JP3477114B2 - Communication service providing method and communication system using artificial satellites - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an artificial satellite,
In particular, the present invention relates to an artificial satellite that can be used in the field of communication such as satellite communication and mobile communication, its orbit, and its orbit control method.

[0002]

2. Description of the Related Art Conventionally, it is desired to transmit medical data on an emergency patient being transported from an ambulance to an emergency lifesaving center in the form of an image, and to give an appropriate treatment instruction to an emergency patient during transportation from the emergency lifesaving center. And needs.

However, when trying to send a large amount of data such as an image from a moving body such as an automobile, the communication infrastructure on the ground cannot handle it. Even through a geostationary satellite currently in service in orbit or a mobile communication satellite scheduled to start service, it is difficult to transmit from a mobile object for a long time due to a shield such as a building or a grove.

A large amount of data can be transmitted from a moving body such as an automobile by using a satellite using a special orbit.
The specific method of obtaining the trajectory has not been established. Therefore, no firm concrete proposal has been made regarding the orbital elements of the special orbital.

[0005]

The conventional techniques and problems will be specifically described below based on known examples.

(A) Technology and problems of existing communication infrastructure (A-1) Technology and problems of terrestrial communication infrastructure When sending a large amount of data such as images from a mobile body such as an automobile to a fixed station on the ground, Communication via terrestrial communication infrastructure or communication satellites is conceivable, but the ones that currently exist do not satisfy all of the requirements.

The case of an ambulance will be described as an example. Regarding the transportation of emergency patients by ambulance, the current average transportation time is
There are about 27 minutes. In the case of a seriously ill patient, there are many cases where death occurs unless proper treatment is performed during this period, and it is necessary to have appropriate treatment or guidance of treatment by a specialist during emergency transportation. However, it is not realistic that more than about 15,000 full-time doctors are needed in order to have 5,000 ambulances nationwide to carry doctors at all times, and it is not realistic. Is efficient. However, the current terrestrial communication system only realizes telephone-level communication that tends to be interrupted, and the emergency center cannot give sufficient instructions for appropriate treatment. It is said that considerable diagnosis and treatment instructions can be made if image information from an endoscope, an electrocardiogram, an echo, a camera, etc. is sent to an emergency center. However, in the terrestrial communication infrastructure, transmission band limitation,
There are many problems such as limitation of the communicable area, cross-linking with other communication, and interference due to reflection on an artificial structure, and it is practically difficult to apply.

[0008] Similarly, there are many demands regarding the transmission of a large amount of data from a mobile body such as a television relay of a marathon, but the current terrestrial communication infrastructure cannot meet the demand.

(A-2) Geostationary Communication Satellite System Technology and Problems In satellite communication using artificial satellites, one using a geostationary satellite and one using a medium or low altitude orbit are known. The conventional communication satellites have the following problems.

Since the geostationary satellite has a period of about 24 hours, which is almost the same as the rotation period of the earth, it appears stationary above the equator from the ground. However, the elevation angle is generally low, and even in good conditions, the elevation angle in Tokyo is about 45 degrees. Since moving objects in urban areas pass on roads surrounded by artificial structures such as buildings and trees, low-angle ranges are blocked by these objects, and satellite communications by geostationary satellites are apt to be blocked. is there. Geostationary satellites are visible from southeast to southwest, so if you are moving in the north-south direction, you can communicate because the field of view of the geostationary satellites is open, but if you are moving in the east-west direction, especially in the west direction. When moving, communication will be interrupted by man-made structures and trees in a considerable period of time. Therefore, satellite communication using geostationary satellites has not been satisfactory in non-flat areas such as urban areas and mountainous areas.

(B) Technology and problems of satellite communication systems currently under development Satellites using medium or low altitude orbits such as Iridium and Odyssey, which are being implemented for mobile phone services using mobile communication satellites In the case of a communication system, due to restrictions such as the number of satellite orbital planes and the number of satellites, the time period during which the communicable satellite remains within a high elevation angle when viewed from the ground is generally short. In particular, low-orbit satellites orbit the earth with an orbital period of 90 to 100 minutes, so that they remain at a high elevation angle from the ground for only a few minutes. Therefore, when trying to communicate with a large amount of data for a certain time (for example, 27 minutes or more) without being interrupted by obstacles such as artificial buildings, plants, and natural terrain as in the case of the above-mentioned ambulance, When applying or trying to apply these satellite communication systems, the satellites must always appear alternately in the high elevation direction. In that case, several hundred or more satellites are required, and it is unavoidable economically considering the procurement problem of the satellite itself, its operation cost, and launch cost.

When a high elevation angle is required as described above, the geostationary satellites that have been put to practical use up to now and the low-to-middle altitude satellites that are now in practical use are not sufficient.

(C) Technologies and Problems of Satellite Communication Systems at the Current Research Stage For example, Technical Report of IEICE (Communication Technical Report) Vol.
In 89, No. 57, research reports such as "Possibility of mobile communication missions using non-geostationary satellite orbits" discuss the satellite communication system at the present research stage. In particular, an elliptical orbit with a large eccentricity has been proposed including the above research report.

According to Kepler's law, the velocity on the orbit becomes slow near the apogee. This is because if this is used to set an orbit in which the apogee is located above the service area, the satellite can stay longer in the high elevation range. Therefore, in order to secure a communication line for a long time without communication interruption due to artificial buildings, plants, or natural terrain, it is essential to use a long elliptical orbit.

As an example of an elliptical orbit, for example, in Russia, the perigee altitude is several hundred km and the orbit inclination angle is about 12 hours in a cycle.
The 63.4-degree Molnia orbit has been in practical use since 1960s for communication satellites and military reconnaissance satellites in Russia. This orbit is a stable orbit in which the perigee argument in the orbit plane is fixed, but although it is practical in Russia where the national land is distributed at high latitudes, it has a wide spread north and south in the low latitude range. In Japan, it is also a trajectory that becomes less practical.
Also in Japan, some proposals have been made for orbits of about 8 hours, 12 hours, and 24 hours. However, these proposals are merely point designs, and regarding the orbits that are adapted to the Japanese land that extends in the north-south direction and the east-west direction, specific proposals are made regarding the optimal orbit and the method of setting the orbit. No solution has been presented. This is considered to be because, in general, the method of determining the six elements of the orbit based on the analogy of the designer's experience was the mainstream in setting the orbit.

There are various parameter setting methods for defining a trajectory, but in general, the following six trajectory elements are often used. These are defined as values at a certain standard time. Orbital major radius a: Ellipse major radius (shown as 54 in Fig. 5) Eccentricity e: Elliptic flatness (0≤e <1) Orbital inclination angle i: Orbit Of the plane from the equatorial plane (64 in Fig. 6)
(0 degrees ≤ i ≤ 180 degrees) Ascending node RA Ω: Angle measured from the vernal equinox direction to the east around the point where the orbit crosses the equatorial plane from the southern hemisphere to the northern hemisphere (ascending node, indicated by 62 in Fig. 6). (Shown as 63 in FIG. 6) (0 degree ≤
Ω ≤ 360 degrees) Perigee argument ω: Angle measured from the ascending point 62 of the position of perigee on the orbital plane (shown as 63 in Fig. 6) (0 degrees ≤ ω ≤ 360 degrees) Closer point deviation angle θ: With perigee The angle formed by the line segment connecting the focus of the ellipse, the position of the satellite in orbit, and the line segment connecting the focus of the ellipse (Fig. 5
58) (0 degree ≦ θ ≦ 360 degrees) is often used. These geometric relationships will be described with reference to FIGS. 5 and 6. Satellite 51 is the focus of the ellipse
It moves with 50 as the focal point of the elliptical orbit. The distance between the perigee 53 of the ellipse and the focal point 50 of the ellipse is represented by the perigee radius Rp, which is represented by 57 in FIG. The distance between the apogee 52 of the ellipse and the focal point 50 of the ellipse is represented by the apogee radius Ra, 56 in FIG. Perigee radius Rp, apogee radius Ra, orbital major radius a, Fig. 5
The following relationship exists between the orbital short radius b indicated by 55 and the eccentricity e.

Rp = a (1-e) Ra = a (1 + e) b = a (1-e2) 1/2 e = (Ra-Rp) / (Ra + Rp) In FIG. Here is an example of the case. The elliptical orbit traverses the equatorial plane 61 at the ascending node 62 from the southern hemisphere to the northern hemisphere, and the perigee is 65 and the apogee is 66. An angle 64 between the equatorial plane 61 and the orbital plane becomes an orbital inclination angle i. The ascending node RA is defined by the angle 68 measured eastward from the vernal equinox, and the perigee argument is defined by the angle 63 from the ascending point 62 to the perigee 65.

Even if the major axis of the orbit can be selected from the orbital period, the eccentricity, which is the main parameter of other orbits, is 0.
Any real number from 0 to less than 1.0, orbital inclination angle is 0.0 degree or more 18
Any real number less than or equal to 0.0 degrees, perigee argument is greater than or equal to 0.0 degrees and 360.0
Since it is possible to select any real number less than or equal to a degree, and considering these combinations, there are infinite combinations of orbital elements. Therefore, there is an aspect that the designer has to set those parameters intuitively or by analogy from his own experience.

If an orbit which can be visible in the zenith direction of the service area for a long time can be realized, "large-capacity data transmission from a moving object for a long time" can be realized by communication via a satellite. Therefore, there is a need for specific setpoints of orbital elements that are adapted to the Japanese land and have economic efficiency, that is, the number of satellites that make up the entire system is as small as possible, and a specific methodology for that setting. Was there.

As described above, in order to transmit large-capacity data such as image data from a moving body such as an automobile for a long time, an artificial satellite is placed in the zenith direction so as to be visible as long as possible, and the artificial It is necessary to communicate via satellite.

In order to realize this, it is generally considered that an elliptical orbit in which an apogee is located above the service target area is preferable, but an appropriate setting method and algorithm of the orbital elements have been proposed. Not not. Moreover, for example, no proposal has been made specifically for an appropriate orbital element when the whole of Japan is targeted for service.

The present invention has been made in view of the above problems, presents a specific methodology devised for setting orbital elements, and limits the range of orbital elements required using the methodologies. The purpose is to set.

Further, in order to solve the above problems, it is an object of the present invention to construct various systems using artificial satellites arranged so as to be visible in the zenith direction for a long time. I am trying.

Another object of the present invention is to provide orbit control means for carrying out orbit control of an artificial satellite based on the orbit elements set above.

[0025]

In order to achieve the above object, according to the present invention, in an artificial satellite orbiting on an elliptical orbit, the elliptical orbit is a target area of a service performed using the artificial satellite, It is assumed that it is defined by six elements of the orbit obtained by using as input conditions the allowable range of the elevation angle at which the artificial satellite should be seen from the service area and the reference time defining the orbital element.

Here, the satellite in the elliptical orbit according to the present invention is
The satellite orbits in a long elliptical orbit that makes the satellite visible at an angle position that is larger than the maximum elevation angle when the geostationary satellite is viewed from the service area of the satellite.

More specifically, in determining the orbital elements, the orbital long radius setting step, the perigee argument setting step, the half apex angle setting step, the required service time setting step, and the service target area are included. Polygon setting step, number of satellites and ascending node right ascension and proximate point deviation angle setting step, initial value of orbital inclination angle setting step, calculation step of visible time from each vertex of the polygon, The six elements of the orbit are determined by the step of setting the combination of the orbital inclination angle and the eccentricity, and the step of resetting the ascending node RA and the closest point declination angle.

In order to achieve the above object, according to the present invention, in an artificial satellite group consisting of a plurality of artificial satellites orbiting in an elliptical orbit, the six orbital elements of the elliptical orbit of each artificial satellite are the artificial satellite group. The target area of the service to be performed using, the allowable range of elevation angle at which one of the artificial satellites of the relevant artificial satellite group can be seen from the target area, and the reference time defining the orbital element are obtained as input conditions. A plurality of the elliptical orbits are combined so that at least one or more artificial satellites are always visible within a predetermined elevation range in the direction of the zenith viewed from the service area, and one orbital plane is used for each orbital plane. A group of artificial satellites, which is characterized by arranging more than one artificial satellite.

In order to achieve the above object, the present invention provides
Orbit control systems for controlling the orbits of artificial satellites, satellite communication systems that perform satellite communication via artificial satellites, systems that use various artificial satellites, such as earth observation systems that use artificial satellites equipped with earth observation equipment. In, the artificial satellite provided with the orbit according to the present invention is used.

Here, the satellite communication terminal in the satellite communication system is such that when the artificial satellite according to the present invention is used in a target service area, the artificial satellite appears within a predetermined elevation range in the zenith direction. It is provided with a transmitting / receiving means for transmitting / receiving a signal to / from a satellite, and may be mounted on a mobile body that mainly moves within the service area. Also, for satellite communication terminals, GPS means for receiving radio waves from GPS satellites that make up the Global Positioning System and at least measuring their position, and those subject to utility charges such as electricity, gas and water, You may make it further provide the measuring means which measures the usage amount for every house.

In order to achieve the above object, the present invention is a method for determining an orbital element of an artificial satellite that orbits on an elliptical orbit, and a target area of a service performed using the artificial satellite and the service target area. Then, the allowable range of the elevation angle at which the artificial satellite can be seen and the reference time defining the orbital element are used as input conditions, and six orbital elements that satisfy the input condition are obtained. In addition, when arranging a plurality of artificial satellites, the elliptical orbits are arranged so that at least one artificial satellite is always visible within a predetermined elevation range in the zenith direction viewed from the service area. In combination, it is recommended to place one or more artificial satellites on each orbital plane.

Further, the above-mentioned object is to set a polygon including an orbital long radius, a perigee argument, a half-vertical angle, a service period, and a service target area, and the number of satellites and each satellite from the set values. Means for setting the right ascension and astigmatism declination of the satellite; means for setting the initial value of the orbital inclination angle; means for calculating the visible time from each vertex of the polygon; orbital inclination angle And an eccentricity ratio setting means, and means for resetting the ascending intersection right ascension and the proximate point separation angle.

In order to achieve the above-mentioned object, the present invention provides an artificial satellite and a satellite communication terminal for performing satellite communication via the artificial satellite in a satellite communication system for performing satellite communication via the artificial satellite. , At least a base station that communicates with the satellite communication terminal via the artificial satellite, wherein the artificial satellite is higher than the maximum elevation angle of the geostationary satellite viewed from the service area of the artificial satellite. It is an artificial satellite that orbits in an elliptical orbit that makes the artificial satellite visible in the elevation position, and the satellite communication terminal can be mounted on a mobile body and is used within the service target area of the artificial satellite. In this case, a transmitter / receiver is provided for transmitting / receiving a signal to / from the artificial satellite appearing within a predetermined elevation range in the zenith direction.

In order to achieve the above object, the present invention provides a satellite communication system for performing satellite communication via an artificial satellite, and an artificial satellite and a plurality of satellite communication for performing satellite communication via the artificial satellite. At least a terminal, wherein the artificial satellite orbits a long elliptical orbit that makes the artificial satellite visible at an angle position larger than the maximum elevation angle of the geostationary satellite as viewed from the main service area of the artificial satellite. The satellite communication terminals are provided with transmitting / receiving means for transmitting / receiving a signal to / from another satellite communication terminal via the artificial satellite. At least one of them is located within the main service target area, and the other is located outside the main service target area and is capable of satellite communication with the artificial satellite. Located between the satellite communication terminals located in the main service target area according to the elevation angle of the satellite viewed from the main service target area of the artificial satellite, and the main service target area. One of the relay modes is selected from the relay between the satellite communication terminals in the inside and the satellite communication terminals located in other areas and the relay between the satellite communication terminals located in areas other than the main service target area. It

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention is applied: -A method (algorithm) for setting an appropriate trajectory element; -Setting a trajectory element by the algorithm; -Realizing and controlling the set trajectory element Embodiments of the above will be described in order.

(1) Method (algorithm) for setting an appropriate orbital element In order to make the artificial satellite visible for a long time in the zenith direction, which is less occluded by artificial buildings, plants and natural topography, An elliptical orbit with an apogee above the area is effective. Here, the method of setting the trajectory element according to the present invention will be described in order. This setting method is shown in the flow chart of FIG.

(1-1) Orbital major radius setting (step 4) Considering the operation of the satellite itself and the operation of satellite communication using the satellite, an integer multiple of the length of a day or an integral multiple If an orbit with a cycle is adopted, the same satellite will be visible every day in the same time zone, so periodic operation becomes possible. Table 1 shows an example of the results of satellite visual analysis when the orbit period is set to 4, 6, 8, 12, 16, 24, 32, and 36 hours.

[0038]

[Table 1]

When the orbital inclination angle of each orbit is 63.4 degrees, the length of time that satellites are seen from each city in the zenith direction with an elevation angle of 70 degrees or more is arranged, but it is overwhelmingly 12 and 24.
It can be seen that selecting a satellite orbit with a time period is advantageous in terms of system configuration. Therefore, even if the orbital inclination angle changes,
In particular, an orbit with a period of about 12 hours or a period of about 24 hours can be judged to be practical. Orbit major radius 11 is about 26,562 km or about 24 if the orbit has a period of about 12 hours from the satellite period.
If it is an orbit with a period of time, it is uniquely determined as about 42,178 km.

(1-2) Setting of Perigee Argument (Step 5) The perigee argument 12 depends on the location of the target area to receive the communication service using satellites or the earth observation service. If the target area is the northern hemisphere, the perigee is The perigee argument is about 270 degrees so that the apogee comes over the northern hemisphere.
Similarly, if the service area is the Southern Hemisphere, the argument of perigee should be about 90 degrees. These are essential conditions for placing apogee over the service area.

(1-3) Setting of eccentricity, orbital inclination angle, ascending node right ascension, and proximate point declination angle (a) Setting of half-vertical angle (step 1) First, qualitatively the "zenith direction" Therefore, the allowable range from the zenith direction as the view direction of the satellite, such as 20 degrees and 40 degrees, is defined by the half-vertical angle. At this time, the elevation angle becomes 70 degrees and 50 degrees, respectively. The satellite is visible for a long time in a cone centered on the zenith formed by this half-vertical angle. Obviously, the smaller the half apex angle, the more absolute number of satellites will be required.

(B) Setting of required service time (step 2) The length of time to receive service by the satellite is set. For example, an ambulance requires 24 hours of continuous service.

(C) Setting of polygon including the service area (step 3) Since the conventional geostationary satellite looks stationary from the ground, it can be dealt with by forming an antenna beam for the service area. It was In addition, Iridium using low and medium altitude orbit
Systems such as Odyssey and Odyssey use a design concept that covers the ground in order with many satellites.
It was not necessary to limit the scope of service to a detailed examination. However, the elliptical orbit currently targeted does not appear to be stationary from the ground, and it is preferable that the number of satellites is small. Therefore, it is necessary to select a track shape suitable for the service area.

In the present invention, first, the latitude, longitude and height of the four points of the northernmost point, the southernmost point, the westernmost point and the easternmost point of the service area are given. In the case of Japan, the points shown in Table 2 are considered to be the northernmost point, the easternmost point, the southernmost point and the westernmost point.

[0045]

[Table 2]

These four points are scattered as shown in FIG. 7, and their latitude and longitude generally do not have the same value. If the service area is not included in the quadrangle with these four points as vertices, consider a polygon that includes all the service areas, and specify the latitude of the vertices other than these four points.
Set the longitude and altitude. This polygon may be formed so that a plurality of triangles are adjacent to each other.

The steps (a) to (c) described above may be performed in any order.

(D) Setting of the number of satellites, ascending node RA and RA of each satellite (step 6) If a 24-hour continuous service is performed in an elliptical orbit, it cannot be realized by one satellite. Is clear. Therefore, set the number of satellites required to configure the system, such as two or three. In order to continuously service a certain area, it is effective to place one satellite on each orbital plane. Further, it is desirable that the shapes of the tracks are the same. The RAs of the ascending nodes in each orbit should be separated by 360 degrees divided by the number of satellites. In other words, if the number of satellites is three, the right ascending node is 12
The satellite will move on three orbital planes separated by 0 degrees.

The right ascending node rotates at a constant cycle around the earth's axis under the influence of the earth's gravitational potential. In other words, the orbital surface rotates around the earth axis. Therefore, the ascending node RA should be defined at the reference time so that the apogee is located above the service area. At this stage, any numerical value convenient for analysis may be given. Further, the position of the service target area on the inertial space may be given an arbitrary value convenient for analysis.

Further, in setting the closest point separation angle, when one satellite is at a perigee point in its orbit, the closest point separation angles of the other satellites divide that cycle by the number of satellites constituting the system. It is enough to separate them by an angle that corresponds to the time. For example, in the case of three satellites, the proximate point separation angles of adjacent satellites on orbits may be separated by 1/3 of the orbit cycle in order.

By setting the ascending node RA and the proximate point separation angle as described above, the ground trajectories of the orbits are substantially the same, and the satellites can appear in order over the same area.

(E) Setting the initial value of the orbital inclination angle (step 7) It is considered that if the apogee of the orbit comes above the center of gravity of this polygon, a substantially uniform service can be performed in the entire service area. . However, this arrangement is not always ideal because of the movement of each point due to rotation and the relative movement due to the orbital motion of the satellite. Therefore, the analysis is performed as follows with the orbital inclination angle of the same angle as the latitude near the center of gravity of this polygon as the initial value.

(F) Calculation of the visible time from each vertex of the polygon (steps 8 and 9) Up to this point, the orbital major radius of each orbit 11, the perigee argument 12, the ascending node RA, the near point separation angle, the orbital The initial value of the tilt angle is determined. That is, five of the six elements are determined.

For each satellite, the time during which the satellite is seen inside the cone formed by the half-vertical angle in the zenith direction from each polygon point is determined. This is obtained by geometrical calculation and Kepler's law, but numerical calculation by a computer is also possible. As shown in step 8 of FIG. 1, the eccentricity is changed from 0.0 to 1.0 to obtain the range of the eccentricity where the visible time lengths from the respective polygon points are almost the same. When using a computer, a method of sequentially changing the eccentricity with a finite step size and comparing the visible time from each vertex of the polygon can be considered.

Next, as shown in step 9 of FIG. 1, the orbit inclination angle is slightly changed from the initial value, and the eccentricity is changed in the same manner, so that the visible time from each polygon point becomes almost the same time length. Find the range of eccentricity. Similarly, when a computer is used, it is possible to change the orbital inclination angle with a finite step size and compare the visible times from the respective vertices of the polygon. If the reference time is set, the RA of the ascending node and the position in the inertial space of the service area are set accordingly, the orbit is propagated by a computer, and the visible time is calculated within the time range. Then, the time when it can be seen inside the cone formed by the half-vertical angle in the zenith direction can be obtained.

At this time, the length of time that the satellite stays within the half-vertical angle is the length of time that one satellite can service each orbital surface, which is a divisor of about 24 hours, which is the rotation period of the earth. , About 1, about 2, about 4, about 6, about 8, about 12 and about 24 hours are convenient because the service and the satellite operation can be performed periodically. Obviously, in order to carry out the service 24 hours a day, that is, without interruption, it is necessary to have at least one satellite if this time is about 24 hours and at least two satellites if this time is about 12 hours. I understand. Therefore, based on this, if necessary, the process (d) (step 6) can be returned to and the number of satellites can be redefined.

(G) Setting of combination of orbital inclination angle and eccentricity By repeating the analysis shown in steps 8 and 9 above, a uniform service can be provided at all points of the polygon including the service target area. , The orbital inclination angle and the eccentricity value are combined to obtain the range of numerical values as shown in 13 and 14 of FIG.

(H) Re-setting of RA and RA of ascending point (step 10) Finally, the reference time is set in accordance with the satellite launch time, and the appropriate ascending point red corresponding to that time is set. It suffices to set the meridian 15 and the closest point separation angle 16.

A program corresponding to all or part of the above-mentioned algorithm may be generated and executed by a computer. For example, after the user inputs the data set in steps 1 to 5, the computer may execute the program corresponding to steps 6 to 10 based on these setting conditions.

(2) Setting of orbital elements by the above algorithm (2-1) When Japan is the service target area By using the above method (algorithm), in the area including all the territories of Japan, Table 3 The elliptical orbits of the orbital elements shown in Case 2 are obtained as a combination of orbital element ranges in which one satellite is visible for approximately 12 hours per day in the zenith direction with an elevation angle of 55 degrees or more from all over Japan. At this time, if two satellites are placed 180 degrees apart from the ascending node RA and 180 degrees apart from the proximate point, which corresponds to half the orbit period, the zenith with an elevation angle of 55 degrees or more will be continuous for 24 hours a day. Visible from all over Japan in the direction.

In addition, when considering the whole of Japan excluding remote islands on the southern sea such as offshore Torishima and Minamitorishima, 4
Case 1 in Table 3 with the RAs of the ascending nodes of the two satellites separated by 90 degrees
By using the elliptical orbit of the orbital element shown in, it is possible to make any satellite always visible in the zenith direction with an elevation angle of 70 degrees or more.

[0062]

[Table 3]

The orbit of the artificial satellite is the earth's gravity field, the moon
Due to the influence of the attractive force of the sun, etc., it constantly fluctuates in both short and long cycles, and is generally controlled within a certain allowable range. For this reason, with respect to the orbital elements discussed in the present specification and tables, approximate values or target nominal values after orbital control are shown.

When the orbit has a period of about 12 hours, the elliptical orbits of the orbital elements shown in Case 3 of Table 4 are Hokkaido, Honshu, Shikoku,
In Kyushu and Okinawa, it can be obtained as a combination of orbital elements that make the satellite visible for about 6 hours in the zenith direction with an elevation angle of 70 degrees or more.

[0065]

[Table 4]

When an orbital element other than the above range is selected, for example, in the case of the orbital case where the above cycle is about 24 hours, the satellite is moved in the zenith direction with an elevation angle of 55 degrees or more in a part of Japan. Sometimes it becomes invisible. For example, the orbital inclination angle is 45
If it is less than 135 degrees or more than 135 degrees, the service time at the northernmost end will be less than 24 hours a day,
On the contrary, if the orbital inclination angle is 55 degrees or more and 125 degrees or less, the service time at the southernmost end is less than 24 hours a day. If the eccentricity is less than about 0.25, it is the northernmost point, and if it is about 0.38 or more, it is the westernmost point and the easternmost point. Fig. 8 shows that the eccentricity is 0 with a cycle of about 24 hours.
The orbital ground trajectory for an orbit of 25 and an orbital inclination angle of 55 degrees and a perigee argument of 270 degrees is shown in Fig. 9 with a period of about 24 hours, an eccentricity of 0.38, an orbital inclination angle of 45 degrees, and an astigmatic argument. Shows the ground trajectory of the orbit for a 270 degree orbit. The ground track spreads in the east-west direction as the eccentricity increases,
As the orbital inclination angle increases, the orbital inclination angle becomes 0 degrees to 90 degrees.
This is the case in the range of degrees, and if the orbital inclination angle is in the range of 90 degrees to 180 degrees, it will spread in the north-south direction as it gets smaller. From the comparison of the ground trajectories shown in the figure, it can be understood that the service will be incomplete at any point if it goes out of the range of the orbital element given above.

From the above, Table 5 summarizes the range of orbital elements suitable for covering the whole of Japan. As an example,
The service target area, allowable elevation angle, and number of required satellites set for each case above are added.

[0068]

[Table 5]

(2-2) When the whole world is targeted When the whole world is targeted for service, the whole world is divided into areas of a certain area, and the above concept is applied to each area. Just do it. Note that it may be better to use a geostationary orbit rather than an elliptical orbit for the region near the equator. Therefore, when targeting the entire world, combine the elliptical orbit and geostationary orbit described above. Is effective. For example, it is possible to cover the whole world by combining a plurality of elliptical orbits of the orbital elements shown in Table 6 and further combining geostationary satellites.

[0070]

[Table 6]

As described above, a large eccentricity causes the ground track of the orbit to spread in the east-west direction, and a large tilt angle of the track allows the ground track of the orbit to spread in the north and south directions. Inside the range of the ground trajectory of the orbit, especially near its center, there is a region where the satellite cannot receive any service. This can be solved by arranging the trajectories that are adjacent to each other on the ground track so that the ground tracks overlap as shown in FIG.

(3) Measures for realizing and controlling the set orbital element The orbit of the artificial satellite having the orbital element thus set is controlled and realized as follows.

As shown in FIG. 2, at the time of launching the artificial satellite 20, the information of the six orbital elements 17 suitable for the service area previously set is input to the launcher tracking control facility 21 and from there, the launcher is controlled. Information on the target input trajectory element 22 is transmitted. Based on this information, the launch vehicle 23 is launched into the target trajectory automatically or under the control of the tracking and control equipment 21.

After the artificial satellite 20 is put into orbit, the information of the six orbital elements 17 suitable for the service area is periodically input to the artificial satellite tracking and control equipment 18, and the information of the control command 19 is sent to the artificial satellite 20. It is transmitted and controlled by the control system mounted on the artificial satellite 20 to the target orbital six elements 17.

This orbit control method is based on a generally used method, and its details will be described later.

Next, more specific examples of the above-mentioned embodiments will be described. In the present invention, there are two concepts: an orbital element obtained by the algorithm of the present invention and its range; a system applying a satellite moving in the orbit; This will be described separately. Following that, concrete examples of measures for actually controlling the six orbital elements of the artificial satellite to be suitable for the service area will be described.

(4) Orbital elements obtained by the algorithm of the present invention and their ranges (4-1) Orbital arrangement example 1 This orbital arrangement example is intended to serve the whole of Japan. The orbit of the artificial satellite constantly changes due to the influence of the gravity field of the earth, the attractive force of the moon and the sun, etc., and the orbit is generally controlled within a certain allowable range. Therefore, the value of each orbital element shown in each orbital arrangement example below indicates a target nominal value after orbital control.

In this orbital arrangement example, there are two orbital planes as shown in FIG. 11, and one satellite 110 and one satellite 111 are arranged on each orbit. The satellite 110 orbits on the orbit 112 in about 24 hours, and the satellite 111 orbits on the orbit 113 in about 24 hours. The orbital period of satellite 110 and satellite 111 is about 24 hours,
And the eccentricity is in the range of 0.24 to 0.38, and the orbital inclination angle is in the range of 47 to 52 degrees or 128 to 133 degrees, and the perigee argument is 270 degrees.
The ascending node RAs of the two satellites are 180 degrees apart as shown in Fig. 11, and the apogee appears at an appropriate position above Japan. As a positional relationship of each satellite in each orbit, when the satellite 110 is at a perigee on its orbit 112, the satellite 111 is arranged at an apogee on its orbit 113. This track arrangement is obtained by the algorithm whose outline is shown in FIG. 1, and is realized by the control method shown in FIG.

By this orbital arrangement, the elevation angle can be obtained over the whole of Japan including the northernmost point, the southernmost point, the easternmost point and the westernmost point of Japan.
Either satellite 110 or satellite 111 is always visible in the zenith direction of 55 degrees or more. Since the satellite 110 and the satellite 111 have a cycle of about 24 hours, it is regular and regular to see or disappear in the zenith direction with an elevation angle of 55 degrees or more. In this case, the satellite 110 and the satellite 111 appear alternately in the zenith direction with an elevation angle of 55 degrees or more in a cycle of about 12 hours throughout Japan, and each appears to stay for about 12 hours in the zenith direction with an elevation angle of 55 degrees or more. There is also a time zone in which both satellites can be seen in the zenith direction with an elevation angle of 55 degrees or more at the same time. This is repeated every 24 hours.

Therefore, by using a satellite represented by the artificial satellite 90 in FIGS. 13 to 16 showing an example of a system using this orbital arrangement for satellite communication, there is less communication interruption due to shields and obstacles. It becomes possible to construct a communication system.

(4-2) Orbit Arrangement Example 2 This orbit arrangement example is for the case where the whole of Japan is targeted for service.

In this orbital arrangement example, there are four orbital planes as shown in FIG. 12, and satellites 120a, 120b, and 12 are provided on each orbital plane.
0c and satellite 120d are arranged one by one. The satellite 120a makes an orbit in the orbit 121a, the satellite 120b makes an orbit 121b, the satellite 120c makes an orbit 121c, and the satellite 120d makes an orbit 121d. The satellite 120a, satellite 120b, satellite 120c, and satellite 120d have an orbit period of about 12 hours and an eccentricity of 0.70.
It is within the range of 0.80 or less and the orbital inclination angle is 30 degrees or more and 45 degrees or less or 135 degrees or more and 150 degrees or less,
And the perigee argument is 270 degrees. The ascending node RAs of the four satellites are 90 degrees apart as shown in Fig. 12,
The apogee is set to appear at an appropriate position over Japan. As for the positional relationship of each satellite in each orbit, the satellites 120a and 120c have their orbits 121
The satellites 120b and 120d are arranged so that they are at apogee on their orbits 121b and 121d when they are at perigee on a and 121c.

Due to this orbital arrangement, satellite 12 represented by artificial satellite 90 in the zenith direction with an elevation angle of 70 degrees or more in Hokkaido, Honshu, Shikoku, and the four islands of Kyushu and Okinawa.
Either 0a, satellite 120b, satellite 120c or satellite 120d is always visible. Since the satellites 120a, 120b, 120c, and 120d have a cycle of 12 hours, it is regular and regular that they can be seen in the zenith direction with an elevation angle of 70 degrees or more and disappear. This orbital arrangement is outlined in Figure 1.
It is obtained by the algorithm shown in FIG. 2 and is realized by the control method shown in FIG. In this case, satellite 120a, satellite 120b, satellite 120c and satellite 120d have an elevation angle of 70 degrees in the four islands of Hokkaido, Honshu, Shikoku and Kyushu and Okinawa.
Appearing one after another every day in the direction of the zenith more than once,
It seems to stay for about 6 hours each. As a result, one of the satellites is visible in the zenith direction with an elevation angle of 70 degrees or more for 24 hours a day. In addition, there are times when multiple satellites can be seen in the zenith direction with an elevation angle of 70 degrees or more. This is repeated every 24 hours.

Therefore, in FIGS. 13 to 16 showing an example in which this orbital arrangement is applied to the system, a satellite represented by the artificial satellite 90 is used for satellite communication, so that communication with less interruption of communication due to a shield or an obstacle is less likely to occur. It becomes possible to build a system.

The above description is for Case 3 in Table 4, but also for Case 2 in Table 3 by the orbital arrangement in which the RA of the ascending node is shifted by 90 degrees in the same manner as described above, the offshore Torishima and Minamitorishima are exactly the same. It is possible to make one of the satellites visible at any time in the zenith direction with an elevation angle of 70 degrees or more throughout Japan except for remote islands on the southern sea.

(4-3) Orbital Arrangement Example 3 This orbital arrangement example is for the case where the service range is about 70 degrees north latitude to about 70 degrees south latitude.

In this example of the orbital elements, the orbits and satellites are used properly according to the latitude of the service area.
Orbital period is 24 hours, eccentricity is 0.42 or more and 0.48 or less, and orbit inclination angle is 62 ° or more and 66 ° or less, or 114 ° or more and 118 ° or less, and perigee argument for the service from the area of about 70 ° north latitude to 30 ° north latitude. On the orbital plane of 270 degrees, the ascending node RA
The satellites are arranged in six planes, offset by two degrees, and two satellites are arranged in each orbital plane. The position of the two satellites in the same orbit plane should be such that one is at the perigee and the other at the apogee. north latitude
Twelve geostationary satellites will be placed in geostationary orbits, offset by 30 degrees in the longitude direction, in geostationary orbits, covering the region from 30 degrees to 30 degrees south latitude. In addition, the orbital period is approximately 24 hours, the eccentricity is 0.42 or more and 0.48 or less, and the orbit inclination angle is 62 ° or more and 66 ° or less, or 114 ° or more and 118 ° or less, and perigee, from 30 ° S to 70 ° S. Orbital planes with an argument of 90 degrees are arranged in six planes, with the right ascension of the ascending direction shifted by 60 degrees, and two satellites are placed in each orbital plane. The position of the two satellites in the same orbit plane should be such that one is at the perigee and the other at the apogee. The orbital planes will be shared for the six orbital planes that cover the range of 70 degrees north to 30 degrees north and the six orbital planes that cover the range of 70 degrees south to 30 degrees south. That is, on a certain orbital plane,
There are a total of four orbiters, two satellites whose perigees are above the Southern Hemisphere and two satellites whose perigees are above the Northern Hemisphere, and there are six such orbital planes 60 degrees apart from the earth axis. It will be.

This orbital arrangement is obtained by the algorithm whose outline is shown in FIG. 1. The orbital elements are shown in Table 4, and are realized by the control method shown in FIG. Due to such orbital plane and satellite arrangement,
In an area from 70 degrees to about 70 degrees south latitude, at least one of the above 36 satellites will always be visible in the zenith direction with an elevation angle of 50 degrees or more. In the region of latitudes from 70 degrees to 30 degrees, four or six satellites orbiting adjacent orbital planes alternately appear in the zenith direction, so that a communication line can be secured at all times. In the region from 30 degrees north latitude to 30 degrees south latitude, geostationary satellites are used, so satellites are always visible in a fixed direction, and stable communication is possible.

As described above, the satellite represented by the artificial satellite 90 in FIGS. 13 to 16 which is an example in which this orbital arrangement is applied to the system is used for satellite communication, so that communication interruption due to a shield or an obstacle is less likely to occur. It becomes possible to construct a communication system.

(4-4) Orbital element example 4 This orbital element example is for the case where the whole world from about 85 degrees north latitude to about 85 degrees south latitude is targeted for service.

In this orbital element example, the orbits and satellites are used properly according to the latitude of the service area.
Orbital period is about 24 hours, eccentricity is 0.42 or more and 0.48 or less, and orbit inclination is 62 or more and 66 or less or 114 or more 118
Orbital planes with a perigee argument less than or equal to 270 degrees are arranged in four planes with the ascending node RA being shifted by 90 degrees, and three satellites are placed in each orbital plane. The positional relationship of the three satellites in the same orbit plane is
Make sure that the perigee passing times on the orbit are offset by about 8 hours each. Twelve geostationary satellites are placed in geostationary orbits, offset by 30 degrees in the longitude direction, in geostationary orbits, covering the region from north latitude 30 degrees to south latitude 30 degrees. Furthermore, the orbital period is approximately 24, targeting service from 30 ° S to 85 ° S.
Time and eccentricity 0.42 or more and 0.48 or less and orbit inclination angle 62
Orbital planes with a degree of 66 degrees or less or 114 degrees or more and 118 degrees or less and a perigee argument of 90 degrees are arranged in four planes by shifting the ascending right ascension by 90 degrees and three satellites are arranged in each orbital plane. The positional relationship between the two satellites in the same orbit plane should be such that the perigee transit times in orbit are offset by about 8 hours. The orbital planes will be shared for the four orbital planes that service from about 85 degrees north latitude to 30 degrees north latitude and the four orbital planes that service the latitude of about 85 degrees south latitude to 30 degrees south latitude. In other words, a certain orbital plane is orbiting with three satellites whose perigee is above the southern hemisphere and three satellites whose perigee is above the northern hemisphere, which makes a total of six orbits, and such orbital planes are each 90 degrees around the earth axis. There will be four sides apart.

This orbital arrangement is obtained by the algorithm whose outline is shown in FIG. 1, whose orbital elements are shown in Table 4, and is realized by the control method shown in FIG. Due to such orbital plane and satellite arrangement,
In the area from 85 degrees to about 85 degrees south latitude, at least one of the above 36 satellites will always be visible in the zenith direction with an elevation angle of 50 degrees or more. In the area from about 85 degrees latitude to 30 degrees latitude, satellites orbiting adjacent orbital planes alternately appear in the zenith direction, so that a communication line can be always secured. In the region from 30 degrees north latitude to 30 degrees south latitude, geostationary satellites are used, so satellites are always visible in a fixed direction, and stable communication is possible.

According to each orbital arrangement example described above, at least one satellite is always visible in the cone formed by the allowable half-vertical angle centered on the zenith. It can be composed of numbers. It is possible to reduce the number of required artificial satellites as compared with other systems that perform global communication using low and middle altitude satellites. For example, in the above-mentioned orbital arrangement 1, at least two satellites are used for continuous communication. The line can be secured. Since the number of satellites is small, satellite development, launch, and operation costs can be suppressed, so that the cost required for system construction can be suppressed. As a result, inexpensive communication services can be finally provided.

(4-5) Orbital Arrangement Example 5 This orbital arrangement example is for the case where the whole of Japan is targeted for service.

In this orbital arrangement example, there are four orbital planes as shown in FIG. 12, and satellites 120a, 120b, and 12 are provided on each orbital plane.
0c and satellite 120d are arranged one by one. The satellite 120a makes an orbit in the orbit 121a, the satellite 120b makes an orbit 121b, the satellite 120c makes an orbit 121c, and the satellite 120d makes an orbit 121d. The satellite 120a, satellite 120b, satellite 120c, and satellite 120d have an orbit period of about 24 hours and an eccentricity of 0.24.
Within the range of 0.38 or less and the orbital inclination angle within the range of 35 degrees or more and 40 degrees or less or 140 degrees or more and 145 degrees or less,
And the argument of perigee is about 270 degrees. The ascending node RAs of the four satellites are 90 degrees apart as shown in Fig. 12, and the apogee appears at an appropriate position above Japan.

As for the positional relationship of the respective satellites in their respective orbits, when the satellite 120a is at a perigee on its orbit 121a, the satellites 120b and 120d have their orbits 121b and 121d.
122.5 degrees away from each perigee above, satellite 120
c is placed so that it is at an apogee on its orbit 121c.

According to such an orbital arrangement example, satellite 120a, satellite 120b, satellite 120c represented by artificial satellite 90 in the zenith direction with an elevation angle of 70 degrees or more in Hokkaido, Honshu, Shikoku, and four islands of Kyushu and Okinawa. Alternatively, one of the satellites 120d is always visible. Satellite 120a, satellite 120b, satellite 12
Since 0c and satellite 120d have a period of about 24 hours, it is regular and regular to see or not to see in the zenith direction with an elevation angle of 70 degrees or more.

This orbital arrangement example is obtained by the algorithm whose outline is shown in FIG. 1, and is realized by the control method shown in FIG. In this case, satellite 120a in Hokkaido, Honshu, Shikoku and four islands of Kyushu and Okinawa.
The satellite 120b, the satellite 120c, and the satellite 120d appear one after another in the zenith direction with an elevation angle of 70 degrees or more, and appear to stay for about 6 hours.

As a result, one of the satellites is visible in the zenith direction with an elevation angle of 70 degrees or more for 24 hours a day. In addition, there are times when multiple satellites can be seen in the zenith direction with an elevation angle of 70 degrees or more. This is repeated every 24 hours.

Therefore, in FIGS. 13 to 16 showing an example in which this orbital arrangement is applied to the system, a satellite represented by the artificial satellite 90 is used for satellite communication, so that communication with less interruption due to shields or obstacles is possible. It becomes possible to build a system.

In the above-mentioned orbital arrangement example 1, one day from all over Japan
An example was shown in which one of the satellites was visible in the zenith direction with an elevation angle of 55 degrees or more over 24 hours, but in Orbital placement example 5 with four satellites, the elevation angle is over 24 hours a day from all over Japan. It is designed so that either satellite is visible in the direction of the zenith of 70 degrees or more. Tables 7, 8 and 9 show examples of daily visibility of satellites from 10 cities.

[0102]

[Table 7]

[0103]

[Table 8]

[0104]

[Table 9]

In Tables 7 to 9 above, Ambsat-1 to Ambs
at-4 is a tentative name given to identify the satellite. When each satellite is viewed from each city, the time zone in which the elevation angle is 70 degrees or more is indicated by a thin line. The time zone in which the thin line is partly thick is the time zone in which the satellite can be seen above the city at an elevation angle of 80 degrees or more.

According to this arrangement example, in the area from Sendai to Osaka, in a time zone of 80% or more of 24 hours a day,
Any satellite can be made visible in the zenith direction with an elevation angle of 80 degrees or more.

(5) System to which satellites moving in orbit according to the present invention are applied (5-1) System example 1 System example 1 is a satellite communication system for service throughout Japan. An application example as a telephone system is shown.

As shown in FIG. 13, in this system example, an artificial satellite 90 equipped with subsystems such as an attitude control system, a power supply system, a communication system, and a heat control system suitable for the above elliptical orbit, It is composed of a terrestrial mobile communication terminal 91 capable of performing satellite communication via an artificial satellite 90, a fixed telephone 92, a fixed telephone network 93, a mobile telephone 95, a mobile telephone network 96, and a gateway communication station 94. Has been done.

The terrestrial mobile communication terminal 91 enables communication with the fixed telephone 92 or the mobile telephone 95, and is one of the input conditions for determining the six elements of the orbit of the artificial satellite according to the present invention. When it is used in the service target area, the transmission / reception means has been determined to be used on the assumption that the signal is transmitted / received to / from the artificial satellite 90 that appears within a predetermined elevation angle range in the zenith direction. Therefore, for example, when a directional antenna is used as the transmitting / receiving means of the terrestrial mobile communication terminal 91, it suffices to simply point the antenna in the zenith direction in any area, and there is an artificial satellite. There is no need for the user to search for directions (North, South, East, West).

According to this system example, it is also possible to perform communication about mobile objects such as mobile phones and car phones for the whole world. Since a worldwide communication system can be constructed with a small number of satellites, it is possible to provide inexpensive communication services.

(5-2) System Example 2 System example 2 is a satellite communication system intended for service throughout Japan, and FIG. 14 shows an example of application as a system centered on image transmission from a moving body such as an ambulance. Is shown.

In FIG. 14, the system includes an artificial satellite 90 having subsystems such as an attitude control system, a power supply system, a communication system, and a thermal control system suitable for the above elliptical orbit, and an ambulance 97.
And the Emergency and Lifesaving Center 98. ambulance
Image data 99 of the endoscope, echo, electrocardiogram, camera, etc. regarding the emergency patient being transported by 97 is transmitted to the emergency lifesaving center 98 via the artificial satellite 90, and from the emergency lifesaving center 98,
The appropriate treatment for the patient can be transmitted like 100. Although the ambulance 97 is taken as an example here, the same system as this example can be applied to the case where a large amount of data is transmitted from a mobile body in general.

According to this system example, since at least one satellite can always be seen in the cone formed by the allowable half-vertical angle centered on the zenith, a shield that obstructs the field of view such as artificial buildings, plants and natural terrain. Even in areas where there is a satellite, it is possible to easily secure a communication line for a long time by using this satellite. As a result, image communication from a moving body such as an ambulance or a sports broadcast vehicle is almost always possible regardless of the surrounding obstacles. Furthermore, according to this system example, by transmitting the image data of the patient from the ambulance to the emergency center, it is possible to inform the appropriate treatment method from the specialist in the emergency center. You can take various measures. This allows
It becomes possible to save lives in cases that could be saved if appropriate measures were taken during emergency transportation.
It can also be applied to TV programs for sports broadcasts, etc., and can transmit high-quality images in real time.

(5-3) System Example 3 System example 3 is a satellite communication system intended for service throughout Japan, and FIG. 15 shows an application example as a system for rescue of victims in mountains and oceans. There is.

In FIG. 15, the system is an artificial satellite 90 having subsystems such as an attitude control system, a power supply system, a communication system, and a thermal control system suitable for the above elliptical orbit, and an artificial satellite forming a global positioning system. A satellite 102, a mobile communication terminal 107 having a function of measuring its own position by a positioning signal from the global positioning system and capable of communicating via an artificial satellite 90, and a mountain rescue center 105 for police, fire, etc. It consists of and. The victims 101 in the mountains
By receiving the positioning signal 103 from the artificial satellite 102 that constitutes the global positioning system, the mobile communication terminal 107 measures the position of the user and obtains the data 104 such as the position, the user ID, and the number of the user. Police, via satellite 90
Transmitted to the mountain rescue center 105 such as fire fighting. Based on the data 104, the mountain rescue center will immediately begin rescue work. At this time, if the rescue helicopter 106 or the like can be used, the rescue operation can be quickly performed by transmitting the previous data 104. Although the example of mountain distress is shown here, it can also be applied to maritime distress.

According to this system example, the victims of the mountainous area and the ocean can communicate their positions via satellites regardless of the surrounding natural topography. Currently, when searching for mountain victims, multiple helicopters are flying or rescue teams from the mountain club actually roam the mountains to search for and rescue victims, but as in this system example If the location of the victim is known prior to rescue, the activities of the rescue team can be minimized,
We can provide prompt rescue.

(5-4) System Example 4 System example 4 is a satellite communication system intended for service throughout Japan, and FIG. 16 shows an example of application to an automatic billing system for public utility charges.

As shown in FIG. 16, in this system example, an artificial satellite 90 equipped with subsystems such as an attitude control system, a power supply system, a communication system, and a thermal control system suitable for the above elliptical orbit.
, A utility billing center 108, a fixed communication terminal 109 capable of communicating via an artificial satellite 90, and terminals 109a, 109 for measuring various usages of electricity, gas, water and sewage, etc.
It is composed of b, 109c and 109d. Fixed communication terminal 109
And a terminal 109a for measuring the usage amount of electricity, gas, water, etc.
109b, 109c, and 109d are provided in each home, apartment house, building, and building, and the usage amount in each is measured, and the measured usage amount is periodically sent to the utility billing center 108 via the satellite 90. Is transmitted. As a result, it is possible to efficiently measure electricity, gas, water, etc., which are currently being made by visiting each house door to door, and to perform billing processing for utility bills collectively.

In this system example, by using the satellite in the orbit according to the present invention, the satellite communication line can be easily secured even with the antenna equipment installed in a house surrounded by high-rise buildings. If this is applied, it will also be possible to aggregate via the satellite the public charges for electricity, gas, water, etc., which are currently being used to calculate the amount used, and the labor costs required for counting the amount used can be significantly reduced. . Due to this personnel cost reduction effect, further reduction of public utility charges can be expected.

In the above-mentioned system examples 1 to 4, the artificial satellite 90 is one as shown in FIGS. 13 to 16, but it represents a plurality of satellites. Similarly, the artificial satellite 102 is a representative of the Navstar satellite that constitutes the Global Positioning System (GPS) in the United States, the Russian GLONASS satellite for navigation, the Japanese transportation multipurpose satellite, and the like.

(5-5) System Example 5 FIG. 17 shows a system example of the satellite communication mobile station mounted on the ambulance 97 shown in FIG.

This system uses a high elevation satellite according to the present invention to secure a normal moving image, a high-quality still image, or a high-quality still image through a stable transmission path that is not affected by the movement of the ambulance 97. This is for transmitting moving images and other data detected regarding the condition of the patient, and for receiving treatment instructions and the like from the emergency lifesaving center 98 or the like serving as a base station.

Specifically, the present system has a transmitting / receiving antenna 201, a power amplifier 202, a frequency converter 203, and a modulator 20 as means for transmitting / receiving data via a satellite.
4, camera 205, microphone 206, image compression coding device 207, contact telephone 208, low noise amplifier 212, frequency converter 213, and demodulator 214.

Furthermore, this system is based on the ambulance 9 that moves.
The beacon receiver 217 and the antenna controller 2 are provided as means for controlling the attitude of the transmission / reception antenna 201 attached to the antenna 7.
16, motor driver 215, elevation motor 209, polarization angle motor 21
0, and an azimuth motor 211.

Further, the present system provides accelerometer 224, gyro 225, GPS antenna 218, VICS antenna 220, as means for supplying auxiliary data for optimizing the means for controlling the attitude of the transmitting / receiving antenna. G
A PS receiver 219, a VICS receiver 221, and an image display device 222 are provided.

In this system example, the paramedic on board the ambulance can communicate with the doctor working at the paramedic center 98 via the satellite 90 by the contact telephone 208. Information such as images and sounds obtained by the contact telephone 208 and the condition of the patient being transported by the camera 205 and the microphone 206 is image-compressed and encoded by the image-compression encoding device 207, and then the modulator 204. Is modulated by the frequency converter 203, frequency-converted by the frequency converter 203, power-amplified by the power amplifier 202, and then transmitted to the artificial satellite 90 via the transmission / reception antenna 201.

The above information received by the artificial satellite 90 is transmitted from the artificial satellite 90 to the emergency lifesaving center 98. At the emergency lifesaving center 98, a doctor or the like views the data regarding the patient and sends an appropriate treatment instruction to the ambulance 97 via the artificial satellite 90.

The information related to this instruction is received by the transmitting / receiving antenna 201 provided in the ambulance 97, amplified by the low noise amplifier 212, frequency-converted by the frequency converter 213, and demodulated by the demodulator 214. The emergency paramedic who is on board the ambulance 97 can receive a treatment instruction from the doctor in the emergency lifesaving center 98.

The strength of the signal received by the transmission / reception antenna 201 is adjusted so that the beacon signal separated by the frequency converter 213 is received by the beacon receiver and the strength of the beacon signal is optimized. Receives the signal from the antenna controller 216, drives the elevation angle motor 209, the polarization angle motor 210, and the azimuth angle motor 211, and changes the direction of the transmission / reception antenna 201, thereby optimizing.

Further, in changing the direction of the antenna, the GPS antenna 218 and the GPS receiver 219 are used to receive positioning signals from GPS satellites constituting the global positioning system, thereby helping the optimization. good. Further, by detecting the change in the moving direction of the ambulance by using the accelerometer 224 and the gyro 225, the auxiliary data of the attitude control operation of the antenna is configured to be supplied, so that the antenna attitude with higher adaptability can be obtained. It may be configured to realize control.

GPS is used when selecting the travel route of the ambulance.
The receiver 219 and GPS antenna may help, as well as
Information from the VICS antenna 220 and VICS receiver 221 may be helpful.

(5-6) System Example 6 This system example 6 is, for example, a satellite communication system intended for service throughout Japan, and FIG. 18 shows an application example to a program providing system for a plurality of mobile units. ing.

As shown in FIG. 18, in this system example, an artificial satellite 232 equipped with subsystems such as an attitude control system, a power supply system, a communication system, and a thermal control system suitable for the above elliptical orbit.
And a satellite communication earth station 231 for providing programs to a plurality of mobiles, and an artificial satellite 233 which constitutes a global positioning system.
A mobile unit 235 for public transportation such as a taxi or a rail car, a general mobile unit 236 such as a private car, and a transmitting station 234 for transmitting VICS information. Here, the mobile units 235 and 236 are equipped with communication-related devices shown in FIG. 19 described later.

The mobile units 235 and 236 are equipped with a GPS antenna 256 and a GPS receiver 257, respectively, and receive a positioning signal from an artificial satellite 233 that constitutes the global positioning system to determine their own position and attitude. , And has a function of measuring speed and the like, and the measured information is sent to the transmitting / receiving terminal 244.
In addition, the mobile units 235 and 236 are equipped with a reception antenna 257 and a VICS receiver 259 that receive a signal from the VICS information transmission station 234, and have a function of receiving road congestion information and the like, and the received information is Similarly, it is sent to the transmitting / receiving terminal 244.
The transmission / reception terminal 244 has a function of receiving an operation instruction input by the user of the system to select desired information from the selectable information, and acquiring the selected information.

Information obtained by the above GPS receiver 258,
The information obtained by the VICS receiver 259 and the selected desired information are signal-processed on the transmission / reception terminal 244, modulated by the modulator 243, and frequency-converted by the frequency converter 242.
After the power is amplified by the power amplifier 241, the transmitting / receiving antenna 240
Is transmitted to the artificial satellite 232 via.

This signal is transmitted to the satellite communication earth station 231 of the program provider via the artificial satellite 232. In the satellite communication earth station 231, on the basis of the information transmitted from the mobile units 235 and 236, select a program according to the moving location of the mobile unit, time zone, hope, etc., and via the artificial satellite 232, Mobile 235
And 236 to deliver the program.

The types of programs distributed in the present invention are as follows:
There is no particular limitation. According to the present invention, since the artificial satellite 232 can always be positioned at a high elevation angle, it is possible to always secure a stable and continuous transmission path via the artificial satellite 232 regardless of the moving state of the moving body. You can Therefore, it is possible to receive not only moving images but also still images and teletext. Note that a signal processing method, a frame memory, or the like is provided as appropriate depending on the type of information to be received.

As a concrete program to be distributed, for example,
Department stores belonging to the area where the mobile is moving, supermarket time service information, museum / museum exhibition information, movie theater performance information, criminal / wanderer information,
Information on the Internet can be cited.

In the mobile units 235 and 236, the information transmitted from the satellite communication earth station 231 of the program provider via the artificial satellite 232 is received by the transmitting / receiving antenna 240 provided in the mobile unit. The received signal is amplified by the low noise amplifier 248, frequency-converted by the frequency converter 249, demodulated by the demodulator 247, video information is displayed on the image display 245, and audio information is obtained by the speaker 246. .

The signal demodulated by the demodulator 247 includes program information that can be selected in the area in which the mobile unit is moving, and this information is displayed as video or audio on the image display 245 or the speaker 246. At the same time as it can be confirmed, it is also sent to the new transmission / reception terminal 244.

The strength of the signal received by the transmission / reception antenna 240 is determined by the motor driver 252 so that the beacon signal separated by the frequency converter 249 is received by the beacon receiver and the strength of the beacon signal is optimized. Receives the signal from the antenna controller 251, drives the elevation angle motor 253, the polarization angle motor 254, and the azimuth angle motor 255, and changes the direction of the transmission / reception antenna 240, thereby optimizing.

According to this system example, the information according to the location in the urban area can be transmitted to the moving body more reliably. That is, a television mounted on a moving body that receives a television signal transmitted from a ground station or a geostationary satellite by a conventional method can enjoy television broadcasting under the influence of buildings and trees while the moving body is moving. Have difficulty. However, the television broadcast signal is sent from the zenith direction in the transmission path in this system. Therefore, you can enjoy stable broadcasting without being affected by buildings and trees.

Furthermore, according to this system example, in department stores and supermarkets, information such as time service can be appropriately transmitted to a moving body moving in a nearby area, so that an effect of attracting customers is expected to increase. You can do it.

Furthermore, by sending a photograph or a characteristic of a criminal or a loitering person to a moving body, an effect of speeding up the discovery of the criminal or loitering person can be expected.

The above system example 1 to system example 6 should be used when the service area of the elliptical orbit satellite according to the present invention is Japan and the elevation angle when the satellite is viewed from the service area is high. However, the present invention is not limited to this. For example, when the elevation angle when the satellite is viewed from the service area is low, the following uses are possible.

That is, depending on the orbital position of the elliptical orbit satellite, when the elevation angle is low when viewed from the service target area, the communication between the service target area and the area other than the service target is relayed. When the elevation angle is further lowered, it is possible to relay communication between regions other than the service target region.

(6) Example of satellite orbit control system The orbits of the above satellites are controlled as follows.

Six orbital elements 17 (orbital major radius 11, perigee argument 12, eccentricity) obtained in FIG. 1 and suitable for the service target area
13, orbital inclination angle 14, ascending intersection RA 15 and proximate departure angle 16)
2 is input to the launcher tracking control facility 21 as a target input trajectory element as shown in FIG. This information is transmitted from the launch vehicle tracking and control equipment 21 to the launch vehicle 23 to inject the artificial satellite 20 into the target orbital element. If the launch vehicle 23 equipped with the artificial satellite 20 is likely to deviate from the target trajectory at the launch stage, the launch vehicle 23 may automatically correct the trajectory, or the launch vehicle tracking control facility 21 may correct the trajectory. The command may be transmitted to the launch vehicle 23 for guidance.

Even after reaching the target orbital element 22 by the launch vehicle 23 in this way, the orbital element is perturbed by the influence of the gravity field of the earth, the gravity of the sun and the moon, the solar wind, etc. And the orbital elements constantly change in a long cycle. In this case, the satellite 20 needs orbit control.

As shown in FIG. 3, the orbital six elements 31 of the orbit currently in flight by the artificial satellite 20 are the telemetry and ranging signals 27 transmitted by the artificial satellite 20, and the transmission / reception system 24 of the artificial satellite tracking and control equipment 18 After receiving and extracting the ranging signal 28, it is transmitted to the ranging system 25, and the orbit determination program 30 in the computer system 26 calculates and determines the distance and the distance change rate 29 measured here as the final input. To be done. The trajectory control program 32 in the computer system 26 is compared by comparing the trajectory six elements 31 thus obtained with the trajectory six elements 17 suitable for the target service area.
Calculates the required attitude control amount and orbit control amount 33. This determines which thruster of the propulsion system of the artificial satellite should be injected for what time and for what length of time. This is converted into a control command 35 by the command generation program 34 in the computer system 26, and transmitted to the artificial satellite 20 via the transmission / reception system 24 of the artificial satellite tracking and control equipment 18.

As shown in FIG. 4, the control command transmitted to the artificial satellite 20 is received by the communication system 37 mounted on the artificial satellite 20 and then the command transmitted by the data processing system 38 is decoded. Attitude control amount and orbit control amount information 41 is appropriately processed from the decoded command in the satellite-mounted attitude / orbit control system 39, and the attitude control actuator 42 if necessary.
Finally, the artificial satellite 20 is indicated by six orbital elements 17 suitable for the service area by driving the aircraft and changing its attitude, or by injecting the thruster of the artificial satellite-based propulsion system 40 as commanded. It is put into the orbit and controlled.
In addition, satellite 20 is a GPS that makes up the global positioning system.
If a (Global Positioning System) or GLONASS receiver is installed, the satellite 20 itself stores six orbital elements 17 suitable for the service area in advance, and uses this to autonomously orbit. It may be configured to control.

In this way, the trajectory element 17 suitable for the service area determined by the algorithm shown in FIG.
Is controlled and realized.

[0153]

According to the present invention, the orbits of artificial satellites required to be visible in the zenith direction for a long time, the six orbital element setting methods for defining the orbits, and various types of satellites using the orbits A system can be provided.

Further, according to the present invention, it is possible to provide an orbit control system which realizes orbit control of an artificial satellite based on the above-set six orbit elements.

[Brief description of drawings]

FIG. 1 is a flowchart showing a method of setting six orbital elements in which a satellite is visible in the zenith direction for a long time according to the present invention.

FIG. 2 is an explanatory diagram showing a flow of information for controlling the orbit of the artificial satellite into six orbit elements set by the algorithm of the present invention.

FIG. 3 is an explanatory diagram showing a work and a flow of information performed by an artificial satellite tracking and control facility for controlling the orbit of the artificial satellite.

FIG. 4 is an explanatory diagram showing processing and information flow performed inside the artificial satellite for controlling the orbit of the artificial satellite.

FIG. 5 is an explanatory diagram of six orbits that define the shape of the orbit, and is a view of the orbit viewed from the direction normal to the orbital surface.

FIG. 6 is an explanatory diagram of six orbital elements that define the orbital shape, and is a bird's-eye view of the orbital and the earth.

FIG. 7 is a diagram for explaining that it is necessary to set six orbital elements in consideration of the service target area, and is a bird's-eye view of the earth.

[Fig. 8] For an orbit with a period of about 24 hours, an eccentricity of 0.25, an orbit inclination angle of 55 degrees, and a perigee argument of 270 degrees,
It is an explanatory view showing the ground locus of the orbit on the world map, and the world map shows the angles at equal intervals in the latitude direction and the longitude direction.

[Fig. 9] An orbit with a period of about 24 hours, an eccentricity of 0.38, an orbital inclination angle of 45 degrees, and a perigee argument of 270 degrees.
It is an explanatory view showing the ground locus of the orbit on the world map, and the world map shows the angles at equal intervals in the latitude direction and the longitude direction.

[Fig. 10] An explanatory diagram showing a world map at equal intervals in the latitude and longitude directions. On this map, a 24-hour cycle, an eccentricity of 0.35, an orbital inclination angle of 63.4 degrees, and a perigee argument For a 270 degree orbit, it is possible to obtain a ground locus that overlaps with the ground locus 82 in the orbit having the same ground period, eccentricity, orbit inclination angle, and perigee argument as the ground locus 82 that gives the ground locus 82. A ground locus 83 of the orbit with the right ascension of the ascending node is shown.

FIG. 11 is an explanatory diagram of the orbital arrangement example 1 obtained by the algorithm of the present invention, in which the orbits are overlooked centering on the earth.

FIG. 12 is an explanatory view of the orbital arrangement example 2 obtained by the algorithm of the present invention, which is a bird's-eye view of the orbit around the earth.

FIG. 13 is an explanatory diagram showing an application example as a mobile phone system.

FIG. 14 is an explanatory diagram showing an application example as a system centered on image transmission from a moving body such as an ambulance.

FIG. 15 is an explanatory diagram showing an application example as a system for rescue of a victim in a mountain or the ocean.

FIG. 16 is an explanatory diagram showing an example of application of a utility bill to an automatic billing system.

FIG. 17 is an explanatory diagram showing another application example as a system centered on image transmission from an ambulance.

FIG. 18 is an explanatory diagram showing an application example to a system for delivering a program to a plurality of mobile bodies.

19 is an explanatory diagram showing a configuration example of a communication system in a mobile body in the system example of FIG.

[Explanation of symbols]

1. Half-vertical angle setting (work process) 2. Setting required service time (work process) 3. 3. Setting a polygon that covers the service area (work process) 4. Setting of major radius of orbit (work process) 5. Perigee argument setting (work process) 6. 6. Number of satellites, ascending / descending RA and astigmatic declination of each satellite (work process) 7. Setting the initial value of the track inclination angle (work process) 8. Change the eccentricity and calculate the visible time from the polygon vertices (work process) 9. Calculate the visible time from the polygon vertex by changing the orbital inclination angle (work process) 10. Setting the right ascension and the declination of the closest point (work process) 11. Orbital major radius (output information) 12. Perigee argument (output information) 13. Range of eccentricity where the visible time from each polygon vertex is almost the same (output information) 14. Range of orbital inclination angles from which the visible time from each polygon vertex is almost the same (output information) 15. Ascending intersection RA (output information) 16. Nearest point departure angle (output information) 17. Six orbits suitable for the service area (information input to each tracking control facility) 50. Elliptical focus 51. Artificial satellite 52. The apogee of the ellipse (apogee if the ellipse is focused on the earth) 53. Perigee of ellipse (perigee if the focus of the ellipse is the earth) 54. Orbital major radius 55. Short radius of orbit 56. Apogee radius 57. Perigee radius 58. Nearest point separation angle 60. Earth 61. Equatorial plane of the earth 62. Ascending intersection 63. Perigee argument 64. Orbit inclination angle 65. Perigee 66. Appointment 70. The westernmost part of the service area 71. The easternmost edge of the service area 72. The northernmost part of the service area 73. The southernmost part of the service area 74. The meridian passing through the westernmost point 75. Meridian passing through the easternmost point 76. Latitude line passing through the northernmost point 77. Latitude line passing through the southernmost point 78. Equator 79. Earth axis 80. Orbital ground trajectories for trajectories with approximately 24-hour period, eccentricity of 0.25, orbital inclination angle of 55 degrees, and perigee argument of 270 degrees. Orbital ground trajectories for orbits with a period of about 24 hours, an eccentricity of 0.38, an orbital inclination angle of 45 degrees, and a perigee argument of 270 degrees. Orbital ground trajectories for orbits with a period of approximately 24 hours, an eccentricity of 0.35, an orbital inclination angle of 63.4 degrees, and a perigee argument of 270 degrees. The same orbital period and eccentricity as the orbit that gives the ground track 82,
A ground trajectory 90. An orbit with an inclination angle and a perigee argument, in which the right ascending node RA is set so that a ground trajectory that overlaps the ground trajectory 82 can be obtained. Artificial satellite equipped with subsystems such as an attitude control system, a power supply system, a communication system, and a thermal control system suitable for the elliptical orbit of the present invention 91. A ground-based mobile communication terminal capable of performing satellite communication via the artificial satellite 90. Fixed telephone terminal 93. Fixed telephone network 94. Gateway communication station 95. Mobile phone terminal 96. Mobile telephone network 97. Ambulance 98. Emergency and lifesaving center 99. Image data of endoscope, echo, electrocardiogram, camera, etc. for emergency patients 100. Instructions for treatment from the Emergency and Critical Care Center 101. Victims 102. Artificial satellites that make up the Global Positioning System 103. Positioning signal 104. Data such as ID of victims, number of victims, location of accident, etc. 105. Mountain rescue center for police and fire departments 106. Rescue helicopter 107. A ground-based mobile terminal 108 which has a function of receiving the positioning signal 103 from the artificial satellite 102 and capable of measuring its own position and the like and capable of communicating via the artificial satellite 90. Utility billing center 109. Ground fixed communication terminal 109a. Electricity consumption measuring terminal 109b. Gas consumption measuring terminal 109c. Water and sewage usage measurement terminal 109d. Other public utility meter 110. Artificial satellite 111. Artificial satellite 112. Orbit of satellite 110 113. Orbit of artificial satellite 112 114. Equatorial plane of the earth 116. Ascending intersection of orbit 112. Ascending points 120a, 120b, 120c, 120d of the orbit 113. Artificial satellites 121a, 121b, 121c, 121d. Artificial satellites 120a, 120b, 120c,
120d trajectories 122a, 122b, 122c, 122d. Orbit 121a, 121b, 121c, 121d
Ascending intersection.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Watano Hamano               4-6 Kanda Surugadai, Chiyoda-ku, Tokyo                 Hitachi, Ltd. Space Technology Promotion Book               Department (72) Inventor Shigeki Nakamura               216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa               Hitachi, Ltd. Space Technology Promotion Division               Within (72) Inventor Tomiji Yoshida               3-1-1, Saiwaicho, Hitachi-shi, Ibaraki               Hitachi, Ltd., Hitachi factory (72) Inventor Masataka Owada               3-1-1, Saiwaicho, Hitachi-shi, Ibaraki               Hitachi, Ltd., Hitachi factory (72) Inventor Masahiko Ikeda               3-1-1, Saiwaicho, Hitachi-shi, Ibaraki               Hitachi, Ltd., Hitachi factory (72) Inventor Takashi Yabutani               4-6 Kanda Surugadai, Chiyoda-ku, Tokyo                 Hitachi Research Institute, Inc. (72) Inventor Masahiro Ito               4-6 Kanda Surugadai, Chiyoda-ku, Tokyo                 Hitachi Research Institute, Inc.                (56) References The Institute of Electronics, Information and Communication Engineers, Vol. 79 N               o. 4 PP. 344-349, 1996 Ouchi               Two others “Mobile Satellite Communication System”

Claims (7)

(57) [Claims] 1. Use of three artificial satellites to place the satellite in Japan
A communication system for providing communication services, which is located in a polygonal service area including Hokkaido, Honshu, Shikoku, Kyushu, and Okinawa, and transmits radio signals within an elevation angle range of 55 degrees to 90 degrees. a device, Hokkaido, Honshu, Shikoku, located in Kyushu and service target area of a polygon shape including Okinawa, anda receiver for receiving radio signals at an elevation angle range of 90 degrees 55 degrees, the 3 aircraft of satellites, ascension of ascending node is, there is induced to circulate three <br/> each elliptical orbit which is set shifted 120 degrees from each other, the set right ascension of ascending node, 24 The orbital long radius corresponding to the time period, and the perigee argument set to 270 degrees ,
And 1/3 of the orbit period for adjacent satellites in orbit
Based on the near point separation angle set to a value
55 at any point in the service area
The visible time that alternates for 24 hours continuously within the elevation range of 90 degrees or more and 90 degrees or less, and the visibility time seen in the elevation range from each vertex of the polygonal area matches with each vertex within a predetermined error range. in the range of eccentricity and the orbit inclination angle is arranged in an elliptical orbit of the orbital elements obtained for the transmission apparatus and the reception apparatus, a satellite of the three aircraft
Then, a communication system is characterized in that communication is carried out by an artificial satellite which becomes visible within the elevation angle range. 2. A communication service is provided by transmitting a radio signal from a transmitting device mounted on a mobile body and transmitting the radio signal to a receiving device via a transmitting / receiving device mounted on a plurality of artificial satellites. In the method for providing a communication service using an artificial satellite, the transmitting device is one of Hokkaido, Honshu, Shikoku, Kyushu and Okinawa.
Including located a transmitting antenna unit in Japan service target area, and transmitting a radio wave signal towards the elevation angle range of 90 degrees 55 degrees, with three aircraft satellite as the plurality of artificial satellites, each person The engineering satellite sets an orbital tilt angle near the center of gravity of the service target area , and based on the tilt angle set near the center of gravity, the elevation angle of 55 degrees or more and 90 degrees or less in the service target area . obtains the visible become eccentricity alternative satellite replaces at 24 hour continuous within, change repeatedly the orbit inclination angle from near the center of gravity, said in said service target area <br/> for respective change 55 The eccentricity that makes the artificial satellite alternate and visible for 24 hours continuously within the elevation angle range of 90 degrees or more and 90 degrees or less is obtained, and the eccentricity is arranged in three elliptical orbits selected from the combination of the calculated orbit inclination angle and eccentricity. Ruko Communication service providing method using the artificial satellite characterized by. 3. Use of three artificial satellites in Japan
A communication device for providing a communication service, which is located within a service target area including Hokkaido, Honshu, Shikoku, Kyushu, and Okinawa, and transmits a radio signal in an elevation range of 55 degrees or more and 90 degrees or less, and Hokkaido. , Honshu, Shikoku, located in the service target area including the Kyushu and Okinawa, anda receiver for receiving radio signals at an elevation angle range of 90 degrees 55 degrees, the three aircraft artificial satellites, orbits A tilt angle is set near the center of gravity of the service target area, and the service target is set based on the set tilt angle.
24 in elevation range of the 55 degrees 90 degrees in the region
The seek visible become eccentricity alternative satellite replaces time continuously modify repeatedly the orbit inclination angle from near the center of gravity, it said in said service target area for respective change 5
Obtain and calculate the eccentricity at which the artificial satellite alternates for 24 hours continuously within the elevation angle range of 5 degrees or more and 90 degrees or less.
Are arranged in three orbits obtained by selecting a combination of the orbital inclination angle and the eccentricity, and the transmitter and the receiver are connected to each other by the three satellites.
Then, a communication system is characterized in that communication is carried out by an artificial satellite which becomes visible within the elevation angle range. 4. Use of three artificial satellites in Japan
A communication system for providing communication services, which is located in a polygonal service area including Hokkaido, Honshu, Shikoku, Kyushu, and Okinawa, and transmits radio signals within an elevation angle range of 55 degrees to 90 degrees. A device , wherein the transmitting device is located within the coverage area, and
Since 5 degrees or more and 90 degrees or less elevation range communicating services to a receiving device for receiving radio signals, the three aircraft human
Performs transmission using any of Engineering satellites, the three aircraft artificial satellite, in which ascension of ascending node is caused to orbit three <br/> each elliptical orbit which is set shifted 120 degrees from each other Then, the right ascension of the ascending point, the orbital long radius corresponding to a 24-hour period, and the perigee argument set to 270 degrees ,
And 1/3 of the orbit period for adjacent satellites in orbit
Based on the near point separation angle set to a value
55 at any point in the service area
The visible time that alternates for 24 hours continuously within the elevation range of 90 degrees or more and 90 degrees or less, and the visibility time seen in the elevation range from each vertex of the polygonal area matches with each vertex within a predetermined error range. The eccentricity and the range of the inclination angle of the orbit are arranged in the elliptical orbits of the orbital elements for which the ranges are determined, and the transmitting device is arranged to transmit the three satellites to the receiving device.
Among them, a communication system characterized by performing communication by an artificial satellite which becomes visible within the elevation angle range. 5. A communication using an artificial satellite, which provides a communication service by transmitting a radio signal transmitted from a transmitting device to a receiving device via any one of a plurality of artificial satellites having a communication function. In the service providing method, three satellites are used as the plurality of artificial satellites, and each artificial satellite orbits near the center of gravity of a service target area in Japan including Hokkaido, Honshu, Shikoku, Kyushu, and Okinawa. A tilt angle is set, and based on the set tilt angle, an eccentricity that becomes visible instead of the artificial satellite is obtained for 24 hours continuously within the elevation angle range of 55 degrees or more and 90 degrees or less in the service target area . the change repeatedly the orbit inclination angle from near the center of gravity, instead the artificial satellite 24 hour continuous to the service object the 55 degrees 90 degrees within the following range of elevation angles in the region for respective change replaces Seeking a visible eccentricity, arranged into three elliptical <br/> circular path which is selected from a combination of the obtained orbit inclination angle and the eccentricity, located the transmission antenna section to the service target area, 5
A communication service providing method using an artificial satellite, comprising: providing a communication service to a transmitting device that transmits a radio wave signal in an elevation angle range of 5 degrees or more and 90 degrees or less. 6. The communication service providing method according to claim 5, wherein the communication service is provided for a radio wave signal transmitted from a transmitting device mounted on a mobile body. . 7. Use of three artificial satellites to place the satellite in Japan
A communication system for providing communication services, which is located within a polygonal service area including Hokkaido, Honshu, Shikoku, Kyushu, and Okinawa, and transmits radio signals within an elevation angle range of 55 degrees to 90 degrees. A device , wherein the transmitting device is located within the coverage area, and
Since 5 degrees or more and 90 degrees or less elevation range communicating services to a receiving device for receiving radio signals, the three aircraft human
Transmission is performed using one of the engineering satellites, and the three satellites set the orbital inclination angle near the center of gravity of the service target area , and the service target based on the inclination angle set near the center of gravity. The eccentricity at which the artificial satellite becomes visible alternately for 24 hours is obtained within the elevation range of 55 degrees or more and 90 degrees or less in the region, and the orbit inclination angle is repeatedly changed from the vicinity of the center of gravity, and each change is performed. In the service target area, the visible eccentricity that alternates the artificial satellites for 24 hours continuously is obtained within the elevation range of 55 degrees or more and 90 degrees or less, and the orbit inclination angle and the eccentricity obtained are calculated. The satellites are respectively arranged in three orbits obtained by selecting from combinations, and the transmitting device is provided to the receiving device by the three satellites.
Passing by one, it is visible in the elevation angle range satellite
A communication system characterized by performing communication.