High-altitude platform system

Abstract

This high-altitude platform system comprises a plurality of solar planes, each equipped with a communication platform, a solar cell mounted to at least an upper surface of a plane body, and an electricity storage device that stores electricity converted by the solar cell. The plurality of solar planes fly in a circular path, including a first area in which an electricity generation amount generated by the solar cell exceeds an electricity consumption amount consumed by the solar plane in a reference flight period and a second area in which the electricity generation amount is less than the electricity consumption amount in the reference flight period, such that a state in which a stored electricity amount stored in the electricity storage device is greater than 0 is maintained. In a period in which any one of the plurality of solar planes flies in the first area, another solar plane flies in the second area.

Description

High-altitude platform system

[0001] The present disclosure relates to a high-altitude platform system.

[0002] In recent years, a HAPS (High Altitude Platform Station) is known, which constructs a wireless communication network between the ground by mounting a base station of a communication device such as a smartphone on an unmanned aircraft such as a solar plane and flying it in the stratosphere (about 20 km above the ground).

[0003] Japanese Patent No. 7177747

[0004] The above-mentioned HAPS is required to perform continuous flight for a long time using solar energy. In the sky over an area with a high latitude, since the sunshine intensity decreases, it is necessary to increase the capacity of solar cells and storage batteries. However, increasing the capacity increases the weight of the aircraft and also increases the power consumption, so it is not necessarily an effective countermeasure. For this reason, the maximum latitude at which the HAPS can be operated is limited. In such a HAPS, a configuration that can be operated at a higher latitude is required.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a high-altitude platform system that can be operated at a higher latitude.

[0006] The high-altitude platform system according to the present disclosure includes a plurality of solar planes equipped with a communication platform, at least a solar cell provided on the upper surface of the aircraft body, and a power storage device for storing the power converted by the solar cell, and a control device for controlling the plurality of solar planes. The plurality of solar planes fly along a circular route including a first area where the power generation amount generated by the solar cell exceeds the power consumption amount consumed by the solar plane during a reference flight period and a second area where the power generation amount is less than the power consumption amount during the reference flight period, so as to maintain a state where the stored power amount stored in the power storage device is greater than 0. During the period when any one of the plurality of solar planes flies in the first area, another one of the solar planes flies in the second area.

[0007] The high-altitude platform system according to this disclosure comprises a communication platform, a solar panel provided on at least the upper surface of the aircraft, a power storage device for storing the electricity converted by the solar panel, a plurality of solar planes that fly along a predetermined orbital path, and a control device for controlling the plurality of solar planes. During the day, the plurality of solar planes fly with their noses down when heading towards the sun and with their noses up when heading away from the sun, thereby charging while flying along the orbital path, and at night or when charging is complete, they fly with their noses facing horizontally.

[0008] This disclosure provides a high-altitude platform system that can be operated at higher latitudes.

[0009] Figure 1 is a schematic diagram showing an example of a high-altitude platform system according to an embodiment. Figure 2 is a schematic diagram showing an example of the operation of multiple solar planes in a high-altitude platform system. Figure 3A is a schematic diagram showing the relationship between the amount of power generated by the solar planes, the amount of power consumed, and the amount of power stored in the energy storage device during a standard flight period for each area. Figure 3B is a schematic diagram showing the relationship between the amount of power generated by the solar planes, the amount of power consumed, and the amount of power stored in the energy storage device during a standard flight period for each area. Figure 3C is a schematic diagram showing the relationship between the amount of power generated by the solar planes, the amount of power consumed, and the amount of power stored in the energy storage device during a standard flight period for each area. Figure 4 is a diagram showing the case where the decrease in the amount of power stored in the energy storage device in the second area during the standard flight period is equal to the increase in the amount of power stored in the energy storage device in the first area. Figure 5A is a schematic diagram showing another example of the operation of multiple solar planes in a high-altitude platform system. Figure 5B is a schematic diagram showing another example of the operation of multiple solar planes in a high-altitude platform system. Figure 5C is a schematic diagram showing the orbiting of a solar plane. Figure 5D is a schematic diagram showing the orbiting of a solar plane. Figure 6 is a schematic diagram showing another example of the operation of multiple solar planes in a high-altitude platform system. Figure 7 is a schematic diagram showing another example of the operation of multiple solar planes in a high-altitude platform system.

[0010] Hereinafter, embodiments of the high-altitude platform system according to this disclosure will be described with reference to the drawings. However, this embodiment does not limit the present invention. Furthermore, the components in the following embodiments include those that are easily substituted or substantially identical to those that are easily substituted by those skilled in the art.

[0011] Figure 1 is a schematic diagram showing an example of a high-altitude platform system 100 according to this embodiment. As shown in Figure 1, the high-altitude platform system 100 comprises a plurality of solar planes 10 and a control device 20.

[0012] The solar plane 10 flies, for example, in the stratosphere. The solar plane 10 has a propulsion device 11 such as a propeller. The solar plane 10 is equipped with a communication platform 12. The communication platform 12 is a base station that can communicate with, for example, an information and communication terminal 30 such as a smartphone on the ground or a control device 20. The solar plane 10 has solar cells 13 on the upper surface 10a of the aircraft. In this embodiment, the upper surface 10a of the aircraft is given as, for example, the upper surface of the wing portion 10w of the solar plane 10. In Figure 1, a solid line shows a cross-section of a part of the wing portion 10w of one solar plane 10, and a dashed line shows the outer shape of the wing portion 10w.

[0013] The solar cell 13 converts light energy such as sunlight into electrical energy and supplies it to the energy storage device 14. The energy storage device 14 is mounted on the solar plane 10, stores the power converted by the solar cell 13, and supplies it to the propulsion system 11, communication platform 12, and control unit 15 of the solar plane 10. The solar plane 10 has various detection units, such as a position detection unit capable of detecting altitude, latitude, longitude, etc., and a charge detection unit that detects the amount of charge in the energy storage device 14. The solar plane 10 has a control unit 15 that controls each of its parts. The control unit 15 controls the flight operation of the propulsion system 11 based on preset setting information or commands from the control unit 20. The control unit 15 transmits the detection results from the detection units to the control unit 20 from the communication platform 12.

[0014] The control system 20 controls the flight of each solar plane 10. The control system 20 controls the flight operation of each solar plane 10. The control system 20 has a communication unit 21, a storage unit 22, and a processing unit 23. The communication unit 21 communicates with each solar plane 10. The storage unit 22 stores data and programs necessary for controlling the solar planes 10, such as map information and flight paths. The processing unit 23 performs the processing necessary for controlling each solar plane 10.

[0015] Figure 2 is a schematic diagram illustrating an example of the operation of multiple solar planes 10 in the high-altitude platform system 100. As shown in Figure 2, the multiple solar planes 10 fly along a circular path R that includes the first area AR1 and the second area AR2. Specifically, the multiple solar planes 10 circle in the first area AR1 and the second area AR2 respectively, staying for a certain period of time to provide communication services, and then move between the first area AR1 and the second area AR2 at predetermined timings, thereby flying along the circular path R as a whole. Figure 2 shows an example where four solar planes 10 fly along the circular path R, but the system is not limited to this case, and there may be three or fewer, or five or more.

[0016] The first area AR1 is the area where the amount of electricity generated by the solar plane 10 during its standard flight period exceeds the amount of electricity consumed. The second area AR2 is the area where the amount of electricity generated by the solar plane 10 during its standard flight period falls below the amount of electricity consumed. In this embodiment, the standard flight period is, for example, one day. However, the standard flight period is not limited to one day.

[0017] The first area AR1 is located at a lower latitude than the reference area AR0. The second area AR2 is located at a higher latitude than the reference area AR0. The reference area AR0 is the area where the power stored and the power consumed during the reference flight period of the solar plane 10 are equal. The first area AR1 can be an area where the total amount of daily sunshine during the flight period is greater than that of the reference area AR0 and the second area AR2. The second area AR2 can be an area where the total amount of daily sunshine during the flight period is less than that of the reference area AR0 and the first area AR1.

[0018] Figures 3A to 3C schematically show the relationship between the amount of energy stored in the solar plane 10, the amount of energy consumed, and the amount of energy stored in the energy storage device 14 for each area during a standard flight period (1 day). In Figures 3A to 3C, the horizontal axis represents the time of day, and the vertical axis represents the magnitude of power or energy. Note that the amount of energy stored is shown as a positive value, and the amount of energy consumed is shown as a negative value. As shown in Figures 3A to 3C, in the solar plane 10, power is stored during the period of the day when the amount of power generated exceeds the amount of energy consumed. Also, in the solar plane 10, power is consumed throughout the day, that is, throughout the entire period of daytime when the sun is up and nighttime when the sun is down.

[0019] Figure 3A shows the reference area AR0. As shown in Figure 3A, in reference area AR0, the amount of charge stored in the energy storage device 14 is equal at the beginning and end of the reference flight period. That is, in reference area AR0, the amount of electricity generated by the solar cells 13 during the daytime is equal to the amount of electricity consumed over the entire reference flight period. Therefore, in reference area AR0, if the amount of charge stored in the energy storage device 14 is greater than zero at the beginning of the reference flight period, the amount of charge stored in the energy storage device 14 can be maintained above zero over multiple reference flight periods.

[0020] Figure 3B shows the first area AR1. As shown in Figure 3B, in the first area AR1, the amount of energy stored in the energy storage device 14 is greater at the end of the reference flight period than at the beginning. In other words, in the first area AR1, the amount of electricity generated by the solar cells 13 during the daytime is greater than the amount of electricity consumed over the entire reference flight period. Therefore, in the first area AR1, if the aircraft flies over multiple reference flight periods, the amount of energy stored in the energy storage device 14 will gradually increase up to the maximum capacity of the energy storage device 14.

[0021] Figure 3C shows the second area, AR2. As shown in Figure 3C, in the second area, AR2, the amount of energy stored in the energy storage device 14 is less at the end of the reference flight period than at the beginning. In other words, in the second area, AR2, the amount of electricity consumed over the entire reference flight period is greater than the amount of electricity generated by the solar cells 13 during the daytime. Therefore, in the second area, AR2, if the flight spans multiple reference flight periods, the amount of energy stored in the energy storage device 14 will gradually decrease. Note that the daytime sunlight intensity is weaker in winter than in summer, and is weakest around the winter solstice. In other words, the amount of electricity generated by the solar cells 13 during the reference flight period is lowest around the winter solstice. Therefore, it is preferable to use the value for the amount of electricity generated by the solar cells 13 during the daytime in the second area, AR2, which is under the most severe conditions around the winter solstice.

[0022] For example, if the solar plane 10 continues to fly in the second area AR2, the amount of charge stored in the power storage device 14 will gradually decrease to zero. When the amount of charge stored in the power storage device 14 reaches zero, the solar plane 10 will be unable to fly. Therefore, in this embodiment, the solar plane 10 flies along a circular path R that includes the first area AR1 and the second area AR2, such that the amount of charge stored in the power storage device 14 exceeds zero.

[0023] Figure 4 schematically shows the relationship between the amount of power generated by the solar plane 10, the amount of power consumed, and the amount of power stored in the energy storage device 14 when the solar plane 10 flies through the second area AR2, then through the reference area AR0 to the first area AR1. The example shown in Figure 4 is when the solar plane stays and flies in the second area AR2 during the daytime on a certain day (day 1), moves to the first area AR1 via the reference area AR0 at night, and stays and flies in the first area AR1 during the daytime on the following day (day 2).

[0024] As shown in Figure 4, by flying through the second area AR2 during the daytime on the first day and moving through the reference area AR0 at night, the amount of charge stored in the energy storage device 14 at 24:00 on the first day decreases compared to the amount of charge stored at 0:00 on the same day. Subsequently, by flying through the reference area AR0 and then through the first area AR1 for the reference flight period during the daytime on the second day, the amount of charge stored in the energy storage device 14 at 24:00 on the second day increases compared to the amount of charge stored at 0:00 on the second day (24:00 on the first day). Figure 4 shows the case where the amount of charge stored in the energy storage device 14 at 0:00 on the first day is equal to the amount of charge stored in the energy storage device 14 at 24:00 on the second day. In this case, the decrease in the amount of charge stored in the energy storage device 14 in the second area AR2 during the reference flight period is equal to the increase in the amount of charge stored in the energy storage device 14 in the first area AR1. As shown in this example, the first area AR1 and the second area AR2 may be set so that the increase and decrease in the amount of charge stored in the energy storage device 14 during the reference flight period are equal. By flying in this manner, the solar plane 10 can continuously fly a circular path R including the first area AR1 and the second area AR2 for a long period of time so that the amount of charge stored in the energy storage device 14 exceeds zero.

[0025] Furthermore, as shown in Figure 2, in this embodiment, while one of the solar planes 10 flies in the first area AR1, another solar plane 10 flies in the second area AR2. In this way, by simultaneously positioning the solar planes 10 in both the first area AR1 and the second area AR2, communication becomes possible between the communication platform 12 and the ground area corresponding to the first area AR1 and the ground area corresponding to the second area AR2. Therefore, the communication platform 12 of the high-altitude platform system 100 according to this embodiment can be operated even in areas with high latitude, i.e., areas with low sunlight intensity.

[0026] For example, by using a solar plane 10 with a reference area AR0 at approximately 40 degrees north latitude (e.g., Akita), and using multiple solar planes 10 to orbit a second area AR2 at 43 degrees north latitude (e.g., Sapporo), which is higher than the reference area AR0, and a first area AR1 at 36 degrees north latitude (e.g., Tokyo), it becomes possible to operate on the higher latitude side of 43 degrees north latitude.

[0027] Figures 5A and 5B schematically illustrate other examples of the operation of multiple solar planes 10 in the high-altitude platform system 100. As shown in Figures 5A and 5B, during the daytime, the solar planes 10 fly with their noses 10c lowered when heading towards the sun and with their noses 10c raised when heading away from the sun, thereby charging while in flight.

[0028] When heading towards high latitudes, as shown in Figure 5A, by pointing the nose 10c of the solar plane 10 downwards, the angle of incidence α1 of sunlight on the solar cell 13 can be made smaller compared to when the nose 10c is pointed horizontally, allowing the solar cell 13 to receive sunlight more efficiently. Similarly, when heading towards low latitudes, as shown in Figure 5B, by pointing the nose 10c of the solar plane 10 upwards, the angle of incidence α2 of sunlight on the solar cell 13 can be made smaller compared to when the nose 10c is pointed horizontally, allowing the solar cell 13 to receive sunlight more efficiently.

[0029] Figures 5C and 5D schematically illustrate the orbit of a solar plane. Figure 5C shows a conventional example, and Figure 5D shows an example of this embodiment. In Figure 5D, the contour lines LH are shown corresponding to the orbit of the solar plane 10.

[0030] As shown in Figure 5C, conventionally, when the solar plane 10R stays in the air, it is common to orbit equial points in a circular pattern.

[0031] In contrast, as shown in Figure 5D, in this embodiment, when the solar plane 10 is in the upper atmosphere, during the period when the sun is at a lower latitude, if it is moving from a high latitude to a low latitude, it moves by pointing its nose 10c downwards, thereby decreasing its altitude. Conversely, if it is moving from a low latitude to a high latitude, it moves by pointing its nose 10c upwards, thereby increasing its altitude. As shown in Figure 5D, the trajectory of the solar plane 10 is a circular orbit extending in a straight line between the high latitude and the low latitude.

[0032] Furthermore, during nighttime hours when charging is not performed, or when the energy storage device 14 is fully charged, the solar plane 10 can fly with its nose pointed horizontally. The tilt angle of the nose 10c of the solar plane 10 may also be changed according to the time of day, season, etc.

[0033] Figures 6 and 7 schematically illustrate other examples of the operation of multiple solar planes 10 in the high-altitude platform system 100.

[0034] As shown in Figure 6, each solar plane 10 may have additional solar cells 13 arranged on the underside 10b of the aircraft. In this embodiment, the upper surface 10a of the aircraft is, for example, the underside of the wing portion 10w of the solar plane 10. In other words, the wing portion 10w of the solar plane 10 has a configuration in which solar cells 13 are arranged on both the upper and lower surfaces.

[0035] In this configuration, the solar plane 10 can be charged by reflected sunlight arriving from below. Such reflected light includes, for example, at least one of reflected sunlight L1 from the ground surface 51, reflected sunlight L2 from snow 52 on the ground surface, and reflected sunlight L3 from clouds 53. Such reflected light L1, L2, and L3 from the ground surface 51, snow 52, ​​and clouds 53 can be used when flying in the above-mentioned reference area AR0, first area AR1, and second area AR2. In this way, power generation can be carried out by appropriately utilizing reflected light according to the ground surface conditions and cloud conditions. Furthermore, even in areas with low sunlight intensity (for example, second area AR2) and during seasons with low sunlight intensity (such as winter), charging can be carried out appropriately by reflected light.

[0036] Furthermore, as shown in Figure 7, the solar plane 10 may fly in a circular path between the area where the ground surface 51, snow 52, ​​and clouds 53 are located below, as shown in Figure 6, and the area where urban areas 54, farmlands 55, etc., are located. By flying in such a way, the electricity stored by the reflected light L1, L2, L3 from the ground surface 51, snow 52, ​​and clouds 53 in areas with relatively high levels of reflected light can be used as power when flying over urban areas 54, farmlands 55, etc., where reflected light is relatively low.

[0037] As described above, the high-altitude platform system 100 according to this disclosure comprises a plurality of solar planes 10, each equipped with a communication platform 12, solar cells 13 on at least the upper surface 10a of the aircraft, and a power storage device 14 for storing the power converted by the solar cells 13, and a control device 20 for controlling the plurality of solar planes 10. The plurality of solar planes 10 fly a circular route R that includes a first area AR1 where the amount of power generated by the solar cells 13 exceeds the amount of power consumed by the solar planes 10 during a standard flight period, and a second area AR2 where the amount of power generated is less than the amount of power consumed during a standard flight period, so as to maintain a state in which the amount of power stored in the power storage device 14 is greater than zero. During the period when one of the plurality of solar planes 10 flies in the first area AR1, the other solar planes 10 fly in the second area AR2.

[0038] With this configuration, the solar plane 10 can continuously fly stably for a long period of time along a circular path R that includes the first area AR1 and the second area AR2, such that the amount of charge stored in the energy storage device 14 exceeds zero. In this way, by simultaneously positioning the solar plane 10 in both the first area AR1 and the second area AR2, communication becomes possible between the solar plane 10 and the communication platform 12 in the ground area corresponding to the first area AR1 and the ground area corresponding to the second area AR2.

[0039] In the high-altitude platform system 100 relating to this disclosure, the first area AR1 is located at a lower latitude than the reference area AR0, where the amount of power generated and the amount of power consumed are equal during the reference flight period, and the second area AR2 is located at a higher latitude than the reference area AR0.

[0040] This configuration makes it possible to provide a high-altitude platform system 100 that can be operated even in areas with high latitude, i.e., areas with low sunlight intensity.

[0041] In the high-altitude platform system 100 described herein, multiple solar planes 10 fly with their noses 10c lowered when heading towards the sun during the day, and with their noses 10c raised when heading away from the sun, thereby charging while flying along a circular path R. At night or when charging is complete, they fly with their noses 10c facing horizontally.

[0042] With this configuration, the angle of incidence of sunlight on the solar cell 13 can be made smaller compared to when the nose 10c is pointed horizontally, so that sunlight can be efficiently received by the solar cell 13.

[0043] The high-altitude platform system 100 according to the present disclosure is equipped with a communication platform 12, has solar cells 13 provided at least on the upper surface 10a of the aircraft body, and has a power storage device 14 that stores the power converted by the solar cells 13. It includes a plurality of solar planes 10 that fly along a predetermined circular route R and a control device 20 that controls the plurality of solar planes 10. During the period when the sun is on the low-latitude side during the day, when the plurality of solar planes 10 fly toward the low-latitude side, they fly with the nose 10c facing downward, and when flying toward the high-latitude side, they fly with the nose 10c facing upward. While flying along the circular route R, charging is performed, and at night or when charging is completed, it flies with the nose 10c facing horizontally.

[0044] According to this configuration, compared with the case where the nose 10c is facing horizontally, the incident angle of sunlight on the solar cell 13 can be made smaller, so sunlight can be received by the solar cell 13 efficiently.

[0045] In the high-altitude platform system 100 according to the present disclosure, the solar cells 13 are further arranged on the lower surface 10b of the aircraft body, and charging is performed by the reflected light of sunlight reaching from below.

[0046] According to this configuration, since charging can be performed by the reflected light of sunlight reaching from below, power generation can be performed by appropriately using the reflected light according to the situation below the solar plane 10.

[0047] In the high-altitude platform system 100 according to the present disclosure, the reflected light includes at least one of the reflected light of sunlight by the ground surface 51, the reflected light of sunlight by the snow 52 on the ground surface, and the reflected light of sunlight by the cloud 53.

[0048] According to this configuration, power generation can be performed by appropriately using the reflected light according to the state of the ground surface and the state of the cloud.

[0049] The technical scope of the present invention is not limited to the above embodiments, and appropriate changes can be made without departing from the spirit of the present invention.

[0050] 10 Solar plane 10a Top surface of fuselage 10b Bottom surface of fuselage 10c Nose 10w Wings 11 Propulsion system 12 Communication platform 13 Solar cell 14 Energy storage device 15 Control unit 20 Control system 21 Communication unit 22 Memory unit 23 Processing unit 30 Information and communication terminal 51 Ground surface 52 Snow 53 Clouds 54 Urban area 55 Fields and farms 100 High-altitude platform system AR0 Reference area AR1 First area AR2 Second area L1, L2, L3 Reflected light R Orbital path

Claims

1. A high-altitude platform system comprising: a plurality of solar planes equipped with a communication platform, having solar cells on at least the upper surface of the aircraft and having a power storage device for storing the power converted by the solar cells; and a control device for controlling the plurality of solar planes, wherein the plurality of solar planes fly a circular route including a first area in a standard flight period where the amount of power generated by the solar cells exceeds the amount of power consumed by the solar planes, and a second area in the standard flight period where the amount of power generated is less than the amount of power consumed, so as to maintain a state in which the amount of power stored in the power storage device is greater than zero, and during the period in which any of the plurality of solar planes flies in the first area, the other solar planes fly in the second area.

2. The high-altitude platform system according to claim 1, wherein the first area is located at a lower latitude than a reference area where the amount of power generated and the amount of power consumed are equal during the reference flight period, and the second area is located at a higher latitude than the reference area.

3. The high-altitude platform system according to claim 1, wherein the multiple solar planes, during the daytime, fly with their noses pointed downward when heading towards low latitudes and with their noses pointed upward when heading towards high latitudes, thereby charging while flying along the circular path, and at night or when charging is complete, fly with their noses pointed horizontally.

4. A high-altitude platform system comprising a plurality of solar planes that fly along a predetermined circular path, each equipped with a communication platform, solar cells provided on at least the upper surface of the aircraft, and a power storage device for storing the electricity converted by the solar cells, wherein the plurality of solar planes charge themselves while flying along the circular path during the day by flying with their noses down when facing the sun and with their noses up when facing away from the sun, and at night or when charging is complete, they fly with their noses facing horizontally.

5. The high-altitude platform system according to claim 1 or 4, wherein multiple solar planes have solar cells further arranged on the underside of the aircraft and are charged by reflected sunlight arriving from below.

6. The high-altitude platform system according to claim 5, wherein the reflected light includes at least one of the following: reflected light from sunlight on the ground surface, reflected light from sunlight on snow on the ground surface, and reflected light from sunlight on clouds located below the circular path.

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