A second flying vehicle equipped with a transmitting phased array antenna system, The second flying vehicle, a modulation means for performing a modulation process to modulate a reference frequency signal with a predetermined signal; a first transmitting means for outputting a first transmission signal to each of a plurality of first flying vehicles included in the transmitting phased array antenna system based on an output from the modulating means; Each of the plurality of first aircraft is a first receiving means for receiving the first transmission signal transmitted from the second aircraft; demodulation means for performing demodulation processing corresponding to the modulation processing on a first received signal generated based on reception of the first transmitted signal by the first receiving means; phase shifting means for varying the phase of the output from the demodulation means based at least on the distance between the second air vehicle and the first air vehicle and the distance between the first air vehicle and a receiver; and second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shifting means. 2nd flight vehicle. [Explanation of symbols]

[0085] 1...satellite communications system, 2...phased array antenna system, 2R...receiving phased array antenna system, 2S...transmitting phased array antenna system, 3...transmitter, 4...receiver, 10...array element satellite, 20...transmitting / receiving satellite, 100...satellite, 110...receiving module, 111...antenna, 112...antenna, 120...transmitting module, 121...antenna, 122...antenna, 130...controller, 131...processor, 132...storage device, 140...attitude control device, 141...electromagnet, 210...receiving module, 211...antenna, 220...transmitting Module, 221...antenna, 230...control device, 231...processor, 232...storage device, 240...attitude control device, 241...electromagnet, 31...antenna, 32...reference frequency signal generation unit, 30...third satellite, 151...light-projecting unit, 152...light-receiving unit, 251...light-receiving unit, 261...light-projecting unit, 113...receiving unit, 114...phase-shifting unit, 115...modulating unit, 116...reference frequency signal generation unit, 117...transmitting unit, 123...receiving unit, 124...demodulating unit, 125...phase-shifting unit, 126...transmitting unit, 212...receiving unit, 213...demodulating unit, 222...modulating unit, 223...reference frequency signal generation unit, 224...transmitting unit

Claims

1. A transmitting phased array antenna system including a plurality of first flying vehicles and a second flying vehicle arranged in an array, The second flying vehicle, a modulation means for performing a modulation process to modulate a reference frequency signal with a predetermined signal; a first transmitting means for outputting a first transmission signal to each of the first flying bodies of the plurality of first flying bodies based on the output from the modulating means; Each of the plurality of first flying bodies is a first receiving means for receiving the first transmission signal transmitted from the second aircraft; demodulation means for performing demodulation processing corresponding to the modulation processing on a first received signal generated based on reception of the first transmitted signal by the first receiving means; phase shifting means for varying the phase of the output from the demodulation means based at least on the distance between the second air vehicle and the first air vehicle and the distance between the first air vehicle and a receiver; and second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shifting means. Transmitting phased array antenna system.

2. The modulation means performs the modulation process by amplitude modulating the reference frequency signal with the predetermined signal.

2. The transmitting phased array antenna system according to claim 1.

3. The second flying vehicle further includes a reference frequency signal generating means for generating the reference frequency signal.

2. The transmitting phased array antenna system according to claim 1.

4. The second flying vehicle further includes a second receiving means for receiving the reference frequency signal.

2. The transmitting phased array antenna system according to claim 1.

5. the transmitting phased array antenna system further comprises a third air vehicle; The third flying vehicle includes a reference frequency signal generating means for generating the reference frequency signal.

5. The transmitting phased array antenna system according to claim 4.

6. the first transmission signal is a radio wave, the first transmitting means is a transmitting antenna unit that transmits the first transmission signal, which is a radio wave; the first receiving means is a receiving antenna unit that receives the first transmission signal, which is a radio wave; 2. The transmitting phased array antenna system according to claim 1.

7. the first transmission signal is an optical signal; the first transmitting means is a light projecting unit that projects the first transmission signal, which is an optical signal; the first receiving means is a light receiving unit that receives the first transmission signal, which is an optical signal; 2. The transmitting phased array antenna system according to claim 1.

8. A first flying vehicle constituting a plurality of first flying vehicles arranged in an array provided in a transmitting phased array antenna system, a second flying vehicle equipped with the transmitting phased array antenna system, a modulation means for performing a modulation process to modulate a reference frequency signal with a predetermined signal; a first transmitting means for outputting a first transmission signal to each of the first flying bodies of the plurality of first flying bodies based on the output from the modulating means; Each of the plurality of first flying bodies is a first receiving means for receiving the first transmission signal transmitted from the second aircraft; demodulation means for performing demodulation processing corresponding to the modulation processing on a first received signal generated based on reception of the first transmitted signal by the first receiving means; phase shifting means for varying the phase of the output from the demodulation means based at least on the distance between the second air vehicle and the first air vehicle and the distance between the first air vehicle and a receiver; and second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shifting means. The first flying object.

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