Space solar energy transmission and reception system, energy transmission and reception method, and receiving station

Abstract

To increase energy reception efficiency of a space solar energy transmission and reception system.SOLUTION: An artificial satellite 2 controls a direction of an electromagnetic wave 13 to be transmitted on the basis of an arrival direction of a received pilot signal 14. A pilot signal control device 11 of a reception station 3 controls a pilot signal transmission point 20 of a pilot signal transmission device 12 on the basis of intensity distribution of an electromagnetic wave or track information of the artificial satellite received in an energy reception device 9.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a space solar energy power transmission and reception system, an energy transmission and reception method, and a receiving station. [Background technology]

[0002] Space solar power satellite / station / system (SPS or SSPS) requires highly accurate power transmission direction control.

[0003] Patent Document 1 discloses a method for providing a power transmission beam direction control device capable of realizing highly accurate direction control of a power transmission beam, in which a power transmitting satellite detects the arrival angles of multiple pilot signals transmitted from multiple points (pilot stations) of a power receiving facility and calculates the relative angle between the power receiving facility and the power transmitting satellite from the multiple arrival angles in a retrodirective beam system, which is one type of phased array antenna. Furthermore, it discloses a method for controlling the irradiation direction by combining pilot signals from the ground with position information of the ground station and navigation system sensors (AGPS, sun sensor, star sensor).

[0004] Patent Document 2 discloses a space solar power generation system that uses microwaves from a power generation satellite to directly irradiate power consumption areas such as urban areas and residential areas, and a space solar power generation system that can obtain as much power as needed by using an unspecified number of small, dispersed rectennas. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-032879 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-309938 Summary of the Invention [Problem to be solved by the invention]

[0006] When microwaves diffused from a power satellite are simultaneously irradiated to multiple receiving stations, as in Patent Document 2, the energy density decreases when received by the rectennas at each receiving station. On the other hand, in Patent Document 1, the microwaves are irradiated to a single rectenna panel, so there is no reduction in energy density. Here, in Patent Document 1, the direction of the power transmission beam is controlled by the satellite.

[0007] However, especially when a satellite is in a quasi-geostationary orbit, the relative position and altitude between the receiving station and the satellite change constantly. Furthermore, factors that cause deviations in the position of the irradiated energy from the satellite include the effects of spatial medium inhomogeneities, such as electron density inhomogeneities and disturbances in the atmosphere and ionosphere, and various other disturbances (perturbations, solar pressure, etc.) acting on the satellite. Because these factors are difficult to predict in advance, precise power transmission direction control is required at all times to ensure that the irradiated energy is appropriately irradiated to the receiving station. This increases the computational load required to control the satellite attitude and the direction of the irradiated energy, which can be difficult in satellite orbit. Even if the computation is possible, there is a risk that the phase control and power transmission direction control by the transmitting phased array antenna may not be performed as calculated.

[0008] The present invention aims to improve the energy receiving efficiency by reducing the calculation load and control load on a satellite orbit. [Means for solving the problem]

[0009] A space solar energy power transmission and reception system according to one embodiment of the present invention is a space solar energy power transmission and reception system including a satellite and a receiving station, wherein the satellite comprises a solar cell, an energy transmitting device that converts the power generated by the solar cell into electromagnetic waves and transmits the electromagnetic waves, and an energy transmission direction control device that controls the direction of the electromagnetic waves transmitted by the energy transmitting device, and the receiving station comprises an energy receiving device that receives the electromagnetic waves transmitted from the energy transmitting device of the satellite, a pilot signal transmitting device that transmits pilot signals, and a pilot signal control device that controls the pilot signal transmitting device, The energy transmission direction control device of the satellite controls the direction of the electromagnetic waves transmitted by the energy transmitting device based on the direction of arrival of the pilot signal received at the satellite, and the pilot signal control device of the receiving station controls the pilot signal transmission point of the pilot signal control device based on the intensity distribution of the electromagnetic waves received at the energy receiving device or the orbital information of the satellite. [Effects of the Invention]

[0010] The present invention provides a space solar energy power transmission and reception system that reduces the computational load and control load in satellite orbit. Other problems, configurations, and effects will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an overall configuration diagram of a space solar energy power transmission and reception system. [Figure 2] FIG. 10 is a diagram showing a method for switching pilot signal transmission points. [Figure 3] 1 is a time sequence for transmitting pilot signals from a plurality of pilot signal transmitting devices. [Figure 4] 10 is a flowchart showing switching of a pilot signal transmission point; [Figure 5] FIG. 10 is a diagram for explaining a method for switching pilot signal transmission points. [Figure 6] FIG. 10 is a diagram illustrating a method for switching energy transmission to multiple receiving stations. [Figure 7] This is a configuration example in which pilot signals are transmitted using an array antenna. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a space solar energy power transmission and reception system will be described with reference to the accompanying drawings. In the following description and the accompanying drawings, components having the same functional configuration are designated by the same reference numerals, and redundant description will be omitted. [Example]

[0013] Figure 1 shows the overall configuration of a space solar energy power transmission and reception system 1. The space solar energy power transmission and reception system 1 includes an artificial satellite 2 and a ground station, a receiving station 3. Figure 2 also shows how solar energy from the artificial satellite 2 is received at the receiving station 3 while switching the pilot signal transmission point.

[0014] The artificial satellite 2 includes a solar cell 4, an energy conversion device 5, an energy transmission device 6, an energy transmission direction control device 7, and a pilot signal receiving device 8. The receiving station 3 includes an energy receiving device 9, an analysis device 10, a pilot signal control device 11, and a plurality of pilot signal transmitting devices 12.

[0015] First, the elements of the satellite 2 will be briefly described.

[0016] The solar cell 4 is, for example, a solar panel that converts solar energy into DC power through photoelectric conversion. The energy conversion device 5 converts the DC power generated by the solar cell 4 into electromagnetic waves suitable for transmission to the receiving station 3. The energy conversion device 5 is, for example, a microwave generation device such as a magnetron, and in this case, the energy conversion device 5 converts the DC power into microwaves. The energy transmission device 6 is an antenna for transmitting solar energy to the receiving station 3 as electromagnetic waves (irradiation energy 13).

[0017] The energy transmitting device 6 is capable of controlling the transmission direction of the irradiated energy 13 (electromagnetic waves) so that the irradiated energy 13 can be properly received by the receiving station 3. The energy transmitting device 6 may be provided with a mechanical mechanism for changing the antenna orientation, or, for example, a phased array antenna in which dipole antennas or patch antennas are arranged in an array may be used to electrically control the phase of the electromagnetic waves transmitted from each antenna element, thereby electrically controlling the transmission direction. The energy transmission direction control device 7 controls the transmission direction of the irradiated energy 13 from the energy transmitting device 6. For example, if the energy transmitting device 6 is a phased array antenna, the energy transmission direction control device 7 is its phase control circuit. The transmission direction of the irradiated energy 13 is determined according to a pilot signal 14 transmitted from the receiving station 3.

[0018] The pilot signal 14 is received by a pilot signal receiving device 8. The pilot signal receiving device 8 is, for example, a microwave receiver equipped with an antenna and a radio. The antenna of the pilot signal receiving device 8 may be shared with the antenna of the energy transmitting device 6. The energy transmission direction control device 7 calculates the arrival direction of the pilot signal 14 from the phase information of the pilot signal 14, and controls the energy transmitting device 6 to transmit the irradiated energy 13 (electromagnetic waves) in the direction of the transmission point of the pilot signal 14. For example, when retrodirective transmission direction control is applied, the transmission direction of the electromagnetic waves is set to the same direction as the arrival direction of the pilot signal.

[0019] Next, the elements of the receiving station 3 will be briefly described.

[0020] The energy receiving device 9 receives the irradiated energy 13 from the satellite 2 and is, for example, a rectenna or an electrical circuit in which a rectifier circuit is coupled to an antenna. The analysis device 10 is, for example, a computer, and performs analysis to control the transmission point of a pilot signal based on the energy reception status of the energy receiving device 9. The analysis content will be described later. The pilot signal transmitting device 12 transmits a pilot signal 14 toward the satellite 2 and is, for example, a parabolic antenna and its associated devices. The multiple pilot signal transmitting devices 12 are controlled by a pilot signal control device 11. The pilot signal control device 11 is an electronic circuit that switches between the pilot signal transmitting devices 12 that transmit the pilot signal 14 based on the analysis results of the analysis device 10 and may include an antenna rotator or direction control device. Note that in FIG. 1, the multiple pilot signal transmitting devices 12 are identified by identifiers (A, B, C, etc.) to distinguish them from one another. For example, the receiving station 3 includes pilot signal transmitting devices 12A, 12B, 12C, etc., one of which transmits the pilot signal 14.

[0021] In FIG. 2, for convenience of illustration, the pilot signal transmitting device 12 is depicted as being disposed around the energy receiving device 9. However, in reality, the diameter of the energy receiving device 9 may be several kilometers, and multiple pilot signal transmitting devices 12 may be disposed so as to overlap the energy receiving device 9 as viewed from the satellite 2. The energy receiving device 9 is configured with a receiving rectenna array or the like, and the analyzing device 10 calculates the energy reception intensity distribution at the energy receiving device 9 and calculates, for example, its center of gravity. It is expected that the calculated center of gravity will deviate from the desired energy reception point. Causes of the deviation include signal delay due to internal delays in the circuitry, changes in relative velocity due to the Earth's rotation, changes in the satellite's orbital altitude, and temporal and spatial changes in the material 21 within the energy propagation path. In particular, if the satellite 2 is not in a geostationary orbit but is, for example, in a quasi-geostationary orbit, the degree of signal delay will change depending on the altitude and position of the satellite 2. In this case, the transmission direction of the pilot signal 14 needs to be controlled according to the orbital position and relative velocity of the artificial satellite 2. In addition, as the altitude of the artificial satellite 2 changes, the signal delay caused by the rotation of the Earth also changes, resulting in multiple overlapping causes of the deviation.

[0022] In this embodiment, in order to shift the center of gravity 22 of the energy intensity distribution of the irradiation energy 13 caused by such various causes to a desired point without imposing an excessive computational load and control load on the satellite 2, which has limited computational and hardware resources, the pilot signal transmission point 20 (in the example of FIG. 2, the pilot signal transmitting device 12A is the transmission point) is displaced. For example, when retrodirective transmission direction control is applied, control is performed to move the pilot signal transmission point 20 in the same direction as the direction in which the center of gravity is desired to be shifted.

[0023] For example, when retrodirective transmission direction control is applied, multiple pilot signal transmission devices 12 may be provided in advance, and the pilot signal may be switched to be emitted from the device closest to the desired irradiation point of irradiation energy. FIG. 3 shows an example of a time sequence in which pilot signals 14 are transmitted from multiple pilot signal transmission devices A to N. The pilot signals are time-shared, and one of the pilot signal transmission devices 12 always transmits the pilot signal 14. The pilot signal transmission devices are not used simultaneously, but are switched between, and the destination of the pilot signal transmission device 12 is determined based on the difference between the center of gravity point 22 of the energy intensity distribution and the desired point. Therefore, it is possible for the same pilot signal transmission device to transmit pilot signals 14 in multiple consecutive time slots.

[0024] As described above, the received intensity distribution of the irradiated energy is controlled from the ground to be optimal, and the received irradiated energy 13 is rectified, for example, by a rectenna array, converted into commercial power, and then used in the commercial power grid 24 via a connection line 23 to the commercial power grid (see Figure 2). The advantage of feedback-controlling the transmission direction of the irradiated energy from the ground based on the received intensity distribution of the irradiated energy is that it is possible to address deviations in the energy received intensity distribution caused by difficult-to-predict factors such as disturbances on the satellite side, which is constantly moving relative to the Earth, or atmospheric disturbances. Even in such cases, the center of gravity point 22 of the energy intensity distribution can be corrected by feedback control by controlling the pilot signal transmission point from the ground.

[0025] Fig. 4 shows a flowchart for switching the pilot signal transmission point. The flowchart will be explained with reference to Fig. 5. Pilot signal transmittable area 33 is set so as to include at least energy receiving device 9. In this example, pilot signal transmittable area 33 corresponds to the range in which pilot signal transmitting device 12 is installed.

[0026] First, the receiving station 3 transmits a pilot signal 14 from one of the pilot signal transmitters 12 toward the satellite (step S301). The installation location of the pilot signal transmitter 12 that transmitted the pilot signal 14 is the pilot signal transmission point 20. Next, the receiving station 3 receives an energy signal or pilot signal from the artificial satellite 2 (step S302). If, for some reason, there is a risk that the arrival position of the irradiated energy 13 from the artificial satellite 2 will be significantly different from the desired position, the intensity of the irradiated energy 13 may be weakened and transmitted as a pilot signal that notifies the receiving station 3 of the transmission direction of the irradiated energy, rather than as an electromagnetic wave as the irradiated energy 13.

[0027] Next, the analysis device 10 calculates the reception intensity distribution by measuring the current or voltage in the electric circuit in the energy receiving device 9, and calculates the energy intensity distribution center-of-gravity point 22 from the reception intensity distribution (step S303). Next, the analysis device 10 calculates a reception point correction vector p to the desired center-of-gravity point of the energy intensity distribution (step S304). As shown in Fig. 5, the reception point correction vector p is a vector whose start point is the energy intensity distribution center-of-gravity point 22 and whose end point is the desired center-of-gravity point 34.

[0028] Next, the pilot signal control device 11 shifts the pilot signal transmission point 20 according to the transmission point correction vector q (step S305). The transmission point correction vector q is determined based on the reception point correction vector p, and FIG. 5 shows an example where q = αp. In this case, the transmission point correction vector q is a vector that starts from the pilot signal transmission point 20 and is oriented in the same direction as the reception point correction vector p. The constant α may take a value between 0 and 1, for example, and may be set to a predetermined amount, or may be a variable value to control the control speed (set to a value closer to 1 to increase the control speed). Furthermore, the directions of the reception point correction vector p and the transmission point correction vector q do not need to coincide; for example, a predetermined offset vector may be added to the transmission point correction vector q. Adding an offset vector allows for accurate correction of a certain amount of deviation that occurs in a certain direction over a certain period of time, such as due to the influence of the Earth's rotation.

[0029] If the energy transmission and reception is to be continued (Yes in step S306), step S301 is executed, and if the energy transmission and reception is not to be continued (No in step S306), the process ends.

[0030] In this embodiment, an example has been disclosed in which the pilot signal transmission point is shifted using the energy intensity distribution center of gravity point 22 as an index, but the control index is not limited to the intensity distribution center of gravity point. The received intensity distribution at the energy receiving device 9 may be controlled to match a predetermined two-dimensional intensity distribution. Energy irradiated from outer space generally has an intensity distribution that is not uniform. A configuration may be adopted in which the received intensity distribution at the energy receiving device 9 is controlled to match the predetermined pattern.

[0031] Although the present embodiment has described feedback control using the reception intensity distribution, the pilot signal transmission point may also be controlled using orbital information of the satellite 2. By taking into account the relative displacement between the satellite 2 and the rotating Earth, and the arrival of the pilot signal and the irradiated energy at the speed of light, it is also possible to geometrically calculate the pilot signal transmission point 20 where the energy intensity distribution becomes the desired center of gravity point 34.

[0032] The pilot signal control device 11 controls the transmission direction of the pilot signal from the pilot signal transmitting device 12 that transmits the pilot signal 14. The transmission direction of the pilot signal 14 needs to be determined by predicting the position of the artificial satellite 2 when the pilot signal 14 arrives. The transmission direction of the pilot signal can be determined by the angular difference θ determined by the relative velocity vector q, the relative velocity vector v, and the speed of light c, where r is the relative position vector of the artificial satellite 2 with respect to the pilot signal transmitting point 20 or the receiving station 3, v is the relative velocity vector of the artificial satellite 2 with respect to the receiving station 3, and c is the speed of light. Specifically, the angular difference θ is determined by the component of the relative velocity vector v that is perpendicular to the line of sight direction (relative position vector r) from the receiving station 3 to the artificial satellite 2, as expressed by the vector v p When θ≒2v p / c can be approximately expressed as:

[0033] In addition, in this embodiment, an example has been described in which a plurality of pilot signal transmitters 12 are provided and pilot signal transmission point 20 is displaced by one of pilot signal transmitters 12 transmitting a pilot signal 14, but this is not limiting. Pilot signal transmission point 20 may also be displaced by mounting pilot signal transmitter 12 on a moving object such as a vehicle and moving it. The moving object may be an aircraft, a ship, or the like. [Example]

[0034] FIG. 6 shows an embodiment in which multiple receiving stations 3 are installed. Receiving station A (3A), receiving station B (3B), and receiving station C (3C) are shown here. The satellite 2 transmits irradiated energy to these multiple receiving stations. In this case, a receiving station control device 40 is provided to control these receiving stations and adjust the pilot signals 14 transmitted by each receiving station so that they do not interfere with each other. The receiving station control device 40 may synchronize the operation of each receiving station 3 to prevent multiple receiving stations 3 from transmitting pilot signals 14 at the same time, or the receiving station control device 40 may arbitrate among receiving stations attempting to receive irradiated energy from the satellite 2. This allows adjustments to be made so that the receiving stations 3 attempting to receive power can receive it more efficiently. [Example]

[0035] FIG. 7 shows an example in which a receiving station 3 transmits a pilot signal 14 using an array antenna. The receiving station 3 includes an array antenna 15 arranged in a pilot signal transmission area 33 and an antenna element switching device 17 that selects and switches the antenna element used to transmit the pilot signal 14. The antenna element switching device 17 can be realized, for example, by an electrical circuit that switches the power supply to each antenna element power supply on and off. The antenna element switching device 17 turns on the power supply to the antenna in the transmission area 16 used to transmit the pilot signal 14, thereby setting the array antenna for the pilot signal transmission area 16. If necessary, each element may be equipped with a phase controller, which controls the phase of each antenna element to control the transmission direction of the pilot signal 14. This allows a directional antenna array to be used to transmit the pilot signal 14, thereby minimizing the mechanical range of movement. The antenna element switching device 17 also allows for continuous switching of the pilot signal transmission point.

[0036] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present disclosure, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0037] 1: Space solar energy transmission and reception system, 2: Satellite, 3: Receiving station, 4: Solar cell, 5: Energy conversion device, 6: Energy transmitting device, 7: Energy transmission direction control device, 8: Pilot signal receiving device, 9: Energy receiving device, 10: Analysis device, 11: Pilot signal control device, 12: Pilot signal transmitting device, 13: Irradiation energy, 14: Pilot signal, 15: Array antenna, 16: Pilot signal transmission area, 17: Antenna element switching device, 20: Pilot signal transmission point, 21: Material in energy propagation path, 22: Energy intensity distribution center of gravity point, 23: Connecting line, 24: Commercial power grid, 33: Pilot signal transmittable area, 34: Desired center of gravity point, 40: Receiving station control device.

Claims

1. In a space solar energy power transmission and reception system including an artificial satellite and a receiving station, The artificial satellite A solar cell and an energy transmitting device that converts the power generated by the solar cell into electromagnetic waves and transmits the electromagnetic waves; an energy transmission direction control device that controls the direction of the electromagnetic waves transmitted by the energy transmission device, The receiving station an energy receiving device that receives electromagnetic waves transmitted from the energy transmitting device of the artificial satellite; a pilot signal transmitting device for transmitting a pilot signal; a pilot signal control device for controlling the pilot signal transmitting device, the energy transmission direction control device of the satellite controls the direction of the electromagnetic wave transmitted by the energy transmission device based on the direction of arrival of the pilot signal received by the satellite; A space solar energy transmission and reception system characterized in that the pilot signal control device of the receiving station controls the pilot signal transmission point of the pilot signal transmitting device based on the intensity distribution of the electromagnetic waves received by the energy receiving device or the orbital information of the artificial satellite.

2. In claim 1, A space solar energy transmission and reception system characterized in that the pilot signal control device of the receiving station calculates a transmission point correction vector for displacing the pilot signal transmission point based on a reception point correction vector that starts from the center of gravity of the intensity distribution of the electromagnetic wave received at the energy receiving device and ends at a desired center of gravity.

3. In claim 2, A space solar energy transmission and reception system characterized in that the transmission point correction vector is obtained by adding an offset vector to a vector in the same direction as the reception point correction vector.

4. In claim 1, A space solar energy power transmission and reception system characterized in that the pilot signal control device of the receiving station controls the transmission direction of the pilot signal transmitted by the pilot signal transmitting device based on orbital information of the artificial satellite.

5. In claim 1, the receiving station comprises a plurality of the pilot signal transmitting devices; A space solar energy transmission and reception system characterized in that the pilot signal control device of the receiving station time-divides the pilot signal and determines one of the multiple pilot signal transmitting devices as the pilot signal transmission point for each time slot.

6. In claim 1, A space solar energy power transmission and reception system characterized in that the pilot signal transmitter of the receiving station is mounted on a mobile body that can move to the pilot signal transmission point.

7. In claim 1, the pilot signal transmitting device of the receiving station is an array antenna arranged in a pilot signal transmitting area, the receiving station further includes an antenna element switching device that switches ON / OFF of antenna elements that constitute the array antenna; The antenna element switching device turns on an array antenna in a transmission area corresponding to the pilot signal transmission point and transmits the pilot signal.

8. In claim 1, a plurality of said receiving stations; A space solar energy power transmission and reception system further comprising a receiving station control device that adjusts the pilot signals transmitted from the plurality of receiving stations so that they do not interfere with each other.

9. An energy transmission and reception method in a space solar energy transmission and reception system including an artificial satellite and a receiving station, the artificial satellite comprises a solar cell, an energy transmitting device that converts the power generated by the solar cell into electromagnetic waves and transmits the electromagnetic waves, and an energy transmission direction control device that controls the direction of the electromagnetic waves transmitted by the energy transmitting device; the receiving station includes an energy receiving device that receives electromagnetic waves transmitted from the energy transmitting device of the artificial satellite, a pilot signal transmitting device that transmits a pilot signal, and a pilot signal control device that controls the pilot signal transmitting device; the energy transmission direction control device of the satellite controls the direction of the electromagnetic wave transmitted by the energy transmission device based on the direction of arrival of the pilot signal received by the satellite; The energy transmission and reception method is characterized in that the pilot signal control device of the receiving station controls the pilot signal transmission point of the pilot signal transmitting device based on the intensity distribution of the electromagnetic waves received at the energy receiving device or the orbital information of the artificial satellite.

10. In claim 9, the receiving station comprises a plurality of the pilot signal transmitting devices; The energy transmission and reception method is characterized in that the pilot signal control device of the receiving station time-divides the pilot signal and determines one of the plurality of pilot signal transmitting devices as the pilot signal transmission point for each time slot.

11. a receiving device for receiving electromagnetic waves transmitted from an artificial satellite; a pilot signal transmitting device for transmitting a pilot signal; a pilot signal control device for controlling the pilot signal transmitting device, the pilot signal is used by the satellite to control the direction of the electromagnetic wave it transmits based on its direction of arrival; The receiving station is characterized in that the pilot signal control device controls the pilot signal transmission point of the pilot signal transmitting device based on the intensity distribution of the electromagnetic waves received by the receiving device or orbit information of the artificial satellite.

12. In claim 11, The receiving station is characterized in that the artificial satellite is equipped with a solar cell, and the power generated by the solar cell is converted into the electromagnetic wave and transmitted.

13. In claim 11, The pilot signal control device is characterized in that it calculates a transmission point correction vector for displacing the pilot signal transmission point based on a reception point correction vector whose starting point is the center of gravity of the intensity distribution of the electromagnetic wave received by the receiving device and whose ending point is a desired center of gravity.

14. In claim 11, a plurality of the pilot signal transmitting devices; The receiving station is characterized in that the pilot signal control device divides the pilot signal into time slots and determines one of a plurality of pilot signal transmitting devices as the pilot signal transmitting point for each time slot.

15. In claim 11, the pilot signal transmitting device is an array antenna arranged in a pilot signal transmitting area, The antenna element switching device further includes an antenna element switching device for switching on / off the antenna elements that configure the array antenna, The receiving station is characterized in that the antenna element switching device turns on an array antenna in a transmission area corresponding to the pilot signal transmission point and transmits the pilot signal.

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