RU2155447C1 - Satellite system for data transmission between customer satellites and ground station - Google Patents

Abstract

FIELD: satellite communication equipment. SUBSTANCE: satellite communication system consists of low-orbiting retransmitter satellites and receiving-transmitting equipment, which is mounted on low-orbiting retransmitter satellites and customer satellites and ensures continuous communication. Retransmitter satellites are arranged into at least two orbital groups, each of which has at least three retransmitter satellites, are located on same orbit and are connected by means of receiving-transmitting equipment, which ensures continuous communication. Orbit inclination angle I for each orbital group with respect to ecliptic plane is within range from (Δ_min+β_max) to 180^°-(Δ_min+β_max), where Δ_min - is minimal tolerant value of angle Δ between mutual visibility line of connected satellites and pointing direction to Sun from satellite, β_max - is maximal half cone funnel of total optical conjugation of board receiving-transmitting equipment of retransmitter satellites and customer satellites. Angle between line of intersection of orbital plane of k-th orbital group of retransmitter satellites and ecliptic plane and line of intersection of orbital plane of j-th orbital group of retransmitter satellites is within range from (ΔΩ_j+ΔΩ_k) to (180^°-(ΔΩ_j+ΔΩ_k), where

Description

 The invention relates to the field of space technology, in particular to the field of satellite data transmission systems between satellites and a ground station using space optical communications between satellites, which can be artificial Earth satellites, spacecraft, orbital stations, etc.

 Known satellite data transmission system (SSPD) between the low-orbit subscriber-satellite (SA) and ground-based point (NP), containing two relay satellites (DRS-1 and DRS-2) in near-earth geostationary orbits (see, for example, [1] , [2]).

 In the well-known SSPD, relay satellites (SRs) and SAs have on-board transmit-receive equipment (PPS) installed on them for communication between subscriber-satellites and SRs. In addition, the NP and the SR have PAP for radio communication between them. The information data stream is transferred from the NP to the SR in the radio frequency range of 30 GHz, and in the opposite direction (from the SR to the NP) - in the frequency range of 20 GHz. For data transmission between SA and SR, the S-band (2-4 GHz) and Ka-band (26-40 GHz) frequencies are used.

The use of the known DSSD radio frequency band for inter-satellite communication has the following disadvantages:
limited bandwidth (data transfer rate is of the order of hundreds of Mbaud and not more), which is associated with the limitation of the radio range of the electromagnetic spectrum to frequencies of not more than hundreds of GHz,
the impossibility of simultaneously creating broadband duplex communication channels between one of the SRs and several SAs located at distances of less than a thousand - hundreds of kilometers from each other, due to the mutual electromagnetic influence of the channels,
weak noise immunity of inter-satellite communication channels, due to the inability to create a radiation pattern with an angle of divergence of the order of units of arc seconds.

 The known SSPDs using the optical frequency range of electromagnetic waves are deprived of these shortcomings.

 There is a well-known SSDB between a low-flying subscriber satellite and a ground station under the SILEX project, developed by the European Space Agency from the mid-1980s (see, for example, [3], [4]).

 This SSPD, which is the prototype of the proposed technical solution, uses two relay satellites in geostationary orbit. On board each SR and on board the SA, an optical inter-satellite communication line is installed, through which the SRs are connected by data channels to each other and to a low-orbit SA. SR also has PAP lines of optical and radio communications with a ground station. Information data streams are transmitted between the NP and the SA via a duplex communication channel formed by the PSA of the NP-SR communication channel and the PSA of the SR-SR-SA or SR-SA optical inter-satellite communication channel.

 The disadvantage of this SSPD is that it does not provide the possibility of continuous two-way communication of a ground point with any low-orbit CA, including simultaneously with several specified CA from the list of subscribers.

 This is due to the following circumstances.

 Firstly, at any point in the orbit of the subscriber’s satellite, optical pairing of its PSA with the PSA of at least one of the SRs is not ensured due to the presence in the satellite’s orbit of the subscriber’s areas in which there is no direct mutual visibility between him and one of the SRs, how two SRs cannot globally cover the near-Earth space region where the subscriber satellites are located, and at the same time provide direct mutual visibility to each other.

 Secondly, in certain time periods the optical inter-satellite communication between the SRs is interrupted due to the risk of damage to the corresponding PSA due to exposure to its optical and photodetector devices of solar radiation falling into the optical path of the PSA at small (unit degrees) angles Δ between the mutual visibility lines of the SR and the line of sight of the Sun from aboard any of the SRs. As a result of this, it is necessary to either turn off the PSA on the SR or deploy the optical antennas of their PSA at a large angle from the direction to the Sun, and, accordingly, the SR-SR optical communication channel at these annual time intervals twice a day (for the period of the revolution of the SR around the Earth ) must be disabled.

 The aforementioned danger of damage to the optical PSA by solar radiation falling into its optical paths can also occur in the optical communication channels between SA and SR for some parts of the SA orbit at separate time intervals during the year at certain mutual angular positions of the SA and SR orbits. For example, this can happen at small, close to zero, angles between the planes of their orbits. As a result, in the marked time periods in separate parts of the orbit of the SA, communication between it and the SR is impossible. In addition, for the same reason, the inclinations of the SA orbits and, accordingly, the possibility (and feasibility) of including one or another satellite in the number of potential subscribers to the SDSP are limited.

 In the present invention, the task is to provide the possibility of continuous two-way communication of a ground station with any satellite subscriber (if necessary - constantly), including simultaneously with several preset CAs from the list of subscribers.

 The problem is solved as follows.

According to the invention, SRs are located in at least two orbital groups, in each of which no less than three SRs are located on one and in the well-known SSDD between the SA and the NP, which contains SRs in near-Earth orbits and installed on them and subscriber on-board PPS of optical inter-satellite communication orbit and are interconnected using PAP optical communication. The orbit plane of each group of relay satellites forms an inclination angle 1 with the ecliptic plane, set in the range of values from (Δ _min + β _max ) to 180 ^° - (Δ _min + β _max ),
where Δ _min is the minimum allowable PSA angle Δ between the mutual visibility of satellites connected by optical inter-satellite communication channels, and the line of sight of the Sun from the satellite,
β _max - the maximum value of the half-angle of the cone of the region of the possible full optical conjugation of the on-board PAP of the satellite-relay from the PAP of satellite subscribers,
the angle between the line of intersection of the orbit plane of the kth group of relay satellites with the ecliptic plane and the line of intersection of the orbit plane of the jth group of satellite relays with the ecliptic plane is set in the range from (ΔΩ _j + ΔΩ _k ) to 180 ^° - (ΔΩ _j + ΔΩ _k ),
where ΔΩ = arcsin (sin (Δ _min + β _max ) / sinI), I = I _j and l = l _k according to the number of the CP group.

 Moreover, the satellite of the subscriber of the subscriber is optically coupled with the satellite of at least one SR at any point in the orbit of the satellite.

The placement of SRs in at least two groups, in each of which at least three SRs is located in one orbit, allows you to implement:
- firstly, the provision of non-stop communication channels by NPs with any (any) SA, involving optical communication channels of that group of CPs out of the total number of which, on each turn of the orbit of the corresponding CPs, optical communication channels between adjacent CPs will not be disconnected for the risk of damage to the PSA by solar radiation,
- secondly, the simultaneous global overlap of near-Earth space where the subscriber satellites can be located, with the cones of the areas of possible optical conjugation of the on-board PSA of satellite repeaters from the satellite of satellite subscribers, as a result of which the satellite of any satellite subscriber at any point in its orbit can be optically coupled to a PSA of at least one CP.

Placement of each group of satellite repeaters in orbit, the plane of which forms an angle of inclination of the aforementioned value with the ecliptic plane, enables continuous optical communication of any of the satellite subscribers with one of the SRs of this group due to the guaranteed uninterrupted operation of the optical communication channels "CA- CP "due to lack of need to disconnect the corresponding PAP when moving the CP into orbits portions where the angles become smaller Δ Δ _min (at certain time intervals a possible link CA eat with one relay satellite).

The location in the space of the orbital planes of the kth and jth groups of relay satellites relative to each other so that the specified angle is established between the lines of their intersection with the ecliptic plane, which allows continuous two-way communication of the satellite with any of the SA regardless of the time of year, t .e. the position of the Sun relative to the planes of the orbits of the SR. This is achieved by the fact that, at angles δ of the declination of the Sun over the orbital plane of the kth group of SRs, at which abc (δ) <(Δ _min + β _max ), the optical communication channels between the SRs in the jth group and the optical the interfacing of the PAS of the satellite subscribers with the PAS of the satellite transponders of this j-th group will not be guaranteed to be violated due to the risk of damage to the PAS by solar radiation.

In this case, the angles “Sun-SA-SR” for none of the SA and SR of the j-th group will be less than the value Δ _min in the areas of direct mutual visibility of the satellite-subscriber and satellite-relay.

p_max ≥ 2,q_p ≥ 3;
2 - околоземная орбита СР, причем индекс внизу поз. 2 соответствует номеру p группы СР;
3 - наземный пункт;
4 - ППА оптической межспутниковой связи;
5 - спутник-абонент, причем индекс внизу поз. 5 соответствует номеру n СА, n ∈ (1,..., n_max);
6 - околоземная орбита СА, причем индекс n внизу поз. 6 соответствует номеру n СА;
7 - ППА широкополосного канала связи;
8 - линия канала дуплексной межспутниковой связи между СА, причем индексы вида p, q, n внизу поз. 8 соответствуют номеру p группы СР, номеру q СР из состава p-группы и номеру n СА;
9 - линия канала дуплексной межспутниковой связи между СР данной группы, причем индексы вида p, q, m внизу поз. 9 соответствуют номеру p группы СР, номеру q СР из состава p-группы и номеру m СР этой же группы, m ∈ {1,..., q_p}; m ≠ q; m = g+1+l при q < q_p; m = 1 при q = q_p;
10 - Земля;
11 - линия широкополосного канала дуплексной связи между НП и СР, причем пара индексов p, q внизу поз. 11 соответствуют СР с номером q из состава p-группы СР;
П - плоскость орбиты группы СР, причем индекс p внизу поз. П со ответствует номеру p группы СР;
12 - линия пересечения плоскости орбиты одной группы СР с плоскостью орбиты другой группы СР;
13 - Солнце в некотором его положении относительно Земли при ее годовом движении (далее рассматриваемым положениям Солнца присваиваются нижние индексы у поз. 13);
14 - солнечное излучение;
фиг. 2 - схематичное изображение областей ограничений по допустимому ППА минимальному значению Δ_min угла Δ между линией взаимной видимости СР и направлением на Солнце, где обозначено:
15 - направление на Солнце с борта СР, причем нижние индексы а и d для данной поз. , как и для поз. 13 и угла Δ, соответствуют неблагоприятным положениям Солнца для взаимной видимости двух СР в части воздействия солнечного излучения, а индексы b и с - благоприятным положениям;
16 - прямой круговой конус с вершиной в центре СР и углом полураствора Δ_min, ограничивающий неблагоприятные направления 15 на Солнце, причем нижние пары индексов (p, q) и (p, m) для поз. 16, как и для поз. 1, соответствуют СР p-группы, у которых номера равны q и m;
фиг. 3 - схематичное изображение областей ограничений по допустимому ППА минимальному значению Δ_min угла Δ между линией взаимной видимости СР и СА и направлением на Солнце, где обозначено:
17 - прямой круговой конус с вершиной в центре СР и углом полураствора β_max, соответствующий зоне прямой видимости СА с борта СР, т.е. ограничивающий направления линий 8, причем индексы p, q внизу поз. 17, как и у поз. 1, 16, 18, соответствуют СР p-группы, имеющему номер q, а индекс n у поз. 17 (поз. 5,8, 16)- СА, имеющему номер n;
18 - ось конуса 17;
f, h -нижние индексы для поз. 13 и 15, соответствующие неблагоприятному для оптической связи положению Солнца;
e, g - нижние индексы для поз. 13 и 15, соответствующие благоприятному для оптической связи положению Солнца;
фиг. 4 - схема размещения орбит двух групп СР (j- и k-группы) и Солнца, где обозначено:
19 - плоскость эклиптики;
О - точка, соответствующая центру Земли;
I - угол наклона плоскости орбиты СР к плоскости эклиптики, причем индексы j и k соответствуют номеру группы СР;
U, U^* - точки пересечения орбиты СР с плоскостью эклиптики, причем индексы j и k соответствуют номеру группы СР;
δ - угол склонения Солнца относительно плоскости орбиты СР, причем индексы j и k соответствуют номеру группы СР;
V, V^* - точки на орбите, для которых положение Солнца относительно плоскости орбиты характеризуется углом δ склонения, равным сумме (Δ_min+β_max), причем индексы j и k соответствуют номеру группы СР;
W, W^* - точки на эклиптике, для которых положение Солнца относительно плоскости орбиты характеризуется углом δ склонения, равным сумме (Δ_min+β_max), причем индексы i и k соответствуют номеру группы СР, а подчеркивание - точкам, симметричным точкам W,W^*;
ΔΩ - угол, соответствующий смещению Солнца по эклиптике относительно точки U_j (или U_k ^*) в положение, при котором его угол δ над плоскостью орбиты СР равен сумме (Δ_min+β_max), причем индексы j и k соответствуют номеру группы СР;
20 - линия пересечения плоскости орбиты СР с плоскостью эклиптики, причем индексы j и k соответствуют номеру группы СР;,
ΔΩ_jk - угол между линией пересечения плоскости орбиты CP j-группы с плоскостью эклиптики и линией пересечения плоскости орбиты СР k-группы с плоскостью эклиптики;
фиг. 5 - схематичное изображение одного из вариантов предпочтительного размещения спутников-ретрансляторов на орбитах, где обозначено:
П_j, П_k - плоскость орбиты CP j- и k-группы, соответственно;
21 - линия пересечения плоскости экватора Земли с плоскостью эклиптики;
22 - плоскость экватора Земли;
i - наклонение орбиты СР, причем нижние индексы j и k соответствуют номеру группы СР;
ε - угол наклона плоскости экватора Земли к плоскости эклиптики;
ξ,ξ^* - точки пересечения орбиты СР с плоскостью экватора Земли (т.е. точки восходящего и нисходящего узла орбиты), причем нижние индексы j и k соответствуют номеру группы СР;
γ,γ^* - точка весеннего и осеннего равноденствия на небесной сфере, соответственно;
фиг. 6 - трассы геосинхронных орбит спутников-ретрансляторов в проекции на прямоугольную сетку географических координат, где обозначено:
23 - трасса СР на прямоугольную географическую систему координат, причем индексы вида p внизу поз. 23 соответствуют номеру p группы СР (p может быть равно 1 или 2), a q - номеру СР в данной группе (q может быть равно 1, 2 или 3, - так же, как и для поз. 1,9, 11);
24 - зона видимости СР с НП, внутри которой СР гарантированно наблюдаем с НП при прохождении его по указанной трассе.The invention is illustrated in FIG. 1-6 for a possible version of the SPDD:
figure 1 is a schematic representation of the SSPD, where indicated:
1 - repeater satellite, with indices of the form p, q below pos. 1 correspond to the number p of the CP group and the q number of this CP in this group, the values

p _max ≥ 2, q _p ≥ 3;
2 - near-Earth orbit of the SR, with the index below pos. 2 corresponds to the number p of the CP group;
3 - ground station;
4 - PAP optical inter-satellite communications;
5 - satellite subscriber, with the index below pos. 5 corresponds to the number n CA, n ∈ (1, ..., n _max );
6 - near-Earth orbit of the SA, with the index n at the bottom of the pos. 6 corresponds to the number n CA;
7 - PAP broadband communication channel;
8 - channel line of the duplex inter-satellite communication between the SA, with indices of the form p, q, n below pos. 8 correspond to the number p of the CP group, the q number of the CP from the p-group, and the number n of the CA;
9 - channel line of the duplex inter-satellite communication between the SRs of this group, with indices of the form p, q, m below pos. 9 correspond to the number p of the group CP, the number q of the CP from the p-group and the number m of the CP of the same group, m ∈ {1, ..., q _p }; m ≠ q; m = g + 1 + l for q <q _p ; m = 1 at q = q _p ;
10 - Earth;
11 - line of the broadband duplex communication channel between the NP and SR, and the pair of indices p, q below pos. 11 correspond to CP with number q from the composition of the p-group of CP;
P is the plane of the orbit of the CP group, with the index p below pos. P corresponds to the number p of the group CP;
12 - line of intersection of the orbit plane of one CP group with the orbit plane of another CP group;
13 - the Sun in some of its positions relative to the Earth during its annual movement (hereinafter, the Sun's indices are assigned lower indices at position 13);
14 - solar radiation;
FIG. 2 is a schematic representation of the areas of restrictions on the permissible PAP minimum value Δ _{min of the} angle Δ between the mutual visibility line of the SR and the direction to the Sun, where it is indicated:
15 - direction to the Sun from the board of the SR, with the lower indices a and d for this position. as for pos. 13 and angle Δ, correspond to unfavorable positions of the Sun for mutual visibility of two superlattices in terms of exposure to solar radiation, and indices b and c correspond to favorable positions;
16 - a straight circular cone with a vertex in the center of the superlattice and a half-angle Δ _min limiting the unfavorable directions 15 to the Sun, and the lower pairs of indices (p, q) and (p, m) for pos. 16, as for pos. 1, correspond to the p-group SR, for which the numbers are q and m;
FIG. 3 - a schematic representation of the areas of restrictions on the permissible PAP minimum value Δ _{min of the} angle Δ between the line of mutual visibility of SR and SA and the direction to the Sun, where it is indicated:
17 - a straight circular cone with a vertex in the center of the CP and a half-angle β _max corresponding to the line of sight of the SA from the side of the CP, i.e. restricting the directions of lines 8, and the indices p, q below pos. 17, as in pos. 1, 16, 18, correspond to the CP of the p-group having the number q, and the index n at pos. 17 (items 5.8, 16) - CA having the number n;
18 - axis of the cone 17;
f, h - lower indices for pos. 13 and 15, corresponding to the unfavorable position of the Sun for optical communication;
e, g - subscripts for pos. 13 and 15, corresponding to the position of the Sun favorable for optical communication;
FIG. 4 - the layout of the orbits of two groups of superlattices (j- and k-groups) and the Sun, where it is indicated:
19 - the plane of the ecliptic;
O is the point corresponding to the center of the earth;
I is the angle of inclination of the plane of the orbit of the CP to the plane of the ecliptic, and the indices j and k correspond to the number of the CP group;
U, U ^* are the points of intersection of the CP orbit with the ecliptic plane, and the indices j and k correspond to the number of the CP group;
δ is the declination angle of the Sun relative to the plane of the orbit of the superlattice, and the indices j and k correspond to the number of the superlattice group;
V, V ^* are points in orbit for which the position of the Sun relative to the plane of the orbit is characterized by a declination angle δ equal to the sum (Δ _min + β _max ), and the indices j and k correspond to the number of the CP group;
W, W ^* are points on the ecliptic for which the position of the Sun relative to the orbital plane is characterized by a declination angle δ equal to the sum (Δ _min + β _max ), and the indices i and k correspond to the number of the CP group, and the underscore corresponds to points symmetric to the points W, W ^* ;
ΔΩ is the angle corresponding to the displacement of the Sun along the ecliptic relative to the point U _j (or U _k ^* ) to the position at which its angle δ above the plane of the CP orbit is equal to the sum (Δ _min + β _max ), and the indices j and k correspond to the number of the CP group ;
20 is the line of intersection of the plane of the CP orbit with the ecliptic plane, and the indices j and k correspond to the number of the CP group ;,
ΔΩ _jk is the angle between the line of intersection of the orbit plane CP of the j-group with the ecliptic plane and the line of intersection of the orbit plane of the CP of the k-group with the ecliptic plane;
FIG. 5 is a schematic representation of one embodiment of a preferred arrangement of satellite transponders in orbits, where:
P _j , P _k - orbital plane of CP j- and k-groups, respectively;
21 is the line of intersection of the plane of the equator of the Earth with the plane of the ecliptic;
22 - the plane of the equator of the Earth;
i is the inclination of the orbit of the SR, and the lower indices j and k correspond to the number of the SR group;
ε is the angle of inclination of the plane of the equator of the Earth to the plane of the ecliptic;
ξ, ξ ^* are the points of intersection of the orbit of the SR with the plane of the Earth's equator (i.e., the points of the ascending and descending nodes of the orbit), with the lower indices j and k corresponding to the number of the CP group;
γ, γ ^* - point of the spring and autumn equinox on the celestial sphere, respectively;
FIG. 6 - paths of geosynchronous orbits of relay satellites in projection onto a rectangular grid of geographical coordinates, where it is indicated:
23 - track SR on a rectangular geographic coordinate system, with indices of the form p below pos. 23 correspond to the p number of the CP group (p can be equal to 1 or 2), aq - to the CP number in this group (q can be 1, 2 or 3, - the same as for pos. 1,9, 11);
24 — visibility zone of the SR with the NP, inside which the SR is guaranteed to be observed from the NP when passing along the specified route.

 The device SSPD according to the invention consists in the following (Fig. 1).

p_max≥ 2, q_p ≥ 3.The satellite data transmission system contains relay satellites 1, placed in groups in near-earth orbits 2, mainly circumcircular with the same periods of revolution around the Earth, at which iso-route flight paths of each SR relative to ground point 3 are realized. In general, a pair of indices p, q below the corresponding position . denote the number p of the group CP and the number q of a particular CP in this group, and

p _max ≥ 2, q _p ≥ 3.

On each SR, PAP 4 optical inter-satellite communications are installed. A similar PAP 4 is installed on the CA 5. The subscriber satellites are mainly located at altitudes lower than the orbits of the 2 satellite transponders. In the general case, the indices n at the bottom of the corresponding poses. denote the number CA, n ∈ (1, ..., n _max ), and the value of n _max is determined by the completeness of PSA 4 on board the SR, as well as the values of p _max , g _p and the requirement for the schedule of communication sessions between CA and NP.

 At NP 3 and on board at least one of the SRs, PPA 7 sets of a broadband communication channel are installed, operating in the optical or radio frequency range of electromagnetic waves. PSA 4, placed on board CA 5, is optically coupled at any point in the orbit 6 of this CA with PSA 4, located on board at least one of CP 1 with the formation of lines 8 of the SA-SR type inter-satellite communication channels.

 PPA 4, placed on board the p-group SL, is optically permanently coupled to the PAP 4 of neighboring SRs of the same group with the formation of lines of 9 channels of duplex inter-satellite communications of the form “SR-SR”. The triad of indices p, q, m below pos. 9 corresponds to the number of the CP group, the number of this CP of this group and the number of the CP of another neighboring CP of the same group.

 The currently operating communication lines 8 and 9 in FIG. 1 and further are shown by double lines with arrows, and non-working ones by double dashed and dashed-dotted arrows, and the double dashed lines correspond to the possibility of episodic inclusion of the corresponding lines of communication channels in specific orbital positions of CP and SA.

 The indicated constant optical conjugation of the PAP of all neighboring SRs of this group forms an information "bus" rotating around the Earth 10. This "bus" can be implemented as a closed or open circuit of communication channels. PPA of the corresponding CAs are connected to the "bus" via lines 8, and the "bus" itself is in constant communication with NP 3 via lines 11 of the duplex communication channels of the NP-SR type.

 The planes P of the orbits 2 of the corresponding pairs of CP groups pairwise intersect with each other along lines 12. The position of the orbits 2 in space is such that at least one CP group of the pair under consideration obviously satisfies the condition of constant optical conjugation of the PSA sequentially of all CPs with each other at each turn orbits of the superlattice, moreover, for no communication line 9 of the sun 13 by the influence of its radiation 14 will not lead to the risk of damage to the SPA 4 for any of the superlatives of this group. Another SR group from the considered pair of groups will provide similar conditions after the corresponding movement of the Sun in its annual motion, i.e. when the first group will be disconnected.

The above condition for constant optical conjugation of the PAP for the SR of this group means that the angle Δ _{b /} or Δ _c (Fig. 2) between the direction of the communication channel line 9, which coincides with the mutual visibility line of the CP, and the direction of 15 _b or 15 _c on the Sun 13 (13 _b or 13 _c ) is always greater than the value Δ _{min of the} angle Δ allowed by the design of the PAP 4, moreover, for any SR of this group. That is, the direction 15 on the Sun 13 from aboard any SR of this group will be outside the cone 16 with a vertex in the center of this SR (16 _{p, g} or 16 _{p, m} , respectively), having a half-angle Δ _min and an axis of symmetry coinciding with the direction of the line of mutual visibility of the considered SR. Thus, for this group of superlatives over long periods of the year, there will always be cases of the position of the Sun similar to 13 _e and 13 _c , and there will be no cases of the position of the Sun similar to 13 _a , 13 _d , when the PSA can be damaged by radiation 14.

и достигается при I = 90^o, где

- средняя угловая скорость движения Земли вокруг Солнца.Note that the time intervals of the SR group’s flight, at which their PSA does not turn off at each turn due to the risk of damage by solar radiation, exist only when the angle 1 of the inclination of the plane of the SR orbit to the ecliptic is in the range from Δ _min to 180 ^° -Δ _min . Moreover, there are only two such intervals. The largest value of each of them is

and is achieved at I = 90 ^o , where

- the average angular velocity of the Earth around the Sun.

The condition for the optical conjugation of PPA 4, located on CA 5, at any point in the orbit 6 with PSA 4, located on board at least one of CP 1, is similar to the above condition for the position of the direction line 15 on the Sun 13 relative to line 8 of the optical communication channel ( Fig. 3), coinciding with the line of mutual visibility of CP and CA. Those. the direction 15 on the Sun 13 from the side of CP 1 will be outside cone 16 with the apex in the center of the CP and the half-angle Δ _min relative to line 8 (case of type 15 _e ), and the direction 15 on the Sun 13 from the side of CA 5 will be outside the cone 16 s the vertex in the center of the SA and the half-angle Δ _min relative to line 8 (case of the form 15 _g ). In this case, CA 5 should simultaneously be in the zone of its direct line of sight from the side of CP 1, which corresponds to the movement of the CA inside the cavity of the cone 17 with the vertex in the center of CP 1 and the half-angle β _max relative to the axis 18 of this cone, which coincides with the local vertical at the CP flight point .

The angle β _max can be determined by the formula:
β _max = arcsin (max r _CA / r _CP ),
where r _CA , r _CP are the moduli of the radius vectors of the position of CA and CP, respectively.

и достигается при I=90^o.From FIG. 3 it follows that if for CA 5 located on the axis 18 of the cone 17, л л между between the direction to the Sun from the side of the CP and the direction to the CA from the side of this CP is equal to or greater (Δ _min + β _max ), then when the CA moves inside the cavity cone 17 always takes place Δ> Δ _min .
In order to ensure this for any inclination of the orbit of 6 CA, it is necessary to set the angle of 1 inclination of the plane of the CP orbit to the ecliptic plane within the range from (Δ _min + β _max ) to 180 ^° - (Δ _min + β _max ).
The greatest value of the duration of such time intervals is

and is achieved at I = 90 ^o .

Thus, the angle 1 of inclination of the orbital plane CP of this group to the ecliptic determined by the condition of the optical coupling PAP-subscriber satellite with PAP CP of this group, and it is advisable inclination angle 1 groups orbital planes CP installed as close as possible to 90 ^o.

 Obviously, since one SR group cannot provide continuous optical conjugation with PSA 4 of any CA 5 for a year, it is necessary to use several SR groups whose angular position of the orbit planes in space is such that, ultimately, is achieved Possibility of year-round continuous communication of NPs with any SA through the appropriate SR group with PSA sets of inter-satellite optical communication channels that are stationary on each orbit.

 The above explains the layout of the orbits of 2 two groups of CP (j and k) relative to each other and the ecliptic plane 19, shown in figure 4, where the point O corresponds to the center of the Earth.

с углом полураствора, который определяется по формуле
ΔΩ = arcsin[sin(Δ_min+β_max)/sinI].
Эти сектора находятся в окрестности линии 20 пересечения плоскости орбиты 2 СР с плоскостью эклиптики. Если линии направления из точки О на Солнце находятся внутри этих секторов, то условие Δ ≥ Δ_min+β_max невыполнимо для всех точек орбиты СА при любом наклонении орбиты 6. То есть невозможно в соответствующий период года выполнить требование постоянного оптического сопряжения ППА 4, установленной на борту СА, с ППА 4, находящейся на борту хотя бы одного из СР. Если же линии 20_j и 20_k пересечения с плоскостью эклиптики 19 плоскостей двух выделенных групп СР (j-й и k-й групп) будут отстоять друг от друга на угол ΔΩ_jk, устанавливаемый в диапазоне от (ΔΩ_j+ΔΩ_k) до 180^°-(ΔΩ_j+ΔΩ_k), то эти группы будут взаимно дополнять друг друга, обеспечивая в совокупности постоянное оптическое сопряжение всех комплектов ППА в цепях каналов связи "СА-СР-...-СР".In the general case, the angles 1 of the inclination of the planes of the orbits 2 of these superlattice groups to the ecliptic plane 19 are not equal to each other (l _j ± I _k ). From spherical triangles of the form UWV, for which the arc WV is equal to the sum (Δ _min + β _max ), it is clear that there are angular sectors in the plane of the ecliptic

with a half-solution angle, which is determined by the formula
ΔΩ = arcsin [sin (Δ _min + β _max ) / sinI].
These sectors are located in the vicinity of the line 20 of the intersection of the plane of the orbit 2 of the superlattice with the ecliptic plane. If the direction lines from the point O to the Sun are inside these sectors, then the condition Δ ≥ Δ _min + β _{max is} not feasible for all points of the SA orbit for any inclination of the orbit 6. That is, it is impossible to fulfill the requirement of constant optical conjugation of PSA 4 established by the appropriate period of the year aboard the SA, with PSA 4 on board at least one of the SRs. If the lines 20 _j and 20 _{k of} intersection with the ecliptic plane of 19 planes of two selected CP groups (jth and kth groups) are separated from each other by an angle ΔΩ _jk , set in the range from (ΔΩ _j + ΔΩ _k ) to 180 ^° - (ΔΩ _j + ΔΩ _k ), then these groups will mutually supplement each other, providing in aggregate constant optical conjugation of all PSA sets in the communication channel chains "CA-SR -...- SR".

 A global survey of the Earth and near-Earth outer space, where spacecraft can be located in orbits 6 of arbitrary inclination with a height of no more than 3-5 thousand km, can be carried out using three equally spaced SRs located in a circular orbit with a period of 24 hours (the so-called GShO - geosynchronous orbit). Consequently, the minimum required amount of CP in the group is three, and the minimum necessary and sufficient number of CP groups when using GCO is two.

If I ≈ 90 and (Δ _min + β _max ) ≤ 45 ^° , then this is equivalent to achieving at least six months of the operating time of this group of SRs under conditions of stationary conjugation of the PSA of all SRs of this group with each other on each orbit of the orbit. And if the angle ΔΩ _jk ≈ 90 ^° , then the possibility of year-round conjugation of the PSA of any CA with the PSA of one of the SRs, which is part of the corresponding orbital group operating in the stationary inter-satellite optical communication mode on each orbit of the orbit and creating the corresponding global information bus, is ensured.

In this regard, one of the preferred embodiments of the invention is the position of the planes P _j and P _k orbits 2 _j and 2 _k at which the angles I _j and I _k are ≈ 90 ± 20 ^o (Fig. 5).

Moreover, if we arrange the lines 20 _j and 20 _{k of the} intersection of the orbits 2 _j and 2 _k with the ecliptic plane 19 so that they are symmetric with respect to the line 21 of the intersection of the ecliptic plane 19 with the plane 22 of the Earth's equator, then the inclination i of the corresponding orbits 2 will be equal to each other friend, and their value can be determined by the formula
i = arccos [cosε • cosI-sinε • sinI • cos (ΔΩ _jk / 2)],
where ε ≈ 23 ^° 30 ′ is the angle of inclination of the plane of the equator of the Earth to the plane of the ecliptic.

In this embodiment, the inclination i can be in the range of values from 51.6 to 90 ^o at ΔΩ _jk from 70 to 110 ^o . The choice of the specific value of this inclination is determined by the capabilities of launching the SR into the working orbit, permissible secular evolutions of the working orbits, the placement of the NP, the value of the angle Δ _min , etc. Note that for circular GSOs with an inclination of 51.6-70 ^{o the} secular departure of their planes along the ascending angle is not more than 3-1.7 ^o per year, which may require the correction of SR orbits no more than once every 1-2 years, providing a given passage of the path relative to the NP.

 Having established the corresponding initial angular positions of the SR in the GCO planes of both groups, we can obtain a situation (Fig. 6) in which the orbits of the SR in projection onto a rectangular geographical coordinate system will have traces 23 in the form of three "eights" grouped in pairs from two different orbital groups . At the same time, in zone 24 of visibility of NP 3 at any time of the day there will be at least one SR of any group, i.e. The NP can be connected by line 11 of the communication channel to one of the SRs, and through the existing lines of 9 communication channels between the control stations of the working group of the SR, transfer data to any low-orbit CA and, accordingly, receive necessary data from the CA

 The proposed SSPD works as follows (Fig. 1, 4, 6).

Optical communication PPA sets 4, located onboard satellite repeaters 1 of one of the orbital groups, for example, the k-th group, for which at some point in time the declination angle δ _{k of the} Sun 13 above the plane of their orbit becomes greater than the sum of the angles (Δ _min + β _max ) and continues to grow, they are interconnected sequentially by lines of 9 optical communication channels with each other (shown by double solid line segments), forming a "bus" of data transmission (circulation) operating in stationary mode. This "bus", consisting of lines 9 of a quasistationary length, is maintained (maintained) by means of PSA 4 sets operating in stationary mode for the entire time interval corresponding to the condition abs (δ _k ) ≥ (Δ _min + β _max ) and lasting several months .

The receiving and transmitting equipment 7 at the NP 3 is connected by a line of type 11 of the communication channel to the PSA 7 of that CP of the k-th working orbital group, which is currently in zone 24 of its visibility from this NP. As a result, NP 3 receives communication channels with the necessary CA 5, which, in accordance with the existing schedule of the communication session, are connected with one or another CP 1 of this group. These channels are formed by lines of the type "11-8-9" of the corresponding communication channels using PAP 4 installed on CP 1 and specified by CA 5. Including some of these channels can operate continuously on each orbit of the corresponding CP for long periods of time annually. Moreover, with
NP 3 transmits the necessary data streams for controlling subscriber-satellites 5, and from CA 5 to NP 3 - telemetry and target information, for example, weather observation results.

With the annual movement of the Sun 13, the angle of its declination above the plane of this group of superlattices increases from 0 to a maximum value (≈ 90 ^o ), and then decreases to 0 and then to a minimum value (≈ -90 ^o ), after which it increases again. That is, twice a year for this SR group, there are such time intervals when abs (δ _k ) ≥ (Δ _min + β _max ). Therefore, when abs (δ _k ) decreases from ≈ 90 ^° and becomes equal to the maximum possible for optical communication with any SA, this orbital group of the SR is put into standby mode, and another group begins to work (for example, with number j). In the process of transferring this k-group SR to standby mode, both groups can simultaneously work, providing switching of communication channels of NP 3 with the corresponding CA 5 without losing communication with them, and also providing the possibility of communication of NP 3 with the necessary CA 5.

If necessary, in some situations NP 3 can communicate with CA 5 through the SR of another group, in which abs (δ _j ) <(Δ _min + β _max ), along lines 9 of the temporary connection (shown by double dashed straight line segments). However, this mode of operation is not always desirable, because PAS 4 on board the SR of this group must be switched on at each orbit of the orbit flight at each orbit, enter into communication with each other, and then turn off to avoid the risk of damage to the PAS from sunlight, and these operations are performed twice for each pair of mated PAP 4 on the coil.

 We note that the placement of SR orbital groups on the GCW with an orbital inclination substantially different from zero provides the possibility of wider use of the near-Earth space compared with the geostationary orbit, for which the satellite’s “standing points” are regulated by international agreements.

 At the same time, SR groups can be placed in other orbits, for example, with a period of 12 hours (circular or elliptical). However, in these cases, to ensure the possibility of global and continuous communication between NPs and any CAs, the number of CPs will increase.

Thus, as a result of:
the placement of SRs by at least two orbital groups, in each of which at least three SRs are located in the same orbit and are periodically permanently connected to each other by means of optical communication devices, and the orbital plane of each group of relay satellites forms the inclination angle indicated above with the ecliptic plane,
the location of the orbital planes of the kth and jth groups of relay satellites relative to each other so that between the lines of their intersection with the ecliptic plane a predetermined angle ΔΩ _jk is set in the range of its values defined above,
optical pairing of the satellite of the subscriber’s satellite with the satellite of at least one SR at any point in the orbit of the SA,
a solution to the problem is provided - continuous bilateral communication between the NP and any SA becomes possible through the channels provided by the optical communication board installed onboard the SR that are part of a particular orbital group.

SOURCES
1. Dinwiddy SE, Dickinson A. The European Data Relay System. Collection of articles "The 14th Int. Commun. Satell. Syst. Conf. And Exib.", March 22-24, 1992: Collect Techn. Pap.Rt, 1. Washington (DC) -1992, pp. 596-610.

 2. Abstract 6B117. Review journal VINITI, 29, "Communication", consolidated volume, 6.1994.

 3. Chukovsky N.N. Optical communication in space. The journal "Radio", Russia, 2, 1994, p. 2,3,42.

 4. Laser space communication. Sat under the editorship of M. Katzman. M .: Radio and communications, 1993, p. 188.

Claims (1)

A satellite data transmission system between subscriber-satellites and a ground station, containing relay satellites (SR) in near-earth orbits and installed on-board satellite and subscriber-receivers on-board optical inter-satellite communication between satellite-relay transponders and satellite-relay transmitters subscribers, characterized in that the relay satellites are located in at least two orbital groups, in each of which at least three relay satellites are located in one orbit e and periodically fixedly interconnected receiving and transmitting optical communications equipment, and the plane of the orbit of each group of relay satellites forms with the plane of the ecliptic angle I tilt adjustable in the range of (Δ _min + β _max) up to 180 ^° - (Δ _min + β _max ), where Δ _min is the minimum admissible value of the angle Δ between the mutual visibility of two satellites connected by optical inter-satellite communication and the line of sight of the Sun from any of this pair of satellites, β _max is the maximum value the half-angle of the cone of the region of possible optical conjugation of the onboard transmitting and receiving equipment of the relay satellite with the receiving and transmitting equipment of satellite subscribers, the angle between the line of intersection of the orbit plane of the kth group of relay satellites with the ecliptic plane and the line of intersection of the orbit plane of the jth group of satellites -relayers with an ecliptic plane is set in the range from (ΔΩ _j + ΔΩ _k ) to (180 ^° - (ΔΩ _j + ΔΩ _k ), where ΔΩ = arcsin (sin (Δ _min + β _max ) / sinI), I = Ij and I = Iк, respectively, to the number of the CP group, while the satellite’s transmitting equipment is optically coupled to the transmitting and receiving equipment of at least one repeater satellite at any point in the satellite’s orbit.

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