Radio wave transmitter / receiver, distributed phased array antenna system, distributed electromagnetic wave observation data collection system, and distributed synthetic aperture radar system

Abstract

To provide a radio wave transceiver that can suppress deterioration in beam quality.SOLUTION: A radio wave transceiver 2 transmits and receives codes to and from another radio wave transceiver 2 via a synchronization antenna 27, and acquires spatiotemporal difference information including both temporal difference information which is a temporal error from a radio wave transceiver 2 serving as a reference and spatial difference information which is a spatial error from the radio wave transceiver 2 serving as the reference using a spatiotemporal difference information acquisition unit 28. Based on the spatiotemporal difference information, a phase shift adjustment unit 24 acts on a phase shifter 221 of a transmitting / receiving module 22 to control an amount of phase shift of a high frequency signal emitted from a communication antenna 21 so as to correct a spatiotemporal error, and suppresses deterioration in beam quality caused by the spatiotemporal error.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a radio wave transceiver capable of acquiring spatiotemporal difference information of its own aircraft, a distributed phased array antenna system using multiple radio wave transceivers, a distributed electromagnetic wave observation data collection system using multiple radio wave transceivers, and a distributed synthetic aperture radar system using multiple radio wave transceivers. [Background technology]

[0002] Among array antennas consisting of an array of multiple small antennas, there is a phased array antenna in which each antenna element is connected to a phase shifter and beamforming is performed by controlling the relative phase shift between the antennas. Compared to conventional mechanically driven scanning beam control, the beam control of a phased array antenna has advantages such as improved speed and controllability, and a reduced failure rate due to fewer moving parts. Phased array antennas have a wide range of applications, including adaptively directing the main lobe toward a specific destination to improve data transfer efficiency, and being used as an intelligence gathering radar.

[0003] There is also Synthetic Aperture Radar (SAR), which uses a radar mounted on a flying object such as a satellite or aircraft to emit radio waves to the ground as it moves, and receives and combines the reflected waves, effectively synthesizing the image of a large-aperture antenna with a relatively small aperture. SAR is used in Earth observation and planetary exploration because it can obtain high-resolution images of terrain and other features in all weather conditions, day or night. There are also SARs that use phased arrays (for example, PALSAR: Phased Array Type L-band Synthetic Aperture Radar).

[0004] In the phased array antenna and SAR that utilizes it, relative phase control between antenna elements is important in order to synthesize the radio waves emitted from each antenna element and obtain the desired beam characteristics. Therefore, multiple antenna elements and phase shifters are generally individually connected, and the relative phase of the radio waves emitted from each antenna element is centrally controlled to obtain the desired beam characteristics.

[0005] Furthermore, in phased array antennas and SARs that utilize them, there is distributed antenna / distributed SAR technology in which each antenna element that makes up the array antenna has its own reference signal generator and amplifier and independently controls its own phase. In such distributed antenna / distributed SAR, if the arrangement of each antenna element is maintained stably, the desired beam characteristics can be achieved by adjusting the phase according to the arrangement of each antenna element. However, if the arrangement of each antenna element changes, autonomous control is required, taking into account the relative phase of the radio waves between each antenna element.

[0006] For example, if a satellite launched into orbit with its antenna panels folded unfolds, it will be subject to mechanical or thermal distortion, preventing it from achieving an ideal phased array antenna radiation surface shape and ideal performance. A technology has been proposed that uses optical technology to detect phase errors induced by such antenna shape distortion, calculates the phase correction values ​​necessary to compensate for these errors, and performs real-time shape compensation (see, for example, Patent Document 1). In the phased array antenna described in Patent Document 1, each antenna panel is divided into a module (a unit consisting of an antenna element, amplifier, phase shifter, and controller). Therefore, by miniaturizing and folding each module into a stack, it becomes easier to store it within the payload fairing of the launch vehicle.

[0007] Furthermore, a distributed aperture system has been proposed in which multiple small satellites are each equipped with an antenna element and maintain their positional relationships in cooperation with each other or with the support of a control satellite to form a phased array antenna (see, for example, Patent Document 2).The distributed aperture system described in Patent Document 2 employs a technology that uses electromagnetic coils to change the relative distance between each satellite so as to maintain distance x and angle y in order to maintain constant relative positions between the small satellites and between the small satellites and the control satellite. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 4951622 [Patent Document 2] Patent No. 6506365 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the phased array antenna described in Patent Document 1, antenna modules that perform independent phase control are connected by wire and mounted on the same mobile object (satellite), so as the number of modules increases, the overall size increases, making it difficult to store in a small space. Moreover, since the phased array antenna described in Patent Document 1 cannot arbitrarily rearrange the antenna modules, it lacks the flexibility to replace a faulty antenna module with a working one and operate it, or the scalability to increase or decrease the number of antenna modules or change the antenna module arrangement structure as needed.

[0010] On the other hand, the distributed aperture system described in Patent Document 2 has antenna elements mounted on multiple mobile objects (satellites), which together form an array antenna. This allows for flexibility, such as replacing a faulty mobile object with another with a functioning antenna element, and allows for the number of mobile objects to be increased or decreased or the mobile object's layout to be changed as needed, resulting in excellent scalability. However, in the distributed aperture system described in Patent Document 2, each mobile object must maintain its relative position to form an array. Since the positioning accuracy depends on the means of movement of the mobile object and external disturbances, deviations from the ideal layout due to misalignment can result in significant errors. In other words, if the ideal layout of the antenna elements cannot be maintained, the quality of the beam emitted by the entire array antenna will deteriorate. This issue is not limited to cases where antenna elements are mounted on mobile objects; it also applies to portable, fixed distributed antennas, where misalignment when installing each antenna will deteriorate the quality of the beam emitted by the entire array antenna. Furthermore, since the distributed aperture system described in Patent Document 2 uses an array of independent small satellites, it is not possible to achieve high-precision time synchronization using a common clock, as is the case with known phased array antennas. Therefore, the quality of the beam emitted by the entire array antenna will deteriorate due to time differences between each small satellite. Furthermore, even in a beamforming antenna that can form reception beams with various directions by appropriately weighting and combining reception signals received by multiple antenna elements, if there is a phase shift in the reception signals, the quality of the formed beam will deteriorate.Also, in a synthetic aperture radar that moves in the azimuth direction above an image acquisition area and repeatedly transmits and receives pulses to obtain reception signals from multiple antenna elements, and processes the received signals using a synthetic aperture radar signal processing device to generate a two-dimensional image, if there is a phase shift in the transmission signal or the reception signal, the quality of the two-dimensional image will deteriorate.

[0011] Therefore, an object of the present invention is to provide a radio wave transmitter / receiver that can acquire phase shift information that can be used as correction information to suppress degradation of beam quality, a distributed phased array antenna system using multiple radio wave transmitters / receivers, a distributed electromagnetic wave observation data collection system using multiple radio wave transmitters / receivers, and a distributed synthetic aperture radar system using multiple radio wave transmitters / receivers. [Means for solving the problem]

[0012] In order to solve the above problem, the first radio wave transceiver is a radio wave transceiver that can be used as an antenna element of a phased array antenna system in which a plurality of antenna elements are arranged to obtain a desired directivity, and is equipped with N communication antennas (N is any natural number), a space-time difference information acquisition unit, a phase-shift adjustment unit, and a reference oscillator that generates a reference frequency signal, wherein the space-time difference information acquisition unit transmits and receives codes to and from other radio wave transceivers via wireless communication using a synchronization antenna separate from the communication antenna, and measures, based on a time difference between the reference oscillators and a propagation delay time associated with the code transmission and reception, temporal difference information that is a temporal error between the radio wave transceiver serving as a reference and the first radio wave transceiver, and spatial difference information that is a spatial error between the first radio wave transceiver's appropriate position and its current position relative to the reference radio wave transceiver, and acquires space-time difference information including the temporal difference information and the spatial difference information, and the phase-shift adjustment unit adjusts the amount of phase shift of radio waves radiated from the communication antenna so as to correct the temporal error and / or the spatial error, based on the space-time difference information.

[0013] Furthermore, the distributed phased array antenna system according to the present invention is characterized in that it is configured using a plurality of first radio wave transceivers, and the phased array antenna system has a specific directivity due to the superposition of radio waves radiated from the communication antennas of each radio wave transceiver.

[0014] In order to solve the above-mentioned problems, the second radio wave transceiver is a radio wave transceiver that can be used as each antenna element in a beamforming antenna that can form reception beams with various directions by arranging a plurality of antenna elements and performing appropriate phase shift processing and appropriate weighting (amplitude amplification / attenuation) processing on the reception signals received by each antenna element and combining them, and that includes N communication antennas (N is any natural number), a space-time difference information acquisition unit, N signal reception units corresponding to each communication antenna, a reception data transmission unit, and a reference oscillator that generates a reference frequency signal, and the space-time difference information acquisition unit is configured to acquire the information by wireless communication using a synchronization antenna separate from the communication antennas. and transmits and receives codes to and from the other radio wave transceivers, and measures temporal difference information, which is a time error between the radio wave transceiver serving as a reference and the radio wave transceiver itself, and spatial difference information, which is a relative position of the radio wave transceiver itself with respect to the reference radio wave transceiver, based on the time difference between the reference oscillators and the propagation delay time associated with the code transmission and reception, and acquires time-space difference information including the time difference information and the spatial difference information, and the received data transmission unit transmits to the outside of the radio wave transceiver the received data linked to the received signal received by the signal receiving unit, the time-space difference information at the timing of reception, and unique information of the radio wave transceiver itself that is set so as to be able to distinguish between the radio wave transceiver itself and the other radio wave transceivers.

[0015] Furthermore, the distributed electromagnetic wave observation data collection system of the present invention includes a plurality of slave mobility units each having a second radio wave transmitter / receiver mounted on a mobile body, and a master mobility unit each having a data relay mounted on a mobile body that collects the received data transmitted from the plurality of slave mobility units and collectively transfers the collected received data to a predetermined data collection center, and is characterized in that the plurality of slave mobility units and the master mobility unit are arranged in an arbitrarily set electromagnetic wave observation area, and only the master mobility unit that collects the received data from each slave mobility unit transfers the collected received data to the data collection center as electromagnetic wave observation data.

[0016] In order to solve the above-mentioned problems, the third radio wave transceiver is a radio wave transceiver that can be used as each antenna element in a synthetic aperture radar that has a plurality of antenna elements arranged and that can generate a two-dimensional image by processing received signals obtained by repeatedly transmitting and receiving pulses while moving in an azimuth direction above an image acquisition area using a synthetic aperture radar signal processing device, and that includes N communication antennas (N is any natural number), N pulse transmitting and receiving units corresponding to each communication antenna, a space-time difference information acquiring unit, a received data transmitting unit, and a reference oscillator that generates a reference frequency signal, and the space-time difference information acquiring unit transmits and receives the received data to other radio wave transmitting and receiving units by wireless communication using a synchronization antenna separate from the communication antenna. and transmits and receives codes to and from a radio wave transmitter and receiver serving as a reference, and measures temporal difference information, which is a time error between the radio wave transmitter and receiver serving as a reference and its own radio wave transmitter and receiver, and spatial difference information, which is a relative position of the radio wave transmitter and receiver serving as a reference, based on the time difference between the respective reference oscillators and the propagation delay time associated with the code transmission and reception, and acquires spatio-temporal difference information including the temporal difference information and the spatial difference information, and the received data transmitter transmits the reflected signal received by the pulse transmitter and receiver, the spatio-temporal difference information acquired by the spatio-temporal difference information acquisition unit, and its own radio wave transmitter and receiver's unique information, which is set to be able to distinguish between the radio wave transmitter and receiver and the other radio wave transmitter and receiver, as received data to the synthetic aperture radar signal processing device.

[0017] Furthermore, the distributed synthetic aperture radar system according to the present invention includes a master synthetic aperture radar device that is mounted on a mobile body and that transmits pulse signals to the image acquisition area and receives reflected signals from the master synthetic aperture radar device, M slave synthetic aperture radar devices that are mounted on a mobile body and that transmit pulse signals to the same image acquisition area as the master synthetic aperture radar device and receive reflected signals from the master synthetic aperture radar device, where M is an arbitrary natural number, and a synthetic aperture radar signal processing device that processes received data from the master synthetic aperture radar device and the slave synthetic aperture radar device to generate a two-dimensional image, and the slave synthetic aperture radar signal processing device the master synthetic aperture radar device acquires the spatiotemporal difference information using the master synthetic aperture radar device as the radio wave transceiver serving as a reference, and performs phase adjustment to correct the temporal error based on at least the temporal difference information, thereby transmitting a pulse signal synchronized with the pulse transmission of the master synthetic aperture radar device; and the synthetic aperture radar signal processing device performs phase adjustment to correct the spatial error, based on at least the spatial difference information in the spatiotemporal difference information, for reflected signals in the received data from the master synthetic aperture radar device and / or the slave synthetic aperture radar device. [Effects of the Invention]

[0018] The first to third radio wave transceivers according to the present invention can acquire time-space difference information between the first and third radio wave transceivers and other radio wave transceivers. Therefore, a distributed phased array antenna system using a plurality of first radio wave transceivers can suppress degradation of beam quality by using the time-space difference information acquired by each radio wave transceiver as correction information. A distributed electromagnetic wave observation data collection system using a plurality of second radio wave transceivers can suppress degradation of beam quality by using the time-space difference information acquired by each radio wave transceiver as correction information. A distributed synthetic aperture radar system using a plurality of third radio wave transceivers can suppress degradation of two-dimensional image quality by using the time-space difference information acquired by each radio wave transceiver as correction information. [Brief explanation of the drawings]

[0019] [Figure 1] 1A is a schematic diagram of a distributed phased array antenna system according to an embodiment of the present invention, and FIG. 1B is a schematic diagram of a first configuration example of a radio wave transmitter / receiver used in the distributed phased array antenna system. [Figure 2] (A) is an image diagram showing a first example of radiation characteristics of a distributed phased array antenna system in which radio wave transmitters and receivers are arranged at equal intervals in a straight line to function as a linear array antenna. (B) is an image diagram showing a second example of radiation characteristics of a distributed phased array antenna system in which radio wave transmitters and receivers are arranged at equal intervals in a straight line to function as a linear array antenna. [Figure 3] (A) is an image diagram showing the radiation characteristics when there is no time error in the reference oscillator of each radio wave transmitter and receiver used in a distributed phased array antenna system. (B) is an image diagram showing the radiation characteristics when there is a time error in the reference oscillator of each radio wave transmitter and receiver used in a distributed phased array antenna system. (C) is an image diagram showing the radiation characteristics when the time error contained in the reference oscillator of each radio wave transmitter and receiver used in a distributed phased array antenna system is corrected based on time difference information. [Figure 4] FIG. 1 is an explanatory diagram of a correction operation performed by each radio wave transmitter / receiver used in a distributed phased array antenna system to detect a phase difference between them and achieve phase synchronization. [Figure 5] FIG. 10 is a schematic diagram illustrating the configuration of a radio wave transmitter / receiver according to a second configuration example. [Figure 6] FIG. 10 is a schematic diagram illustrating the configuration of a radio wave transmitter / receiver according to a third configuration example. [Figure 7] (A) is a conceptual diagram of a distributed phased array antenna system using radio wave transmitters and receivers mounted on multiple vehicles. (B) is a conceptual diagram of a distributed phased array antenna system using radio wave transmitters and receivers mounted on multiple unmanned aerial vehicles. [Figure 8] This is a schematic diagram of a distributed electromagnetic wave observation data collection system consisting of multiple slave mobility units and one master mobility unit. [Figure 9]1A is a schematic diagram of a radio wave transmitter and receiver used for slave mobility, and FIG. 1B is a schematic diagram of a radio wave transmitter and receiver used for master mobility. [Figure 10] FIG. 1 is a schematic diagram of a distributed synthetic aperture radar system configured with one master synthetic aperture radar device, multiple slave synthetic aperture radar devices, and one mobile control device. [Figure 11] This is a schematic diagram of a distributed synthetic aperture radar system in which pulse signals are transmitted from one master synthetic aperture radar device and M slave synthetic aperture radar devices to an object to be observed, and the reflected signals are received by one master synthetic aperture radar device and M slave synthetic aperture radar devices. [Figure 12] This is a schematic diagram of a distributed synthetic aperture radar system in which one master synthetic aperture radar device transmits a pulse signal to an object to be observed, and one master synthetic aperture radar device and M slave synthetic aperture radar devices receive the reflected signal. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1(A) shows a distributed phased array antenna system 1, which comprises four radio wave transceivers 2 (e.g., a first radio wave transceiver 2A, a second radio wave transceiver 2B, a third radio wave transceiver 2C, and a fourth radio wave transceiver 2D) arranged on a substantially flat surface facing the communication direction, and a system control device 11. The first to fourth radio wave transceivers 2A to 2D, which are arranged in appropriate distributed locations, all have common functions (see, for example, Fig. 1(B)). When there is no need to distinguish between the first to fourth radio wave transceivers 2A to 2D, they are simply referred to as radio wave transceivers 2. Furthermore, the number of radio wave transceivers 2 used in the distributed phased array antenna system 1 is not limited to four, but may be two, three, five, or more.

[0021] The radio wave transmitter / receiver 2 can be used as an antenna element constituting a "phased array antenna system in which a plurality of antenna elements are arranged to obtain a desired directivity." That is, in the distributed phased array antenna system 1, a plurality of radio wave transmitter / receivers 2 are arranged, and all or some of the antennas of these radio wave transmitters / receivers 2 are excited in response to instructions from the system control device 11, and the desired directivity is obtained by superimposing the radio waves obtained by controlling the excitation amplitude and excitation phase.

[0022] Array antennas are classified into linear arrays, planar arrays, circular arrays, conformal arrays, etc. depending on the arrangement method. Furthermore, an array antenna that controls the beam direction and radiation pattern by the relative phase of each radiating element is specifically called a phased array antenna. An antenna in which the radiating elements are separated without being electrically connected and each radiating element controls itself independently is called a distributed array antenna. Based on these existing technologies, the present invention, which is a system that controls the beam direction and radiation pattern by the relative phase of radio wave transmitters and receivers 2, which are independent radiating elements, is called a distributed phased array antenna system 1.

[0023] Furthermore, for the distributed phased array antenna system 1 to function as a phased array antenna, the system control device 11 must issue directional pattern control instructions to the first to fourth radio wave transceivers 2A to 2D, and the first to fourth radio wave transceivers 2A to 2D must transmit received signals to the system control device 11. Therefore, the system control device 11 and the first to fourth radio wave transceivers 2A to 2D must have a bidirectional signal transmission function. While FIG. 1A shows an example in which the system control device 11 and the first to fourth radio wave transceivers 2A to 2D are connected by wire, wireless connections are also acceptable. Furthermore, if the functionality of the system control device 11 is added to any one of the first to fourth radio wave transceivers 2A to 2D that make up the distributed phased array antenna system 1, there is no need to provide a separate system control device 11.

[0024] Each radio wave transmitter / receiver 2 is housed in an independent housing and can be handled individually. Therefore, if the size and weight of the radio wave transmitter / receiver 2 are sufficiently reduced, the radio wave transmitter / receiver 2 can be highly portable. Furthermore, the number and arrangement of the radio wave transmitters / receivers 2 used in the distributed phased array antenna system 1 can be freely changed to control the radiation characteristics, thereby increasing the flexibility of the system. However, a drawback of distributing the radiation elements is that it is difficult to precisely align the radio wave transmitters / receivers 2 to achieve an ideal arrangement, which can lead to errors. Furthermore, because each radio wave transmitter / receiver 2 is independent, the generation of a reference clock and other clocks must be performed separately for each radio wave transmitter / receiver 2. Unlike known phased array antennas, high-precision synchronization using a common clock cannot be achieved, which can lead to errors. Therefore, the radio wave transmitter / receiver 2 of this embodiment is equipped with a function that can correct temporal and spatial errors, thereby suppressing degradation of the beam quality obtained by the distributed phased array antenna system 1.

[0025] The error correction function of the radio wave transceiver 2 shown as the first configuration example will be described in detail below with reference to Fig. 1(B). Note that the signal communication function and processing operations that the radio wave transceiver 2 performs with the system control device 11 are omitted in Fig. 1(B) because various technologies employed in known phased array antennas can be applied.

[0026] The radio wave transceiver 2 comprises a communication antenna 21, a transmission / reception module 22, a radiation control unit 23, a phase adjustment unit 24, a transmission / reception control unit 25, a reference oscillator 26, a synchronization antenna 27, and a spatiotemporal difference information acquisition unit 28. The communication antenna 21 is preferably a dipole antenna, a slot antenna, or a microstrip antenna. The communication antenna 21, the transmission / reception module 22, the radiation control unit 23, and the phase adjustment unit 24 function as a radiation element constituting a phased array. The radiation control unit 23 controls the frequency and intensity of the high-frequency wave fed to the antenna, and the phase adjustment unit 24 controls the phase of the high-frequency wave. The transmission / reception module 22 includes a phase shifter 221 and an amplifier circuit (e.g., a transmission amplifier 222 and a reception low-noise amplifier 223) that can arbitrarily adjust the phase of each of the transmission path and reception path. The transmission / reception module 22 switches between transmitting the high-frequency wave fed via the radiation control unit 23 and the phase shifter 221 to the communication antenna 21 or phase-shifting the high-frequency wave received by the communication antenna 21 and demodulating it. That is, the radio wave transceiver 2 can radiate and receive radio waves whose phases are controlled as desired from the communication antenna 21. Note that the following description of the radio wave transceiver 2 will focus on an example of operation for radiating radio waves, but similar effects can also be obtained when receiving radio waves.

[0027] 2(A) shows a distributed phased array antenna system 1 having a linear array configuration in which first to fourth radio wave transmitters and receivers 2A to 2D are aligned in a straight line at a distance d from each other. The clocks of the first to fourth radio wave transmitters and receivers 2A to 2D are synchronized with ideal accuracy. Therefore, when high-frequency waves synchronized with an excitation phase Φ are transmitted from the transmitting antennas 21 of the first to fourth radio wave receivers 2A to 2D, a wavefront WF of a composite wave is generated whose directivity is perpendicular to the arrangement direction of the first to fourth radio wave transmitters and receivers 2A to 2D. 2(B) shows a case in which a high frequency wave with an excitation phase Φ is transmitted from the transmitting antenna 21 of the first radio wave transceiver 2A, a high frequency wave with an excitation phase Φ+Δφ is transmitted from the transmitting antenna 21 of the second radio wave transceiver 2B, a high frequency wave with an excitation phase Φ+2Δφ is transmitted from the transmitting antenna 21 of the third radio wave transceiver 2C, and a high frequency wave with an excitation phase Φ+3Δφ is transmitted from the transmitting antenna 21 of the fourth radio wave transceiver 2D. When high frequencies whose phases are adjusted in accordance with the arrangement positions of the first to fourth radio wave transceivers 2A to 2D are transmitted in this way, a wavefront WF of a composite wave is generated whose directivity direction is inclined at an angle θ with respect to the directivity direction of FIG. 2(A).

[0028] However, unlike known array antennas, each radio wave transceiver 2 used in a distributed phased array antenna system 1 is not centrally managed. Instead, it operates independently of other radio wave transceivers 2. Therefore, the state of its own high-frequency signal, such as its excitation amplitude and phase, must be individually monitored and controlled. The challenge here is to align the phase with other radio wave transceivers 2 according to a set rule. To achieve this, it is essential to monitor the time difference information, which is the time error between the reference radio wave transceiver 2 and the radio wave transceiver itself, and the spatial difference information, which is the spatial error between the appropriate position of the radio wave transceiver 2 and its current position relative to the reference radio wave transceiver 2, and control the radio frequency state to correct the phase shift required to obtain the desired composite wave. The time difference information may be the error between the reference oscillator 26 of the reference radio wave transceiver 2 and the reference oscillator 26 of the radio wave transceiver itself, or it may be the error between the clock counting the reference frequency signal (e.g., a reference clock signal) generated by the reference oscillator 26 of the reference radio wave transceiver 2 and the clock of the radio wave transceiver itself. The spatial difference information is obtained based on the position of a reference radio wave transceiver 2 (hereinafter referred to as the reference device) to determine the spatial error between the current position of the device and the ideal position (proper position) assigned to the device in the distributed phased array antenna system 1. Even if the position of the reference device is slightly deviated from the proper position, the distributed phased array antenna system 1 can achieve the intended directivity as long as the other radio wave transceivers 2 are placed in proper positions relative to the reference device.

[0029] Therefore, in addition to the reference oscillator 26, the radio wave transceiver 2 is provided with a synchronization antenna 27 and a spatiotemporal difference information acquisition unit 28. The spatiotemporal difference information acquisition unit 28 acquires spatiotemporal difference information, including both temporal difference information with other radio wave transceivers 2 and spatial difference information with other radio wave transceivers 2. Based on this spatiotemporal difference information, the phase adjustment unit 24 controls the phase shifter 221 of the transceiver module 22 to control the phase shift amount of the high-frequency signal emitted from the communication antenna 21. In this way, by grasping the spatiotemporal difference information, including the above-mentioned temporal difference information and spatial difference information, and correcting temporal and spatial errors, it is possible to obtain a desired composite wave in cooperation with multiple radio wave transceivers 2 operating independently. For example, the spatiotemporal difference information acquisition unit 28 transmits and receives codes with other radio wave transceivers 2 via wireless communication via the synchronization antenna 27, and measures the temporal difference information and the spatial difference information based on the time difference between the reference oscillators 26 and the propagation delay time associated with the code transmission and reception. It is also possible to measure the phase shift by communicating with another radio wave transmitter / receiver 2 connected by wire, without using the synchronization antenna 27.

[0030] The spatiotemporal difference information, including the temporal difference information and the spatial difference information, acquired by the spatiotemporal difference information acquisition unit 28 is supplied to the phase adjustment unit 24 via the transmission / reception control unit 25 and used to control phase shift correction. Specifically, the radiation control unit 23 excites the high-frequency signal based on the clock source of the reference oscillator 26, and the phase adjustment unit 24 controls the phase amount of the phase shifter 221 based on the spatiotemporal difference information to correct spatiotemporal errors in the high-frequency signal, and transmits the high-frequency signal with reduced degradation in beam quality from the communication antenna 21. This makes it possible to obtain a desired composite wave as a distributed phased array antenna system 1 using multiple independently operating radio wave transceivers 2. This phase correction operation will be described with reference to FIG. 3. For simplicity of explanation, FIG. 3 shows a linear array structure in which the first to third radio wave transceivers 2A to 2C are arranged in a row at equal intervals.

[0031] For example, as shown in FIG. 3A, if the reference oscillators 26 of the first to third radio wave transceivers 2A to 2C are synchronized with high precision and there is no time error in the time TM, no time error will occur in the high-frequency signal supplied to the transceiver module 22. First, if the phase shift amount Φa0 used for phase adjustment in the transceiver module 22 of the first radio wave transceiver 2A is set to 0 (zero) as instructed by the system control device 11, the high-frequency signal emitted from the communication antenna 21 will have the instructed phase. Similarly, if the phase shift amount Φb0 used for phase adjustment in the transceiver module 22 of the second radio wave transceiver 2B is set to π / 6 as instructed by the system control device 11, the high-frequency signal emitted from the communication antenna 21 will have the instructed phase. Similarly, if the phase shift amount Φc0 used for phase adjustment in the transceiver module 22 of the third radio wave transceiver 2C is set to π / 3 (=2π / 6) as instructed by the system control device 11, the high-frequency signal emitted from the communication antenna 21 will have the instructed phase. In this way, if there is no time error in the times TM of the first to third radio wave transmitters / receivers 2A to 2C, the wavefronts will be aligned in the directional direction according to the phase difference of the high frequency signals emitted from each communication antenna 21, and suitable directivity will be obtained.

[0032] However, as shown in FIG. 3B, if the times of the first to third radio wave transmitters / receivers 2A to 2C are not synchronized with the master clock, a time error occurs in the high-frequency signal supplied to the transmitter / receiver module 22. First, because the clock of the first radio wave transmitter / receiver 2A is synchronized with the master clock (matching time TM), the high-frequency signal phase-adjusted (phase shift Φa0 = 0) in the transmitter / receiver module 22 has the specified phase. However, because the clock of the second radio wave transmitter / receiver 2B is ahead of the master clock by Δtb, time TM + Δtb becomes the oscillation reference for the high-frequency signal, and the high-frequency signal phase-adjusted (phase shift Φb0 = π / 6) in the transmitter / receiver module 22 has a phase shifted from the originally specified phase. Furthermore, because the clock of the third radio wave transmitter / receiver 2C is ahead of the master clock by Δtc, time TM + Δtc becomes the oscillation reference for the high-frequency signal, and the high-frequency signal phase-adjusted (phase shift Φc0 = π / 3) in the transmitter / receiver module 22 has a phase shifted from the originally specified phase. Therefore, the wavefronts of the high frequency signals emitted from the communication antennas 21 in FIG. 3B are not aligned in the direction corresponding to the phase difference, and suitable directivity cannot be obtained.

[0033] On the other hand, as shown in Fig. 3(C), even if the times of the first to third radio wave transceivers 2A to 2C are not synchronized with the master clock, the time error that has occurred in the high frequency signal can be eliminated by adjusting the phase amount to correct the time discrepancy using the phase adjustment unit 24. In the following, the period of the transmitted high frequency signal is assumed to be P. First, since the clock of the first radio wave transceiver 2A is synchronized with the master clock (matches the time TM), the corrected phase adjustment amount ΦaC that the phase adjustment unit 24 instructs the transmission / reception module 22 to remain Φa0 (= 0), and the high frequency signal emitted from the communication antenna 21 has the phase as instructed. However, because the clock of the second radio wave transceiver 2B is ahead of the master clock by Δtb, the phase adjustment unit 24 instructs the transceiver module 22 to use a corrected phase adjustment amount ΦbC=Φb0-2πΔtb / P (=π / 6-2πΔtb / P) that takes into account the phase shift (2πΔtb / P) caused by Δtb, so that the high-frequency signal emitted from the communication antenna 21 has the instructed phase. Also, because the clock of the third radio wave transceiver 2C is ahead of the master clock by Δtc, the phase adjustment unit 24 instructs the transceiver module 22 to use a corrected phase adjustment amount ΦcC=Φc0-2πΔtc / P (=π / 3-2πΔtc / P) that takes into account the phase shift (2πΔtc / P) caused by Δtc, so that the high-frequency signal emitted from the communication antenna 21 has the instructed phase. In this way, even if there is a time error in the times TM of the first to third radio wave transmitters / receivers 2A to 2C, by adjusting the phase amount to correct the time difference, the wavefronts will be aligned in the direction corresponding to the phase difference of the high frequency signals emitted from each communication antenna 21, and suitable directivity will be obtained.

[0034] As described above, by acquiring time-space difference information between the independently operating radio wave transmitters and receivers 2 and correcting the phase shift of the high-frequency signals, it is possible to reduce unintended phase shifts in the wave sources that form the composite wave, thereby improving the beam quality of the distributed phased array antenna system 1. Note that while Figure 3 only shows a method for correcting temporal errors, the method for correcting spatial errors is similar. By acquiring time-space difference information between the radio wave transmitters and receivers 2 and correcting the phase shift of the high-frequency signals, it is possible to reduce unintended phase shifts in the wave sources that form the composite wave. Of course, when both temporal and spatial errors occur, it is possible to reduce unintended phase shifts in the wave sources that form the composite wave by correcting the phase of the high-frequency signals taking both the temporal and spatial errors into account.

[0035] The method for acquiring the temporal difference information and the spatial difference information by the time-space difference information acquisition unit 28 is not particularly limited, and any appropriate known method may be used. For example, when using the Global Navigation Satellite System (GNSS), a GNSS satellite can be used as a master clock, and each radio wave transceiver 2 performs a correction operation to synchronize with that time. The GNSS time synchronization method is effective on the ground and in the air where GNSS signals can reach. Various time synchronization methods, such as IEEE802.1AS-2011, which uses the propagation delay time between each radio wave transceiver 2, may also be used. In this case, one of the multiple radio wave transceivers 2 constituting the distributed phased array antenna system 1 functions as a master clock, or is designed to detect the relative time offset with respect to the reference radio wave transceiver 2. For example, as shown in FIG. 4, a first radio wave transceiver 2A is assumed to have a master clock, and a second radio wave transceiver 2B corrects its own clock using an error φAB based on the propagation delay time with respect to the first radio wave transceiver 2A. Similarly, the third radio wave transceiver 2C corrects its internal clock using an error φAC based on the propagation delay time with the first radio wave transceiver 2A. The third radio wave transceiver 2C may correct its internal clock using an error φBC based on the propagation delay time with the second radio wave transceiver 2B after clock correction, or may correct its internal clock using the average value of the errors φAC and φBC. The fourth radio wave transceiver 2D may correct its internal clock using an error φBD based on the propagation delay time with the second radio wave transceiver 2B after clock correction or an error φCD based on the propagation delay time with the third radio wave transceiver 2C after clock correction, or may correct its internal clock using the average value of the errors φBD and φCD. This method using the propagation delay time (RTT) provides high synchronization accuracy and is therefore desirable from the perspective of improving beam quality.

[0036] Alternatively, instead of correcting the temporal phase shift, the phase shift of the reference oscillator 26 may be adjusted to cancel (i.e., synchronize) the detected phase shift. For example, the radio wave transceiver 2′ shown in FIG. 5 includes a frequency-adjustable reference oscillator 26′ such as a VCO or OCXO, and the spatiotemporal difference information acquisition unit 28′ includes a spatial difference information detector 281 and a temporal difference information detector 282. The temporal difference information detector 282 receives the master clock or information indicating its phase from the synchronization antenna 27 and adjusts the excitation phase of the reference oscillator 26′ to the master clock based on the received information. More specifically, the synchronization antenna 27 receives radio waves of a specific frequency transmitted from the master clock, and the temporal difference information detector 282 detects the phase shift between the radio waves and the clock of the reference oscillator 26′. By feeding back the temporal error obtained by the temporal difference information detector 282 to the reference oscillator 26′, the reference oscillator 26′ can be excited in phase with the master clock. In this way, by synchronizing the oscillation clock of the reference oscillator 26' with the master clock at the phase level, it is possible to minimize the phase shift and improve the beam quality. Furthermore, the master clock does not have to be a global one, and local synchronization established only among the multiple radio wave transceivers 2 that make up the distributed phased array antenna system 1 is also acceptable. In this case, it is sufficient to arbitrarily select a radio wave transceiver 2 that will serve as the master clock from the multiple radio wave transceivers 2 that make up the distributed phased array antenna system 1.

[0037] On the other hand, spatial difference information, i.e., the positional relationship between multiple radio wave transmitters and receivers 2, can be detected using wireless positioning technologies such as distance estimation using GNSS, AoA (Angle of Arrival), AoD (Angle of Departure), and RSSI (Received Signal Strength Indicator). GNSS is particularly effective when the radio wave transmitters and receivers 2 are located in locations where GNSS signals can reach, such as on the ground or in the air. Furthermore, spatial difference information can be acquired not only using global positions such as latitude, longitude, and altitude, but also using local positions that allow the relative positional relationship to be determined only between the multiple radio wave transmitters and receivers 2 constituting the distributed phased array antenna system 1. Therefore, positioning technologies that allow the mutual positions of multiple radio wave transmitters and receivers 2 to be determined using AoA, AoD, RSSI, etc. may also be used. Furthermore, the positional relationship may be determined by measuring the distance between them using the propagation delay time of radio waves. In this case, it is sufficient to know the distance between the multiple radio wave transmitters and receivers 2.

[0038] The spatial difference information obtained in this way is used to determine the amount of phase shift determined by the transmission / reception control unit 25. For example, if the device is misaligned from the ideal array antenna position, the phase shift due to the spatial error is calculated, and the amount of phase shift is adjusted to minimize the impact on beam quality. This phase shift is preferably calculated using techniques such as Maxwell's equations, Fresnel-Kirchhoff diffraction theory, and ray tracing, and a value that results in an optimal beam overall is used. A simpler approach would be to calculate the phase shift from the distance representing the deviation from the ideal position and the propagation wavelength of the radio waves, and then adjust the phase of the high-frequency signal to correct this spatial error.

[0039] Furthermore, the radio wave transceiver 2 is not limited to having one radiating element function, and may have N (N is any natural number) communication antennas 21 and transceiver modules 22 corresponding to each transmitting antenna 21. The radio wave transceiver 2'' shown in FIG. 6 has two sets (N=2) of radiating element functions, and includes a first communication antenna 21A and a second communication antenna 21B, and a first transceiver module 22A and a second transceiver module 22B corresponding to the first and second transmitting antennas 21A and 21B, respectively. Furthermore, since the high-frequency signal radiated from the first communication antenna 21A and the high-frequency signal radiated from the second communication antenna 21B are controlled independently, a first radiation control unit 23A and a first phase adjustment unit 24A corresponding to the first transceiver module 22A are provided, and a second radiation control unit 23B and a second phase adjustment unit 24B corresponding to the second transceiver module 22B are provided. In this way, in a radio wave transceiver 2'' having multiple radiating element functions, the radiating element functions can be arranged with narrow intervals. For example, if the element spacing is d, the signal wavelength is λ, and the maximum scanning angle is θ, then d / λ=1 / (1+sinθ), and therefore, if the element spacing d is adjusted so that d≦λ / (1+sinθ), the occurrence of grating lobes can be suppressed.

[0040] As described above, the radio wave transceiver 2, which can acquire temporal difference information and spatial difference information and adjust the phase of the high-frequency signal to correct the spatiotemporal error, can be used as an array antenna radiating element independently, or can be mounted on a vehicle to form a mobile distributed phased array antenna system. Examples of mobile objects that can be equipped with the radio wave transceiver 2 include vehicles 3 (see Figure 7(A)) traveling on the ground, ships sailing on the sea, aircraft and UAVs (Unmanned Aerial Vehicles) 4 (see Figure 7(B)) flying in the airspace, and artificial satellites in orbit. The mobile object and the radio wave transceiver 2 do not need to be separate entities, but may be integrated into one structure.

[0041] 7A shows a mobile distributed phased array antenna system 1′ in which first to eighth radio wave transceivers 2A to 2H are mounted on first to eighth vehicles 3A to 3H, respectively. For example, the first radio wave transceiver 2A functions as a system control device 11. In this distributed phased array antenna system 1′, unlike the distributed phased array antenna system 1 described above, the radio wave transceivers 2 are not fixedly installed. Therefore, as the first to eighth vehicles 3A to 3H move, the relative positions of the first to eighth radio wave transceivers 2A to 2H change from moment to moment. However, each radio wave transceiver 2 is provided with a spatiotemporal difference information acquisition unit 28. This allows the radio wave transceiver 2 to acquire temporal difference information and spatial difference information and emit high-frequency signals with the spatiotemporal error corrected, thereby enabling tracking of changes in the spatiotemporal error as the first to eighth vehicles 3A to 3H move. Therefore, even in a mobile distributed phased array antenna system 1' using a vehicle 3, which is a moving body, it is possible to form a composite wave with a main lobe directed in a specific direction.

[0042] If the first to eighth vehicles 3A-3H are autonomous vehicles, the first to eighth vehicles 3A-3H can move in formation so that the first to eighth radio wave transmitters and receivers 2A-2H are ideally positioned as array antennas, thereby maintaining the beam quality of the distributed phased array antenna system 1′. Furthermore, the first to eighth radio wave transmitters and receivers 2A-2H can determine their respective positions from the time-space difference information acquired by the time-space difference information acquisition unit 28. Therefore, each radio wave transmitter and receiver 2 can determine how to move to achieve the ideal position as an array antenna. Therefore, by providing a movement correction instruction means in each radio wave transmitter and receiver 2 and transmitting movement correction information from the movement correction instruction means to a movement control device of each moving object (e.g., an autonomous driving control device of the vehicle 3), the movement control device of each moving object can correct the movement direction and movement speed based on the movement correction information, allowing each moving object to move its radio wave transmitter and receiver 2 to its optimal position. Even if the optimal placement of each radio wave transmitter / receiver 2 cannot be achieved by simply correcting the movement of each moving object, each radio wave transmitter / receiver 2 performs phase correction of the high frequency signal based on the spatiotemporal difference information detected at that time, so that the distributed phased array antenna system 1' can minimize degradation of beam quality. Of course, even if proper correction of the movement of the moving object cannot be performed (for example, when a person is driving a vehicle), it may be possible to suppress degradation of the quality of the composite wave by the phase correction of the high frequency signal by each radio wave transmitter / receiver 2.

[0043] The mobile distributed phased array antenna system 1″ shown in FIG. 7(B) has first to ninth UAVs 4A to 4I equipped with first to ninth radio wave transceivers 2A to 2I, respectively. For example, the first radio wave transceiver 2A functions as a system control device 11. In this distributed phased array antenna system 1″, each radio wave transceiver 2 is mounted on a UAV 4, which is a flyable mobile object, so an array arrangement that utilizes space three-dimensionally can be realized. For example, the distributed phased array antenna system 1″ can easily realize the function of an array antenna with a three-dimensional curved surface, which is difficult to achieve with a large aperture. Furthermore, if the gain of the power amplifiers of the transceiver modules 22 of each radio wave transceiver 2 is not variable, the three-dimensional arrangement of each radio wave transceiver 2 can be fine-tuned to suppress individual variations, thereby suppressing degradation of beam quality.

[0044] Furthermore, if the UAV 4 is an autonomous flying type, each radio wave transceiver 2 may be provided with a movement correction instruction means, and the movement correction instruction means may transmit movement correction information to the movement control device of each moving object (e.g., the autonomous flight control device of the UAV 4). The movement control device of each moving object may then correct the movement direction and movement speed based on the movement correction information, allowing each moving object to move each radio wave transceiver 2 to an optimal position. If each UAV 4 is an unmanned aircraft that can be remotely controlled wirelessly, each radio wave transceiver 2 may be provided with a movement control unit that controls the movement of the moving object, and the movement control unit of each radio wave transceiver 2 may directly control each UAV 4. In this case, the movement control unit not only controls the relative movement of each radio wave transceiver 2 constituting the distributed phased array antenna system 1″, but also performs movement control to correct phase shifts based on the spatiotemporal difference information acquired by the spatiotemporal difference information acquisition unit 28. Until each radio wave transceiver 2 moves to an ideal position through the movement control of each UAV 4 by the movement control unit of each radio wave transceiver 2, the phase correction of the high-frequency signal by each radio wave transceiver 2 can suppress degradation of beam quality.

[0045] Furthermore, in the distributed phased array antenna system 1", by taking advantage of the fact that each UAV4 can freely form a formation, the radio wave transceivers 2 can be arranged so that they form an unequally spaced array as a whole. By adopting an unequally spaced array arrangement, the elements can be arranged with wider element spacing than the normal conditions for grating lobe occurrence, making it possible to reduce the number of elements (the number of radio wave transceivers 2 used). Moreover, in an unequally spaced array, an equivalent amplitude distribution can be created depending on the element arrangement density, so low side lobes can be achieved even if the amplitude distribution of each radio wave transceiver 2 is constant, and the distributed phased array antenna system 1" can have even greater directivity.

[0046] As described above, when the radio wave transceiver 2 is mounted on a mobile object such as a vehicle 3 or a UAV 4, the distributed phased array antenna system 1', 1" as a whole is provided with a means of transportation, making it highly convenient. Moreover, the arrangement of each radio wave transceiver 2 can be changed by moving the mobile object depending on the purpose of use of the distributed phased array antenna system 1', 1", providing a high degree of flexibility. In addition, when the radio wave transceiver 2 is mounted on a mobile object and a mobility function is added, scalability can be achieved that can flexibly respond to changes in the scale of the distributed phased array antenna system 1', 1", making it possible to maximize the advantages of a distributed system.

[0047] For example, each radio wave transceiver 2 may be equipped with a self-diagnosis unit capable of diagnosing any malfunctions that may occur within itself, and an autonomous movement control unit capable of arbitrarily controlling the movement of the mobile body on which it is mounted. When a radio wave transceiver 2 constituting the distributed phased array antenna system 1', 1" is determined to have failed by its self-diagnosis unit, the autonomous movement control unit autonomously moves it out of the array configuration. If the other radio wave transceivers 2 autonomously adjust their arrangement to fill the gap, the impact of the malfunction of one of the radio wave transceivers 2 can be minimized and the distributed phased array antenna system 1', 1" can continue to operate. Note that if there is a standby radio wave transceiver 2, the standby unit may autonomously move to an appropriate position in place of the radio wave transceiver 2 that has fallen due to malfunction, thereby quickly restoring the appropriate array configuration. Furthermore, if the diagnosis by the self-diagnosis unit of the radio wave transceiver 2 indicates that it cannot radiate radio waves at its original output but can radiate weak radio waves, the impact of the malfunction can be reduced by relocating the radio wave transceiver 2 with weaker radiation capabilities to the outermost position of the array configuration. Furthermore, the arrangement of the radio wave transmitters and receivers 2 may be arranged to form an optimal unevenly spaced array, taking into consideration variations in the radiation characteristics of each radio wave transmitter and receiver 2. Furthermore, if the autonomous mobile control unit of each radio wave transmitter and receiver 2 has a self-learning function using reinforcement learning, the autonomous mobile control unit of each radio wave transmitter and receiver 2 can self-learn an optimal solution that can obtain a desired composite wave as the distributed phased array antenna system 1', 1" and autonomously rearrange the arrangement taking into consideration the radiation characteristics of each radio wave transmitter and receiver 2. If each radio wave transmitter and receiver 2 has such a self-learning function, degradation of the composite wave as the distributed phased array antenna system 1', 1" can be minimized even when the radiation characteristics of each radio wave transmitter and receiver 2 change due to aging or other reasons.

[0048] The distributed phased array antenna systems 1, 1', 1" described above use radio wave transceivers 2, 2', 2" that can acquire spatiotemporal differential information to suppress degradation in the quality of the transmitted beam. Radio wave transceivers that can acquire spatiotemporal differential information can also be applied to beamforming, which can form receiving beams with various directions by combining received signals through appropriate phase shift processing and appropriate weighting (amplitude amplification and attenuation). Figure 8 shows a distributed electromagnetic wave observation data collection system 5 that uses beamforming technology to collect data for observing incoming electromagnetic waves. This distributed electromagnetic wave observation data collection system 5 can be used independently for radio wave observations, and can also be used as a distributed antenna (e.g., a radio telescope) for observations using Very Long Baseline Interferometry (VLBI).

[0049] This distributed electromagnetic wave observation data collection system 5 is, for example, configured with one master mobility 51M and first to eighth slave mobility 51S1 to 51S8 (simply referred to as slave mobility 51S when no particular distinction is required) above an arbitrarily set radio wave observation area OA. The first to eighth slave mobility 51S1 to 51S8 and the master mobility 51M each receive radio waves arriving in the radio wave observation area OA, and the first to eighth slave mobility 51S1 to 51S8 transmit the received data (observation data) to the master mobility 51M. After collecting the observation data, the master mobility 51M moves to low altitude at a predetermined data transfer timing (for example, at regular intervals or when the accumulated capacity of observation data reaches a predetermined value) and transmits the observation data from a relatively short distance to an observation data collection station CP, which serves as an observation data collection point. In this way, if Master Mobility 51M moves to a low altitude to transmit observation data, it will be possible to reduce transmission power and perform large-capacity communications compared to transmitting directly from the sky to the observation data collection station CP.

[0050] The observation data collection station CP that receives the observation data can generate a reception beam by combining the reception signals of the observation data collected by the master mobility 51M and the first to eighth slave mobilities 51S1 to 51S8 through appropriate phase shift processing and appropriate weighting processing. At this time, by varying the combination of phase shift processing and weighting for each reception signal, reception beams of different patterns can be generated. In other words, various beam pattern outputs can be obtained from the observation data of electromagnetic waves received in a predetermined arrangement by the master mobility 51M and the first to eighth slave mobilities 51S1 to 51S8.

[0051] The method for transferring the observation data collected by the master mobility 51M to the observation data collection station is not particularly limited. For example, a data collection vehicle CV that receives the observation data may be kept waiting in the electromagnetic wave observation area OA, and the data may be transmitted directly from the master mobility 51M to the data collection vehicle CV. Alternatively, the master mobility 51M may store the observation data on a recording medium, and when the data transfer time arrives, an investigator or the like may remove the recording medium containing the stored observation data from the master mobility 51M that has descended to the ground, replace it with a recording medium with sufficient free space, and quickly return the master mobility 51M to its designated position in the sky. Alternatively, the master mobility 51M and the first through eighth slave mobility 51S1 through 51S8 may move to the electromagnetic wave observation area OA, conduct electromagnetic wave observations on the ground, and when the predetermined data transfer time arrives, only the master mobility 51M may move to the observation data collection station CP or the like to transfer the stored observation data.

[0052] The master mobility 51M is a UAV 4 equipped with a radio wave transceiver 52M. Meanwhile, the first slave mobility 51S1 is a UAV 4 equipped with a radio wave transceiver 52S. Similarly, the second slave mobility 51S2, the third slave mobility 51S3, the fourth slave mobility 51S4, the fifth slave mobility 51S5, the sixth slave mobility 51S6, the seventh slave mobility 51S7, and the eighth slave mobility 51S8 are also UAVs 4 equipped with a radio wave transceiver 52S. Below, the slave radio wave transceiver 52S and the master radio wave transceiver 52M will be described with reference to FIG. 9.

[0053] FIG. 9(A) shows the schematic configuration of the radio wave transceiver 52S for the slave mobility 51S. The radio wave transceiver 52S for the slave mobility 51S does not need to emit a beam by itself, so only the receiving function is shown in FIG. 9(A). However, it may also have a phase-correctable transmitting function similar to the radio wave transceivers 2, 2', and 2" described above. A radio wave transceiver that combines a transmitting function that uses time-space difference information for phase correction during transmission and a receiving function that enables time-space difference information to be used for phase correction of received signals can be used as both a distributed phased array antenna system 1, 1', and 1" and a distributed electromagnetic wave observation data collection system 5, making it highly versatile. Note that in FIGS. 9(A) and 9(B), the same functions as the radio wave transceiver 2 in FIG. 1(B), the radio wave transceiver 2' in FIG. 5, and the radio wave transceiver 2" in FIG. 6 are designated by the same reference numerals, and their descriptions are omitted.

[0054] The radio wave transceiver 52S includes one communication antenna 21, a time-space difference information acquisition unit 28, a transmission / reception module 22 as a signal receiving unit corresponding to the communication antenna 21, a received data transmission unit 524, and a reference oscillator 26 that generates a reference frequency signal. A signal received by the transmission / reception module 22 is converted into an easy-to-handle intermediate frequency or the like by a downconverter 521, and further converted into a digital signal by an A / D conversion unit 522 and input to a transmission / reception control unit 523S. Note that, although beamforming processing using received signals obtained from multiple antennas can be achieved using analog circuits, digital signal processing is more flexible and practical.

[0055] On the other hand, the spatiotemporal difference information acquisition unit 28 transmits and receives codes to and from another radio wave transceiver 52S or 52M via wireless communication using a synchronization antenna 27 separate from the communication antenna 21, and measures temporal difference information, which is the temporal error between the radio wave transceiver 52S, 52M serving as the reference and its own radio wave transceiver, and spatial difference information, which is the spatial error between the appropriate position of the own radio wave transceiver 52S, 52M and its own current position, based on the time difference between the respective reference oscillators 26 and the propagation delay time associated with the code transmission and reception, and acquires spatiotemporal difference information including the temporal difference information and spatial difference information. This spatiotemporal difference information is input to the transmission / reception control unit 523S. Furthermore, if a reference device is selected from the radio wave transceiver 52M in the master mobility 51M and the radio wave transceiver 52S in all slave mobility 51S, and the reference oscillator 26 of the selected reference device is used as the master clock, and the reference oscillators 26 of the other radio wave transceivers 52M and 52S are synchronized, no time error will occur in the received signal, so only spatial difference information can be obtained as time-space difference information.

[0056] The transmission / reception control unit 523S, which has received the received signal and the spatiotemporal difference information as described above, passes a set of the digitized received signal and the spatiotemporal difference information at the time of reception to the received data transmission unit 524. The received data transmission unit 524 links the received signal received by the transmission / reception module 22 as a receiving unit, the spatiotemporal difference information at the time of reception, and its own device's unique information (for example, an arbitrarily set ID number or a chip ID unique to the transmission / reception module 22) that is set so as to be able to distinguish its own device from the other radio wave transceivers 52S and 52M, and transmits this received data to the radio wave transceiver 52M of the master mobility 51M via the received data transmission antenna 525.

[0057] In addition, when multiple communication antennas 21 and corresponding receiving units (transmission / reception modules 22, downconverter 521, A / D conversion unit 522) are provided, the received data transmission unit 524 may include information that can identify each receiving unit in the radio wave transceiver 52S in the received data. Also, a mobile object position control unit 523a may be provided in the transmission / reception control unit 523, and the UAV4 as a mobile object may be moved so as to correct its own position based on the spatial difference information of the time-space difference information, thereby controlling the UAV4 to approach an appropriate position.

[0058] FIG. 9B shows a schematic configuration of the radio wave transceiver 52M of the master mobility 51M to which the received data is transmitted from the radio wave transceiver 52S of the slave mobility 51S described above.

[0059] The received data received from each radio wave transceiver 52S via the observation data receiving antenna 526 and the observation data receiving unit is accumulated as observation data in the observation data accumulation unit 523b. Note that while it is sufficient for the master mobility 51M to have the function of collecting observation data and transferring it to a data collection point, the radio wave transceiver 52S is provided with a receiving unit (transmission / reception module 22, downconverter 521, A / D conversion unit 522) so that the master mobility 51M can also perform electromagnetic wave observation. Therefore, the received signal received by the radio wave transceiver 52M, the time-space difference information, and the unique information of the radio wave transceiver 52M are also accumulated as observation data in the observation data accumulation unit 523b.

[0060] Then, when the transmission / reception control unit 523M determines that the predetermined data transfer timing has arrived, the mobile unit position control unit 523a instructs the UAV4 as a mobile unit to move to low altitude and transfer the observation data to the data collection station via the observation data transmission unit 528 and the observation data transmission antenna 529. When the transfer of the observation data is completed, the master mobility 51M returns to the predetermined observation position again and resumes radio wave observation.

[0061] In this way, the distributed electromagnetic wave observation data collection system 5, which uses the master mobility 51M equipped with a radio wave transceiver 52M on a UAV 4 and the first through eighth slave mobility 51S1-51S8 equipped with a radio wave transceiver 52S on a UAV 4, can suppress degradation of beam quality by using the spatiotemporal difference information acquired by each radio wave transceiver 52M, 52S as correction information. That is, the observation data collection station CP that receives the observation data corrects the phase of the received signals of the observation data collected by the master mobility 51M and the first through eighth slave mobility 51S1-51S8 based on the respective spatiotemporal difference information, thereby improving the accuracy of the received signals. By combining the highly accurate received signals through appropriate phase shift processing and appropriate weighting processing, a high-quality receiving beam can be generated. The spatiotemporal difference information acquisition unit 28 provided in the radio wave transceivers 52S, 52M may also acquire the current relative position of the radio wave transceiver 52S, 52M with respect to the reference radio wave transceiver 52S, 52M as spatial difference information. The observation data collection station CP that receives observation data from the master mobility 51M can perform appropriate phase shift processing and appropriate weighting processing that take into account the relative positional shift of the radio transmitter / receivers 52S, 52M if it can grasp the relative positions of the other radio transmitter / receivers 52S, 52S with respect to the reference radio transmitter / receiver 52S, 52S in the observation data each time radio waves are received.

[0062] In addition, while the radio wave transmitters and receivers 2, 2', 2", 52M, and 52S capable of acquiring time-space differential information have been shown as examples for use in the distributed phased array antenna systems 1, 1', and 1" and the distributed electromagnetic wave observation data collection system 5, they can also be used as passive radars or active radars. The larger the aperture diameter of a radar, the higher the resolution, but manufacturing and operating a large aperture radar is not easy. However, distributed radars such as the radio wave transmitters and receivers 2, 2', 2", 52M, and 52S described above are easy to manufacture and operate. As an example, Figure 10 shows a distributed synthetic aperture radar system 6 applied to a synthetic aperture radar (SAR) that can generate two-dimensional images by processing the received signals obtained by repeatedly transmitting and receiving pulses while moving in the azimuth direction above the image acquisition area.

[0063] The distributed synthetic aperture radar system 6 is composed of, for example, a master synthetic aperture radar device 61M, a first slave synthetic aperture radar device 61S1, a second slave synthetic aperture radar device 61S2, and a phase control device 64. The master synthetic aperture radar device 61M is configured by mounting a radio wave transceiver 62M on a UAV4 as a moving body. The first slave synthetic aperture radar device 61S1 and the second slave synthetic aperture radar device 61S2 are configured by mounting a radio wave transceiver 62S on the UAV4 as a moving body. The phase control device 64 is configured by mounting a synthetic aperture radar signal processing device 63 on the UAV4 as a moving body.

[0064] The flight direction of the master synthetic aperture radar device 61M is the azimuth direction, and the master synthetic aperture radar device 61M repeatedly transmits observation pulse signals and receives reflected signals so that an observation area OA is formed as an image acquisition area in the ground range direction perpendicular to the azimuth direction. The first slave synthetic aperture radar device 61S1 and the second slave synthetic aperture radar device 61S2 are arranged in a row with the master synthetic aperture radar device 61M in an arrangement direction parallel to the ground range direction, and repeatedly transmit pulse signals and receive reflected signals to the same observation area OA as the master synthetic aperture radar device 61M. In other words, the emitted beam BM of the master synthetic aperture radar device 61M, the emitted beam BS1 of the first slave synthetic aperture radar device 61S1, and the emitted beam MS2 of the second slave synthetic aperture radar device 61S2 are equally emitted to the observation area OA, and the observation area OA gradually shifts in the azimuth direction (slip mapping). Furthermore, the distance between the master synthetic aperture radar device 61M, the first slave synthetic aperture radar device 61S1, and the second slave synthetic aperture radar device 61S2 is approximately several tens of centimeters to several meters, and when flying at an altitude of several hundred meters, it can be considered that a pulse signal is transmitted from a single radiation source from the observation area OA. The number of slave synthetic aperture radar devices 61S is not limited to two, and may be one, or three or more.

[0065] The movement control device 64 flies following the master synthetic aperture radar device 61M and the first and second slave synthetic aperture radar devices 61S1, 61S2, and receives reception data from the master synthetic aperture radar device 61M and the first and second slave synthetic aperture radar devices 61S1, 61S2. The synthetic aperture radar signal processing device 63 receives the reception data from the master synthetic aperture radar device 61M and the first and second slave synthetic aperture radar devices 61S1, 61S2, and processes the reception data to generate a two-dimensional image. As a processing step performed by the synthetic aperture radar signal processing device 63, for example, a correlation process is performed between the reflected signal obtained by transmitting a frequency-modulated chirp signal to the observation area OA and a reference signal (a partial section of the chirp pulse) to resolve the ground range direction, and an azimuth direction is resolved by a correlation process between the received signal and a reference wave calculated taking into account the Doppler effect due to the flight speeds of the master synthetic aperture radar device 61M and the first and second slave synthetic aperture radar devices 61S1, 61S2.

[0066] Next, detailed functions of the master synthetic aperture radar device 61M, the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm, and the phase control device 64 that constitute the distributed synthetic aperture radar system 6 will be described with reference to FIG.

[0067] For example, the radio wave transceiver 62M of the master synthetic aperture radar device 61M includes a pulse transceiver unit 622 that transmits and receives pulse signals via a communication antenna 621. The master radio wave transceiver 62M also includes a space-time difference information acquisition unit 6232 that transmits and receives codes to and from another radio wave transceiver 62S by wireless communication using a synchronization antenna 6231 that is separate from the communication antenna 621, and that measures temporal difference information that is a temporal error with the reference radio wave transceiver 62S and spatial difference information that is a spatial error between the appropriate position of the master radio wave transceiver 62M and its current position with respect to the reference radio wave transceiver 62S based on the time difference between the two and the propagation delay time associated with the code transmission and reception, and acquires space-time difference information including the temporal difference information and the spatial difference information.

[0068] However, in the distributed synthetic aperture radar system 6 of this embodiment, the reference oscillator 624 of the radio wave transceiver 62M in the master synthetic aperture radar device 61M is selected as the master clock to synchronize the reference oscillators 624 of the radio wave transceivers 62S of the first to M slave synthetic aperture radar devices 61S1 to 61Sm. Therefore, the synchronization control unit 6233 controls the spatiotemporal difference information acquisition unit 6232 to perform phase shift detection using the reference oscillator 624 as the master clock. Therefore, the spatiotemporal difference information acquisition unit 6232 of the radio wave transceiver 62M does not acquire temporal difference information, and only spatial difference information is stored in the spatiotemporal difference information storage unit 625. Furthermore, when spatial difference information of the other radio wave transceivers 62S is detected based on the flight position of the master synthetic aperture radar device 61M, the spatiotemporal difference information acquisition unit 6232 of the radio wave transceiver 62M does not detect spatial difference information. When storing the spatiotemporal difference information in the spatiotemporal difference information storage unit 625, a timestamp is also stored to clarify the timing of storage.

[0069] The pulse transmitting / receiving unit 622 generates a frequency-modulated chirp signal using a chirp pulse generating unit 6221, and emits the pulse signal from the communication antenna 621 driven to an appropriate emission position by an antenna driving unit 6222. The reflected signal reflected by the observation target is received by a reflected signal receiving unit 6223 and stored in a reflected signal storage unit 626. At this time, a timestamp is added to store the reflected signal so that the timing of saving the reflected signal is clear.

[0070] Then, the received data transmission unit 6271 transmits the reflected signal received by the pulse transmission / reception unit 622 and stored in the reflected signal storage unit 626, the time-space difference information stored in the time-space difference information storage unit 625, and the unique information of the radio wave transceiver 62M as received data to the synthetic aperture radar signal processing device 63 of the movement control device 64. Note that the synthetic aperture radar signal processing device 63 can determine the correspondence between the reflected signal and the time-space difference information from their respective time stamps.

[0071] On the other hand, the radio wave transceiver 62S of the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm has a configuration almost identical to that of the radio wave transceiver 62M in the master synthetic aperture radar device 61M described above. Therefore, the same functions are given the same symbols and their explanations are omitted, and only the differences will be explained below.

[0072] The spatiotemporal difference information acquisition unit 6232 of the radio wave transceiver 62S acquires temporal difference information using the reference oscillator 624 of the radio wave transceiver 62M as a master clock via wireless communication using the synchronization antenna 6231, and the synchronization control unit 6233 controls the reference oscillator 624 to correct the temporal error. This synchronizes the reference oscillator 624 of the radio wave transceiver 62S with the reference oscillator 624 of the radio wave transceiver 62M. Therefore, the phases of the chirp pulses generated by the chirp pulse generation units 6221 of the radio wave transceivers 62S of the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm can be aligned with high precision. In other words, when pulse signals are simultaneously emitted from the master synthetic aperture radar device 61M and the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm toward the observation area OA, it appears as if a high-power chirp pulse is being emitted from a single antenna. This increases the reception level of the reflected signal from the observation target, reducing the effects of noise. In addition, the reflected signal from the observation target is received simultaneously by the master synthetic aperture radar device 61M and the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm, so that the reflected signal appears to be received by an antenna with a large diameter.

[0073] The control functions in the distributed synthetic aperture radar system 6 (such as control of flight speed and direction of the communication antenna 621) may be provided to the master synthetic aperture radar device 61M or the movement control device 64.

[0074] The synthetic aperture radar signal processing device 63 of the mobile control device 64 acquires received data from the master synthetic aperture radar device 61M and the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm via a data receiving antenna 631 and a wireless communication unit 632. A phase adjustment unit 633 performs phase adjustment on the reflected signals in the received data from the master synthetic aperture radar device 61M to correct spatial errors based on the spatial difference information in the space-time difference information. This results in received data from the master synthetic aperture radar device 61M with the spatial errors corrected based on the space-time difference information. Similarly, the phase adjustment unit 633 performs phase adjustment on the reflected signals in the received data from the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm to correct spatial errors based on the spatial difference information in the space-time difference information. This results in received data from the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm with the phase shifts corrected based on the space-time difference information.

[0075] As described above, the reflected signals simultaneously received by the master synthetic aperture radar device 61M and the first to Mth slave synthetic aperture radar devices 61S1 to 61Sm are considered to be data for the same observation area OA. If these simultaneously acquired reflected signals are phase-adjusted and combined to generate composite received data, the effects of irregular noise can be reduced. Therefore, if the correlation processing execution unit 634 performs correlation processing on the composite received data and resolves it, a highly accurate two-dimensional image can be obtained.

[0076] 12, chirp pulses may be emitted only by the master synthetic aperture radar device 61M, and the radio wave transceivers 62S' of the first to M slave synthetic aperture radar devices 61S1' to 61Sm' may only receive pulses. In this case, the radio wave transceiver 62S' does not need to synchronize the reference oscillator 624 with the master clock, and the pulse transmission function of the pulse transceiver unit 622 may not be used. Alternatively, a pulse receiver 628 may be provided instead of the pulse transceiver unit 622, and only an antenna driver 6281 that drives the communication antenna 621 and a reflected signal receiver 6282 may be provided. In this distributed synthetic aperture radar system 6', highly accurate two-dimensional images can be obtained by combining and correlating the reflected signals simultaneously received by the master synthetic aperture radar device 61M and the first to M slave synthetic aperture radar devices 61S1' to 61Sm'.

[0077] The above describes embodiments of the radio wave transmitter / receiver, distributed phased array antenna system, distributed electromagnetic wave observation data collection system, and distributed synthetic aperture radar system according to the present invention based on the accompanying drawings. However, the present invention is not limited to these embodiments, and may be implemented by converting publicly known, existing equivalent technical means within the scope of the claims. [Explanation of symbols]

[0078] 1. Distributed Phased Array Antenna System 2 Radio wave transmitter and receiver 21 Communication antenna 24 Phase adjustment section 26 Reference Oscillator 28 Spatio-temporal difference information acquisition unit

Claims

1. A radio wave transceiver usable as an antenna element constituting a phased array antenna system in which a plurality of antenna elements are arranged to obtain a desired directivity, The system includes N communication antennas (N is any natural number), a space-time difference information acquisition unit, a phase adjustment unit, and a reference oscillator that generates a reference frequency signal, the time-space difference information acquisition unit transmits and receives codes to and from another radio wave transceiver by wireless communication using a synchronization antenna separate from the communication antenna, and measures temporal difference information, which is a temporal error between the radio wave transceiver serving as a reference and its own device, and spatial difference information, which is a spatial error between its own device's appropriate position and its own device's current position relative to the radio wave transceiver serving as a reference, based on a time difference between the respective reference oscillators and a propagation delay time associated with the code transmission and reception, and acquires time-space difference information including the temporal difference information and the spatial difference information; the phase-shift adjusting unit adjusts the amount of phase shift of the radio wave radiated from the communication antenna so as to correct the temporal error and / or the spatial error based on the time-space difference information. A radio wave transmitter / receiver characterized by:

2. 10. A distributed phased array antenna system comprising a plurality of the radio wave transceivers according to claim 1, wherein the phased array antenna system has a specific directivity due to superposition of radio waves radiated from the communication antennas of the respective radio wave transceivers.

3. A radio wave transceiver that can be used as each antenna element in a beamforming antenna that can form reception beams with various directions by arranging multiple antenna elements and performing appropriate phase shift processing and appropriate weighting (amplitude amplification / attenuation) processing on the reception signals received by each antenna element and combining the received signals, The system includes N communication antennas (N is any natural number), a time-space difference information acquisition unit, N signal receiving units corresponding to the respective communication antennas, a received data transmitting unit, and a reference oscillator that generates a reference frequency signal, the time-space difference information acquisition unit transmits and receives codes to and from another radio wave transceiver by wireless communication using a synchronization antenna separate from the communication antenna, and measures time difference information, which is a time error between the radio wave transceiver serving as a reference and its own device, and spatial difference information, which is a relative position of its own device with respect to the radio wave transceiver serving as a reference, based on a time difference between the mutual reference oscillators and a propagation delay time associated with the code transmission and reception, and acquires time-space difference information including the time difference information and the spatial difference information; the received data transmitting unit transmits to the outside of the device received data that is linked to the received signal received by the signal receiving unit, the time-space difference information at the reception timing of the signal, and unique information of the device that is set so as to be able to distinguish the device from the other radio wave transceivers; A radio wave transmitter / receiver characterized by:

4. a plurality of slave mobilities each having the radio wave transceiver according to claim 3 mounted thereon; a master mobility having a data relay device mounted on a moving body that collects at least the received data transmitted from the plurality of slave mobility devices and transfers the collected received data to a predetermined data collection point; Including, A distributed electromagnetic wave observation data collection system characterized in that multiple slave mobilities and the master mobility are placed in an arbitrarily set electromagnetic wave observation area, and only the master mobility that collects the received data from each slave mobility forwards the collected received data to the data collection center as electromagnetic wave observation data.

5. A radio wave transmitter / receiver that can be used as each antenna element in a synthetic aperture radar that has a plurality of antenna elements arranged, and that can generate a two-dimensional image by processing received signals obtained by repeatedly transmitting and receiving pulses while moving in an azimuth direction above an image acquisition area using a synthetic aperture radar signal processing device, The system includes N communication antennas (N is any natural number), N pulse transmitting / receiving units corresponding to the respective communication antennas, a space-time difference information acquiring unit, a received data transmitting unit, and a reference oscillator that generates a reference frequency signal, the time-space difference information acquisition unit transmits and receives codes to and from another radio wave transceiver by wireless communication using a synchronization antenna separate from the communication antenna, and measures temporal difference information, which is a temporal error between the radio wave transceiver serving as a reference and its own device, and spatial difference information, which is a spatial error between its own device's appropriate position and its own device's current position relative to the radio wave transceiver serving as a reference, based on a time difference between the respective reference oscillators and a propagation delay time associated with the code transmission and reception, and acquires time-space difference information including the temporal difference information and the spatial difference information; the received data transmitting unit transmits, as received data, to the synthetic aperture radar signal processing device, the reflected signal received by the pulse transmitting / receiving unit, the time-space difference information acquired by the time-space difference information acquiring unit, and unique information of the own device set to be able to distinguish between the own device and the other radio wave transceivers; A radio wave transmitter / receiver characterized by:

6. a master synthetic aperture radar device that is mounted on a moving body and that transmits pulse signals to the image acquisition area and receives reflected signals; M slave synthetic aperture radar devices (M is any natural number) each equipped with the radio wave transmitter / receiver according to claim 5 and configured to transmit pulse signals and receive reflected signals from the same image acquisition area as the master synthetic aperture radar device; a synthetic aperture radar signal processing device that processes received data from the master synthetic aperture radar device and the slave synthetic aperture radar device to generate a two-dimensional image; Including, the slave synthetic aperture radar device acquires the spatiotemporal difference information using the master synthetic aperture radar device as the reference radio wave transceiver, and performs phase adjustment to correct the temporal error based on at least the temporal difference information, thereby transmitting a pulse signal synchronized with the pulse transmission of the master synthetic aperture radar device; the synthetic aperture radar signal processing device performs phase adjustment on the reflected signals in the received data from the master synthetic aperture radar device and / or the slave synthetic aperture radar device to correct the spatial error based on at least the spatial difference information in the spatiotemporal difference information; A distributed synthetic aperture radar system comprising:

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