RU2366086C1 - Method of developing space relay system incorporating geosynchronous relay-satellites - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering, namely to relay-satellites (RS) used on high elliptic orbits (HEO). Proposed method uses geosynchronous satellites with longitudes ascending nodes spaced apart through 120° and RS connected via at least, one feeder line with central station. Data line is switched over from Earth Users from RS leaving the their service zone to RS entering aforesaid zone. Proposed method differs from known versions in that every RS is furnished with multi-beam antenna with maximum angle of its beams deviation from the axis passing through RS location and Earth center restricted by angle α=arcsin [R_sv/(R₃+H_op)], where R_sv is the radius of sphere of possible locations of space Users, R₃ is the Earth radius, H_op is the RS orbit perigee. Central group of beams is isolated from those formed by RS covering the Users service zone, as well as peripheral group covering the remaining zone restricted by angle α. Via previously mentioned zones, data exchange with space Users is performed. Note that RS staying outside service zone effects data exchange with space objects through central and peripheral groups of multi-beam antenna beams. Inter-satellite radio lines are used to communicate RS with two other RSs staying outside above specified service zone.

EFFECT: maximum period of RS operation.

4 dwg

Description

The invention relates to the field of radio communications using satellite transponders (SR) in high elliptical orbits (HEO) of the Tundra type and is intended for primary use in space relay and communication systems whose subscribers are earth stations and low-orbit spacecraft operating in the general range waves.

There is a method of building a satellite digital broadcasting system for Sirius motorists using three geosynchronous satellites / U. Zhuravin. Sirius 1 in orbit // "Cosmonautics News", 2000, No. 8, p. 35-36 /.

There is also a method of constructing a satellite communication system with terrestrial mobile objects Sycomores ("Aeronautical Journal", 1989, 93, No. 930, 387-393, US patent No. 4943808, HB04/19, HBB 7/185, 1990), which selected as a prototype.

Sirius and Sycomores systems are built using geosynchronous relay satellites that travel in a high elliptical orbit and have uplink nodes separated by 120 °. Communication with terrestrial subscribers is carried out during the period of at least one SR above their service area, while the CP is connected via a feeder radio link to at least one central station located in the terrestrial subscriber service area during the period the SR is located above the specified zone. Before the CP leaves the service area, the information flow from terrestrial subscribers is switched to the CP included in the service area.

The disadvantage of both systems is that the relay equipment of satellite transponders of both systems, oriented to servicing terrestrial subscribers located in certain areas of the Northern Hemisphere, is turned off before the SR leaves the indicated zones by commands of the central control stations, after which the SR performs its flight in idle mode until the next appearance above the subscriber service area. The service area, for example, of mobile subscribers, is selected in such a way that at any of its points the SR is visible at a sufficiently high elevation angle (usually not less than 40 °). The time spent by SR over such a zone is about 8 hours, i.e. SR is in working condition not more than 33% of its time in orbit.

It should also be noted that modern existing mobile communication systems are based on expensive geostationary SRs equipped with large multi-beam antennas with an equivalent aperture diameter of about 12 m (for example, systems based on the Turaiya, Garuda and Inmarsat-4 satellites). To service a certain region, one such SR is required, which, due to its constant location over this region, has a round-the-clock load. When creating a regional mobile communication system based on SRs on VEO (such as the Sycomores system mentioned above), three such SRs are required to provide round-the-clock service for a given region, of which only one is active. Ultimately, despite the fact that regional mobile communication systems on VEO are attractive for high-latitude territories due to the possibility of communication at higher elevation angles than in the case of using geostationary systems, the economic efficiency of VEO systems is inferior to systems in geostationary orbit.

The aim of the invention is to provide conditions for close to the maximum time of the use of SR in orbit.

This goal is achieved in that each SR is equipped with a multi-beam antenna (MLA), the maximum angle of deviation of the axis of the rays of which from the axis passing through the point of location of the satellite-relay and the center of the Earth is limited by the angle α = arc sin [R _KA / (R _З + Н _PSR )], where R _KA is the radius of the sphere of possible positions of space subscribers, R _З is the radius of the Earth, N _PSR is the height of the perigee of the SR orbit, the central group of rays is distinguished from the number of rays formed by the MLA of the relay satellite located above the service area of the Earth subscribers covering the service area terrestrial subscribers during the period when the repeater satellite is above the specified zone through which information is exchanged with terrestrial subscribers, and a peripheral group of rays covering the rest of the space limited by angle α, through which information is exchanged with space subscribers, and on satellites -translators outside the specified service area carry out information exchange with space subscribers through the central and peripheral group of MDA rays, in t chenie period of operation of the system by means of radio links support intersatellite communication satellite repeater located above the zone service subscriber earth, with the other two satellite repeaters located outside of said coverage area.

The essence of the invention is illustrated in figures 1-4, where

- figure 1 presents a General view of a system that implements the proposed method;

- figure 2 shows the distribution of the rays of the MDA in the Central and peripheral groups;

- figure 3 shows the geometric construction, explaining the proposed method, as well as the relationship between the SR;

- figure 4 shows a functional diagram of an airborne relay complex of satellite transponders.

In accordance with figure 1, the space relay system includes satellite transponders 1, 2 and 3, circulating through the HEO 4 and equipped with multi-beam antennas 5 (receiving) and 6 (transmitting). CP 1 is located above the service area of terrestrial subscribers 7, for communication with which the MLA 5 and 6 form the central group of rays, and the zone of rays 8 fill the entire specified zone 7. The formation area of the central group of rays is limited by a conical surface 9, the maximum angular size of which is determined by the dimensions zone 7, visible from CP 1 at the time of CP 1 above the center of this zone. In addition to the terrestrial subscribers 10 located in zone 7 (for convenience, shown separately in FIG. 1), CP 1 carries out information exchange with the space subscribers 11 in its field of vision, circulating in low Earth orbits 12. For this purpose, the MLA 5 and 6 form a peripheral group of rays covering the part of the sphere of possible positions of space users 11 in their orbits 12 visible from the SR. (For simplicity, Fig. 1 shows only one beam 13 from the specified peripheral group). In the service area of earth subscribers 7 there is also a central station 14, which carries out information exchange with CP 1 (and through it with CP 2 and 3) and the management of these CPs.

Repeater satellites 2 and 3 are located outside the service area of terrestrial subscribers, and all the rays formed by their antennas can be used to service space subscribers. (For simplicity, figure 1 shows only one beam 13 for CP 2 and 3, aimed at space subscribers 11).

To explain the principle of separation of beams, Fig. 2 shows the projections of the MDA rays as applied to SR 1 from Fig. 1, covering part of the sphere of possible positions of space users 15 visible from the SR (black circle). Of these MDA rays, rays with projections 16 (gray circles) cover the service area of earth subscribers 7 shown in FIG. 1 and form a central group of rays. Rays with projections 17 form a peripheral group and are designed to serve space subscribers.

The separation of MDA rays into central and peripheral groups is due to the difference in the nature of the service of terrestrial and space subscribers. So, as applied to space subscribers, information exchange is carried out only between them, on the one hand, and information management and reception centers, on the other hand, for earth subscribers, information exchange is carried out not only between them and central (or base) stations, but also directly between subscribers. Accordingly, the transmission of information in the interests of space subscribers can be carried out using simple transponders, and in the interests of terrestrial subscribers using complex transponders with circuit switching on board the SR.

In addition, even at close transmission speeds for terrestrial and space subscribers, the number of served terrestrial subscribers significantly exceeds the number of space subscribers, which leads to the use of repeaters not only with different construction principles, but also with different throughputs.

To determine the size of the region of formation of the rays of the MLA SR, we turn to the geometric constructions in figure 3, made in the plane of the HEO 4.

Figure 3, explaining, in addition, the principle of operation of the space relay system, the following conventions are given. Points A and P are, respectively, the apogee and perigee of orbit 4, points C and D, respectively, the points of CP ascension and entry above the service area of earth subscribers 7, point B, the point of contact of the line of sight “CP - space subscriber” of the sphere of possible positions of space subscribers 18, О is the center of the Earth and one of the focuses of the VEO 4, 14 is the central control station of the SR, NP is the direction of flight of the SR, R _З is the radius of the Earth,

R _KA is the radius of the sphere of possible positions of space subscribers, N _PSR is the height of the perigee of the SR, α is the maximum angle of deviation of the axis of the beam of the MLA SR from the direction "SR - center of the Earth" when servicing space subscribers.

From figure 3 it follows that the maximum viewing angle of the sphere of possible positions of space subscribers 2α will take place when the SR is in the perigee of its orbit, i.e. at point P. From the right-angled triangle of the DOM, according to known geometric relations, we obtain the maximum value of the angle of deviation of the axis of the rays of the MLA CP from the axis passing through the point of location of the CP and the center of the Earth, equal to

With regard to the daily TEC of the Tundra type with a perigee height of about 24,600 km (apogee height of 46,700 km), with R _KA not exceeding 8370 km and R _З equal to 6370 km, calculation by formula (1) gives a value of α equal to 15 , 7 °.

To explain the operation of the space relay system in accordance with the claimed method, we turn to the aforementioned figure 3 and figure 4, which is a functional diagram of the airborne relay complex (DBK) 19 of the relay satellite 1 (designated as CP1 in figures 3 and 4) in interaction with terrestrial 10 and space 11 subscribers, the central station 14 and neighboring CP 2 and 3 (in FIGS. 3 and 4 - CP 2 and CP 3).

For the initial state of the system, we will take the arrangement of satellite transponders on VEO 4 shown in Fig. 3 with a separation of 120 ° between them, which corresponds to the time of successive passage of points C, D and P by each SR after 8 hours. At point C CP1 appears above the service area of terrestrial subscribers 7.

When CP1 follows in orbit 4 from point C to point D, its DBK 19 works as follows. To form the beams that communicate with terrestrial subscribers (earth stations - ЗС) 10 and space subscribers (KA) 11, both mirrored antennas with an irradiating antenna array and active phased antenna arrays can be used as MLA 5 and 6. Diagram-forming circuits (DOS) 20 and 21 (Fig. 4), respectively, of the receiving MLA 5 and transmitting MLA 6 form the central group of rays (CTL) and the peripheral group of rays (PGL). The signals emitted by the ZS 10 are received by the TsGL DOS beams of the receiving MLA (DOS PRM) 21 and through the first switching matrix (KM1) 22 they enter the path of the RTR ZS - TsS 23 repeater (hereinafter, in the name of each relay, the direction of transmission that it serves) appears. The signals emitted by KA 11 are received by the PGL DOS PRM 20 beams and sent to the path of the RTR KA-TsS 24 repeater. Next, the signals from the RTR 23 and 24 outputs are fed to the feeder line transmitter (FL PD) 25 for subsequent radiation through the first diplexer (D1) 26 and a transceiver antenna feeder line (AFL) 27 to the central station (CA) 14.

In the opposite direction, the signals from the DS 14 for ZS 10 and KA 11 arrive through the AFL 27 and D1 26 to the receiver of the feeder line (PFP FL) 28, where they are separated. The signals for ZS 10 enter the path of the RTR TsS - ZS 29 repeater and through the second switching matrix (KM2) 30 and the TsGL DOS PRD 21 rays are emitted in the direction to the ZS 10. The signals for KA 11 after passing through the RTR TsS - KA 31 through the PGL rays emitted in the direction of spacecraft 11.

Between the repeaters 23 and 29 there is a connection, due to which a direct connection between the AP 10 is provided.

Signals from SR 2 and SR 3 satellite transponders located outside the range of visibility from the DS are received via inter-satellite links (MSL), respectively, MSL antennas (AMSL1, AMSL2) 32 and 33, second and third diplexers (D2, DZ) 34 and 35, receivers ( PFP MSL1, PFP MSL2) 36 and 37, are combined in the adder 38 and then along the path of the feeder line (devices 25, 26 and 27) are transmitted to the CA. In the opposite direction, the signals received from the TS 14 PFP FL 28 are transmitted to the transmitters (PFM MSL1, PFM MSL2) 39 and 40, then, through diplexers 34 and 35 and antennas 32 and 33 are emitted in the direction of CP2 and CP3.

As part of the CPK CP 19, there is a repeater control unit (BUR) 41. At the time when CP1 approaches point D (Fig. 3) and prepares to go beyond the service area of earth subscribers 7, the mode changes according to the received BUR 41 commands from the CA 14 operation of the switching matrices 22 and 30, due to which the outputs of the receiving and inputs of the transmitting rays of the CTL are connected to the paths of the RTR KA - TsS 24 and TsS - KA 31 repeaters. Thus, CP1 at the DPC orbit section switches to communication exclusively with space subscribers. Also, according to the adopted BUR 41 command, the MSL is disconnected from CP2, because communication with both neighboring CPs will now be supported by CP3 arriving at point C (before its transition to point D). Before CP1 passes the point of perigee P by a command from CA 14 transmitted via CP3 (currently on the way to point D), CPL is turned on for CP1 to work with CP2 suitable for point C, and MSL is turned off for working with CP3. When CP1 reappears at point C, the mode of operation of matrices 22 and 30 is changed again, after which the CGL rays of the MLA switch to communication with the ZS 10, and the PGL rays continue to serve the spacecraft 11. At the same time, communication with the CP3 is restored.

Using the proposed method provides the loading of highly elliptical satellite transponders on sections of the track that is not visible, for example, from the territory of Russia, which allows to increase the period of their active operation, and therefore the throughput of the space relay system as a whole and its economic efficiency.

From the sources of patent and information materials known to the authors, the totality of the features of the claimed objects is not known, therefore, the applicant is inclined to consider the technical solution to be consistent with the features of novelty.

This solution is technically feasible, because it is based on well-known and well-established devices, and is supposed to be used in the space relay system, designed for information exchange with terrestrial and space subscribers.

Claims (1)

A method of constructing a space relay system using geosynchronous relay satellites in high elliptical orbit and having 120 ° longitude nodes ascending for communication with terrestrial and space subscribers, in which communication with terrestrial subscribers is carried out while at least one a repeater satellite above the earth subscriber service area, wherein said geosynchronous repeater satellite is connected via a feeder radio link at least with at least one central station located in the service area of terrestrial subscribers, during the period when the repeater satellite is above the specified zone, the information flow from terrestrial subscribers from the repeater satellite leaving the terrestrial subscriber service area is switched to the repeater satellite included in the specified zone, characterized in that each repeater satellite is equipped with a multi-beam antenna, the maximum angle of deviation of the axis of the rays of which from the axis passing through the point of location of the satellite-relay and the center of the Earth is limited by the angle α = arcsin [R _KA / (R ₃ + Н _СПС )], where R _KA is the radius of the sphere of possible positions of space subscribers; R ₃ is the radius of the Earth; N _PSR is the perigee height of the orbit of the satellite-relay, distinguish from the number of rays generated by the multi-beam antenna of the satellite-relay located above the service area of terrestrial subscribers, the central group of beams covering the service area of terrestrial subscribers during the period of stay of the satellite-relay above the specified zone, through which carry out information exchange with terrestrial subscribers, and a peripheral group of rays covering the rest of the space, limited by angle α, through which formation exchange with space subscribers, moreover, on relay satellites located outside the specified service area, information exchange with space subscribers is carried out through the central and peripheral group of beams of the multi-beam antenna; during the period of the system’s operation, the satellite-relay located above the zone is supported by inter-satellite radio lines Earth subscriber service, with the other two relay satellites outside the specified service area.

Images