JP2995296B1 - Energy transfer method between ground and stratospheric airship - Google Patents

Abstract

[Summary] [Problem] A stratospheric airship that stays in a weak wind zone in the stratosphere and is used for communication relay, environmental observation, supply of emergency power to isolated islands, disaster areas, accident sites, etc. It is possible to efficiently transmit power for staying and power for performing an original function of an airship. SOLUTION: A moored airship 2 staying in a weak wind zone in the stratosphere
Is moored to the mooring base 1 on the ground by the mooring line 3, and energy transmission by laser is performed between the mooring base 1 and the mooring airship 2 through an optical fiber along the mooring line 3. In the moored airship 2, the power for staying of the airship itself is obtained by photoelectric conversion, and at the same time, the transmitted energy is output from the moored airship 2 to the second airship 12 that is staying in or near the stratosphere. Aerial wireless transmission is performed by the laser L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for relaying communications, monitoring the environment, relaying power transmission, supplying emergency power to isolated islands, disaster-stricken areas, accident sites, etc., by staying in a weak wind zone in the stratosphere.
The present invention relates to a method for transmitting energy between the ground and a stratospheric airship, which is used to supply power for retaining the airship itself and power for performing the functions of the airship to a stratospheric airship used for other purposes.

[0002]

2. Description of the Related Art It is planned to use an airship staying in a weak wind zone in the stratosphere as a relay for communication and as an environmental observation means, and research and development for that purpose have been started. The lower part of the stratosphere, at an altitude of about 20 km from the ground, is clear all year round, with gentle winds and the mildest. A stratospheric platform that stays in this airspace for a long time and opens up new fields for environmental observation and information relay will be realized as an unmanned airship in the near future. In this case, the airship needs propulsion power to maintain its position against weak winds in the stratosphere and power to perform the airship's essential functions such as communication and environmental observation. As a way to get power,
In general, a method of storing solar energy and a method of transmitting the energy from the ground by using a microwave or a laser can be considered.

[0003] However, the method of photoelectrically converting solar energy to store electricity has a limit in the payload of an airship, and therefore, it is necessary to wait for technological development such as weight reduction of a storage battery.
Moreover, in winter in polar regions, there is a place where sufficient or no sunlight can be obtained. Therefore, in order to stay in this area for a long period of time, sunlight cannot be used, and instead, technical means of wireless transmission using microwaves, lasers, etc., which can continuously supply energy from the ground for a long period of time Need to be considered.

[0004] However, microwaves, which are well-known wireless transmission means, have recently been concerned about electromagnetic pollution, and thus have a problem in use. In addition, transmission by microwaves affects communication on the ground and aircraft, and there is also a problem in this respect. That is, when microwaves oscillate, the leakage of radio waves in directions other than the main radiation direction, such as side ropes, and the leakage of radio waves into the air other than wireless power transmission due to reflection from the power receiving antenna are large, causing electromagnetic pollution. Cause
There is an effect on communication in the frequency band that is already in use. In order to avoid this effect, if power is transmitted through the atmosphere using radio waves with frequencies higher than those already used, the attenuation of clouds and rain in the atmosphere will be large, and Efficiency. On the other hand, wireless transmission of energy by high-power laser is different from transmission by general microwave, and is greatly attenuated by moisture in the air.In particular, it is absorbed by clouds, rain, etc. Medium long distance transmission is difficult.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and its technical problem is basically that the communication relay is carried out by staying in a stratospheric weak wind zone. Power for supplying emergency power to isolated remote islands, affected areas, accident sites, etc., for stratospheric airships used for other purposes, for powering the airships themselves and for performing their functions It is an object of the present invention to provide a method of transmitting energy between the ground and a stratospheric airship, which enables efficient transmission of radio waves.

Another technical object of the present invention is to efficiently transmit air, which has been relatively efficiently transmitted to a stratospheric airship, to a second airship staying at or near the stratosphere as described above. Or transmitting the second airship as a relay airship to a third airship,
Accordingly, it is an object of the present invention to provide a method for transmitting energy to an airship that enables long-distance transmission to the second and third airships at a long distance from the energy supply base.

A more specific technical problem of the present invention is that in the troposphere where it is difficult to wirelessly transmit energy over the air due to the presence of a large amount of moisture, energy can be efficiently transmitted by wire so that energy due to moisture is reduced. Prevents attenuation and transmits long-range radio transmissions in the air in the stratosphere where there is almost no moisture, thereby efficiently transferring energy between the ground and stratospheric airships or the second and third airships that stay in distant airspace. It is an object of the present invention to provide an energy transmission method which can be performed at a high speed. Another technical object of the present invention is to provide an energy transmission method capable of sufficiently transmitting energy between the ground and a stratospheric airship without causing electromagnetic pollution by microwaves.

[0008]

According to a basic energy transmission method of the present invention for solving the above-mentioned problems, a moored airship staying in a weak wind zone in the stratosphere is moored to a mooring base on the ground by a mooring line. Laser energy is transmitted between the base and the mooring airship via optical fibers along the mooring lines, and the photoelectric conversion of the mooring airship obtains the power for the airship to stay and perform its functions. is there.

Further, the transmission method of the present invention for transmitting energy over a long distance to an airship staying in a long-distance airspace by using the above method is a method for mooring an airship staying in a weak wind zone in the stratosphere at a mooring base on the ground. Moored by a rope, energy transmission by laser is performed between the mooring base and the mooring airship through an optical fiber along the mooring line, and at the mooring airship, power for staying of the airship itself is obtained by photoelectric conversion at the same time as transmission. The received energy is transmitted wirelessly from the moored airship to the second airship staying at an arbitrary position in or near the stratosphere using a high-power laser.

[0010] The energy transmitted to the second airship is used as power for retaining and performing the function of the second airship, or as energy for retaining or performing the function of the second airship.
The second airship is used as a force, or the second airship is used as a relay airship for energy transmission, and the energy transmitted to the second airship is transmitted to the third airship wirelessly in the air using a similar laser. To power the airship for its stay and function , or to stay or
It can also be used as power to perform a function or transmit energy to a fourth airship. In aerial wireless transmission of high-power lasers from an airship to another airship, a phase conjugate mirror is used to reflect part of the laser light received by the light-receiving mirror to the light-emitting side, and then receive it at the light-emitting side. ,
It is effective to track the projection direction of the laser on the light emitting side so that the projection laser is incident on the light receiving side mirror.

In the implementation of the energy transmission method of the present invention, first, a mooring base (an energy supply) on the ground for mooring the moored airship on a route of an aircraft or in a mountainous area or a remote island away from a dense city. Base)
A mooring airship moored by a mooring line is retained in a low wind zone of about 20 km from the ground below the stratosphere, and energy transmission by a laser is performed on the airship through an optical fiber along the mooring line. The energy transmitted by the laser is converted by the photoelectric conversion of the moored airship into propulsion power for the airship itself to stay against the wind, or
It is used to power the airship itself to perform its functions.

As described above, when the stratospheric airship is moored at the mooring base and the energy is transmitted by the laser through the optical fiber along the mooring line in the troposphere where there is a lot of moisture, the energy is efficiently transmitted, and the airborne radio transmission is performed. As in the case, the energy can be prevented from decay due to moisture. In addition, when energy is transmitted by a laser through an optical fiber along a mooring line, the amount of energy transmission increases by one to two orders of magnitude compared to, for example, a case where electric energy is directly transmitted to an airship by an electrical conductor along the mooring line. High-density energy transmission can be performed by a light-weight optical fiber, and the mooring line, which reaches 20 km, can be significantly reduced in weight compared to the amount of transmitted energy. Furthermore, sufficient energy transmission between the ground and the stratospheric airship can be performed without causing electromagnetic pollution as in the case of using microwaves.

Also, the energy of the high-power laser transmitted through the optical fiber to the mooring airship staying in the lower wind zone in the lower stratosphere does not undergo photoelectric conversion and flies at a similar altitude in the airspace remote from the mooring airship. Over-the-air wireless transmission directly to a second unmanned airship that continues to operate with a high-power laser. In this case, since there is almost no moisture in the weak wind zone below the stratosphere, the long distance (10
0 to 300 km) over the air.
In addition, energy can be efficiently transmitted to the third airship.

[0014]

FIG. 1 schematically shows an embodiment in which energy is transmitted between the ground and a stratospheric airship by the method according to the present invention. As can be seen from the figure, when implementing the present invention, first, a mooring base 1 for mooring an unmanned moored airship 2 is installed on a route of an aircraft or in a mountainous area or a remote island away from a dense city. Is done. The mooring airship 2 is moored at the mooring base 1 by the mooring line 3 and stays in a weak wind zone of about 20 km from the ground below the stratosphere, but all the ascent, descent, and horizontal movement of the airship 2 are performed by the mooring line 3. Because it cannot be controlled, the unmanned aerial vehicle 2 itself is provided with a propulsion device 2a for maintaining the altitude in the same altitude and the same airspace for a long time against a weak wind. The propulsion device 2a outputs propulsion power in a required direction, and power propulsion of the airship 2 by the propulsion power reduces the load on the mooring line 3 due to air resistance to the airship 2. Can be.

The stratosphere's weak wind zone, 20 km above the ground
Literature and the like have already suggested the possibility of the technique of levitating a tethered balloon from the ground at a high altitude and holding it in the air (for example, the 11th American Aeronautics and Astronautical Society LTA System Engineering Division Lecture (A. Euler, Badesha & L. Schroeder, Ve
ry High Altitude Tethered Balloon Feasibility Stud
y)), calculations have been made that the ascent process from the ground to the stratosphere is dynamically possible.

The mooring line 3 has an optical fiber along it, and transmits energy from the mooring base 1 equipped with a laser light generator to the mooring airship 2 through the optical fiber by laser. Therefore, the mooring base 1 also serves as an energy supply base. The energy transmitted by the laser is received by the moored airship 2, converted into electrical energy by photoelectric conversion, and used as an energy source such as propulsion power for the stay of the airship itself, or as a power source for a mission, such as a communication relay or an environment. It is used for performing functions such as supplying emergency power to isolated islands, disaster-stricken areas, accident sites, etc. by performing observations and relaying power transmission to other airships. The propulsion power required to make the airship stay in the stratosphere in a weak wind zone for a long time ranges from several tens of kW to 2 to 2 depending on the hull size and airspeed.
It is considered to be about 00 kW. In this way, instead of transmitting airborne radio waves directly to airships and the like by laser, optical fiber transmission to the airship 2 moored at a high altitude,
Energy can be efficiently transmitted to prevent the energy from being attenuated due to moisture.

The mooring line 3 uses a rope made of a fiber having a high specific strength such as aramid fiber, glass fiber or carbon fiber as a strength member, uses an optical fiber such as quartz for energy transmission, and uses a lightning arrester. As a measure, it is desirable to coat the outside of the rope with a metal sheath. As a laser to be transmitted, it is desirable to use a high-output laser suitable for optical fiber light guiding, such as a semiconductor-pumped solid-state laser and an iodine laser. Solid-state lasers and chemical lasers can be expected to have an electrical-to-optical conversion rate of 30% or more, whereas gas lasers can be several hundreds per unit.
Although output of kW is possible, not only is the oscillation device large, but also auxiliary devices such as cooling are large, and the electric-optical conversion efficiency is extremely poor, at most 2 to 5%, making it difficult to use it. There is.

Lasers have significantly different physical characteristics such as energy conversion efficiency and absorption into a substance depending on the wavelength. A laser having a wavelength of 5 μm has a low absorption in the atmosphere. (E.g., carbon oxide) laser whose oscillation efficiency is one order of magnitude lower than that of a solid-state laser or a chemical laser as described above. Therefore, as in the present invention, it can be said that it is a very excellent method to transmit a laser beam through a fiber and select a laser beam having a suitable wavelength and good oscillation efficiency.

As described above, the laser energy transmitted through the optical fiber along the mooring line 3 to the mooring airship 2 staying in the weak wind zone in the stratosphere,
In the above, at the same time as the power for staying of the airship itself by photoelectric conversion, the transmitted energy is transmitted from the light projecting portion 2b of the moored airship 2 to the lower stratosphere or its vicinity at a long distance of about 100 to 300 km. Alternatively, the high-power laser L can be used to perform aerial wireless transmission to the light receiving unit 12b of the second airship 12 that keeps flying. FIG. 2 shows a case where energy transmission by laser L is performed to a plurality of airships 12. The high-power laser L transmitted to the second airship 12 is transferred as it is using a mirror or the like without photoelectrically converting the laser transmitted from the ground through the fiber. In this case, in the weak wind zone in the lower stratosphere where the laser L is wirelessly transmitted in the air, the energy is not attenuated even if the laser is transmitted over a long distance of 100 to 300 km because there is almost no moisture.
Further, the power density of the transmitted laser can be made several times as high as that of sunlight, and the size of the light receiving section at this time is about several meters in diameter at most.

In the second airship 12, the transmitted energy is used as a power for staying the airship 12 and performing the same function as the moored airship 2 , or in flight.
Staying of the ship 12 or performing the same function as the moored airship 2
For this second airship 12
In general, the mooring base 1 is difficult to be installed and the moored airship 2 cannot be moored, so that the moored airship 2 is usually kept in an airspace such as a densely populated city or a remote place. It is used to perform functions such as relaying power transmission and supplying emergency power to isolated islands, disaster areas, accident sites, etc.

As shown in FIG. 2, the second airship 12 uses the energy transmitted to the second airship 12 as a relay airship for transmitting energy, as shown in FIG.
Aerial wireless transmission with a high-power laser L to an arbitrary number of third airships 13 farther away to power the third airship 13 for its stay and function , or
The power can be used for staying or performing functions of the ship 13 . Further, the airborne transmission from the third airship 13 to other necessary airships is also possible. These airships transmit the energy transmitted from the mooring base 1 to the high power between the airships staying in the stratospheric weak wind zone, similarly to the energy transmission between the moored airship 2 and the second airship 12. The air is wirelessly transmitted efficiently by the laser, and the light is converted at each airship, thereby providing the required functions.

These airships can be kept in the stratosphere as a stratosphere platform having various functions such as communication relay and environmental observation. However, these airships can be kept in the airspace remote from the mooring base, isolated islands, In the case of an airship that stays in the airspace such as on the ground or at the accident site, its energy can be retransmitted to the ground as needed.In that case, a separate mooring line should be provided for the airship that retransmits to the ground. Along the way, optical fibers can be used, or any other energy transmission method can be used, depending on atmospheric conditions and the environment.

In the aerial wireless transmission of a high-power laser L from an airship to another airship in the stratosphere, it is necessary to facilitate tracking of the airship on the light-receiving side in the airship on the light-emitting side. For that purpose, it is desirable to track the airship on the light receiving side using a phase conjugate mirror using a photorefractive crystal or the like. This phase conjugate mirror makes the light-emitting side mirror that projects the laser L and the light-receiving side mirror that receives the laser L face each other. At the airship on the light-receiving side, a part of the received laser is reflected to the light emitting side. By receiving the light on the light-emitting side, the projection direction of the laser on the light-emitting side is automatically controlled so that the projected laser is incident on the light-receiving side mirror. Even if the relative position changes, the projection direction of the laser beam follows so that it can enter the light receiving side mirror. With this, it is far from the laser emitting side,
Tracking of the light receiving side mirror whose relative position changes can be facilitated.

[0024]

According to the energy transmission method of the present invention described in detail above, the energy is retained in a weak wind zone in the stratosphere, communication relay, environmental observation, emergency power to isolated islands, disaster areas, accident sites, etc. Optical power along the mooring line enables efficient transmission of the power for the airship's own stay and the power for performing the airship's original functions to the stratospheric airship used for supply and other purposes. The transmitted energy to a second airship in the vicinity of the stratosphere in an efficient aerial wireless transmission, or to transmit the second airship as a relay airship to a third airship, thereby providing energy supply. Long-distance transmission to the second and third airships far from the base can also be performed.

In this energy transmission, the troposphere with much moisture is transmitted by wire, and in the stratosphere where there is little moisture, long-distance wireless transmission in the air prevents energy from being attenuated due to moisture, thereby allowing the energy to travel between the ground and the airship. Energy transmission can be performed efficiently. In addition, compared to the case where electric energy is directly transmitted to the airship via the electric wire along the mooring line, this energy transmission enables higher-density transmission using lightweight optical fibers, and furthermore, such as electromagnetic pollution. Can be transmitted without causing the

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method of transmitting energy between the ground and a stratospheric airship according to the present invention.

FIG. 2 is an explanatory diagram for explaining another example of the energy transmission method according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 mooring base 2 moored airship 2a propulsion device 3 mooring line 12 second airship 13 third airship L laser

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-27131 (JP, A) JP-A-63-133846 (JP, A) JP-A-54-102545 (JP, A) JP-A-7-131 15895 (JP, A) JP-A-6-205549 (JP, A) U.S. Pat. No. 5,678,783 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B64F 3/02 H01S 3/00

Claims (5)

(57) [Claims] A mooring airship staying in a weak wind zone in the stratosphere is moored to a mooring base on the ground by a mooring line, and energy is transmitted between the mooring base and the mooring airship by laser through an optical fiber along the mooring line, A method for transmitting energy between a ground and a stratospheric airship, wherein the moored airship obtains power for staying and performing its function by photoelectric conversion in the moored airship. 2. A mooring airship staying in a weak wind zone in the stratosphere is moored to a mooring base on the ground by a mooring line, and energy transmission is performed by a laser between the mooring base and the mooring airship through an optical fiber along the mooring line, In the moored airship, the power for staying the airship itself is obtained by photoelectric conversion, and at the same time, the transmitted energy is transmitted from the moored airship to a second airship staying at an arbitrary position in or near the stratosphere. A method for transmitting energy between the ground and a stratospheric airship, comprising: 3. The energy transmitted by the high power laser to a second airship staying at or near the stratosphere at an arbitrary position as a power for staying and performing functions of the second airship , or the airship. To stay or perform functions
Energy transmission method between the ground and the stratospheric airship according to claim 2, characterized in that the power. 4. A second airship staying at an arbitrary position in or near the stratosphere is a relay airship for transmitting energy, and the energy transmitted by the high-power laser to the second airship is transmitted to a third airship. Transmitted by the high-power laser to the third airship and used as motive power for its stay and function execution , or for the stay or function execution of this airship
The method for transmitting energy between the ground and a stratospheric airship according to claim 2, wherein the energy is used for power. 5. A phase conjugate mirror is used for aerial wireless transmission of a high-power laser from an airship to another airship, and a part of the laser light received by the light receiving side mirror is reflected to the light emitting side, and the reflected light is reflected on the light emitting side. 5. The terrestrial and stratospheric airship according to any one of claims 2 to 4, wherein the light beam is received and the projection direction of the laser on the light emitting side is tracked so that the projected laser is incident on the light receiving side mirror. Energy transmission method between and.