JPH05268131A - Communication satellite network and its forming method - Google Patents

Abstract

PURPOSE: To continuously provide a service to a very wide elevation covering a wide area, far points much lower than far points of Molniya orbit, and plural regions on the earth by a satellite communication network. CONSTITUTION: Five or six communication satellites 1 to 6 arranged on the same elliptic orbits as ones on the earth are provided. Each orbit has a period of 8 hours, and three far points placed at about 27000km altitude on three prescribed regions of the earth exist on the orbit at intervals of 24 hours. The orbit has an angle of inclination approximately equal to 63.4 degrees. Each satellite has a near point argument of 270 degrees and a super-elliptic orbit which is so selected that a large elevation is obtained in each of three regions, and the satellite acts as if it were approximately stationary to the earth while the satellite exist in parts, where it can be used, within the orbit.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of forming a communication satellite network, and more particularly to broadcast satellites.

[0002]

Direct Broadcast Satellites (DBS-R) have a very interesting perspective. NASA (National Aeronautics and Space Administration) and V
Market research done on behalf of OA (Voice of America) suggests that this type of system could have 50 million users by 2000, and that number by 2005 It shows that the number is likely to increase to 550 million. This market research shows that direct-broadcast satellites could be a viable successor to current shortwave broadcasters, and that they cover wider coverage areas (“coverage” or “coverage areas” with improved quality). The same shall apply).

Another possibility for direct broadcast satellites is compact disc quality Digital Audio Broadcasting (DAB), aimed at users of the highest quality services not available through conventional terrestrial channels. European Broadcasting Union (Eu
rope Broadcasting Union
n) is currently evaluating the potential benefits of DAB services.

The realization and success of direct broadcast satellites depends on the ability to receive satellite signals at all points in the network utilizing small portable or mobile receivers. Whether direct-broadcast satellites have commercial benefits
In essence, it depends on having a signal that is always available and easy to use.

In order to utilize the direct communication satellite and the small receiver, a large transmission power flux density (PFD) is required in the broadcasting service area. Such high power flux density requirements increase the satellite's elevation angle to minimize out-of-service effects in shadowed areas and eliminate all obstacles on the satellite's line of sight (LOS). Only then can it be achieved by a single satellite. Stationary (G
The EO) satellite can cover a large coverage area, but has a small elevation angle at latitudes above 30 degrees. A typical geostationary satellite has a period of 23.934 hours, a tilt angle of 0 degrees, and is in a circular orbit at an altitude of 35786 km.

Geostationary satellites are INTELS
The need for very powerful spacecraft in the sector of AT (International Commercial Satellite Communications) and large complex antenna systems has made it impossible to provide satisfactory service to the Northern Hemisphere countries. For this reason, non-geostationary orbits must be considered for direct broadcast satellites and for communication via mobile satellites (MOB SATs). The reception and service purposes are very similar.

The satellite network has a super elliptical orbit (HE
It was proposed that O) be used. The well-known "LOOPUS" plan, "Sicomoles (S
YCOMORES Plan "," Archimedes (ARCH
The IMEDES Program "plans relevant regional systems covering Northern Europe in this area. The Archimedes plan is the only one considering direct broadcast satellite services.

[0008]

The first stage of the system in the Archimedes project is Mornya.
It proposes to cover Northern Europe at large elevations by using a network of four satellites with a 12-hour orbit in type orbit. This kind of orbit has a 39375km apogee and 1
Perigee of 000 km and angle of inclination of 63.4 degrees (angle of inclinatio)
n). If the apogee is set to 40,000 km, the launch cost will be very high. Moreover, since this service covers only Europe, it is not possible to cover the costs by providing other services to areas outside Europe.

The second stage of the system in the Archimedes project uses the TOUNDRA type orbit. It has the same drawbacks as it has an apogee at 47,000 km and requires a greater launch force.

An object of the present invention is a method of forming a communication satellite network having a combination of the following features.
Its feature is a very large elevation angle covering a large area,
The apogee, which is much lower than the apogee of the Mornya-type orbit, is the continuous coverage (serving) of multiple regions of the earth.

[0011]

SUMMARY OF THE INVENTION In one aspect, the present invention comprises a method of forming a communication satellite network, such as a direct broadcast satellite, having a step of placing a plurality of communication satellites on an elliptical orbit having the same trajectory on the ground surface. Each of its orbits has a period of 8 hours, and every 24 hours, the orbit has three apogees located at approximately 27,000 km altitude on three predetermined regions of the earth. Also, the orbit has a tilt angle approximately equal to 63.4 degrees. The satellite has a perigee argument of 270 degrees and a super-elliptical orbit selected to have a large elevation in each of the three regions, with respect to the Earth while the satellite is in the usable part of those orbits. And behave almost as if it were stationary.

The satellites are located in the orbit such that two adjacent satellites are always on a line that can be seen by a ground station in the given area, and are fixed near the perigee. It is recommended that they be placed so that they can be operated from altitude.

In the first embodiment, five satellites are placed in orbit with a time difference of approximately 4 hours in order to obtain 16 hours of continuous service per day in each area.

In the preferred embodiment, six satellites are placed in orbit with a time difference of approximately 4 hours to provide 24 hours of continuous service per day in each region.

The apogee altitude is approximately equal to 26800 km. The perigee altitude is almost equal to 1000 km.

The zooming ratio between the two satellites should be less than 1.5, preferably approximately equal to 1.32.

Perigee ar of the orbit
The satellite coverage can be optimized by choosing an angle of approximately 270 degrees as the "document".

In another aspect, the present invention provides a communication satellite network such as a direct broadcast satellite in an elliptical orbit having 5 or 6 communication satellites arranged in an elliptical orbit having the same trajectory on the ground surface. Make up. Each of its orbits has a period of 8 hours, and the orbits are located every 24 hours at an altitude of about 27,000 km on three predetermined regions of the Earth.
There are two apogee. Also, the orbit has a tilt angle approximately equal to 63.4 degrees. The satellite has a perigee argument of 270 degrees and a super-elliptical orbit selected to have a large elevation in each of the three regions, with respect to the Earth while the satellite is in the usable part of those orbits. And behave almost as if it were stationary.

In the first embodiment, five satellites are placed in orbit with a time difference of approximately 4 hours in order to obtain continuous 16 hours of service per day in each area.

In the preferred embodiment, six satellites are placed in orbit with a time difference of approximately 4 hours to provide 24 hours of continuous service per day in each region.

The apogee altitude is approximately equal to 26800 km.

The perigee altitude is approximately equal to 1000 km.

The perigee argument is approximately equal to 270 degrees.

The zooming ratio between the two satellites should be less than 1.5, preferably approximately equal to 1.32.

Other features and advantages of the present invention will become apparent from the following description, given by way of non-limiting example, with reference to the accompanying drawings.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a communications satellite network, which satellite network is on an eight-hour elliptical orbit with parameters enabling the results to be achieved which have already been outlined. In the satellite network of the present invention, the satellites apparently move in the same orbit with a time lag from the viewpoint of the observer on the ground. These several types of elliptical orbits have the same trajectory on the surface of the earth. In this super-elliptical orbit with a period of 8 hours, three apogee loops (apo) that determine three service areas are used.
It has a ground loops) of about 27,000 km. As is clear from this description, the three major regions are given elevations in excess of 50 degrees. The three main regions are Western Europe, Japan and South Korea, and the major parts of North America. Compared to the Archimedes project using the Mornier orbit, the satellite network of the present invention uses 5 or 6 satellites instead of 4 but has 3 service areas instead of 1. Since the apogee altitude is much lower in the satellite network of the present invention, the required transmission power can be reduced by a factor of 2.5. The cost of satellites and launches is cheaper than the Archimedes project, and the cost of putting satellites into orbit can be shared among the three main service areas.

A general study of the potential of multisatellite networks with non-geostational orbits can be found in the proceedings of the Second European Conference on Satellite Communications (ESA SP-32, October 1991). This is described by G. PERROTTA in "Comparison of low altitude circular orbits and tilt elliptical orbits for the use of small satellites (Ac
emphasis Between Low-Ci
circular and Elliptical Inc
lined Orbits for Small Sa
"Tellites Applications". This contribution contains the content that using an elliptical orbit with a period of 8 hours would not be advantageous.

The basic idea of the invention lies in particular in the use of satellites with a revolution period of 8 hours to form a communication satellite network providing a multi-regional communication system. And, this multi-region communication system is commercially viable, uses a minimum number of satellites, and has a preferred satellite altitude.

According to the present invention, an eccentricity of the orbit having an orbit which is apparently the same as the 8-hour orbit period is selected so as to cover a wide area in three geographical areas. The longitudes of the three geographical regions are 120 degrees apart (here: Europe, Far East and North America), have very high elevation angles and are continuous (2 per day).
Serving for 4 hours, with minimum number on orbit (5+
1) Have 1 (ie 5 or 6) satellites.

The perigee altitude is 1000 k to avoid that apogeeic satellites are affected by the upper atmosphere.
m or higher is preferred.

As shown in FIG. 1, each spacecraft or satellite is available for four hours in each of the three apogee loops on the three service areas. At the end of each four hours, each satellite hands over the serving role to the next satellite, which is apparently in the same orbit. FIG. 1 shows the trajectories on the surface of various trajectories. They are 1 to 6
It constitutes a single apparent orbit with six satellites numbered up to. Satellite 1 is shown to be at apogee altitude over Europe, and satellite 2 is following satellite 1 at 4 hour intervals at the perigee on the South Pacific west of South America. Satellite 3 is at the apogee on the Far East and satellite 4 is at the perigee on the South Atlantic. Satellite 5 is at an apogee on North America and satellite 6 is at an apogee on the South Atlantic.

The orbital slope is chosen to minimize the fuel required for orbital control. A stable orbital slope of 63.45 degrees is chosen in this example. It is possible to increase the elevation in the area served by the satellite by slightly reducing the orbital tilt. However, in this case, a very large amount of fuel is needed to eliminate the deviation (J ₂ effect) that affects the perigee argument due to the oblate spherical shape of the earth.

Since the value of the perigee argument is important to maximize the serviceable area in the three service areas, deviations affecting the perigee argument must be avoided. The optimum value for the perigee argument is 270 degrees.

The optimal parameters of the satellite network are:

Number of satellites: 6 ((5 + 1), ie, 5 or 6) Apogee altitude: 26800 km Perigee altitude: 1000 km Orbit period: 8 hours Orbital tilt: 63.435 degrees Perigee argument: 270 degrees Per orbit Period of use: 4 hours Ascendant no. Of satellite takeover conditions at the line of sight (LOS) at an altitude of 20500 km
de): ± 60 degrees Mean anomaly: ± 180
Every time.

A multi-region satellite network of this type, utilizing six satellites, allows users to receive broadcast signals at elevations above 50 degrees in major parts of Europe, Southeast Asia, and the Americas. .. 2 to 5 show curves showing equal elevation angles in these regions.

FIG. 2 shows the curves of the area on the surface of the earth with elevation angles of 40, 50 and 60 degrees in the three areas served by the satellite network.

FIG. 3 shows that in Europe, 50 degrees and 60 degrees.
And an elevation angle of 65 degrees.

FIG. 4 shows 40 degrees and 50 degrees in Southeast Asia.
Degrees of elevation of 60 degrees and 65 degrees are shown.

FIG. 5 shows 40 degrees and 5 degrees in the North American continent.
The elevation angle of 0 degrees and 60 degrees is shown.

The curves of FIGS. 2-5 were obtained by overlaying the curves covering the 50 degree elevation angle at the apogee and satellite takeover points. The 40 degree curve covers major populated areas on the east coast of Taiwan, Hong Kong and the United States.

Each of the satellites 1 to 6 covers three service areas at the same local time, but this time shifts slowly throughout the year due to star drift. A yearly gap is approximately 4 minutes. This has implications for interchanging satellite replacement plans and system performance and longevity.

It is also possible to use exactly five satellites which are synchronized. In this case, there are 8 hours when the service is not provided. The sequence of satellites having four intervals of four hours is determined by the relationship of offset of four hours on the orbit (the relationship between adjacent orbits having a deviation of four hours). In this case, the service can be continuously provided in three areas from 8:00 am local time to midnight. The eight hour interval between the fifth satellite and the first satellite is selected to match the midnight time when service interruptions are allowed. Since the local time when crossing the apogee is offset, it is necessary to re-synchronize the five satellites approximately every three months to bring the service into line with the required local time. The life of the system is reduced because the spacecraft in orbit must be fueled to perform such movements.

By utilizing a network of six satellites spaced four hours apart in orbit, there is no penalty for the lifetime of a given satellite that does not require movement to resynchronize. We can provide 24 hours a day continuous service. The system also has some margin to allow for the failure of one satellite.

The design of the satellite depends on the capabilities of the launch vehicle.
Due to the very low apogee altitude, the system of the present invention has significant advantages over conventional Mornier or tundra hyperelliptic systems. Satellite weight is approximately 150kg to 300kg
It can be estimated that it can be reduced.

Since the apogee altitude of the present invention is relatively low, the output of the satellite can be reduced and the loss is 1.5 GH.
In the transmission of z, it is 4 dB lower than the satellite in the Morniya type orbit and 5 dB lower than the satellite in the tundra type orbit along the nadir direction.
Low.

Therefore, the system of the present invention can save the equipment mounted on the satellite and the output required for the broadcasting under the satisfactory condition.

Each service area is limited by the guaranteed minimum elevation (40 degrees), satellite antenna coverage, and power available on the spacecraft.

The optimal trade-off between service area and signal attenuation limits necessitates the selection of a service area whose guaranteed minimum elevation is never less than 50 degrees. As mentioned above, an elevation angle of 50 degrees can only be achieved by geostationary satellites in low latitude areas where latitudes are below 30 degrees. A 50 degree elevation angle can avoid most obstacles that obstruct the line of sight of the satellite. This can reduce the signal attenuation when the satellite is handed over.

As described above, the contour line showing an elevation angle of 50 degrees includes all Europe in the service area (area where satellite 1 exists), the Far East in area where satellite 2 exists, and north in area where satellite 3 exists. Includes major parts of the Americas.

The size of the satellite antenna is dictated by the requirements of three service areas to balance the 50 degree elevation contours, and by the extent of the more populated areas.

It is possible to use a very simple antenna on the satellite that makes the system a reasonably priced spacecraft. In particular, the same single beam reflecting surface can be used to serve three service areas.

Also, only when the communication function is required,
That is, the satellite can be operated only in the service area.

However, more sophisticated antenna systems can be used. According to the multi-beam antenna, the line of sight of the satellite is 40
It extends to areas with degrees of elevation. This is especially beneficial for the east coast of the United States.

The optimum relationship between the contour lines of equal elevation angle and the antenna radiation diagram at the apogee is as follows: a reflecting surface of 2 m and 1.5 GHz.
Obtained with an antenna having a half power beam spread of 7 degrees in z. As the satellite travels on an arc of motion that passes through the apogee of orbit, the antenna beam is always aimed at a destination on the surface of the earth. Antenna gain is approximately 25.5 dB
i.

An important feature of the non-stationary orbital system is the zooming of trajectories in the service area.
g) the changing altitude that causes the The system according to the present invention is apogee-ranged, and combats this zooming effect at lower altitudes where satellite-to-satellite takeover takes place.

FIG. 6 shows a zooming ratio (zooming ratio).
ratio) zooming loss (zo as a function of ZR
FIG. 9 is a graph in which the unit (Ombling loss) ZL is plotted in the unit dB. The zooming ratio ZR is defined by dividing the apogee altitude by the altitude at which a satellite is taken over by the next satellite. Since the satellite has an orbit service period of 4 hours, the altitude at which the satellite is taken over by the next satellite is 2 hours before and after the apogee. In an 8-hour orbit with an apogee altitude of 27,000 km, the following altitude is 2 so that the zooming ratio becomes 1.32.
It is 0500 km. This zooming ratio of 1.32 is the maximum in FIG. The zooming effect does not cause any single level loss and the curve is zero at the starting point.
Note that it is slightly above the dB point. 26
The zooming ratio is 1.3 at the apogee altitude of 800 km.
It is 4. This is very close to the maximum. If the zooming ratio ZR does not exceed 1.5, the zooming loss does not increase, and the zooming loss ZL is about 1 dB.

FIG. 7 shows the antenna gain loss AGL on the satellite as a function of the beam half-width (denoting the depointing angle DEP in degrees). Operating point A corresponds to a gain loss of -3 dB, a DEP of 3.5 degrees, and a beam aperture angle of 7 degrees. The operating point H that gives a gain loss of -5 dB is 9
Corresponds to the beam opening angle in degrees.

8 to 10 show a constant gain curve of -3 dB at apogee in the service area. The broken line is
It shows a constant gain curve of -5 dB at the transition point of the two satellites. 8 to 10 show −3 dB at the apogee.
It is shown that the contour line of -5 dB and the contour line of -5 dB at the takeover point substantially coincide with each other. This means that in the common service area, a contour line with a constant gain of −3 dB at the apogee and −
It is possible to define a constant gain contour line of 5 dB. The average distance of the ground surface near the apogee is about 27.
000 km, and 21,000 km at the transfer point
Therefore, there is a difference of about 6000 km between the two points, and a difference of about 2 dB appears. This results in a constant gain curve of -5 dB at the transfer point and at the apogee.
A constant gain curve of 3 dB corresponds to an approximately equal coverage area and the transmitted power flux density (PFD) is approximately equal. In other words, in FIGS. 8 to 10, the gain loss due to the zooming effect of the antenna due to the average value of the inclination at the satellite takeover point is offset by the small signal loss due to the low satellite altitude at the satellite takeover point. It is shown that. This explains the trend of the curve shown in FIG.

The above discussion emphasizes the important advantage that the standards of all systems can be determined at apogee without loss of general validity.

Therefore, regardless of the position of the satellites in the case of 6 satellites, as a region where the user can receive the guaranteed minimum power flux density (PFD) of 24 hours a day at the guaranteed minimum altitude. Is sufficient to determine the service area of. These areas are shown as continuous lines in FIGS.

From the user's point of view, the receiver has a receiving antenna, an RF section, baseband demodulation, and a signal decoder. The receive antenna must be simple, must not be equipped with a satellite tracking system, and must meet satellite line-of-sight criteria. It should be small and easy to equip even a mobile receiver.

The specifications of the receiving antenna are obtained by analyzing the changes in the enveloping angle and height of the test points in the three service areas.

The results are shown in FIGS. 11 to 20.
These drawings are polar drawings of the ground satellite trajectory at the antenna plane. The antenna plane is assumed to coincide with the horizontal plane of the area. The center of the polar drawing represents an elevation angle of 90 degrees. Concentric circles represent points with the same elevation.

Each figure shows the available area of the satellite's trajectory on the ground, ie the area between two takeover points. In Madrid (Fig. 11), the elevation angle is almost 55 degrees and 7
It is between 5 degrees and the elevation angle is almost 50 in Oslo (Fig. 12).
Between 80 and 80 degrees, in Athens (figure 13) the elevation angle is between slightly above 55 and 70 degrees and in Amsterdam (figure 14) the elevation angle is between approximately 65 and 78 degrees. Yes, in Tokyo (Fig. 15) the altitude is between 55 and 68 degrees, and in Seoul (Fig. 16) the elevation is 58 and 65 degrees.
In Beijing (Fig. 17) the elevation angle is between approximately 55 and 73 degrees, in Vancouver (Fig. 18) the elevation angle is between approximately 60 and 85 degrees and in San Francisco (Fig. 19). The elevation angle is between approximately 58 and 65 degrees, and in New York (FIG. 20) the elevation angle is between approximately 45 and 72 degrees.

11 to 20 show that Athens, which provides the service area in the northern hemisphere, can have an omnidirectional azimuth diagram and an opening of -3 dB at approximately 90 degrees, and can be used in each of the three service areas. You can Each of the three service areas has a low elevation angle (4
0 degree) is included.

The antenna having the above specifications is 1.5 GHz.
Can achieve a maximum gain of 5.5 dBi. Since the azimuth and the aperture width are symmetric, the antenna can also be moved by a typical mobile, small antenna of the horizontal type. The loss due to the movement of the satellite antenna on that side is
It is considered that the additional loss is about 2.5 dB.
3 dB shading effect
Estimated by the loss due to ect), this is the coverage in the area of elevation angle of more than 40 degrees (service provision).
99.9% can be achieved.

[Brief description of drawings]

FIG. 1 shows a global terrestrial trajectory of a network of six satellites in a preferred embodiment of the present invention.

Figure 2: Three regions: North America, Europe,
And the elevation lines of the satellite communication network of Figure 1 in the Far East.

FIG. 3 shows the isometric elevation lines of Europe.

FIG. 4 shows an isoelevation line of the Far East.

FIG. 5 shows isometric elevation lines of North America.

FIG. 6 shows zoom loss as a function of zoom ratio.

[Fig. 7] Decibel (dB) as a function of the service area
Shows the gain of the satellite antenna represented by.

FIG. 8 shows iso PFD curves with gains of −3 dB and −5 dB at apogee in Europe.

[Fig. 9] Gains of -3 dB and -5 d at far points in the Far East.
The iso PFD curve of B is shown.

[Figure 10] Gain of -3 dB at apogee in North America
And -5 dB iso PFD curves are shown.

FIG. 11 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in Madrid.

FIG. 12 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in Oslo.

FIG. 13 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in Athens.

FIG. 14 shows a satellite-based terrestrial trajectory during a 4-hour coverage period for a plane polarized receive antenna in Amsterdam.

FIG. 15 shows a satellite track on the ground during a 4-hour coverage period for a plane polarized receive antenna in Tokyo.

FIG. 16 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in Seoul.

FIG. 17 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in Beijing.

FIG. 18 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in Vancouver.

FIG. 19 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in San Francisco.

FIG. 20 shows a satellite-based surface trajectory during a 4-hour coverage period for a plane polarized receive antenna in New York.

[Explanation of symbols]

 1,3,5 satellites (at apogee) 2,4,6 satellites (at perigee)

Claims (15)

[Claims] 1. A step of placing a plurality of communication satellites on an elliptical orbit having the same trajectory on the ground surface, each of the orbits having a cycle of 8 hours, and the orbits every 24 hours. There are three apogees located at approximately 27,000 km altitude on three given regions of the earth, the orbit has a tilt angle approximately equal to 63.4 degrees, and the satellite has a perigee argument of 270 degrees and the Direct-broadcasting satellites, etc. that have a hyper-elliptical orbit selected to have a large elevation angle in each of the regions, and behave almost as if they were stationary with respect to the Earth while the satellite is in the usable part of those orbits. Method of forming a communication satellite network in Japan. 2. The satellites are arranged in the orbits such that the two adjacent satellites are always in a line that can be seen by a ground station in the predetermined area, and the satellites are perigees. The method of claim 1 wherein the operating condition is reached from a defined altitude near. 3. The method according to claim 2, wherein five satellites are arranged in the orbit with a time difference of approximately 4 hours in order to obtain 16 hours of continuous service per day in each of the regions. 4. The method according to claim 2, wherein six satellites are arranged in the orbit with a time difference of approximately 4 hours in order to obtain 24 hours of continuous service per day in each of the regions. 5. The method of claim 1, wherein the apogee altitude is approximately equal to 26800 km. 6. The method of claim 1, wherein the perigee altitude is approximately equal to 1000 km. 7. A method according to claim 1, wherein the zooming ratio between the two satellites is less than 1.5, preferably approximately equal to 1.32. 8. The method of claim 1, wherein the perigee argument of the orbit is approximately equal to 270 degrees. 9. The vehicle has 5 or 6 communication satellites arranged on an elliptical orbit having the same trajectory on the ground surface, each orbit having a period of 8 hours, and the orbit has 24 There are three apogee located at approximately 27,000 km altitude over three given regions of the earth at each hour, the orbit has a tilt angle approximately equal to 63.4 degrees, and the satellite has a perigee argument of 270 degrees. A direct broadcast that has a super-elliptical orbit selected to have a large elevation angle in each of the three regions and behaves almost stationary relative to the Earth while the satellite is in the usable part of those orbits. Communication satellite network such as satellites. 10. The satellite network according to claim 9, wherein five satellites are arranged on the elliptical orbit so as to obtain 16 hours of continuous service per day in each of the regions. 11. The satellite network according to claim 9, wherein six satellites are arranged on the elliptical orbit with a time difference of approximately 4 hours so as to obtain continuous service in each of the regions. 12. The satellite network of claim 9, wherein the apogee altitude is approximately equal to 26800 km. 13. The satellite network of claim 9, wherein the perigee altitude is approximately equal to 1000 km. 14. The satellite network of claim 9, wherein the perigee argument of the orbit is approximately equal to 270 degrees. 15. The satellite network according to claim 9, wherein the zoom ratio between the two satellites is less than 1.5, preferably approximately equal to 1.32.