Phased array antenna system for transmission

Abstract

In the present invention, communication quality of a phased array antenna system composed of a plurality of satellites is improved. This phased array antenna system for transmission comprises: a plurality of first flight vehicles arranged in an array; and a second flight vehicle. The second flight vehicle comprises: a modulation means for performing modulation processing for modulating a reference frequency signal on the basis of a prescribed signal; and a first transmission means for outputting a first transmission signal toward each of the first flight vehicles on the basis of an output from the modulation means. Each of the first flight vehicle comprises: a first reception means for receiving the first transmission signal transmitted from the second flight vehicle; a demodulation means for performing, on a first reception signal generated on the basis of the reception of the first transmission signal by the first reception means, demodulation processing corresponding to the modulation processing; a phase shifting means for changing the phase of an output from the demodulation means on the basis of at least the distance between the second flight vehicle and the first flight vehicle and the distance between the first flight vehicle and a receiver; and a second transmission means for outputting a second transmission signal to the receiver on the basis of an output from the phase shifting means.

Description

Transmitting Phased Array Antenna System

[0001] The present disclosure relates to a transmitting phased array antenna system.

[0002] It has been proposed that a large number of small satellites are deployed in outer space to perform formation flight, and wireless communication is performed between these small satellites to function 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 and relay communication between ground communication devices.

[0003] Japanese Patent No. 7416468

[0004] However, the small satellites constituting the above-described phased array antenna system receive not only signals transmitted from ground devices but also signals transmitted and received between satellites, and it is desired to prevent interference and signal mixing between these signals.

[0005] One object of the present disclosure is to improve communication quality of a phased array antenna system constituted by a plurality of satellites.

[0006] A transmitting phased array antenna system according to the present disclosure is a transmitting phased array antenna system including a plurality of first aircrafts arranged in an array and a second aircraft, wherein the second aircraft includes: a modulating means that performs modulation processing of modulating a reference frequency signal with a predetermined signal; and a first transmitting means that outputs a first transmission signal toward each of the plurality of first aircrafts based on an output from the modulating means, and each of the plurality of first aircrafts includes: a first receiving means that receives the first transmission signal transmitted from the second aircraft; a demodulating means that performs demodulation processing corresponding to the modulation processing on a first received signal generated based on reception of the first transmission signal by the first receiving means; a phase shifting means that changes a phase of an output from the demodulating means based at least on a distance between the second aircraft and said first aircraft and a distance between said first aircraft and a receiver; and a second transmitting means that outputs a second transmission signal toward the receiver based on an output from the phase shifting means.

[0007] According to this disclosure, it is possible to improve the communication quality of a phased array antenna system composed of multiple satellites.

[0008] This is a conceptual diagram showing the schematic configuration of a satellite communication system according to this embodiment. This is a block diagram showing an example of the functional configuration of a phased array antenna system. This is a diagram illustrating the configuration of a receiving phased array antenna system. This is a diagram illustrating the configuration of a transmitting phased array antenna system. This is a diagram showing a first modified example of the phased array antenna system. This is a diagram showing a second modified example of the phased array antenna system. This is a diagram showing a third modified example of the phased array antenna system.

[0009] Embodiments of this disclosure will be described with reference to the attached drawings.

[0010] (1) Diagram 1 of the satellite communication system 1 is a conceptual diagram for illustrating the outline of the satellite communication system 1 according to this embodiment. The satellite communication system 1 comprises a phased array antenna system 2, a transmitter 3, and a receiver 4.

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

[0012] In this embodiment, ultra-small satellites are used as the array element satellite 10 and / or the transmitting / receiving satellite 20. The array element satellite 10 and the transmitting / receiving satellite 20 may be collectively referred to as "satellite 100". For example, the size of one satellite 100 is several centimeters to 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 tens of thousands or more. The distance between adjacent satellites 100 is, for example, several centimeters to tens of centimeters. The distance between adjacent satellites 100 may be about the same as the wavelength, or 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 about a thousand kilometers.

[0013] Multiple satellites 100 comprising the phased array antenna system 2 may perform formation flight (flight in formation) along a General Circular Orbit (GCO) or a record-like orbit by flying in a predetermined orbit. In formation flight, each satellite 100 constituting the phased array antenna system 2 may fly in such a way that the arrangement of each satellite 100 rotates on a virtual plane (plane of rotation) without changing their relative positions to one another.

[0014] At least some of the satellites 100 in the phased array antenna system 2 may constitute a receiving phased array antenna system 2R (Figure 3) and receive transmission signals transmitted from the transmitter 3. Alternatively, at least some of the satellites 100 in the phased array antenna system 2 may constitute a transmitting phased array antenna system 2S (Figure 4) and transmit transmission signals to the receiver 4. The phased array antenna system 2 may also 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 when the receiving phased array antenna system 2R receives a transmission signal from the transmitter 3, and transmit this signal to the receiver 4. The phased array antenna system 2 may comprise multiple receiving phased array antenna systems 2R and / or multiple transmitting phased array antenna systems 2S, each composed of multiple satellites 100. Each of these multiple receiving phased array antenna systems 2R and / or multiple transmitting phased array antenna systems 2S may communicate individually with a ground station (transmitter 3 and / or receiver 4).

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

[0016] (2) Diagram 2 of the Phased Array Antenna System 2 is a block diagram showing an example of the functional configuration of the Phased Array Antenna System 2 provided by the satellite communication system 1. The Phased Array Antenna System 2 comprises a plurality of array element satellites 10 and a transmitting / receiving satellite 20. In the example of Figure 2, the Phased Array Antenna System 2 has the function of a receiving Phased Array Antenna System 2R and the function of a transmitting Phased Array Antenna System 2S. In this disclosure, when distinguishing individual array element satellites 10 or the configurations provided by individual array element satellites 10, reference numerals such as "A" and "B" may be used.

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

[0018] Antenna 111 generates a received signal by receiving the transmission signal (radio waves) transmitted from transmitter 3 and outputs it to receiving module 110. Under the control of control device 130, receiving module 110 performs predetermined signal processing on the output signal from antenna 111, as described later, and outputs the processed signal to antenna 112. Antenna 112 transmits a transmission signal towards the transmitting / receiving satellite 20 based on the output signal from receiving module 110.

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

[0020] Antennas 111, 112, 121, and 122 can each employ any configuration, such as patch antennas, horn antennas, and dipole antennas. However, in order to achieve high gain as a phased array antenna formed by multiple array element satellites 10, it is desirable to use shapes that allow for easy control of directivity (e.g., an array of patch antennas or an array of slot antennas). At least a portion of antennas 111, 112, 121, and 122 may be configured as a single antenna that is physically or functionally integrated, and the signal path of the receiving phased array antenna system 2R and the signal path of the transmitting phased array antenna system 2S may be switchable by a switch (not shown).

[0021] The control device 130 is a device that controls the operation of the entire 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 communication between the array element satellite 10 and other devices (for example, other array element satellites 10, transmitting / receiving satellites 20, other satellites 100, and ground stations, etc.). 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 "processor 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), etc., and performs various information processing. The storage devices 132 store various information necessary for processing by the processor 131. The storage devices 132 also store 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 through the cooperation of the processor 131 and the storage devices 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 very small array element satellite 10 performing formation flight, the attitude control device 140 may include an electromagnet 141. The electromagnet 141 can adjust the relative positions between adjacent satellites 100 using magnetic force and control them to maintain a desired array shape.

[0024] (2-2) Transmitting and Receiving Satellite 20 The transmitting and receiving satellite 20 comprises 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] Antenna 211 generates a received signal by receiving transmission signals transmitted from each of the multiple array element satellites 10 and outputs it 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 transmission signals (radio waves) transmitted from the multiple array element satellites 10. The content of the signal processing performed by the receiving module 210 is not particularly limited, but may include, for example, demodulation processing corresponding to modulation processing performed by the transmitter 3, etc. 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 processed signal 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. Based on the output signal from the transmitting module 220, the antenna 221 transmits the transmission signal toward each of the multiple array element satellites 10.

[0027] Antennas 211 and 221 can each employ any configuration, such as patch antennas, horn antennas, or dipole antennas, but shapes that allow for easy control of directivity (e.g., arrays of patch antennas or arrays of slot antennas) may also be used. Antennas 211 and 221 may be configured as a single antenna that is physically or functionally integrated, and may be configured to allow switching between the signal path of the receiving phased array antenna system 2R and the signal path of the transmitting phased array antenna system 2S by a switch (not shown).

[0028] The control device 230 controls the transmitting and receiving satellites 20. Specifically, the control device 230 controls the position and attitude of the transmitting and receiving satellites 20 by controlling the attitude control device 240. The control device 230 also controls communication between the transmitting and receiving satellites 20 and other devices (such as the array element satellite 10 and ground stations). Furthermore, the control device 230 performs various signal processing and various 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 devices 232"). The processor 231 includes a CPU and performs various information processing. The storage devices 232 store various information necessary for processing by the processor 231. The storage devices 232 also store 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 through the cooperation of the processor 231 and the storage devices 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 and receiving satellites 20. In the case of ultra-small transmitting and receiving satellites 20 performing formation flight, the attitude control device 240 may include an electromagnet 241. This allows for fine-tuning of the relative position with the array element satellite 10 and assists in the overall formation of the array.

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

[0032] The antennas 111 of 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 the signal processing of the receiving module 110. The control device 130 of 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. This desired value may be calculated by the control device 130 or obtained from other devices (other array element satellites 10, transmitting / receiving satellites 20, other satellites 100, ground devices, etc.). The control device 130 may, for example, control the receiving module 110 to compensate for the phase difference of the received signals of each antenna 111 among the multiple array element satellites 10. The control device 130 may perform the control in such a way that it compensates not only for the phase difference caused by the differences in the positions of each of the multiple array element satellites 10, but also for the phase difference caused by the individual variations of the array element satellites 10 (including information measured before the launch of the array element satellites 10). This makes it possible to control the directivity of the phased array antenna 11 towards the transmitter 3.

[0033] The antennas 112 of 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 the signal processing of the receiving module 110. The control device 130 of 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 is a desired value. This desired value may be calculated by the control device 130 or obtained from other devices (other array element satellites 10, transmitting / receiving satellites 20, other satellites 100, ground devices, etc.). The control device 130 may, for example, control the receiving module 110 to compensate for the phase difference of the received signals of each antenna 112 among the multiple array element satellites 10. The control device 130 may perform the control in such a way that it compensates not only for the phase difference caused by the differences in the positions of each of the multiple array element satellites 10, but also for the phase difference caused by the individual variations of the array element satellites 10 (including information measured before the launch of the array element satellites 10). This makes it possible to control the directivity of the phased array antenna 12 in the direction of the transmitting and receiving satellites 20.

[0034] The receiving module 110 comprises a receiving unit 113, a phase shifting unit 114, a modulation unit 115, a reference frequency signal generation unit 116, and a transmitting unit 117. Under the control of the control device 130, these functional units of the receiving module 110 control the phase and amplitude of the signal in the receiving module 110 so that the excitation weights of antennas 111 and 112, respectively, reach desired values.

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

[0036] The phase shift unit 114 performs phase shift processing to change the phase of the output signal from the receiving unit 113.

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

[0038] The phase shift unit 114 may, for example, change the phase of the signal as a phase shift process, at least based on the distance between the transmitting / receiving satellite 20 and the array element satellite 10 equipped with the phase shift unit 114. In particular, the phase shift unit 114 may change the phase of the signal to compensate for the difference in distance between the transmitting / receiving satellite 20 and each of the array element satellites 10. This makes it possible to control the directivity of the phased array antenna 12 so that it points 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 relationship between the transmitter 3, the array element satellite 10, and the transmitting / receiving satellite 20. In this calculation, for example, the array element satellite 10 and the transmitting / receiving satellite 20 may be equipped with ranging sensors, and the distance measured using the ranging sensors may be used. 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 intensity of the signals. Furthermore, in this calculation, information on the absolute positions of the transmitter 3, the array element satellite 10, and the transmitting / receiving satellite 20 may be used. For example, the array element satellite 10 or the transmitting / receiving satellite 20 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 10 or the transmitting / receiving satellite 20 may acquire information on its own position and attitude in an absolute coordinate system by imaging the sun, moon, earth, or stars using a camera.

[0040] The modulation unit 115 performs modulation processing by modulating the reference frequency signal generated by the reference frequency signal generation unit 116 with the output signal from the phase shift unit 114. The reference frequency signal generation unit 116 may be configured as, for example, an oscillator circuit. Alternatively, the array element satellite 10 may acquire information (such as the value of the reference frequency) for generating the reference frequency signal from an external device (such as another satellite 100), and the reference frequency signal generation unit 116 may generate the reference frequency signal based on this information. The modulation processing method is not particularly limited and may include, for example, amplitude modulation, frequency modulation, and phase modulation. As will be described later, each of the array element satellites 10 emits a transmission signal (radio wave) from its respective antenna 112. The emitted transmission signals are then combined so that their amplitudes are summed in space, and the transmitting / receiving satellite 20 receives the combined transmission signal. Therefore, if the modulation processing performed by the modulation unit 115 is amplitude modulation, the modulation processing makes it possible to more efficiently transmit the amplitude information of the signal on which the baseband information (output signal from the phase shift unit 114) is superimposed to the transmitting and receiving satellite 20 as a transmitted signal synthesized in space. 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 to several tens of times) than the reference frequency of the transmitted signal transmitted from the transmitter 3.

[0041] The transmitting unit 117 is composed of a power amplifier or the like, and amplifies the output signal from the modulation unit 115 and outputs it to the antenna 112. Alternatively, the transmitting unit 117 may superimpose a reference frequency signal generated by the reference frequency signal generation unit 116 onto the output signal from the modulation unit 115 and output it to the antenna 112. The superimposed reference frequency signal may be used for demodulation processing by the demodulation unit 213 of the receiving module 210 of the transmitting / receiving satellite 20.

[0042] Antenna 112 radiates a transmission signal as radio waves based on the output signal from the transmitting unit 117. The transmission signals (radio waves) radiated from each antenna 112 of the multiple array element satellites 10 are combined in space and propagate toward the transmitting / receiving satellites 20 based on the directivity of the phased array antenna 12.

[0043] Furthermore, the transmitting section 117 may perform signal processing on the output signal from the modulating section 115 to direct the directivity of the phased array antenna 12 toward the transmission / reception satellite 20. For example, the transmitting section 117 may change the phase of the output signal from the modulating section 115 so as to compensate for the difference in distance between the transmission / reception satellite 20 and the array element satellite 10 included in each of the plurality of array element satellites 10. Further, for example, the transmitting section 117 may perform time delay processing on the output signal from the modulating section 115 so as to compensate for the difference in distance between the transmission / reception satellite 20 and the array element satellite 10 included in each of the plurality of array element satellites 10.

[0044] The antenna 211 provided in the transmission / reception satellite 20 receives transmission signals (radio waves) transmitted from each antenna 112 of the plurality of 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 section 212 performs predetermined signal processing on the output signal from the antenna 211. For example, the receiving section 212 may be configured by a low-noise amplifier and amplify the output signal from the antenna 211.

[0047] The demodulating section 213 performs, on the output signal from the receiving section 212, demodulation processing corresponding to the modulation processing (amplitude modulation, frequency modulation, phase modulation, etc.) performed by the modulating section 115 of the array element satellite 10. For example, after extracting the reference frequency signal superimposed by the transmitting section 117 of the receiving module 110 provided in the array element satellite 10 from the output signal from the receiving section 212, the demodulating section 213 may use the reference frequency signal for the demodulation processing. Alternatively, the transmission / reception satellite 20 may acquire information (such as the value of the reference frequency) for generating the reference frequency signal from an external device (such as another satellite 100), and the demodulating section 213 may generate the reference frequency signal based on the information and then use the reference frequency signal for the demodulation processing.

[0048] The receiving module 210 may further perform predetermined signal processing on the signal generated by the demodulation processing performed by the demodulation unit 213. The signal processing may include, for example, demodulation processing corresponding to modulation processing performed on the ground such as by the transmitter 3. This enables extraction of desired baseband information. Further, the receiving module 210 may output the signal generated by the demodulation processing performed by the demodulation unit 213 to the transmitting module 220 provided in the transmitting phased array antenna system 2S.

[0049] In the receiving phased array antenna system 2R, modulation processing for superimposing a reference frequency signal on a received signal is performed by the modulation unit 115 provided in each of the plurality of array element satellites 10. Therefore, the reference frequency signal of the signal received by the phased array antenna 11 from the transmitter 3 is different from the reference frequency signal transmitted by the phased array antenna 12 toward the transmission / reception satellite 20. Accordingly, since the reception signals and transmission signals of the plurality of array element satellites 10 have different frequency bands, signal interference within the system can be prevented.

[0050] (3-2) Transmitting Phased Array Antenna System 2S FIG. 4 is a diagram for explaining the 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 the transmission / reception satellite 20, and a transmitting module 120, an antenna 121, and an antenna 122 provided in each of the plurality of array element satellites 10.

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

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

[0053] The predetermined signal, which is the baseband information subject to modulation processing by the modulation unit 222, may be, for example, an output signal from the receiving module 210 of the receiving phased array antenna system 2R, or any signal generated by the control device 230. Furthermore, the predetermined signal may be a signal obtained by modulating a reference frequency signal for ground 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 than the reference frequency of the predetermined signal (for example, twice, or several to several tens of times higher).

[0054] The transmitting unit 224 is composed of a power amplifier or the like, and amplifies the output signal from the modulation unit 222 and outputs it to the antenna 221. Alternatively, the transmitting unit 224 may superimpose a reference frequency signal generated by the reference frequency signal generation unit 223 onto the output signal from the modulation unit 222 and output it to the antenna 221. The superimposed reference frequency signal may be used for demodulation processing by the demodulation unit 124 of the transmitting module 120 of the array element satellite 10.

[0055] Antenna 221 radiates a transmission signal as radio waves based on the output signal from the transmitting unit 224. The transmission signal (radio waves) radiated from antenna 221 propagates toward the multiple array element satellites 10 based on the directivity of antenna 221.

[0056] The antennas 121 of 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 the signal processing of the transmitting module 120. The control device 130 of 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. This desired value may be calculated by the control device 130 or obtained from other devices (other array element satellites 10, transmitting / receiving satellites 20, other satellites 100, ground devices, etc.). The control device 130 may, for example, control the transmitting module 120 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 satellites 20.

[0057] The antennas 122 of 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 the signal processing of the transmitting module 120. The control device 130 of 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 is a desired value. This desired value may be calculated by the control device 130 or obtained from other devices (other array element satellites 10, transmitting / receiving satellites 20, other satellites 100, ground devices, etc.). The control device 130 may, for example, control the transmitting module 120 to compensate for the phase difference of the transmitted 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 toward the receiver 4.

[0058] The transmitting module 120 comprises a receiving unit 123, a demodulation unit 124, a phase shift unit 125, and a transmitting unit 126. Under the control of the control device 130, these functional units of the transmitting module 120 control the phase and amplitude of the signal in the transmitting module 120 so that the excitation weights of antennas 121 and 122, respectively, reach desired values.

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

[0060] The demodulation unit 124 performs demodulation processing on the output signal from the receiving unit 123, corresponding to the modulation processing (amplitude modulation, frequency modulation, and phase modulation, etc.) performed by the modulation unit 222 of the transmitting / receiving satellite 20. The demodulation unit 124 may, for example, extract a reference frequency signal superimposed by the transmitting unit 224 of the transmitting module 220 of the transmitting / receiving satellite 20 from the output signal from the receiving unit 123, and then use this reference frequency signal for demodulation processing. Alternatively, 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 demodulation unit 124 may generate a reference frequency signal based on this information and then use this reference frequency signal for demodulation processing.

[0061] The phase shift unit 125 performs phase shift processing to change the phase of the output signal from the demodulation unit 124.

[0062] The phase shift unit 125 may, for example, change the phase of the signal as a phase shift process, at least based 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 to compensate for the difference in distance between the transmitting / receiving satellite 20 and each of the 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] The phase shift unit 125 may, for example, change the phase of the signal as a phase shift process, at least based on the distance between the receiver 4 and the array element satellite 10. In particular, the phase shift unit 125 may change the phase of the signal to compensate for the difference in distance between the receiver 4 and each of the array element satellites 10. This makes it possible to control the directivity of the phased array antenna 14 so that it points towards 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 relationship between the receiver 4, the array element satellite 10, and the transmitting / receiving satellite 20. In this calculation, for example, the array element satellite 10 and the transmitting / receiving satellite 20 may be equipped with ranging sensors, and the distance measured using the ranging sensors may be used. 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 intensity of the signals. Furthermore, in this calculation, information on the absolute positions of the receiver 4, the array element satellite 10, and the transmitting / receiving satellite 20 may be used. For example, the array element satellite 10 or the transmitting / receiving satellite 20 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 10 or the transmitting / receiving satellite 20 may acquire information on its own position and attitude in an absolute coordinate system by imaging the sun, moon, earth, or stars using a camera.

[0065] The transmitting unit 126 is composed of a power amplifier and the like, and amplifies the output signal from the phase shift unit 125 and outputs it to the antenna 122.

[0066] Antenna 122 radiates a transmission signal as radio waves based on the output signal from the transmitter 126. The transmission signals (radio waves) radiated from each antenna 122 of the multiple array element satellites 10 are combined in space and propagate 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 modulation unit 222 of the transmitting / receiving satellite 20, and then demodulation processing is performed in the demodulation unit 124 of the multiple array element satellites 10. As a result, the reference frequency signal of the signal received by the phased array antenna 13 from the transmitting / receiving satellite 20 and the reference frequency signal transmitted by the phased array antenna 14 to the receiver 4 are different. This makes it possible to prevent signal interference within the system by having the received signals and transmitted signals of the multiple array element satellites 10 have different frequency bands.

[0068] (4) Modifications (4-1) First Modification Figure 5 is a diagram illustrating a first modification of the phased array antenna system 2. In this modification, the phased array antenna system 2 is newly equipped with a third satellite 30. The third satellite 30 may be any of the satellites 100 provided by the phased array antenna system 2.

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

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

[0071] The reference frequency signal generation unit 32 may replace the reference frequency signal generation unit 223 provided in the transmitting / receiving satellite 20. That is, the reference frequency signal generation unit 32 has the function of generating a reference frequency signal used for modulation processing by the modulation unit 222 of the transmitting / receiving satellite 20. The third satellite 30 may transmit the reference frequency signal generated by the reference frequency signal generation unit 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 modulation unit 222 of the transmitting module 220 provided in the transmitting / receiving satellite 20 may, as part of the modulation processing, modulate the received reference frequency signal with a predetermined signal and output it to the transmitting unit 224. Note that the transmitting / receiving satellite 20 does not necessarily have a modulation unit 222.

[0072] According to this modified version, 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 generation unit 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) Figure 6, a second modified example, illustrates 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 to transmit signals from the multiple array element satellites 10 to the transmitting / receiving satellites 20.

[0074] In the modified phased array antenna system 2, the array element satellite 10 can be equipped with a light-emitting unit 151 (such as a LiFi LED or 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 optical signals. The transmitting / receiving satellite 20 accurately receives optical signals from the array element satellite 10 by being equipped with a light-receiving unit 251 instead of the antenna 211.

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

[0076] In this modified version, the transmission and reception of signals from the phased array antenna system 2 are accelerated by employing optical communication. Optical signals have higher frequencies than radio waves and can transmit more data, thus significantly improving the overall communication capacity of the system. Furthermore, by utilizing highly directional laser communication, unwanted interference that occurs in radio communication is reduced, enabling more stable data transmission.

[0077] Thus, this modified example utilizes optical communication technology to provide a faster and less interfering communication environment compared to conventional radio communication.

[0078] (4-3) Figure 7 of the third modification is a diagram illustrating a third modification of the phased array antenna system 2. In this modification, the receiving module 210 of the array element satellite 10 is configured to include multiple sets of antennas 111, receiving units 113, and phase shifting units 114.

[0079] In this modified example, the receiving module 210 includes an adder 118 after each set and before the modulation unit 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 subsequent receiving unit 113 and phase shift unit 114, respectively. The output signals from each set are added together by the adder 118 and then output to the modulation unit 115.

[0080] This configuration allows for amplification of the transmission signal transmitted from the transmitter 3 within a single 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 processed the transmission signal individually, but in this modified configuration, multiple received signals are integrated in the summing unit 118, thereby improving signal strength and the efficiency of reception processing.

[0081] Furthermore, the signal integration by the summing unit 118 ensures that the phase of the received signal is appropriately adjusted before inputting it to the modulation unit 115. This improves transmission and reception efficiency and is expected to enhance communication quality. This modified configuration makes it possible to maintain the functionality of the phased array antenna system 2 with fewer array element satellites 10, leading to a reduction in overall system costs and improved operational efficiency.

[0082] (4-4) In the other embodiments described above, the phased array antenna system 2 was configured to include a satellite 100 as an example of an aircraft. However, the phased array antenna system 2 is not limited to a satellite 100 flying in outer space, but may be configured with any aircraft flying within the atmosphere (such as an airplane or a drone).

[0083] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The elements, arrangement, materials, conditions, shapes, and sizes of the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, it is possible to partially substitute or combine the configurations shown in different embodiments.

[0084] (Note 1) A transmitting phased array antenna system comprising a plurality of first flying bodies and a second flying body arranged in an array, wherein the second flying body comprises: a modulation means for performing modulation processing to modulate a reference frequency signal with a predetermined signal; and a first transmitting means for outputting a first transmission signal toward 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 demodulation processing corresponding to the modulation processing on a first received signal generated based on the reception of the first transmission signal by the first receiving means; a phase shift 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 toward the receiver based on the output from the phase shift means. (Note 2) The transmitting phased array antenna system according to Note 1, wherein the modulation means amplitude modulates the reference frequency signal by the predetermined signal as the modulation process. (Note 3) The transmitting phased array antenna system according to Note 1, wherein the second aircraft further comprises a reference frequency signal generation means for generating the reference frequency signal. (Note 4) The transmitting phased array antenna system according to Note 1, wherein the second aircraft further comprises a second receiving means for receiving the reference frequency signal. (Note 5) The transmitting phased array antenna system according to Note 4, wherein the transmitting phased array antenna system further comprises a third aircraft, the third aircraft comprising a reference frequency signal generation means for generating the reference frequency signal. (Note 6) The transmitting phased array antenna system according to Note 1, wherein the first transmission signal is a radio wave, the first transmission means is a transmitting antenna unit that transmits the first transmission signal which is a radio wave, and the first receiving means is a receiving antenna unit that receives the first transmission signal which is a radio wave.(Note 7) The phased array antenna system for transmitting according to Note 1, wherein the first transmission signal is an optical signal, the first transmission means is a light-emitting unit that emits the first transmission signal which is an optical signal, and the first receiving means is a light-receiving unit that receives the first transmission signal which is an optical signal. (Note 8) A first flying body comprising a plurality of first flying bodies arranged in an array for a transmitting phased array antenna system, wherein the second flying body of the transmitting phased array antenna system comprises: a modulation means for performing modulation processing 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, wherein 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 demodulation processing corresponding to the modulation processing on a first received signal generated based on the reception of the first transmission signal by the first receiving means; a phase shift 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 the receiver; and a second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shift means.(Note 9) A second flying body provided in a transmitting phased array antenna system, the second flying body comprising: modulation means for performing modulation processing to modulate a reference frequency signal with a predetermined signal; first transmitting means for outputting a first transmission signal to each of a plurality of first flying bodies provided in the transmitting phased array antenna system based on the output from the modulation means, each of the plurality of first flying bodies comprising: first receiving means for receiving the first transmission signal transmitted from the second flying body; demodulation means for performing demodulation processing corresponding to the modulation processing on a first received signal generated based on the reception of the first transmission signal by the first receiving means; phase shift 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 second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shift means.

[0085] 1...Satellite communication 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 and receiving satellite, 100...Satellite, 110...Receiving module, 111...Antenna, 112...Antenna, 120...Transmitting module, 121...Antenna, 122...Antenna, 130...Control device, 131...Processor, 132...Memory device, 140...Attitude control device, 141...Electromagnet, 210...Receiving module, 211...Antenna, 220...Transmitter Module, 221... Antenna, 230... Control device, 231... Processor, 232... Memory device, 240... Attitude control device, 241... Electromagnet, 31... Antenna, 32... Reference frequency signal generation unit, 30... Third satellite, 151... Light projection unit, 152... Light receiving unit, 251... Light receiving unit, 261... Light projection unit, 113... Receiving unit, 114... Phase shift unit, 115... Modulation unit, 116... Reference frequency signal generation unit, 117... Transmitting unit, 123... Receiving unit, 124... Demodulation unit, 125... Phase shift unit, 126... Transmitting unit, 212... Receiving unit, 213... Demodulation unit, 222... Modulation unit, 223... Reference frequency signal generation unit, 224... Transmitting unit

Claims

1. A transmitting phased array antenna system comprising a plurality of first flying bodies and a second flying body arranged in an array, wherein the second flying body comprises: a modulation means for performing modulation processing to modulate a reference frequency signal with a predetermined signal; a first transmitting means for outputting a first transmission signal toward each of the plurality of first flying bodies based on the output from the modulation means; 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 demodulation processing corresponding to the modulation processing on a first received signal generated based on the reception of the first transmission signal by the first receiving means; a phase shift 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 toward the receiver based on the output from the phase shift means.

2. The transmitting phased array antenna system according to claim 1, wherein the modulation means amplitude modulates the reference frequency signal with the predetermined signal as the modulation process.

3. The transmitting phased array antenna system according to claim 1, further comprising a reference frequency signal generating means for generating the reference frequency signal, the second flying object.

4. The transmitting phased array antenna system according to claim 1, further comprising a second receiving means for receiving the reference frequency signal, wherein the second flying object further comprises a second receiving means for receiving the reference frequency signal.

5. The transmitting phased array antenna system according to claim 4, further comprising a third flying body, the third flying body comprising a reference frequency signal generating means for generating the reference frequency signal.

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

7. The phased array antenna system for transmitting according to claim 1, wherein the first transmission signal is an optical signal, the first transmission means is a light-emitting unit that emits the first transmission signal which is an optical signal, and the first receiving means is a light-receiving unit that receives the first transmission signal which is an optical signal.

8. A first flying body comprising a plurality of first flying bodies arranged in an array for a transmitting phased array antenna system, wherein the second flying body of the transmitting phased array antenna system comprises: a modulation means for performing modulation processing 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 demodulation processing corresponding to the modulation processing on a first received signal generated based on the reception of the first transmission signal by the first receiving means; a phase shift 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 shift means.

9. A second aircraft comprising a transmitting phased array antenna system, the second aircraft comprising: a modulation means for performing modulation processing 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 aircraft comprising the transmitting phased array antenna system based on the output from the modulation means, the second aircraft comprising: a first receiving means for receiving the first transmission signal transmitted from the second aircraft; a demodulation means for performing demodulation processing corresponding to the modulation processing on a first received signal generated based on the reception of the first transmission signal by the first receiving means; a phase shift means for changing the phase of the output from the demodulation means based at least on the distance between the second aircraft and the first aircraft and the distance between the first aircraft and a receiver; and a second transmitting means for outputting a second transmission signal to the receiver based on the output from the phase shift means.

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