Electronic scanning antenna system and communication method

Abstract

This invention provides an electronically scanning antenna system capable of communicating with communication equipment with high precision and continuous operation. [Solution] The electronic scanning antenna system (1) comprises a plurality of antenna surfaces (S), detection units (12, 131), a selection unit (132) that, based on the detection results of the detection units, selects one of the plurality of antenna surfaces as the main antenna surface and one of the other antenna surfaces as the sub-antenna surface, a receiving unit (134) that receives a received signal from a communication device via the main antenna surface and the sub-antenna surface, and a transmitting unit (135) that transmits a transmitted signal to a communication device via the main antenna surface. Each of the plurality of antenna surfaces is equipped with a plurality of units (U1 to U4) through which the received signal and the transmitted signal are transmitted. The detection unit detects the received signal value of the received signal transmitted to each of the plurality of units.

Description

Technical Field

[0001] The present invention relates to an electronic scanning antenna system and a communication method.

Background Art

[0002] Conventionally, an electronic scanning antenna system (hereinafter referred to as "conventional antenna") capable of communicating with a communication device (communication base station) has been known (see, for example, Patent Document 1). The conventional antenna includes, for example, a plurality of antenna surfaces (such as planar patch antennas) capable of communicating with a communication device. The conventional antenna selects one of the plurality of antenna surfaces based on the reception signal values (such as gain, voltage, etc.) of the reception signals transmitted to each of the plurality of antenna surfaces, and communicates (transmits and receives) with the communication device only through the selected antenna surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] ... ... However, in the conventional antenna, when changes in the relative positional relationship with the communication device, communication adverse effects (such as errors in reception signal values due to reflected waves, errors in reception signal values due to electronic noise, etc.) occur, the conventional antenna may select a non-optimal antenna surface. In this case, the communication accuracy by the conventional antenna may decrease as compared with the case where an optimal antenna surface is selected.

[0005] Furthermore, when the relative positional relationship between the conventional antenna and the communication equipment changes, communication via the selected antenna surface may be interrupted. Therefore, with conventional antennas, from the time communication via the selected antenna surface is interrupted until a new antenna surface is re-selected, the conventional antenna cannot communicate continuously with the communication equipment.

[0006] Thus, conventional antennas cannot communicate (transmit and receive) with communication devices with high precision and continuously. Therefore, there is a need for an electronically scanned antenna system that can communicate with communication devices with high precision and continuously.

[0007] The present invention aims to provide an electronically scanned antenna system and a communication method that can communicate with communication equipment with high precision and continuously. [Means for solving the problem]

[0008] The electronic scanning antenna system according to the present invention is an electronic scanning antenna system that receives a receiving signal from a communication device and transmits a transmission signal to the communication device, comprising: a plurality of antenna surfaces to which the receiving signal and the transmission signal are transmitted; a detection unit that detects the received signal value of the receiving signal; a selection unit that, based on the detection result of the detection unit, selects one of the plurality of antenna surfaces as the main antenna surface and one of the other antenna surfaces as the sub-antenna surface; a receiving unit that receives the receiving signal from the communication device via the main antenna surface and the sub-antenna surface; and a transmitting unit that transmits the transmission signal to the communication device via the main antenna surface, wherein each of the plurality of antenna surfaces comprises a plurality of units to which the receiving signal and the transmission signal are transmitted, and the detection unit detects the received signal value of the receiving signal transmitted to each of the plurality of units. [Effects of the Invention]

[0009] The present invention provides an electronically scanning antenna system and a communication method that can communicate with communication equipment with high precision and continuously. [Brief explanation of the drawing]

[0010] [Figure 1] This is a network configuration diagram of an electronically scanned antenna system according to the present invention, showing an embodiment of the said antenna system. [Figure 2] Figure 1 is a schematic perspective view of the electronic scanning antenna system. [Figure 3] Figure 1 is a schematic diagram of the antenna surface of the electronically scanned antenna system. [Figure 4] Figure 1 is a functional block diagram of the electronic scanning antenna system. [Figure 5] Figure 1 shows the electronic scanning antenna system, Figure 5(a) is a schematic front view of the same electronic scanning antenna system, and Figure 5(b) is a schematic top view of the same electronic scanning antenna system. [Figure 6] Figure 1 shows the electronic scanning antenna system, Figure 6(a) is a schematic front view of the same electronic scanning antenna system, and Figure 6(b) is a schematic top view of the same electronic scanning antenna system. [Figure 7] This is a flowchart showing an embodiment of the communication method according to the present invention. [Figure 8] Figure 7 is a flowchart showing an example of the initial decision process included in the communication method. [Figure 9] Figure 7 is a flowchart showing an example of the specific antenna plane re-determination process included in the communication method. [Figure 10] Figure 10(a) is a schematic front view of the electronic scanning antenna system, and Figure 10(b) is a schematic perspective view of the electronic scanning antenna system, illustrating an example of its operation. [Figure 11] Figure 11(a) is a schematic front view of the electronic scanning antenna system, and Figure 11(b) is a schematic perspective view of the electronic scanning antenna system, illustrating an example of its operation. [Figure 12] Figure 12(a) is a schematic front view of the electronic scanning antenna system, and Figure 12(b) is a schematic perspective view of the electronic scanning antenna system, illustrating an example of its operation. [Figure 13]An example of the operation of the electronic scanning antenna system of FIG. 1 is shown. FIG. 13(a) is a schematic front view of the electronic scanning antenna system, and FIG. 13(b) is a schematic perspective view of the electronic scanning antenna system.

Embodiment for Carrying Out the Invention

[0011] Embodiments of the electronic scanning antenna system (hereinafter referred to as "this antenna") and the communication method (hereinafter referred to as "this method") according to the present invention will be described below together with the respective drawings. In each drawing, the same members and elements are denoted by the same reference numerals, and duplicate explanations are omitted. Also, the dimensional ratios of the respective elements may be exaggerated for convenience of explanation and are not limited to the ratios shown in each drawing.

[0012] In each drawing, the X-axis, the Y-axis, and the Z-axis are mutually orthogonal. The "X-axis direction" is the direction along the X-axis. The "+X direction" is one direction of the X-axis direction. The "-X direction" is the other direction of the X-axis direction. The "Y-axis direction" is the direction along the Y-axis. The "+Y direction" is one direction of the Y-axis direction. The "-Y direction" is the other direction of the Y-axis direction. The "Z-axis direction" is the direction along the Z-axis and is the vertical direction. The "+Z direction" is the upward direction. The "-Z direction" is the downward direction. The "XY direction" is the direction along the X-axis direction and the Y-axis direction. The "XY plane" is a virtual plane parallel to the XY direction.

[0013] In the following description, the "azimuth angle" is the angle formed by a predetermined direction in the XY plane and the +X direction, and is the rotation angle when the Z-axis is the rotation axis. The "azimuth angle direction" is the circumferential direction of a virtual circle centered on the Z-axis. The "elevation angle" is the angle formed by the direction inclined from the XY direction to the +Z direction and the XY plane. The "elevation angle direction" is the direction inclined from the XY direction to the +Z direction.

[0014] ●Embodiment of this Antenna● ●Configuration of this Antenna The configuration of this antenna will be described below.

[0015] FIG. 1 is a network configuration diagram of the present antenna showing an embodiment of the present antenna.

[0016] The present antenna 1 is an electronic scanning antenna system that receives a reception signal from the communication device 2 and transmits a transmission signal to the communication device 2. The present antenna 1 is connected to the communication device 2 via the communication line L. The present antenna 1 is installed, for example, on a lunar exploration vehicle (not shown; the same applies hereinafter) that travels on the lunar surface. That is, the present antenna 1 is installed on the lunar surface. Details of the configuration of the present antenna 1 will be described later.

[0017] The communication device 2 is, for example, an artificial satellite capable of communicating with the present antenna 1. The communication device 2 is arranged in a lunar satellite orbit and orbits the moon. The communication device 2 is connected to the present antenna 1 via the communication line L.

[0018] The communication line L is a wireless communication line connected to the present antenna 1 and the communication device 2.

[0019] The "reception signal" is a signal received by the present antenna 1 and is a signal transmitted from the communication device 2 to the present antenna 1. The reception signal is, for example, a signal necessary for establishing the communication line L, a signal indicating the operation and state of the communication device 2, a signal indicating the position of the communication device 2, and the like.

[0020] The "transmission signal" is a signal transmitted from the present antenna 1 to the communication device 2 and is a signal received by the communication device 2. The transmission signal is, for example, a signal necessary for establishing the communication line L, a signal indicating the operation and state of the exploration vehicle, a signal indicating the state of the lunar surface, a signal indicating the position of the exploration vehicle (the present antenna 1), and the like.

[0021] FIG. 2 is a schematic perspective view of the present antenna 1.

[0022] The present antenna 1 includes 73 antenna surfaces S, 73 phase units 11 (see FIG. 4), 73 generation units 12 (see FIG. 4), and a control unit 13 (see FIG. 4).

[0023] The antenna surface S is capable of receiving received signals and transmitting (radiating) transmitted signals. In other words, both received and transmitted signals are transmitted to the antenna surface S. Each of the antenna surfaces S is oriented in a different direction from the others, forming a roughly hemisphere.

[0024] Each of the 16 antenna surfaces S (hereinafter referred to as "antenna surface S1" when distinguishing it from other antenna surfaces S) is positioned facing in the direction of elevation angle 0° (XY direction). Each of the other 16 antenna surfaces S (hereinafter referred to as "antenna surface S2" when distinguishing it from other antenna surfaces S) is positioned facing in the direction of elevation angle 18°. Each of the yet another 16 antenna surfaces S (hereinafter referred to as "antenna surface S3" when distinguishing it from other antenna surfaces S) is positioned facing in the direction of elevation angle 36°. Each of the yet another 16 antenna surfaces S (hereinafter referred to as "antenna surface S4" when distinguishing it from other antenna surfaces S) is positioned facing in the direction of elevation angle 54°. Each of the yet another 8 antenna surfaces S (hereinafter referred to as "antenna surface S5" when distinguishing it from other antenna surfaces S) is positioned facing in the direction of elevation angle 72°. Furthermore, another antenna surface S (hereinafter referred to as "antenna surface S6" when distinguished from the other antenna surfaces S) is positioned facing a direction with an elevation angle of 90°. In this way, the direction in which each of the antenna surfaces S1 to S5 faces is tilted by an elevation angle of 18°.

[0025] The 16 antenna surfaces S1 are arranged at equal intervals in the azimuth direction (azimuth angle 22.5°). The same applies to antenna surfaces S2 to S4. The 8 antenna surfaces S5 are arranged at equal intervals in the azimuth direction (azimuth angle 45°).

[0026] Of the 73 antenna surfaces S, one antenna surface S functions as the "main antenna surface." Both received and transmitted signals are transmitted to the main antenna surface.

[0027] Of the 73 antenna surfaces S, one antenna surface S, excluding the antenna surface S that functions as the primary antenna surface, functions as a "secondary antenna surface." The received signal is transmitted to the secondary antenna surface.

[0028] Of the 73 antenna surfaces S, some antenna surfaces S function as "specific antenna surfaces." These "specific antenna surfaces" are those antenna surfaces S corresponding to the sum signal and difference signal generated by the generation unit 12 (described later; the same applies hereinafter) during the operation of the main antenna 1 after the initial determination process (described later; the same applies hereinafter). Multiple specific antenna surfaces include at least a main antenna surface and a sub-antenna surface.

[0029] The remaining antenna surfaces S (antenna surfaces S that are not the designated antenna surfaces) function as "non-designated antenna surfaces".

[0030] Figure 3 is a schematic diagram of the antenna surface S.

[0031] The antenna surface S comprises four units U1, U2, U3, and U4.

[0032] In the following explanation, when units U1 to U4 are not specifically distinguished, they will all be collectively referred to as "Unit U".

[0033] Unit U is capable of receiving signals and transmitting (radiating) signals. That is, both received and transmitted signals are transmitted to Unit U. Unit U is, for example, a planar patch antenna. Units U1 to U4 are arranged in a two-dimensional array of 2 rows and 2 columns. Specifically, Unit U1 is placed in the 1st row and 1st column, Unit U2 is placed in the 1st row and 2nd column, Unit U3 is placed in the 2nd row and 1st column, and Unit U4 is placed in the 2nd row and 2nd column. The row direction is the azimuth direction. The column direction is the elevation direction. Unit U comprises 64 known antenna elements (not shown; the same applies hereinafter). That is, the antenna surface S comprises 256 antenna elements. In other words, this antenna 1 comprises 18,688 antenna elements.

[0034] Figure 4 is a functional block diagram of the antenna 1. In this figure, the 70 antenna surfaces S, 70 phase units 11, and 70 generation units 12 are not shown.

[0035] One antenna surface S, four units U1 to U4 on the same antenna surface S, one phase unit 11, and one generation unit 12 correspond to each other.

[0036] The phase unit 11 controls the phase of the received signal and the transmitted signal (the received signal received by each of the corresponding units U1 to U4 and the transmitted signal transmitted by each of the corresponding units U1 to U4) transmitted to each of the corresponding units U1 to U4. The phase unit 11 comprises four receiving phase units 11R and four transmitting phase units 11T.

[0037] One unit U, one receiving phase unit 11R, and one transmitting phase unit 11T correspond to each other.

[0038] The receiving phase unit 11R controls the phase of the received signal (the received signal received by the corresponding unit U) transmitted to the corresponding unit U.

[0039] The transmitting phase unit 11T controls the phase of the transmitted signal transmitted to the corresponding unit U based on the control result of the corresponding receiving phase unit 11R.

[0040] The phase unit 11 combines the phases of the received signals controlled by each of the receiving phase units 11R to control the directivity (beam) of the corresponding antenna surface S. The phase unit 11 also combines the phases of the transmitted signals controlled by each of the transmitting phase units 11T to control the directivity (beam) of the corresponding antenna surface S.

[0041] The generation unit 12 detects the signal values ​​(hereinafter referred to as "received signal values") of the received signals (received signals received by the corresponding units U) transmitted to each of the units U1 to U4 on the corresponding antenna surface S, and generates the sum signal and difference signal of the received signals. The generation unit 12 is, for example, a known RF sensor circuit. Details of the operation of the generation unit 12 will be described later.

[0042] The "received signal value" is, for example, gain, voltage, etc. The received signal value of the received signal transmitted to (received by) unit U will differ depending on the relative position of unit U and communication device 2.

[0043] In the following explanation, "received signal value corresponding to unit U" means the received signal value of the received signal transmitted to unit U.

[0044] The "sum signal" is a signal generated at each antenna surface S based on the received signals transmitted to each of units U1 to U4. The signal value of the sum signal (hereinafter referred to as the "sum signal value") is the sum of the received signal values ​​corresponding to each of units U1 to U4. The sum signal value indicates the magnitude of the received signal values ​​of the received signals transmitted to the antenna surface S.

[0045] In the following explanation, "sum signal corresponding to antenna surface S" refers to the sum signal transmitted to each of the units U1 to U4 on antenna surface S. "Sum signal value corresponding to antenna surface S" refers to the sum signal value transmitted to each of the units U1 to U4 on antenna surface S.

[0046] The "difference signal" is a signal generated at each antenna surface S based on the received signals transmitted to each of units U1 to U4. The signal value of the difference signal (hereinafter referred to as the "difference signal value") is the difference between the received signal values ​​corresponding to each of units U1 to U4. Details of the difference signal value will be described later.

[0047] In the following explanation, "difference signal corresponding to antenna surface S" refers to the difference signal transmitted to each of the units U1 to U4 on antenna surface S. "Difference signal value corresponding to antenna surface S" refers to the difference signal value of the difference signal transmitted to each of the units U1 to U4 on antenna surface S.

[0048] The control unit 13 controls the operation of the entire antenna 1. The control unit 13 includes, for example, a processor such as a CPU (Central Processing Unit) (not shown; the same applies hereinafter), volatile memory such as RAM (Random Access Memory) that functions as a work area for the CPU (not shown; the same applies hereinafter), and non-volatile memory such as ROM (Read Only Memory) that stores various information (not shown; the same applies hereinafter). "Various information" includes, for example, a program that controls the operation of the entire antenna 1, the first threshold, the second threshold, etc., which will be described later. The processor functions as a detection unit 131, a selection unit 132, a determination unit 133, a reception unit 134, and a transmission unit 135. In other words, the control unit 13 includes a detection unit 131, a selection unit 132, a determination unit 133, a reception unit 134, and a transmission unit 135.

[0049] Furthermore, some or all of the control unit in the present invention (specifically, the detection unit, the selection unit, the determination unit, the receiving unit, and the transmission unit) may be implemented by a software-defined radio (SDR).

[0050] The detection unit 131 detects the sum signal value of the sum signal and the difference signal value of the difference signal, which are generated by each of the generation units 12. The generation unit 12 and the detection unit 131 are examples of detection units in the present invention.

[0051] Based on the detection results of the generation unit 12 and the detection unit 131, the selection unit 132 selects one of the 73 antenna surfaces S as the main antenna surface and one of the other antenna surfaces S as the secondary antenna surface. Details of the operation of the selection unit 132 will be described later.

[0052] The determination unit 133 determines a specific antenna surface and a non-specific antenna surface based on the sum signal value and difference signal value corresponding to the main antenna surface and the sub-antenna surface, respectively. The details of the operation of the determination unit 133 will be described later.

[0053] The receiving unit 134 receives the received signal from the communication device 2 via the unit U, the receiving phase unit 11R, and the generation unit 12.

[0054] The transmitting unit 135 transmits the transmission signal to the communication device 2 via the unit U and the transmitting phase unit 11T.

[0055] The "first threshold" is the minimum sum signal value when the antenna 1 and the communication device 2 can communicate stably. That is, when the sum signal value corresponding to each of the 73 antenna surfaces S is smaller than the first threshold, problems such as increased reception time and communication disconnection may occur. In other words, communication between the antenna 1 and the communication device 2 may become unstable. The first threshold is stored in advance in the non-volatile memory of the control unit 13.

[0056] The "second threshold" is the allowable error in the sum signal value when the sum signal is generated. This error is due to factors such as noise added to the received signal, interference with other signals, and reflection of the received signal. For example, when the difference between the sum signal values ​​corresponding to each of the two antenna surfaces S is less than or equal to the second threshold, the difference between the sum signal values ​​is an allowable error, and the sum signal values ​​are considered to be of a similar magnitude.

[0057] ● Communication space Figure 5 is a schematic diagram of the antenna 1. Figure 5(a) is a schematic front view of the antenna 1 showing individual communication spaces ISa corresponding to one antenna surface S1. In Figure 5(a), the thick arrows indicate the movement of individual communication spaces ISa in the elevation direction. Figure 5(b) is a schematic plan view of the antenna 1 showing individual communication spaces ISa corresponding to one antenna surface S1. In Figure 5(b), the thick arrows indicate the movement of individual communication spaces ISa in the azimuth direction.

[0058] The individual communication space ISa is a communicable space corresponding to the antenna surface S. The range of the individual communication space ISa is determined based on the beam scanning angle of the corresponding antenna surface S.

[0059] The "beam scanning angle" is the angle between the direction in which the sum signal value is maximum and the absolute value of the difference signal value is minimum ("0") (hereinafter referred to as the "reference direction") and the direction in which the sum signal value is approximately the same as the first threshold (hereinafter referred to as the "threshold direction"). Therefore, the antenna surface S can communicate stably with the communication equipment 2 located in the corresponding individual communication space ISa. When the phases of the received signal and the transmitted signal are not controlled, the reference direction is the same as the direction in which each antenna surface S is pointed (the normal direction of the antenna surface S). When the phases of the received signal and the transmitted signal are controlled, the reference direction may differ from the direction in which each antenna surface S is pointed.

[0060] If the phases of the received signal and the transmitted signal are not controlled, when a communication device 2 located in the reference direction of the antenna surface S moves in the azimuth direction and / or elevation direction, the sum signal value corresponding to the antenna surface S decreases, and the difference signal value corresponding to the antenna surface S increases.

[0061] On the other hand, when the phases of the received signal and the transmitted signal are controlled, when the communication device 2 located in the reference direction of the antenna surface S moves in the azimuth direction and / or elevation direction, the phase unit 11 controls the directivity (beam) of the antenna surface S so that the communication device 2 is located in the reference direction of the antenna surface S. When the directivity of the antenna surface S is controlled, as shown in Figures 5(a) and 5(b), the individual communication space ISa corresponding to the antenna surface S is movable in both the elevation direction and the azimuth direction within the communication space ISb. That is, the reference direction of the antenna surface S is movable in both the elevation direction and the azimuth direction. Therefore, even if the communication device 2 located in the reference direction of the antenna surface S moves in the azimuth direction and / or elevation direction, the sum signal value can be maximized and the difference signal value can be minimized by controlling the phases of the received signal and the transmitted signal.

[0062] The communication space ISb on the antenna surface S is a space on which the individual communication space ISa corresponding to the antenna surface S can move.

[0063] In the following explanation, Figures 3 and 4 will be referred to as appropriate, along with Figure 5.

[0064] The difference signal value indicates the azimuth angle and elevation angle, respectively, between the reference direction of the antenna surface S and the direction of the communication equipment. In other words, the difference signal value indicates the magnitude and direction of the error (deviation) between the reference direction and the direction of the communication equipment in both the azimuth and elevation directions. The difference signal value includes the first difference signal value and the second difference signal value.

[0065] "Communication equipment direction" refers to the direction in which the communication equipment 2 is located relative to the antenna surface S.

[0066] The "first difference signal value" is the difference between the sum of the received signal values ​​corresponding to units U1 and U2, and the sum of the received signal values ​​corresponding to units U3 and U4. The first difference signal value indicates the elevation angle between the reference direction and the communication device direction. For example, when the first difference signal value is "0", there is no error between the reference direction and the communication device direction in the elevation angle direction. That is, communication device 2 is located in the reference direction.

[0067] The "second difference signal value" is the difference between the sum of the received signal values ​​corresponding to units U1 and U3, and the sum of the received signal values ​​corresponding to units U2 and U4. The second difference signal value indicates the azimuth angle between the reference direction and the direction of the communication device. For example, when the second difference signal value is not "0" (e.g., "+1", "-1", etc.), there is an error between the reference direction and the direction of the communication device in the azimuth direction. That is, communication device 2 is not located in the reference direction.

[0068] The selection unit 132 predicts the movement of the communication device 2 in the azimuth direction and elevation direction (for example, whether or not the communication device 2 moves, the direction of movement, the speed of movement, etc.) based on the difference signal value corresponding to each antenna surface S, and selects the optimal main antenna surface and sub-antenna surface.

[0069] The determination unit 133 predicts the movement of the communication device 2 in the azimuth direction and elevation direction, respectively, based on the difference signal values ​​corresponding to the main antenna surface and the sub-antenna surface, and determines the optimal specific antenna surface and the non-specific antenna surface.

[0070] Figure 6 shows the antenna 1. Figure 6(a) is a schematic front view of the antenna 1, showing the communication spaces ISb corresponding to each of the two antenna surfaces S1 to S5 and the single antenna surface S6. Figure 6(a) shows 11 communication spaces ISb in the elevation direction. Figure 6(b) is a schematic plan view of the antenna 1, showing the communication spaces ISb corresponding to each of the 16 antenna surfaces S1. Figure 6(b) shows 16 communication spaces ISb in the azimuth direction. In the following description, Figure 1 will be referred to as appropriate, along with Figure 6.

[0071] Communication space ISb overlaps with other adjacent communication spaces ISb (communication spaces ISb corresponding to other antenna surfaces S). The 73 communication spaces ISb corresponding to each of the 73 antenna surfaces S form a roughly partially spherical, communicable space centered on antenna 1 (i.e., a part of a roughly spherical space centered on antenna 1). When communication device 2 is located in this space, the received signal value of the received signal received by antenna 1 is greater than or equal to the first threshold. Therefore, antenna 1 can communicate stably with communication device 2 located in the same space. On the other hand, when communication device 2 is located outside this space, the received signal value of the received signal received by antenna 1 is less than the first threshold.

[0072] ● Operation of this antenna The operation of antenna 1 is described below.

[0073] Figure 7 is a flowchart illustrating an embodiment of this method. This figure shows the operation of the antenna 1. The operation of the antenna 1 described below is an example of this method. In the following description, Figures 1 to 6 will be referenced together with Figure 7 as appropriate.

[0074] First, antenna 1 performs the initial decision process (ST1).

[0075] The "initial determination process (ST1)" is the process of determining specific antenna surfaces and non-specific antenna surfaces.

[0076] Figure 8 is a flowchart of the initial decision process (ST1). In the following explanation, Figure 8 will be referred to as appropriate, along with Figures 1-6.

[0077] First, each of the 73 generation units 12 detects the received signal value of the received signal transmitted to the corresponding units U1 to U4 (ST101: detection step).

[0078] Next, each of the 73 generation units 12 generates a sum signal and a difference signal corresponding to each of the antenna surfaces S based on the detection results of each generation unit 12 (ST102: generation step).

[0079] Next, the detection unit 131 detects the sum signal value and difference signal value corresponding to each of the antenna surfaces S, which are generated by each of the 73 generation units 12 (ST103: detection step).

[0080] Next, the selection unit 132 selects a main antenna surface and a sub-antenna surface based on the detection result of the detection unit 131 (ST104: selection step). Specifically, for example, the selection unit 132 selects the antenna surface S corresponding to the first largest sum signal value that is greater than or equal to the first threshold as the main antenna surface. The selection unit 132 selects the antenna surface S corresponding to the second largest sum signal value that is greater than or equal to the first threshold as the sub-antenna surface. Each of the antenna surfaces S selected by the selection unit 132 functions as a main antenna surface and a sub-antenna surface, respectively.

[0081] In this invention, the selection unit only needs to be able to select a main antenna surface and a sub-antenna surface based on the detection result of the detection unit, and the content of the detection result is not particularly limited. That is, for example, the detection result may be the difference signal value corresponding to each antenna surface S. Specifically, for example, in the processing (ST104: selection step), when there are multiple antenna surfaces corresponding to sum signal values ​​of a first threshold or higher, and the difference between the multiple identical sum signal values ​​(for example, the difference between the largest sum signal value and the smallest sum signal value among the multiple identical sum signal values) is less than or equal to the second threshold, the selection unit in this invention may select a main antenna surface and a sub-antenna surface based on the absolute value of the difference signal value corresponding to each antenna surface corresponding to the sum signal value of a sum signal value of a first threshold or higher. That is, for example, the selection unit selects the antenna surface corresponding to the difference signal having the absolute value of the smallest difference signal value among the difference signals as the main antenna surface, and selects the antenna surface corresponding to the difference signal having the absolute value of the second smallest difference signal value as the sub-antenna surface. Furthermore, for example, the selection unit predicts the movement of the communication equipment in the azimuth and elevation directions based on the difference signal values ​​corresponding to each antenna surface S, and selects the optimal sub-antenna surface.

[0082] Next, the determination unit 133 determines the main antenna surface, the sub-antenna surface, and the antenna surface S adjacent to the main antenna surface, based on the detection results of the detection unit 131 for the main antenna surface and the sub-antenna (the sum signal value and difference signal value corresponding to the main antenna surface and the sub-antenna, respectively, detected by the detection unit 131), as specific antenna surfaces, and determines the antenna surfaces S other than the specific antenna surfaces as non-specific antenna surfaces (ST105: determination step). Specifically, for example, when antenna surface S1 functions as the main antenna surface, the determination unit 133 determines 5 specific antenna surfaces. When any of antenna surfaces S2, S3, or S4 functions as the main antenna surface, the determination unit 133 determines 7 specific antenna surfaces. When antenna surface S5 functions as the main antenna surface, the determination unit 133 determines 8 specific antenna surfaces. When antenna surface S6 functions as the main antenna surface, the determination unit 133 determines 9 specific antenna surfaces.

[0083] Next, the initial decision process (ST1) ends.

[0084] The operation of antenna 1 will be explained by referring back to Figure 7.

[0085] Next, each receiving phase unit 11R corresponding to the main antenna surface controls the phase of the received signal transmitted to each corresponding unit U1 to U4 so that the individual communication space ISa corresponding to the main antenna surface moves within the communication space ISb, thereby controlling the directivity of the main antenna surface (ST2: receiving phase control step). At this time, the main antenna surface captures and tracks the communication device 2 moving within the communication space ISb corresponding to the main antenna surface. As a result, for example, the sum signal value corresponding to the main antenna surface becomes larger, and the main antenna 1 can stably receive the received signal from the communication device 2. The same applies to the receiving phase unit 11R corresponding to the sub-antenna surface.

[0086] Next, the receiving unit 134 receives the received signal from the communication device 2 via the main antenna surface and the sub-antenna surface, respectively (ST3: receiving step).

[0087] Next, each transmitting phase unit 11T corresponding to the main antenna surface controls the phase of the transmitted signal transmitted to each corresponding unit U based on the control results of each receiving phase unit 11R corresponding to the main antenna surface, so that the individual communication space ISa corresponding to the main antenna surface moves within the communication space ISb, thereby controlling the directivity of the main antenna surface (ST4: Transmitting Phase Control Step). Specifically, for example, the transmitting phase unit 11T controls the phase of the transmitted signal so that the directivity of the main antenna surface when transmitting a transmitted signal is the same as the directivity of the main antenna surface when receiving a received signal (for example, so that the phase of the transmitted signal is the same as the phase of the received signal controlled by the receiving phase unit 11R). At this time, the main antenna surface captures and tracks the communication device 2 moving within the communication space ISb corresponding to the main antenna surface. As a result, for example, the signal value of the transmitted signal corresponding to the main antenna surface (hereinafter referred to as "transmitted signal value") becomes larger, and the antenna 1 can stably transmit the transmitted signal to the communication device 2.

[0088] Next, the transmitting unit 135 transmits the transmission signal to the communication device 2 via the main antenna surface (ST5: transmission step).

[0089] Next, the selection unit 132 determines whether the magnitude of the sum signal value corresponding to the sub-antenna surface is less than the second largest among the magnitudes of the sum signal values ​​corresponding to each specific antenna surface (ST6: determination step).

[0090] When the magnitude of the sum signal value corresponding to the sub-antenna surface is less than the second largest among the magnitudes of the sum signal values ​​corresponding to each specific antenna surface (ST6: Yes), the selection unit 132 re-selects the sub-antenna surface (ST7: Selection step). Specifically, the selection unit 132 re-selects the antenna surface S corresponding to the second largest sum signal value among the specific antenna surfaces as the new sub-antenna surface.

[0091] In this invention, the selection unit only needs to be able to select a sub-antenna surface based on the detection result of the detection unit, and the content of the detection result is not particularly limited. That is, for example, similar to the processing (ST104: selection step), the detection result may be a difference signal value. Specifically, for example, in processing (ST10), the selection unit in this invention may re-select the sub-antenna surface based on the absolute value of the difference signal value.

[0092] Next, antenna 1 performs a specific antenna plane re-determination process (ST8).

[0093] The "Specific Antenna Plane Re-determination Process (ST8)" is a process that re-determines (updates) the specific antenna plane and the non-specific antenna plane.

[0094] Figure 9 is a flowchart of the specific antenna plane re-determination process (ST8). In the following explanation, Figure 9 will be referred to as appropriate, along with Figures 1-8.

[0095] First, of the 73 generation units 12, only the generation unit 12 corresponding to each specific antenna surface detects the received signal value of the received signal transmitted to each of the units U1 to U4 on the corresponding antenna surface S (ST801: detection step). At this time, unlike the processing (ST101: detection step), the generation unit 12 corresponding to a non-specific antenna surface does not detect the received signal value.

[0096] Next, of the 73 generation units 12, only the generation unit 12 corresponding to each specific antenna surface generates a sum signal and a difference signal corresponding to each specific antenna surface based on the detection results of each generation unit 12 (ST802: generation step). At this time, unlike the processing (ST102: generation step), the generation unit 12 corresponding to a non-specific antenna surface does not generate a sum signal and a difference signal corresponding to the non-specific antenna surface.

[0097] Next, the detection unit 131 detects the sum signal value and difference signal value corresponding to each specific antenna surface, which are generated by the respective generation units 12 corresponding to each specific antenna surface (ST3: detection step). At this time, unlike the processing (ST103: detection step), the detection unit 131 does not detect the sum signal value and difference signal value corresponding to non-specific antenna surfaces.

[0098] Next, the determination unit 133 re-determines (updates) the specific antenna plane and the non-specific antenna plane (ST804: determination step) based on the detection results of the detection unit 131 for the main antenna plane and the sub-antenna newly re-selected by the selection unit 132 in processing (ST10: selection step) (the sum signal value and difference signal value corresponding to the main antenna plane and the sub-antenna, respectively, detected by the detection unit 131). Therefore, when the communication device 2 moves and the detection result in processing (ST103: detection step) differs from the detection result in processing (ST803: detection step), the specific antenna plane and the non-specific antenna plane determined in processing (ST105: determination step) may differ from the specific antenna plane and the non-specific antenna plane re-determined in processing (ST804: determination step).

[0099] Next, the specific antenna plane re-determination process (ST8) is completed.

[0100] The operation of antenna 1 will be explained by referring back to Figure 7.

[0101] Next, the operation of antenna 1 returns to process (ST2).

[0102] On the other hand, if the magnitude of the sum signal value corresponding to the sub-antenna surface is not less than the second largest sum signal value corresponding to each specific antenna surface (ST6: No), the selection unit 132 determines whether the sum signal value corresponding to the sub-antenna surface is greater than the sum signal value corresponding to the main antenna surface (ST9: Determination step).

[0103] When the magnitude of the sum signal value corresponding to the sub-antenna surface is greater than the magnitude of the sum signal value corresponding to the main antenna surface (ST9: Yes), specifically when the magnitude of the sum signal value corresponding to the sub-antenna surface is the first largest and the magnitude of the sum signal value corresponding to the main antenna surface is the second largest, the selection unit 132 re-selects the antenna surface S that was functioning as the sub-antenna surface as the new main antenna surface, and re-selects the antenna surface S that was functioning as the main antenna surface as the new sub-antenna surface (ST10: Selection step).

[0104] In this invention, the selection unit only needs to be able to select a main antenna surface and a sub-antenna surface based on the detection result of the detection unit, and the content of the detection result is not particularly limited. That is, for example, similar to the processing (ST104: selection step), the detection result may be a difference signal value. Specifically, for example, in processing (ST12), when the magnitude of the absolute value of the difference signal value corresponding to the sub-antenna surface is smaller than the absolute value of the difference signal value corresponding to the main antenna surface, the selection unit in this invention re-selects the antenna surface that was functioning as the sub-antenna surface as the new main antenna surface, and re-selects the antenna surface that was functioning as the main antenna surface as the new sub-antenna surface.

[0105] Next, the operation of antenna 1 returns to the specific antenna plane re-determination process (ST8). That is, the determination unit 133 re-determines (updates) the specific antenna plane and the non-specific antenna plane based on the detection results of the detection unit 131 for the main antenna plane and the sub-antenna, respectively, which were newly re-selected by the selection unit 132 in the process (ST10: selection step) (sum signal value and difference signal value corresponding to the main antenna plane and the sub-antenna, respectively, as detected by the detection unit 131) (ST804: determination step).

[0106] On the other hand, when the magnitude of the sum signal value corresponding to the sub-antenna surface is less than or equal to the sum signal value corresponding to the main antenna surface (ST9: No), the control unit 13 determines whether or not the operation of the main antenna 1 is terminated based on the operation of the user using the main antenna 1 (ST11).

[0107] Next, when the operation of antenna 1 is terminated based on the user's actions (ST11:Yes), the operation of antenna 1 terminates.

[0108] On the other hand, if the operation of antenna 1 is not terminated (ST11: No), the operation of antenna 1 returns to process (ST2).

[0109] Figures 10-13 show examples of the operation of antenna 1. Figures 10(a), 11(a), 12(a), and 13(a) are schematic front views of antenna 1. Figures 10(b), 11(b), 12(b), and 13(b) are schematic perspective views of antenna 1.

[0110] Figures 10-13 show how the communication device 2 moves in the elevation direction. In the operation of the antenna 1 shown in Figures 10-13, the communication device 2 does not move in the azimuth direction.

[0111] In Figures 10(a), 11(a), 12(a), and 13(a), the current position of communication device 2 is shown by a solid line, the position of communication device 2 before and after movement is shown by a dashed line, and the direction in which communication device 2 moves (the direction in which communication device 2 orbits the moon) is shown by a thick arrow. In Figures 10(b), 11(b), 12(b), and 13(b), the antenna surface S that functions as the primary antenna is shown in dark gray, the antenna surface that functions as the secondary antenna is shown in light gray, and multiple specific antenna surfaces are shown enclosed by thick black lines. In the following explanation, Figures 1 to 9 will be referred to as appropriate, along with Figures 10 to 13.

[0112] As shown in Figure 10, the communication device 2 is located in the communication space ISb corresponding to the antenna surface S2. As shown in Figure 10, the selection unit 132 selects the antenna surface S2, which faces an elevation angle of 18°, as the primary antenna surface, and the antenna surface S1, which faces an elevation angle of 0°, as the secondary antenna surface. In the following description, the initial determination process (ST1) has been completed.

[0113] First, each receiving phase unit 11R corresponding to the main antenna surface controls the phase of the received signal transmitted to each corresponding unit U1 to U4 so that the individual communication space ISa corresponding to the main antenna surface moves within the communication space ISb, thereby controlling the directivity of the main antenna surface (ST2: receiving phase control step). The same applies to each receiving phase unit 11R corresponding to the sub-antenna surface.

[0114] Next, the receiving unit 134 receives the received signal from the communication device 2 via the main antenna surface and the sub-antenna surface, respectively (ST3: receiving step).

[0115] Next, each transmitting phase unit 11T corresponding to the main antenna surface controls the phase of the transmitted signal transmitted to each corresponding unit U based on the control result of each receiving phase unit 11R corresponding to the main antenna surface, so that the individual communication space ISa corresponding to the main antenna surface moves, thereby controlling the directivity of the main antenna surface (ST4: Transmitting Phase Control Step).

[0116] Next, the transmitting unit 135 transmits the transmission signal to the communication device 2 via the main antenna surface (ST5: transmission step).

[0117] Thus, when the communication device 2 is moving within the communication space ISb corresponding to the main antenna surface, the receiving phase unit 11R and the transmitting phase unit 11T corresponding to the main antenna surface control the phases of the received signal and the transmitted signal, respectively, so that the individual communication space ISa corresponding to the main antenna surface moves within the communication space ISb, thereby controlling the directivity of the main antenna surface. In other words, the main antenna surface captures and tracks the moving communication device 2. Therefore, even if the communication device 2 moves, the sum signal value corresponding to the main antenna surface that captures and tracks the communication device 2 does not easily decrease.

[0118] As shown in Figure 11, the communication device 2 moves in the elevation direction within the communication space ISb corresponding to the antenna surface S2. As a result, the magnitude of the sum signal value corresponding to the sub-antenna surface (antenna surface S1) is less than the second largest, and the magnitude of the sum signal value corresponding to the antenna surface S3 is the second largest (ST6: Yes).

[0119] The selection unit 132 re-selects the antenna surface S3, which corresponds to the second largest sum signal value among the seven specific antenna surfaces, as a new sub-antenna surface (ST7: selection step).

[0120] Next, antenna 1 performs a specific antenna plane re-determination process (ST8).

[0121] At this time, the determination unit 133 re-determines (updates) the specific antenna surface and the non-specific antenna surface based on the detection results of the detection unit 131 on the main antenna surface and the sub-antenna surface newly selected by the selection unit 132 in the processing (ST7: selection step) (ST804: determination step). Specifically, the determination unit 133 determines 7 specific antenna surfaces and 66 non-specific antenna surfaces.

[0122] As shown in Figure 12, the communication device 2 moves in the elevation direction within the communication space ISb corresponding to the antenna plane S2. As a result, the magnitude of the sum signal value corresponding to the main antenna plane (antenna plane S2) becomes the second largest, and the magnitude of the sum signal value corresponding to the secondary antenna plane (antenna plane S3) becomes the largest. In other words, the magnitude of the sum signal value corresponding to the secondary antenna plane (antenna plane S3) is larger than the sum signal value corresponding to the main antenna plane (antenna plane S2) (ST9: Yes).

[0123] The selection unit 132 re-selects the antenna surface S3, which was functioning as a secondary antenna surface, as the new primary antenna surface, and re-selects the antenna surface S2, which was functioning as the primary antenna surface, as the new secondary antenna surface (ST10: Selection step).

[0124] Next, antenna 1 performs a specific antenna plane re-determination process (ST8).

[0125] At this time, the determination unit 133 re-determines (updates) the specific antenna surface and the non-specific antenna surface based on the detection results of the detection unit 131 on the main antenna surface and the sub-antenna newly selected by the selection unit 132 in the processing (ST10: selection step) (ST804: determination step). Specifically, the determination unit 133 determines 7 specific antenna surfaces and 66 non-specific antenna surfaces.

[0126] As shown in Figure 13, the communication device 2 is moving in the elevation direction within the communication space ISb corresponding to the antenna plane S6. As a result, the magnitude of the sum signal value corresponding to the antenna plane S6 is the first, and the magnitude of the sum signal value corresponding to the antenna plane S5 is the second (ST9: Yes).

[0127] The selection unit 132 re-selects antenna surface S6 as the new primary antenna surface and re-selects antenna surface S5 as the new secondary antenna surface (ST10: selection step).

[0128] Next, antenna 1 performs a specific antenna plane re-determination process (ST8).

[0129] At this time, the determination unit 133 re-determines (updates) the specific antenna surface and the non-specific antenna surface based on the detection results of the detection unit 131 at the main antenna surface (antenna surface S6) and sub-antenna (antenna surface S5) newly selected by the selection unit 132 in the processing (ST10: selection step) (ST804: determination step). Specifically, the determination unit 133 determines 9 specific antenna surfaces and 64 non-specific antenna surfaces.

[0130] Here, the control unit 13 constantly determines whether or not the normal operation of the antenna 1 is terminated based on the user's operation (ST13). When the user terminates the normal operation of the antenna 1 (ST13: Yes), the normal operation of the antenna 1 is terminated based on the user's operation.

[0131] In this way, the selection unit 132 selects a main antenna surface and a sub-antenna surface based on the sum signal value and difference signal value corresponding to each antenna surface S. The sum signal and difference signal are generated based on the detection results by the generation unit 12. The generation unit 12 detects the received signal values ​​of multiple received signals (received signals transmitted to each of the units U1 to U4) rather than the received signal value of a single received signal at each of the multiple antenna surfaces S. Therefore, even if changes in the relative positional relationship with the communication equipment 2 occur, or adverse effects on communication occur (for example, errors in the received signal value due to reflected waves, errors in the received signal value due to electronic noise, etc.), the selection unit 132 selects the optimal main antenna surface. For example, when the selection unit 132 selects an antenna surface S corresponding to a large sum signal value as the main antenna surface, problems caused by low received signal values ​​corresponding to some of the units U1 to U4 (for example, malfunction of the main antenna 1 or communication equipment 2, communication failure, etc.) are prevented. Furthermore, for example, the selection unit 132 predicts the movement of the communication device 2 in the azimuth and elevation directions based on the difference signal values ​​corresponding to each antenna surface S, and selects the optimal main antenna surface and sub-antenna surface. As a result, this antenna 1 can communicate with the communication device 2 with high accuracy.

[0132] Furthermore, when the sum signal value corresponding to the sub-antenna surface is larger than the sum signal value corresponding to the main antenna surface, specifically when the sum signal value corresponding to the sub-antenna surface is the largest and the sum signal value corresponding to the main antenna surface is the second largest, the selection unit 132 selects the antenna surface S that was functioning as the sub-antenna surface as the new main antenna surface, and selects the antenna surface S that was functioning as the main antenna surface as the new sub-antenna surface. Therefore, when communication via the main antenna surface is established, communication via the sub-antenna surface is also established. Consequently, before the sum signal value corresponding to the main antenna surface falls below the first threshold, the selection unit 132 selects the antenna surface S that was functioning as the sub-antenna surface as the new main antenna surface. Therefore, the transmission unit 135 can transmit the transmission signal to the communication device 2 without delay via the antenna surface S (the new main antenna surface) from which the received signal had previously been transmitted. Therefore, there is no period of time during which communication between the antenna 1 and the communication device 2 is unstable, from the time when communication via one antenna surface S (main antenna surface) becomes unstable (when communication via one antenna surface S is interrupted) until a new antenna surface S is re-selected. As a result, even if the relative positional relationship between the antenna 1 and the communication device 2 changes, the antenna 1 can continuously communicate with the communication device 2.

[0133] Furthermore, the receiving phase section 11R and the transmitting phase section 11T, which correspond to the main antenna surface, control the phases of the received signal and the transmitted signal, respectively. Therefore, even if the communication device 2 moves, as long as the communication device 2 is located within the communication space ISb corresponding to the main antenna surface, this antenna 1 can establish communication with the communication device 2 via the already selected main antenna without having to re-select a new main antenna surface. In addition, this antenna 1 can communicate with the communication device 2 without increasing the area (aperture area) of the antenna surface S in order to enlarge the communication space ISb. Therefore, this antenna 1 can be miniaturized.

[0134] Furthermore, of the 73 generation units 12, only the generation unit 12 corresponding to each specific antenna surface detects the received signal value corresponding to each specific antenna surface and generates the sum and difference signals corresponding to each specific antenna surface. In other words, the generation unit 12 corresponding to non-specific antenna surfaces does not detect the received signal value corresponding to the non-specific antenna surface and does not generate the sum and difference signals corresponding to the specific antenna surface. Therefore, this antenna 1 can reduce the power required for the operation of the generation unit 12 corresponding to non-specific antenna surfaces.

[0135] ●Summary According to the above description, the antenna 1 receives a received signal from the communication device 2 and transmits a transmitted signal to the communication device 2. The antenna 1 comprises a plurality (73) of antenna surfaces S, a generation unit 12, a detection unit 131, a selection unit 132, a receiving unit 134, and a transmitting unit 135. Each of the plurality of antenna surfaces S comprises a plurality (4) of units U1 to U4. The generation unit 12 detects the received signal value of the received signal transmitted to each of the plurality of units U1 to U4. Based on the detection result of the generation unit 12, the selection unit 132 selects one of the plurality of antenna surfaces S as the main antenna surface and selects one of the other antenna surfaces as the sub-antenna surface. The receiving unit 134 receives the received signal from the communication device 2 via the main antenna surface and the sub-antenna surface. The transmitting unit 135 transmits the transmitted signal to the communication device 2 via the main antenna surface. In this configuration, the detection unit 131 detects the received signal values ​​of multiple received signals, rather than the received signal value of a single received signal, at each of the multiple antenna surfaces S. Therefore, even if changes occur in the relative positional relationship between the antenna 1 and the communication device 2, or adverse effects on communication occur (for example, errors in the received signal value due to reflected waves, errors in the received signal value due to electronic noise, etc.), the selection unit 132 selects the optimal main antenna surface and sub-antenna surface. Furthermore, there is no time when communication via one antenna surface S (main antenna surface) becomes unstable (when communication via one antenna surface S is interrupted) until a new antenna surface S is re-selected, i.e., there is no time when communication between the antenna 1 and the communication device 2 is unstable. As a result, even if the relative positional relationship between the antenna 1 and the communication device 2 changes, the antenna 1 can communicate with the communication device 2 with high accuracy and continuously.

[0136] According to the above explanation, at each of the multiple (73) antenna surfaces S, the generation unit 12 generates a sum signal of the received signals transmitted to each of the multiple (4) units U1 to U4. The detection unit 131 detects the sum signal value. The selection unit 132 selects the main antenna surface and the sub-antenna surface based on the detection result of the detection unit 131. With this configuration, the selection unit 132 selects the optimal main antenna surface based on the sum signal value that can be compared with a first threshold. Therefore, problems caused by low received signal values ​​corresponding to some units U are prevented. As a result, this antenna 1 can communicate with the communication device 2 with high accuracy.

[0137] According to the above description, in each of the multiple (73) antenna surfaces S, the generation unit 12 generates difference signals of the received signals transmitted to each of the multiple (4) units U1 to U4. In each of the multiple antenna surfaces S, the four units U1 to U4 are arranged in a two-dimensional array of two rows and two columns. In each of the corresponding multiple antenna surfaces S, the difference signal value includes the difference between the sum of the received signal values ​​of the received signals transmitted to units U1 and U2 and the sum of the received signal values ​​of the received signals transmitted to units U3 and U3, and the difference between the sum of the received signal values ​​of the received signals transmitted to units U1 and U3 and the sum of the received signal values ​​of the received signals transmitted to units U2 and U4. The detection unit 131 detects the difference signal value of the difference signal. With this configuration, the selection unit 132 predicts the movement of the communication device 2 in the azimuth direction and elevation direction, respectively, based on the difference signal value, and selects the optimal sub-antenna surface. As a result, the main antenna 1 can communicate with the communication device 2 with high accuracy.

[0138] According to the above explanation, the multiple (73) antenna surfaces include a first antenna surface and a second antenna surface different from the first antenna surface. When the sum signal value corresponding to the second antenna surface, which functions as a secondary antenna surface, becomes larger than the sum signal value corresponding to the first antenna surface, which functions as a primary antenna surface, the selection unit 132 selects the second antenna surface as the primary antenna surface instead of the first antenna surface. With this configuration, the receiving unit 134 receives the received signal from the communication device 2 via the second antenna surface corresponding to the larger sum signal value. The transmitting unit 135 transmits the transmitted signal to the communication device 2 via the first antenna surface corresponding to the larger sum signal value. As a result, problems caused by low received signal values ​​are prevented.

[0139] According to the above explanation, the multiple (73) antenna surfaces include a first antenna surface and a second antenna surface different from the first antenna surface. When the sum signal value corresponding to the first antenna surface, which functions as the main antenna surface, becomes smaller than the sum signal value corresponding to the second antenna surface, which functions as the secondary antenna surface, the selection unit 132 selects the first antenna surface as the secondary antenna surface instead of the second antenna surface. With this configuration, when communication via the first antenna surface (main antenna surface) is established, communication via the second antenna surface (secondary antenna surface) is also established. Here, the selection unit 132 always selects an appropriate secondary antenna surface. Therefore, before communication via the first antenna surface becomes unstable (before communication via the first antenna surface is disconnected), the selection unit 132 can select the second antenna surface, from which a received signal had previously been transmitted (communication had been established), as the new main antenna surface. Therefore, the transmitting unit 135 can transmit the transmission signal to the communication device 2 without delay via the second antenna surface, which had previously received the received signal.

[0140] As explained above, the multiple (73) antenna surfaces include a first antenna surface and a second antenna surface different from the first antenna surface. When the absolute value of the difference signal corresponding to the first antenna surface, which functions as the main antenna surface, becomes greater than the absolute value of the difference signal corresponding to the second antenna surface, which functions as the secondary antenna surface, the selection unit 132 selects the first antenna surface as the secondary antenna surface instead of the second antenna surface. With this configuration, the selection unit 132 selects the optimal secondary antenna surface. Therefore, before communication via the first antenna surface becomes unstable (before communication via the first antenna surface is interrupted), the selection unit 132 can select the second antenna surface, from which the received signal had previously been transmitted (communication had been established), as the new main antenna surface. Consequently, the transmission unit 135 can transmit the transmission signal to the communication device 2 without delay via the second antenna surface from which the received signal had previously been transmitted.

[0141] According to the above explanation, the multiple (73) antenna surfaces include a first antenna surface and a second antenna surface different from the first antenna surface. When the absolute value of the difference signal corresponding to the second antenna surface, which functions as a sub-antenna surface, becomes smaller than the absolute value of the difference signal corresponding to the first antenna surface, which functions as a main antenna surface, the selection unit 132 selects the second antenna surface as the main antenna surface instead of the first antenna surface. With this configuration, the selection unit 132 selects the optimal sub-antenna surface. Therefore, malfunctions caused by variations in the received signal values ​​corresponding to each of the units U1 to U4 are prevented. As a result, the antenna 1 can communicate continuously with the communication device 2.

[0142] According to the above explanation, the sum signal value corresponding to the main antenna surface is the largest among the sum signal values ​​corresponding to each of the multiple (73) antenna surfaces S. With this configuration, problems caused by low received signal values ​​are prevented.

[0143] According to the above explanation, the sum signal value corresponding to the sub-antenna surface of antenna 1 is the second largest among the sum signal values ​​corresponding to each of the multiple (73) antenna surfaces S. With this configuration, when communication is established via the main antenna surface, communication is also established via the sub-antenna surface corresponding to the second largest sum signal value. As a result, even if the selection unit 132 selects the sub-antenna surface as the new main antenna surface, problems caused by low received signal values ​​are prevented. Furthermore, when the sum signal value corresponding to the main antenna surface decreases, the selection unit 132 can select the antenna surface S to which the next largest sum signal value is transmitted as the main path.

[0144] As described above, the antenna 1 has multiple (4) receiving phase units 11R corresponding to multiple (4) units U1 to U4 on each of its multiple (73) antenna surfaces. Each of the multiple receiving phase units 11R controls the phase of the received signal transmitted to each of its corresponding units U1 to U4. With this configuration, as long as the communication device 2 is located within the communication space ISb corresponding to the main antenna surface and the sub-antenna surface, even if the communication device 2 moves, the antenna 1 can receive the received signal from the communication device 2 via the already selected main antenna surface and sub-antenna surface without having to re-select a new main antenna surface and sub-antenna surface. Furthermore, the antenna 1 can receive the received signal from the communication device 2 without increasing the area (aperture area) of the antenna surface S in order to enlarge the communication space ISb. Therefore, the antenna 1 can be miniaturized.

[0145] As described above, the antenna 1 is equipped with multiple (4) transmit phase units 11T corresponding to multiple (4) units U1 to U4 on each of its multiple (73) antenna surfaces. Each of the multiple transmit phase units 11T controls the phase of the transmit signal transmitted to each of its corresponding units U1 to U4 based on the control result of the corresponding receive phase unit 11R. With this configuration, even if the communication device 2 moves, as long as the communication device 2 is located within the communication space ISb corresponding to the main antenna surface, the antenna 1 can transmit the transmit signal to the communication device 2 via the already selected main antenna without having to re-select a new main antenna surface. Furthermore, the antenna 1 can transmit the transmit signal to the communication device 2 without increasing the area (aperture area) of the antenna surface S in order to enlarge the communication space ISb. Therefore, the antenna 1 can be miniaturized.

[0146] According to the above explanation, the antenna 1 has multiple (73) antenna surfaces S, which include a first antenna surface and a second antenna surface different from the first antenna surface. When the sum signal value corresponding to the first antenna surface and the sum signal value corresponding to the second antenna surface are each greater than or equal to a predetermined first threshold, and the difference between the sum signal value corresponding to the first antenna surface and the sum signal value corresponding to the second antenna surface is less than or equal to a predetermined second threshold, the selection unit 132 selects the main antenna surface and the sub-antenna surface based on the absolute values ​​of the difference signal values ​​corresponding to the first antenna surface and the second antenna surface, respectively. The first threshold is the minimum sum signal value at which the antenna 1 and the communication device 2 can communicate stably. The second threshold is the allowable error value included in the sum signal value when the sum signal is generated. In this configuration, when the sum signal values ​​corresponding to the first antenna surface and the second antenna surface are approximately the same, the selection unit 132 selects the optimal main antenna surface and sub-antenna surface based on the absolute values ​​of the difference signal values ​​corresponding to the first antenna surface and the second antenna surface (for example, the one with the smaller absolute value of the difference signal is selected as the main antenna surface). As a result, the antenna 1 can communicate with the communication device 2 with high precision.

[0147] According to the above description, the antenna 1 has multiple (73) antenna surfaces S, which include multiple (e.g., 7) specific antenna surfaces and one or more (e.g., 66) non-specific antenna surfaces that are different from the specific antenna surfaces. Each of the multiple specific antenna surfaces includes at least a main antenna surface and a sub-antenna surface. The antenna 1 includes a determination unit 133. The determination unit 133 determines the multiple specific antenna surfaces based on the detection results of the detection unit 131 on each of the main antenna surface and the sub-antenna surface. The generation unit 12 generates sum signals and difference signals corresponding only to each of the multiple specific antenna surfaces. With this configuration, the generation unit 12 does not generate sum signals and difference signals corresponding to the non-specific antenna surfaces. Therefore, the antenna 1 can reduce the power required for the operation of the generation unit 12 (generation of sum signals and difference signals corresponding to the non-specific antenna surfaces).

[0148] According to the above explanation, Antenna 1 will be installed on a lunar rover traveling on the lunar surface, that is, on the lunar surface (the surface of the celestial body). Communication device 2 is an artificial satellite orbiting the Moon (celestial body). With this configuration, Antenna 1 can communicate with the moving artificial satellite (communication device 2) orbiting the Moon with high precision and continuously. Furthermore, Antenna 1 does not require a drive to change the direction in which the antenna surface S is pointed, as is the case with conventional mechanical scanning antenna systems. Antenna 1, which does not require a drive unit for a mechanical scanning antenna, does not suffer from wear and deterioration of the mechanical scanning part or malfunctions due to the effects of regolith.

[0149] According to the above description, this method is performed by the antenna 1. This method includes a detection step (ST3), a selection step (ST12), a reception step (ST7), and a transmission step (ST8). With this configuration, even if the relative positional relationship between the antenna 1 and the communication device 2 changes, the antenna 1 can communicate with the communication device 2 with high accuracy and continuously.

[0150] ●Other Embodiments● Furthermore, the installation location of this antenna is not particularly limited. That is, for example, this antenna may be installed on celestial bodies other than the Moon, artificial satellites (such as Earth-orbiting satellites or lunar-orbiting satellites), or flying objects such as aircraft.

[0151] Furthermore, this antenna may communicate with two or more communication devices, and may also communicate with other antenna systems (e.g., electronically scanned antenna systems, mechanically scanned antenna systems, etc.).

[0152] Furthermore, the shape of this antenna is not particularly limited.

[0153] Furthermore, the antenna surfaces in this invention may be arranged in a divided manner. That is, for example, some of the 73 antenna surfaces may be arranged in physically separate locations from the remaining antenna surfaces. According to the above description, the antenna surfaces are arranged in a divided manner (for example, in two sections) at the installation site of the antenna (for example, a lunar rover). Therefore, the antenna does not require a large installation space. In addition, the antenna may be installed considering its positional relationship with other components installed at the installation site together with the antenna (for example, solar panels installed on a lunar rover).

[0154] Furthermore, the number of antenna surfaces in this invention is not particularly limited. Nor is the direction in which each antenna surface is oriented in this invention particularly limited.

[0155] Furthermore, the number of sub-antenna surfaces in the present invention is not limited to "1". That is, for example, the selection unit in the present invention may select the antenna surface corresponding to the second largest sum signal value and the antenna surface corresponding to the third largest sum signal value as sub-antenna surfaces.

[0156] Furthermore, the specific antenna surface in the present invention may include at least a main antenna surface and a sub-antenna surface, and the number of specific antenna surfaces is not particularly limited.

[0157] Furthermore, the unit in the present invention is not limited to a planar patch antenna. That is, for example, the unit in the present invention may be a known horn antenna (e.g., a pyramidal horn antenna, a conical horn antenna, etc.).

[0158] Furthermore, the units in this invention only need to be arranged in a two-dimensional array of 2N rows and 2M columns, and the number of units on a single antenna surface is not particularly limited.

[0159] Furthermore, the selection unit in the present invention only needs to be able to select the main antenna surface and the sub-antenna surface based on the detection result of the detection unit, and the operation of the selection unit is not particularly limited.

[0160] In this invention, the difference signal value may include at least one of the first difference signal value and the second difference signal value, or it may not include both the first difference signal value and the second difference signal value.

[0161] Furthermore, this antenna may also include a diplexer for separating the transmitted signal and the received signal, an amplification unit for amplifying the transmitted signal and the received signal, and an attenuation unit for attenuating the transmitted signal and the received signal.

[0162] Furthermore, the communication device in this invention is not limited to artificial satellites orbiting celestial bodies, as long as it is capable of communicating with this antenna via a wireless communication line. That is, for example, the communication device in this invention may be a radio station installed on the Earth's surface, or an artificial satellite orbiting a celestial body other than the Moon.

[0163] ●Features of this antenna and method● The features of this antenna and this method, as described above, are summarized below.

[0164] ●Features of this antenna This antenna (for example, Antenna 1) An electronic scanning antenna system that receives a receiving signal from a communication device (for example, communication device 2) and transmits a transmission signal to the communication device, A plurality of antenna surfaces (for example, antenna surface S) on which the received signal and the transmitted signal are transmitted, A detection unit (for example, generation unit 12, detection unit 131) that detects the received signal value of the received signal, Based on the detection result of the detection unit, a selection unit (for example, selection unit 132) selects one of the multiple antenna surfaces as the main antenna surface and selects one of the other antenna surfaces as the secondary antenna surface. A receiving unit (for example, a receiving unit 134) receives the received signal from the communication device via the main antenna surface and the sub-antenna surface, A transmitting unit (for example, a transmitting unit 135) transmits the transmission signal to the communication equipment via the main antenna surface, It has, Each of the multiple antenna surfaces is, Multiple units (for example, units U1 to U4) through which the received signal and the transmitted signal are transmitted, Equipped with, The detection unit detects the received signal value of the received signal transmitted to each of the multiple units. It is characterized by the following:

[0165] This antenna Each of the multiple antenna surfaces generates a sum signal of the received signals transmitted to each of the multiple units, It has, The detection unit detects the sum signal value of the sum signal, It can be anything.

[0166] This antenna A generation unit (for example, generation unit 12) generates a difference signal of the received signal transmitted to each of the multiple units on each of the multiple antenna surfaces. It has, On each of the multiple antenna surfaces, the 2N × 2M units (where N and M are natural numbers greater than or equal to 1) are arranged in a two-dimensional array of 2N rows and 2M columns. The difference signal value corresponding to each of the multiple antenna surfaces is, for each of the corresponding multiple antenna surfaces, The difference between the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the 1st row to the Nth row, and the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the N+1th row to the 2Nth row, The difference between the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the 1st column to the Mth column, and the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the M+1th column to the 2nd Mth column, Including at least one of the following: The detection unit detects the difference signal value of the difference signal. It can be anything.

[0167] In this antenna, The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the sum signal value corresponding to the second antenna surface, which functions as a secondary antenna surface, becomes larger than the sum signal value corresponding to the first antenna surface, which functions as a primary antenna surface, the selection unit selects the second antenna surface as the primary antenna surface instead of the first antenna surface. It can be anything.

[0168] In this antenna, The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the sum signal value corresponding to the first antenna surface, which functions as the main antenna surface, becomes smaller than the sum signal value corresponding to the second antenna surface, which functions as the secondary antenna surface, the selection unit selects the first antenna surface as the secondary antenna surface instead of the second antenna surface. It can be anything.

[0169] In this antenna, The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the absolute value of the difference signal corresponding to the first antenna surface, which functions as the main antenna surface, becomes greater than the absolute value of the difference signal corresponding to the second antenna surface, which functions as the secondary antenna surface, the selection unit selects the first antenna surface as the secondary antenna surface instead of the second antenna surface. It can be anything.

[0170] In this antenna, The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the absolute value of the difference signal corresponding to the second antenna surface, which functions as a secondary antenna surface, becomes smaller than the absolute value of the difference signal corresponding to the first antenna surface, which functions as a primary antenna surface, the selection unit selects the second antenna surface as the primary antenna surface instead of the first antenna surface. It can be anything.

[0171] In this antenna, The sum signal value corresponding to the main antenna surface is the largest of the sum signal values ​​corresponding to each of the multiple antenna surfaces. It can be anything.

[0172] In this antenna, The sum signal value corresponding to the sub-antenna surface is the second largest among the sum signal values ​​corresponding to each of the multiple antenna surfaces. It can be anything.

[0173] This antenna On each of the multiple antenna surfaces, there are multiple receiving phase sections (for example, receiving phase section 11R) corresponding to each of the multiple units, It has, Each of the multiple receiving phase units controls the phase of the received signal transmitted to each of the corresponding units. It can be anything.

[0174] This antenna On each of the multiple antenna surfaces, there are multiple transmission phase sections (for example, transmission phase section 11T) corresponding to each of the multiple units, It has, Each of the multiple transmission phase units controls the phase of the transmission signal transmitted to each of the corresponding units based on the control result of the corresponding reception phase unit. It can be anything.

[0175] In this antenna, The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the sum signal value corresponding to the first antenna surface and the sum signal value corresponding to the second antenna surface are each greater than or equal to a predetermined first threshold, and the difference between the sum signal value corresponding to the first antenna surface and the sum signal value corresponding to the second antenna surface is less than or equal to a predetermined second threshold, the selection unit selects the main antenna surface and the sub-antenna surface based on the absolute values ​​of the difference signal values ​​corresponding to the first antenna surface and the second antenna surface, respectively. It can be anything.

[0176] In this antenna, The first threshold is the minimum value of the sum signal that enables stable communication between the electrical scanning antenna system and the communication equipment. It can be anything.

[0177] In this antenna, The second threshold is the allowable error value included in the sum signal value when the sum signal is generated. It can be anything.

[0178] In this antenna, The multiple antenna surfaces are, Multiple specific antenna surfaces, One or more non-specific antenna surfaces that are different from the specific antenna surface, Includes, The multiple specified antenna surfaces are at least, The main antenna surface and, The aforementioned sub-antenna surface and, Includes, The aforementioned electronic scanning antenna system is A determination unit determines a plurality of specific antenna surfaces based on the detection result of the detection unit on the main antenna surface. It has, The generation unit generates the sum signal and the difference signal corresponding to each of the multiple specific antenna surfaces. It can be anything.

[0179] In this antenna, The determination unit determines the specific antenna surface based on the detection result of the detection unit on the sub-antenna surface. It can be anything.

[0180] In this antenna, The aforementioned electronic scanning antenna system is installed on a celestial body, The aforementioned communication device is an artificial satellite orbiting the aforementioned celestial body. It can be anything.

[0181] ●Features of this method This method, A communication method performed by an electronic scanning antenna system (e.g., this antenna 1) that receives a received signal from a communication device (e.g., communication device 2) and transmits a transmitted signal to the communication device, The aforementioned electronic scanning antenna system is A plurality of antenna surfaces (for example, antenna surface S) on which the received signal and the transmitted signal are transmitted, It has, Each of the multiple antenna surfaces is, The receiving signal and the transmitting signal are transmitted by a unit (for example, units U1 to U4), Equipped with, The aforementioned communication method is, The electronic scanning antenna system includes a detection step (for example, a detection step) of detecting the received signal value of the received signal transmitted to each of the plurality of units, The electronic scanning antenna system includes a selection step (for example, a selection step) in which, based on the detection result in the detection step, one of the plurality of antenna surfaces is selected as the main antenna surface, and one of the other antenna surfaces is selected as the secondary antenna surface. The electronic scanning antenna system includes a receiving step (for example, a receiving step) in which it receives the received signal from the communication equipment via the main antenna surface and the sub-antenna surface, The electronic scanning antenna system includes a transmission step (for example, a transmission step) in which it transmits the transmission signal to the communication device via the main antenna surface, including, It is characterized by the following: [Explanation of Symbols]

[0182] 1 antenna (electronically scanned antenna system) 2. Communication equipment 11 Phase section 11R Receiving Phase Section 11T Transmit Phase Section 12. Generation Unit (Generation Unit, Detection Unit) 131 Detection unit 132 Selection Section 133 Decision Section 134 Receiving Unit 135 Transmitter S Antenna surface U Unit

Claims

1. An electronic scanning antenna system that receives a receiving signal from a communication device and transmits a transmission signal to the same communication device, Multiple antenna surfaces on which the received signal and the transmitted signal are transmitted, Each of the multiple antenna surfaces comprises a generation unit that generates a difference signal of the received signal, A detection unit that detects the received signal value of the received signal, A selection unit that, based on the detection result of the detection unit, selects one of the multiple antenna surfaces as the main antenna surface and selects one of the other antenna surfaces as the secondary antenna surface, A receiving unit that receives the received signal from the communication device via the main antenna surface and the sub-antenna surface, A transmitting unit that transmits the transmission signal to the communication device via the main antenna surface, It has, Each of the multiple antenna surfaces is, Multiple units on which the received signal and the transmitted signal are transmitted, Equipped with, The generation unit generates the difference signal of the received signal to be transmitted to each of the multiple units on each of the multiple antenna surfaces, The detection unit detects the received signal value of the received signal and the difference signal value of the difference signal transmitted to each of the plurality of units, On each of the multiple antenna surfaces, the 2N × 2M units (where N and M are natural numbers greater than or equal to 1) are arranged in a two-dimensional array of 2N rows and 2M columns. The difference signal value corresponding to each of the multiple antenna surfaces is, for each of the corresponding multiple antenna surfaces, The difference between the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the 1st row to the Nth row, and the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the N+1th row to the 2Nth row, The difference between the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the 1st column to the Mth column, and the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the M+1th column to the 2nd Mth column, Including at least one of the following: An electronically scanned antenna system characterized by the following features.

2. The generation unit generates a sum signal of the received signals transmitted to each of the multiple units on each of the multiple antenna surfaces, The detection unit detects the sum signal value of the sum signal, The electronic scanning antenna system according to claim 1.

3. The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the sum signal value corresponding to the second antenna surface, which functions as a secondary antenna surface, becomes larger than the sum signal value corresponding to the first antenna surface, which functions as a primary antenna surface, the selection unit selects the second antenna surface as the primary antenna surface instead of the first antenna surface. The electronic scanning antenna system according to claim 2.

4. The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the sum signal value corresponding to the first antenna surface, which functions as the main antenna surface, becomes smaller than the sum signal value corresponding to the second antenna surface, which functions as the secondary antenna surface, the selection unit selects the first antenna surface as the secondary antenna surface instead of the second antenna surface. The electronic scanning antenna system according to claim 2 or 3.

5. The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the absolute value of the difference signal corresponding to the first antenna surface, which functions as the main antenna surface, becomes greater than the absolute value of the difference signal corresponding to the second antenna surface, which functions as the secondary antenna surface, the selection unit selects the first antenna surface as the secondary antenna surface instead of the second antenna surface. The electronic scanning antenna system according to claim 1.

6. The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the absolute value of the difference signal corresponding to the second antenna surface, which functions as a secondary antenna surface, becomes smaller than the absolute value of the difference signal corresponding to the first antenna surface, which functions as a primary antenna surface, the selection unit selects the second antenna surface as the primary antenna surface instead of the first antenna surface. The electronic scanning antenna system according to claim 1 or 5.

7. The sum signal value corresponding to the main antenna surface is the largest of the sum signal values ​​corresponding to each of the multiple antenna surfaces. The electronic scanning antenna system according to claim 2.

8. The sum signal value corresponding to the sub-antenna surface is the second largest among the sum signal values ​​corresponding to each of the multiple antenna surfaces. The electronic scanning antenna system according to claim 2 or 7.

9. On each of the multiple antenna surfaces, a plurality of receiving phase sections corresponding to each of the multiple units, It has, Each of the multiple receiving phase units controls the phase of the received signal transmitted to each of the corresponding units. The electronic scanning antenna system according to claim 1.

10. On each of the multiple antenna surfaces, a plurality of transmission phase units corresponding to each of the multiple units, It has, Each of the multiple transmission phase units controls the phase of the transmission signal transmitted to each of the corresponding units based on the control result of the corresponding reception phase unit. The electronic scanning antenna system according to claim 9.

11. The multiple antenna surfaces are, The first antenna surface and A second antenna surface different from the first antenna surface, Includes, When the sum signal value corresponding to the first antenna surface and the sum signal value corresponding to the second antenna surface are each equal to or greater than a predetermined first threshold, and the difference between the sum signal value corresponding to the first antenna surface and the sum signal value corresponding to the second antenna surface is less than or equal to a predetermined second threshold, the selection unit selects the main antenna surface and the sub-antenna surface based on the absolute values ​​of the difference signal values ​​corresponding to the first antenna surface and the second antenna surface, respectively. The electronic scanning antenna system according to claim 2.

12. The first threshold is the minimum value of the sum signal that enables stable communication between the electronic scanning antenna system and the communication equipment. The electronic scanning antenna system according to claim 11.

13. The second threshold is the allowable error value included in the sum signal value when the sum signal is generated. The electronic scanning antenna system according to claim 11.

14. The multiple antenna surfaces are, Multiple specific antenna surfaces, One or more non-specific antenna surfaces different from the aforementioned specific antenna surface, Includes, The multiple specified antenna surfaces are at least, The main antenna surface and, The aforementioned sub-antenna surface and, Includes, The aforementioned electronic scanning antenna system is A determination unit determines a plurality of specific antenna surfaces based on the detection result of the detection unit on the main antenna surface. It has, The generation unit generates the sum signal and the difference signal corresponding to each of the plurality of specific antenna surfaces. The electronic scanning antenna system according to claim 2.

15. The determination unit determines the specific antenna surface based on the detection result of the detection unit on the sub-antenna surface. The electronic scanning antenna system according to claim 14.

16. The aforementioned electronic scanning antenna system is installed on a celestial body, The aforementioned communication device is an artificial satellite orbiting the aforementioned celestial body. The electronic scanning antenna system according to claim 1.

17. A communication method performed by an electronic scanning antenna system that receives a signal from a communication device and transmits a signal to the same communication device, The aforementioned electronic scanning antenna system is Multiple antenna surfaces on which the received signal and the transmitted signal are transmitted, It has, Each of the multiple antenna surfaces is, Multiple units on which the received signal and the transmitted signal are transmitted, Equipped with, The aforementioned communication method is, The electronic scanning antenna system includes a generation step of generating a difference signal of the received signal transmitted to each of the multiple units on each of the multiple antenna surfaces, The electronic scanning antenna system includes a detection step of detecting the received signal value of the received signal and the difference signal value of the difference signal transmitted to each of the plurality of units, The electronic scanning antenna system, based on the detection result in the detection step, selects one of the plurality of antenna surfaces as the main antenna surface and selects one of the other antenna surfaces as the secondary antenna surface. The electronic scanning antenna system receives the received signal from the communication device via the main antenna surface and the sub-antenna surface in a receiving step, The electronic scanning antenna system transmits the transmission signal to the communication device via the main antenna surface in a transmission step, Includes, On each of the multiple antenna surfaces, the 2N × 2M units (where N and M are natural numbers greater than or equal to 1) are arranged in a two-dimensional array of 2N rows and 2M columns. The difference signal value corresponding to each of the multiple antenna surfaces is, for each of the corresponding multiple antenna surfaces, The difference between the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the 1st row to the Nth row, and the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the N+1th row to the 2Nth row, The difference between the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the 1st column to the Mth column, and the sum of the received signal values ​​of the received signals transmitted to each of the units arranged from the M+1th column to the 2nd Mth column, Including at least one of the following: A communication method characterized by the following features.

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