RU2496233C2 - Low-orbit satellite communication system - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: artificial earth satellites are grouped into two satellite constellations, one of which consists of N communication satellites, where N is an integer, and is situated on n near-earth orbits at an altitude lower than 2000 km with inclination of 0°…30°, with N/n satellites on each orbit, and the other constellation consists of M communication satellites, where M is an integer, and is situated on m near-earth orbits at an altitude lower than 2000 km with inclination of 60°…90°, with M/m satellites on each orbit, wherein the longitudes of the ascending node of the orbit within each constellation differ by 360/n and 360/m degrees, respectively.

EFFECT: providing continuous global communication between subscribers, facilitating mobile telephony and high-speed data transmission at any points on the Earth using a minimal number of lightweight satellites in the system and minimal cost of constructing the satellite communication system.

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Description

The invention relates to satellite communication systems, in particular to a low-orbit satellite communication system using light satellites operating in low Earth orbits.

It is known that various satellite communication systems use artificial Earth satellites flying in geostationary, highly elliptical and low Earth orbits [V. Kirillov, P. Mikheev. Reducing distances for a moment (review of foreign low-orbit satellite communication systems). TELE-Satellite N8 (22), August 1997].

The choice of the scheme for the orbital construction of satellite communication systems depends on the desire of their creators to provide the required technical and functional characteristics of the system in a particular area of the Earth at minimal cost.

At the same time, the possibilities in the principles of organizing communication substantially depend on the selected orbits and their characteristics, for example:

- the most used geostationary orbit currently used for communication, with many positive qualities, has significant drawbacks. In particular, due to restrictions on radio visibility, it does not provide communication for the Arctic and Antarctic regions of the Earth with latitudes of more than 65-70 ° north and south; due to the high altitude of the orbit, there is a significant delay in the radio signal (up to 0.5-0.6 sec), which significantly reduces the quality of communication in real time. In addition, significant power is required from transponders and satellite power systems;

- highly elliptical orbits, together with a significant change in the flight altitude of the satellite, have a limited radio visibility time (usually no more than 8 hours per day) and to ensure continuous communication they require the creation of a system of several satellites, while creating global communications on these orbits around the globe a balloon is technically and economically challenging;

- a low-orbit satellite communications system, together with the need for a significant number of satellites to organize communications and the need for routing radio signals between subscribers, has several advantages: the proximity of satellites to the Earth and, therefore, to subscribers; minimum signal delays, which improves the quality of voice communications, Internet and interactive television (video calls, video conferencing); the required power and weight of the on-board transceiver equipment and satellite power supply systems, as well as the subscribers' equipment, are reduced. The location of the orbits of the satellite communications system below the Earth’s radiation belts (below 1400-1500 km) protects the satellites and electronic equipment from hard ionizing solar radiation, which increases their active life (CAC), satellites are delivered to a lower, “cheaper” orbit, requiring less the cost of their launch into space.

Known for low-orbit satellite communications systems implemented in the world:

Iridium and Globalstar [N. Panagiotarakis, I. Maglogiannis, G. Kormentzasan. Overview of Major Satellite Systems. University of the Aegean Dept. of Information and Communication Systems, GR-83200, Karlovassi, GREECE (Electronically available information in the URL: http://www.iridium.com) Electronically available information in the URL: http://www.globalstar.com];

"ORBCOMM" [ORBCOMM low-orbit satellite communications system: real and promising opportunities for the European region (http://kunegin.narod.ru/ref3/niz/leo16.htm)].

“The Messenger” [A. Danelyan. Low-orbit satellite communications in Russia - problems and prospects. Published February 18, 2008 (http://daily.sec.ru/publication.cfm?pid=19844)/ Connect! Communication World, 2007].

The characteristics of these low-orbit systems are shown in table 1 [A. Krylov. "Analysis of the creation and development of low-orbit satellite communications systems." Magazine "Satellite Communications and Broadcasting-2011", p.46-49].

Of the data in Table 1 for low-orbit satellite communications systems, only Iridium provides global mobile communications around the globe. However, this system has a significant drawback - in high-latitude regions, in the circumpolar zones of the Earth, where the density of communication subscribers is low, at the same time there is an excess of communication satellites (for example, from each pole from 7 to 14 satellites are located at a time).

Globalstar system with large quantities

satellites (48 + 8 backup) provides continuous mobile communication only in the zone of the globe between 70 ° north and 70 ° south latitudes. Communication in the circumpolar zones is absent.

ORBCOMM and Gonets systems do not have a global coverage of the globe, they are used only for periodic communications and packet data transmission.

Known low-orbit communication system [RF patent No. 65703 "Low-orbit packet data and dispatch telephone communications", IPC (2006/1) H04B 7/185, using satellites of various communication systems, having orbital and terrestrial parts, as well as subscriber stations. The system is intended for organizing communication between users using the technical means of the ORBCOMM and Messenger systems. The system includes many Microstar spacecraft operating in near-Earth circular orbits and equipped with transceiver complexes in the frequency ranges for communication with ground-based satellite access nodes and subscriber stations, as well as on-board computer complex and service systems, many Gonets spacecraft operating on near-Earth circular orbits and equipped with a multi-channel receiving device in the frequency range, a two-channel transmitting device in the frequency ranges for ides with regional ground stations and subscriber terminals, as well as on-board computer system and office systems.

ORBCOMM and Gonets systems do not have a global coverage of the globe, as they are used only for periodic communications and packet data transmission.

Known low-orbit satellite network navigation system [RF patent No. 2299837 "Method for constructing a low-orbit satellite network navigation system", IPC B64G 1/10, G01C 21/02 (2006.1)]. The technical solution consists in creating a low-orbit constellation of N navigation spacecraft, which, in combination with a noise-resistant network of relay and measuring radio links connecting all the spacecraft of the constellation with a navigation radio line illuminating the upper hemisphere, provides navigation definitions for land, sea, air and space low-orbit and high-orbit consumers.

Unfortunately, the invention according to RF patent No. 2299837, like the previous technical solutions, does not provide global coverage of the globe with wireless communications, accordingly, it does not provide continuous communication between subscribers and, therefore, does not allow for high-speed data transmission anywhere in the world.

Known technical solutions using low-orbit satellite communications systems, US patent No. 7,579,987 "Low Earth Orbit Satellite Providing Navigation Signals", Int. Cl. G01S 1/00 (2006.01), owned by The Boeing Company, published applications: US No. 2008/0001818 "Low Earth Orbit Satellite Providing Navigation Signals", Int. Cl. H04B 7/212 (2006.1), publication date: January 3, 2008, US No. 2008/0001819 "Low Earth Orbit Satellite Data Uplink", Int. Cl. H04B 7/185 (2006.1), publication date: January 3, 2008 and US No. 2008/0059059 Generalized High Performance Navigation System, Int. Cl. G01C 21/00, G01C 21/20, H04B 7/185 (2006.1), publication date: March 6, 2008. These technical solutions are aimed at improving the transmission - reception of signals (information) through the use of well-known low-orbit satellite communication systems. However, unfortunately, they do not provide global coverage of the globe with wireless communications, respectively, they do not provide high-quality continuous communication between subscribers and, therefore, do not allow for the implementation of high-quality high-quality data transmission anywhere in the world.

The closest technical solution (prototype) to the claimed invention is a low-orbit satellite communications system "Iridium" ("Iridium") [A. Danelyan. Low-orbit satellite communications in Russia - problems and prospects. Publication February 18, 2008 (http: //daily.sec.m/publication.cfm? Pid = 19844) / Connect! Communication World, 2007], [[N. Panagiotarakis, I. Maglogiannis, G. Kormentzasan. Overview of Major Satellite Systems. University of the Aegean Dept. of Information and Communication Systems, GR-83200, Karlovassi, GREECE (Electronically available information in the URL: http://www.iridium.com)].

The Iridium system uses Earth satellites orbiting in low circular orbits of the same height, uses inter-satellite communications and a network of ground-based communications and satellite constellation control stations.

Of all the low-orbit satellite communications systems listed above, only the Iridium system provides global mobile communications around the globe. However, this system is designed in such a way that in high-latitude regions, in the circumpolar zones of the Earth, where the density of communication subscribers is low, there is at the same time an excessive number of satellites (for example, from each pole there are from 7 to 14 satellites at the same time), which leads to a significant increase in the cost of the system and misallocation of satellites.

The technical result, to which the claimed invention is directed, is to ensure global continuous communication between subscribers, the possibility of implementing mobile telephony and high-speed data transfer anywhere in the world using the minimum necessary (optimal) number of light satellites in the system and the minimum cost of creating a satellite system communication.

The technical result is achieved by the fact that the low-orbit satellite communications system containing many artificial Earth satellites, each of which operates in near-Earth orbit, and is equipped with airborne relays, inter-satellite communications and a network of ground communication stations and control artificial satellites of the Earth,

differs according to the invention in that:

artificial Earth satellites are formed into two groups of communication satellites,

one of which consists of N communication satellites, where N is an integer, and is located in n near-earth orbits with an altitude of less than 2000 km and an inclination of less than 30 °, N / n satellites in each orbit,

another grouping consists of M communication satellites, where M is an integer, and is located in m near-earth orbits with an altitude of less than 2000 km and an inclination of more than 60 °, M / m satellites in each orbit,

while the longitudes of the ascending nodes of the orbits within each group differ by 360 / n and 360 / m degrees, respectively.

In this case, for example, both groups contain the same number of communication satellites, where M = N, the same number of near-earth orbits, m = n, and the same number of satellites in each orbit, M / m = N / n.

The longitudes of the ascending nodes of the orbits within one group coincide with the longitudes of the ascending nodes of the orbits of another group.

Satellites in the orbits of both groups by the latitude argument are evenly distributed, and for orbits from different groups with matching ascending nodes, they have satellite latitude arguments in one group, which coincide with the satellite latitude arguments in another group.

Thus, the common features of the claimed invention and the prototype is that both systems use artificial Earth satellites orbiting in low circular orbits of the same height, use inter-satellite communications and a network of ground communication stations and control satellite constellations.

Salient features of the claimed invention is that the artificial Earth satellites are formed into two groups of communication satellites, one of which consists of N communication satellites, where N is an integer, and is located in n near-earth orbits with a height of less than 2000 km and an inclination of less than 30 °, for N / n satellites in each orbit, the other constellation consists of M communication satellites, where M is an integer, and is located in m near-earth orbits with an altitude of less than 2000 km and an inclination of more than 60 °, M / m satellites in each orbit, while longitude sunrise boiling orbits nodes within each group are distinguished respectively by 360 / n, and 360 / m degrees. It is these distinctive features that allow you to get the best technical effect, namely, to provide global continuous communication between subscribers, make it possible to implement mobile telephony and high-speed data transfer anywhere in the world using the minimum necessary (optimal) number of light satellites in the system and the minimum cost of creating satellite communications systems.

Therefore, the claimed invention has novelty, significant differences and is not obvious.

Further, the description of the invention is illustrated by examples and illustrative materials.

Figure 1 shows an example of the coverage area of the earth's surface by a group of communication satellites with an orbital inclination of about 22.5 ° according to the claimed invention.

Figure 2 is an example of the coverage area of the earth's surface by a group of communication satellites with an inclination of orbits of about 65 ° according to the claimed invention.

Figure 3 illustrates the global coverage of the earth's surface with a low-orbit satellite communications system according to the claimed invention.

Table 1 shows the characteristics of the world-famous low-orbit satellite communications systems: Iridium, Globalstar, ORBCOMM and Messenger.

Table 2 shows the characteristics of the inventive low-orbit satellite communications system and an example of rational use of the system according to the claimed invention, when more satellites are used in areas with a large population.

Carry out the claimed invention as follows.

To build the inventive low-orbit satellite communications system, many light artificial Earth satellites are used, each of which operates in low Earth orbit and is equipped with airborne transponders, inter-satellite communications, and a network of ground-based communications and satellite control stations. In this case, artificial Earth satellites can be used of any known design for a given technical field, for example, the same satellites that the Iridium system uses.

Many artificial Earth satellites are formed into two groups of communication satellites, one of which consists of N communication satellites, where N is an integer, and is located in n near-earth orbits with an altitude of less than 2000 km and an inclination of less than 30 °, with N / n satellites in each orbit .

Another grouping consists of M communication satellites, where M is an integer, and is located in m near-earth orbits with an altitude of less than 2000 km and an inclination of more than 60 °, with M / m satellites in each orbit.

In this case, the longitudes of the ascending nodes of the orbits within each group differ by 360 / n and 360 / m degrees, respectively.

Moreover, for example, both groups may contain (but this is not a prerequisite) the same number of communication satellites, where M = N, the same number of near-earth orbits, m = n, and the same number of satellites in each orbit, M / m = N / n.

The longitudes of the ascending nodes of the orbits within one group may coincide with the longitudes of the ascending nodes of the orbits of another group, but this is not a prerequisite.

Satellites in the orbits of both groups by the latitude argument can be located, for example, evenly, and for orbits from different groups with matching ascending nodes, they can have the satellite latitude arguments in one group, which coincide with the satellite latitude arguments in another group, however, these conditions can be by others.

For a better understanding of the claimed invention, consider FIGS. 1-3 and Table 2, which shows the characteristics of one of the embodiments of the invention.

Figure 1 shows an example of the coverage area of the earth's surface by a group of communication satellites with an orbital inclination of about 22.5 °.

Coverage Area Parameters:

subequatorial zone between 40 ° parallels of north and south latitude;

the number of satellites - N = 24;

the number of orbits - n = 3 (for N / n there are 8 satellites in each orbit); orbital inclination - 22.5 °; the height of the orbits is 1500 km.

Figure 2 shows an example of the coverage area of the earth's surface by a group of communication satellites with an orbital inclination of about 65 °.

Coverage Area Parameters:

polar zones with latitudes of more than 40 ° north latitude and more than 40 ° south latitude;

the number of satellites - M = 3 (for M / m = 8 satellites in each orbit):

orbital inclination - 65 °;

the height of the orbits is 1500 km.

Figure 3 shows an example of global coverage of the earth's surface with a low-orbit satellite communications system.

Coverage Area Parameters:

global coverage of the globe;

the number of satellites N + M = 48;

number of orbits: n = 3 with an inclination of 22.5 ° + m = 3 with an inclination of 65 ° (N / n = M / m = 8 satellites in each orbit);

the height of the orbits is 1500 km.

Thus, unlike the Iridium system with the same quality of coverage, the claimed low-orbit satellite communication system allows using 27% fewer communication satellites, and unlike the Globalstar system with the same number of communication satellites (48 satellites) provides continuous communication around the globe, including in the circumpolar zones with latitudes of more than 70 ° north latitude and more than 70 ° south latitude;

In addition, depending on the need for communication in various regions of the Earth, a low-orbit satellite communication system can be created in stages: a grouping of satellites with an orbital inclination of less than 30 degrees will provide continuous communication for the equatorial zone between 40 ° north latitude (N) and 40 ° South latitude (S), where more than 70% of the planet’s population lives, a constellation of satellites with an orbital inclination of more than 60 degrees will provide continuous communication for polar zones with latitudes of more than 40 ° N and more than 40 ° S, which in the future will acquire strategic importance in connection with the growing development of terrestrial resources.

Table 2 shows the characteristics of the inventive low-orbit satellite communications system and an example of rational use of the system according to the claimed invention, when more satellites are used in areas with a large population.

In this case, the elevation angle at the subscriber’s location (the angle between the beam to the satellite and the local horizon) is 5-15 degrees; the diameter of the radio visibility zone from a satellite in orbit at an altitude of 1,500 km is 5–6 thousand km.

The data shown in table No. 2, confirm the example of the rational use of communication satellites in the low-orbit system according to the claimed invention, when in the areas with a large population there are more satellites. Thus, the loading of each satellite is, on average, the same in the equatorial and polar zones: about 100 / (M + N)% of the Earth’s population falls on each satellite.

The inventive low-orbit satellite communication system has a fairly simple and original structure of the orbits of communication satellites with the same and stable parameters, which ensures the simplicity of their control and grouping.

All these advantages (significant distinguishing features of the claimed invention) allow to obtain the best technical effect, namely to provide global continuous communication between subscribers, implement mobile telephony and high-speed data transfer anywhere in the world, while using the minimum necessary (optimal) number of light communication satellites , which accordingly will lead to a decrease in the cost of creating a low-orbit satellite communications system.

Table 1 Satellite communication system Developer Orbit Characteristics Number of satellites Coverage, type of communication height, km inclination, hail number of planes Iridium Motorola, Lockheed Martin, USA 780 86.4 6 66 + 7 reserve globally mobile satellite Globalstar Globalstar, Inc, USA 1410 52 8 48 + 8 reserve between 70 ° N and 70 ° S sh., mobile satellite ORBCOMM 45 four 31 globally ORBCOMM Global L.P., 830 70 one 2 periodic USA 108 one 2 communication, packet data Messenger JSC "Satellite system" Messenger " 1400 82.5 6 36 Russia, periodic communications, packet data

table 2 Orbital groupings of the system Radio areas Earth population in the zone Earth surface fraction in the zone The number of satellites operating in the zone The number of satellites on% of the Earth’s surface Percentage of population per satellite Grouping number 1: Equatorial zone - number of satellites - 24 between - orbital inclination - 22.5 ° 40 ° N more 64% about 0.6 about 2% - number of orbits - 3 and 70% 36 - orbit altitude - 1500 km 40 ° S Grouping number 2: Polar zones - number of satellites - 24 more - inclination of orbits - 65 ° 40 ° N less about about - number of orbits - 3 and more thirty% 36% 12 0.33 2.5% - orbit altitude - 1500 km 40 ° S Only 48 satellites in 6 orbits, 8 satellites in orbit

Claims (4)

1. A low-orbit satellite communications system containing many artificial Earth satellites, each of which operates in low Earth orbit and is equipped with airborne transponders, inter-satellite communications and a network of ground-based communications and control stations for artificial Earth satellites, characterized in that the artificial Earth satellites are formed into two satellite constellations communications, one of which consists of N communication satellites, where N is an integer, and is located in n near-earth orbits up to 2000 km high with an inclination of 0 ° ... 30 °, along N / n satellites at each orbit, the other constellation consists of M communication satellites, where M is an integer, and is located in m near-earth orbits up to 2000 km high with an inclination of 60 ° ... 90 °, M / m satellites in each orbit, while the longitudes of the ascending nodes of the orbits within each group, they differ by 360 / n and 360 / m degrees, respectively. 2. The system according to claim 1, characterized in that both groups contain the same number of communication satellites, where M = N, the same number of near-earth orbits, m = n, and the same number of satellites in each orbit, M / m = N / n. 3. The system according to claim 1, characterized in that the longitudes of the ascending nodes of the orbits within one group coincide with the longitudes of the ascending nodes of the orbits of another group. 4. The system according to claim 1, characterized in that the satellites in the orbits of both groups with respect to the latitude argument are uniformly located, and for the orbits from different groups with matching ascending nodes, have the arguments for the latitude of satellites in one group, which coincide with the arguments for the latitude of satellites in another group.

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