RU2169990C1 - Space system and data exchange method - Google Patents

Abstract

FIELD: earth and near space monitoring; investigations in radio astronomy and geophysics. SUBSTANCE: space system used for data exchange among ground and space sources and users of information mainly by means of low-orbit cable systems has gravitationally stabilized antenna bundles, and facilities for their phase synchronization. Antenna bundles are placed in vicinity of control point of near-earth circular orbit of system. Antennas are activated during each data-exchange session with spatial configuration ensuring maximal data flow received from source and/or transmitted to user by means of antenna data. EFFECT: enhanced informative capacity; enlarged data exchange area. 7 cl, 7 dwg

Description

 The present invention relates to the field of information exchange between terrestrial and space sources and consumers of information, including space, mainly low-orbit, communication systems, and can also be used to monitor the Earth and near-Earth space, radio astronomy and geophysical research.

 The invention can be applied in a wide wavelength range of electromagnetic radiation, however, it is mainly focused on microwave waves (~ 0.1 ... 100 GHz). In the future, it is possible to extend the basic principles of the invention to the optical and subsequent ranges.

 For many decades, a variety of space information systems have been known to cover the wide range of needs of ground and space users. The latter can be manned or automatic spacecraft of the widest class.

 One of the main trends in the development of space communications is the transition to the ranges of ever shorter waves. Many satellite communication systems now operate almost at frequencies of ~ GHz (in the submeter ... centimeter wavelength ranges). For the ranges of this frequency domain, special ciphers are used: I, L, R, S, ... Q, ... G (see [1]: II Krokhin. Information and control space radio links. M., 1993. S. 59). Millimeter waves (≥ 100 GHz, i.e., F, G bands) and the optical range (for laser communication systems) are promising.

 This is primarily due to the desire to avoid the distorting (reflecting) action of the ionosphere, which is achieved for frequencies> 30 MHz. In addition, the noted trend corresponds to the desire to increase the bandwidth of the channels (expand the frequency band P), their noise immunity, create the best conditions for the exchange of effective FM, MFM and FMN signals, data compression, etc. etc. (see, for example, [1], pp. 16-20, 59-61, 67-74).

 Despite successes in the development of more and more advanced space communications tools and methods, the problem of servicing rapidly growing data streams (although often unjustified for philosophical reasons) does not lose its severity. In this regard, it is necessary to pay closer attention to the spatial factor of communication, i.e. the ability to directly “condense” a multitude of information flows simultaneously flowing in space. An example of this is multipath antenna systems. Here, however, the problem of interference (mutual interference) of the beam channels arises, the most natural solution of which is to increase the bases of the receiving and emitting antennas. The latter is associated with significant technical and economic difficulties (for example, with the construction and operation of expensive large space platforms of a traditional scheme with a "rigid" frame).

 One way to overcome these difficulties can be the use of space systems with flexible connections that form statically or dynamically stabilized plane and / or spatial configurations.

 Known methods and systems for organizing and managing information flows based on the use of orbital cable systems (TS). Their effective application was initially expected in the DW and SDW ranges, including when using ionospheric waveguides. For these ranges, TSs are, theoretically, an ideal tool, because TC antennas can be practically up to 10 ... 100 km long (in low orbits) and ~ 1000 km or more (in geosynchronous orbit). The field of application of such systems is communication with underwater and buried objects, long-wave radar, etc. Geosynchronous vehicles can significantly "relieve" the area of deployment of stationary communication satellites.

 Vehicles of this type can generate DW and LED signals when their conductive elements (cable cables and plasma terminal contactors) interact with near-Earth plasma (in orbits with altitudes <2000 km) - see, for example, [2]: A.V . Andreev, N.N. Khlebnikov. Flexible communications space systems. Results of science and technology. Rocket science and space technology. T. 12.M., 1991.S. 134-136.

 However, the application of information space vehicles is not limited to the indicated DW and SDW wave ranges. On the basis of the vehicle, large-sized information systems (with sizes up to ~ 10 ... 100 km) can be built that operate as multi-band (universal) and quickly tunable orbital receiving-emitting antennas. Here, the principles of a phased array (PAR), a synthesized aperture, a radio interferometer, etc. can be used separately or comprehensively. Such non-traditional means as “light-signal” space communication systems or even more “exotic” ones can be discussed in the future ) holographic orbital systems.

 Using the example of a light-signal system, one can visually verify the materiality of the spatial communication factor noted above. Such a system is described in the source [3]: A.V. Andreev, V.I. Kurkin. On the assessment of the capabilities of light-signal space communication systems. Thes. doc. Intl. Informatization Forum (IFI-97). November 19, 1997, pp. 21-22.

This system is a large-sized (in particular, cable) design, bearing a lot of sources of ordinary or coherent radiation (for example, laser) flickering with a fairly high frequency. These many sources are like a large television screen or a light board. "Image frames" are received by a high resolution telescope. The matrix of radiation receivers (PI) of the telescope is coupled with a computer for processing transmitted information. For real resolutions of optical telescopes (taking into account the “jitter” of the sources caused by the atmosphere), we can distinguish ~ 10,000 sources distributed along the vehicle with a length of 1 ... 10 km at a distance of about 1000 km. With a moderate sensitivity of PI (~ 100 quanta per 1 photoelectron) and a wide solid angle of radiation of ~ 0.01 sr (in a cone with a solution of about 30 ^o ), one can obtain the following estimates illustrating the energy (W) of the transmitted TS information flows (I):
I, Mbps: 10, 100, 10 ³ , 10 ⁴ .

 W, W: 4, 40, 400, 4000.

 Thus, this type of system, theoretically, can successfully compete with existing highly economical satellite communication systems serving broadcasting and other information-strained channels. It is easy to see that high characteristics are achieved almost exclusively due to the spatial factor: a large number of remotely distinguishable emitters.

 In principle, the light signals in the described system can be replaced by radio signals of a sufficiently high frequency, since a slight decrease in this case, the resolution will not reduce the possible information flows too much - but the dependence on weather conditions will be significantly reduced.

 As the closest analogue of the proposed system, an information space vehicle in the form of a gravitationally stabilized linear bunch of antenna elements (AE), in particular small dipoles or quadrupoles equipped with phase synchronization (correction) means, combined with a control and / or relative motion control system, can be indicated (translational and rotational) of these AEs, i.e., with a control system (control) of the shape and vibrations of the ligament. Such a vehicle, which is a variant of the PAR, can form a rather narrow radiation pattern (see [2], pp. 136-137).

 As the closest analogue of the proposed method, a method can be specified that includes deploying and stabilizing the AE bundle in orbit, commissioning a certain number of AEs, controlling (controlling) the relative motion of the AEs and phase synchronizing (correcting) the AEs in reception and / or radiation mode signals (see ibid.).

The disadvantages of the known system and method are the narrowly selective resolution (θ = {θ _L , θ _b }) of this TS antenna (in relation to which this TS has a "beam" type radiation pattern) and relatively small sensitivity, which is determined by its gain (G ):
θ _L ~ λ / L; θ _b ~ λ / b; G ~ Lb / λ ² ,
where L is the effective length of the ligament; b is the effective width of the AE; λ is the wavelength; θ _L , θ _b - resolution "along" and "across" TS.

 In this case, it is impossible to achieve maximum resolution in the most significant work area located near the sub-satellite point (on the earth's surface). However, it is implemented in the plane of the local horizon, which allows this vehicle to effectively scan the "side" space. It would be possible to improve the resolution in connection with the earth's surface due to the horizontal orientation of the vehicle - but the position of the vehicle would be unstable. In any case, with the help of this TS it is impossible to survey arbitrary regions of space with equal efficiency.

 The objective of the invention is to develop a system and method of information exchange that allows you to expand the spatial area in which we carry out a highly informative data exchange between ground and / or space centers through, mainly, low-orbit vehicles.

 This problem is solved in that the known space vehicle containing a gravitationally stabilized linear ligament of AEs, the means of phase synchronization of AEs, combined with a control system and / or control of the relative motion of AEs, are equipped with additional similar ligaments of AEs located in a given neighborhood of the reference point of the vehicle moving in a close to circular near-Earth orbit, and the phase synchronization means and said control and / or control system are configured to implement said phase synchronization tions, management and / or control the movement of any of the selected plurality of AE of the total.

 The sign "predetermined neighborhood" is noted by the fact that the AE ligaments are placed (put into orbit and deployed) so that when they move relative to the reference point of the vehicle, they do not go beyond this neighborhood during the entire time the vehicle operates, maintaining, preferably, a constant spatial structure of the whole vehicle. This, of course, is possible only under certain conditions of the construction of a given orbital group. In this case, preference should be given to such a construction, which does not require constant correction of the movement of ligaments using rocket engines (which is uneconomical and introduces additional interference).

This construction is concretized by the following particular features, namely the fact that the centers of mass of the mentioned AE bundles can be placed near a plane turned to the orbit plane of the vehicle reference point around the tangent to this orbit by an angle of 60 ^o , and the centers of mass of the AE bundles are given circular free motion relative to the reference point of the vehicle parallel to the specified plane with an angular velocity equal to the orbital angular velocity of this reference point.

 Based on the laws of celestial mechanics, it can be shown that in this (resonant) case, the configuration of the system will be preserved (of course, in the idealized case of Kepler’s motion). Corresponding calculations due to space saving are not given here.

 However, some points should be made.

 First, the orbit of any satellite is practically different from the circular - due to a number of known perturbations (first of all, there is some, albeit often small, ellipticity of the orbit). Therefore, the aforementioned "angular velocity" should be understood to mean some of its average value (with typically small periodic variations).

Secondly, each ligament of the TS - as a body of finite dimensions - moves in the gravitational field of the planet different from the material point; the corresponding effects are of the second order of smallness (additional accelerations ~ (L / R) ² , where L is the bundle length, R is the vehicle’s orbit radius; see [2], pp. 32–33). They should be taken into account when constructing a vehicle, and most importantly, it can be used as corrective actions on the movement of ligaments (for example, by changing the lengths L). It should also be noted that, due to the finite size, the centers of mass of the ligaments are not exactly in the indicated rotated plane (there are corresponding centers of gravity slightly spaced from the centers of mass of these ligaments).

 In this context, it can be clarified that by the said “reference point of the vehicle” we mean that point of the orbit (in the ideal case, Keplerian) around which these centers of gravity of the ligaments make a circular motion. This point is conditional - i.e. no material objects may be connected with it.

 Third, bundles with electrically conductive flexible elements and plasma contactors at the ends of these elements (or their sections) can operate in the mode of “orbital generators” or “engines” (see [2], pp. 67–73). This circumstance can also be used to correct the movement (and relative position) of the vehicle bundles, and in addition - for electrical switching of the bundles (including simultaneously operating AEs).

 In view of the foregoing, in the proposed system, the ligaments may contain conducting sections between the AEs and adjustable plasma contactors located on the ligaments and connected to their conducting sections.

 Of course, the proposed vehicle, like any sufficiently complex space object, should contain the necessary auxiliary means to ensure its functioning in orbit (motion control and navigation subsystem, energy, temperature control, telemetry, etc.). These tools can be located on separate modules or preferably be combined with one or more bundles.

 Further, the above problem is also solved in this invention by the fact that in the known method, including deploying and gravitational stabilization in the orbit of the AE bundle, commissioning a certain number of AEs, controlling and / or monitoring the relative motion of the AEs and phase synchronization of the AEs in the receiving mode and / or radiation of signals, deploy and gravitationally stabilize in orbit additional AE bundles that are placed in a given neighborhood of the reference point of the vehicle moving in a close to circular near-earth orbit, each m set of session information exchange AE spatial configuration, which provides maximum flow information received from the source and / or transmitted via a data consumer AE implementing these control and / or monitor the relative motion of the AE and phase synchronization.

In this case, in particular, the centers of mass of the said AE bundles are placed near a plane turned to the orbit plane of the vehicle reference point around the tangent to this orbit by an angle of 60 ^° , and the center of mass of the AE bundles is given circular free movement relative to the vehicle reference point parallel to the specified plane with an angular velocity equal to the orbital angular velocity of a given reference point.

 In addition, in a preferred embodiment, the AE of the selected population is switched by means of electrical circuits formed by the conductive sections of the bundles between these AEs and the electrically conductive areas of the external plasma, into which the plasma contactors placed on the bundles and connected to the indicated conductive sections are introduced.

 With this switching, in particular, the currents in the mentioned circuits are coordinated by transferring some bundles to the energy generating mode, and others to the energy consumption mode, while regulating the operating parameters of the plasma contactors. (This operation can be carried out simultaneously with the aim of phase synchronization of AE and correction of ligament movement, since these modes lead, respectively, to inhibition and acceleration of ligaments).

 In FIG. 1 shows a general view of a space information system according to the invention, built in orbit around the Earth.

 In FIG. 2, 3, 4 schematically show various options for selecting the aggregate and configuration of AEs used in information exchange sessions.

 In FIG. 5 shows one of the possible schemes of information exchange between the orbital system and the ground point of data reception / transmission.

 In FIG. 6 shows a possible structure of the ground station of FIG. 5.

 In FIG. Figure 7 shows the general scheme of AE switching in the environment of a geomagnetic field and near-Earth plasma.

Detailed Description of a Preferred Embodiment
The proposed space system (Fig. 1) contains gravitationally stabilized linear ligaments 1 along which AE 2 are placed. At the ends of the ligaments plasma contactors (PC) 3, 4 of mainly active type with adjustable operating parameters can be installed (see [2], . 67-73). AE 2 can be made in the form of receivers / emitters with different radiation patterns.

 We can restrict ourselves to the simplest case of an omnidirectional diagram of each AE. This case is advisable when the number of ligaments and AE in the system is large enough. Alternatively, with a small number of ligaments and AEs, it is desirable to perform AEs in the form of pointedly oriented antennas.

 Information and control channels between AE, PC and auxiliary subsystems within the same ligament 1 can be implemented via electric and / or fiber optic cables. The latter should be properly shielded. A single (centralized) control of all ligaments and AE can be carried out remotely, in particular - from some special module (ligament) of the system located, preferably, near the reference point of the vehicle (in the center of the rotated circle in Fig. 1). The transfer of commands and other data between the specified module and bundles 1 can be carried out on the "local network" (radio or laser communication lines). For this purpose, it is possible to use switching through plasma (see below, Fig. 7), however, the electrophysical problems associated with “incorporation into the plasma” (primarily, ensuring the stability of the characteristics of the circuit with the plasma section) have not yet been satisfactorily solved .

Ligaments 1 (Fig. 1), using known means and methods, are put into the necessary orbits and deployed to a working position in which they occupy a stable position along local verticals passing through their centers of mass (more precisely, centers of gravity). Since the distances of the ligaments (Δ) from the reference point of the vehicle are small (compared with the radius of the orbit R), we can approximately assume that all the ligaments are elongated along one local vertical passing through the reference point of the circular orbit of the vehicle (angular deviations will be ~ Δ / R, that is, almost 10 ^-4 - 10 ^-3 rad or less than 0.1 ^o ).

It is obvious that although each ligament 1 relative to the Earth has its own orbit different from the others, but these orbits are coordinated so that as a result of the removal of all ligaments 1 freely rotate around the reference point of the system in plane 5 with an angular velocity w ₀ equal to the angular velocity vehicle rotation in orbit 6 (plane 5 is inclined to the orbit plane by an angle of 60 ^o , i.e., by an angle of 30 ^o to the plane of the local horizon). Thus, the entire set of ligaments in the ideal case moves like a “solid”, making a complete revolution around the reference point during the full revolution of the vehicle in orbit. This time is 2π / w _o ≈ 5000 ... 6000 s for low orbits.

 If there is an object in space or on Earth with which a data reception / transmission session should be held, the direction to this object (using navigation tools) is determined and, depending on the requirements for this session, the configuration of active AE systems. In particular, such configurations can be: a system of the "Mills cross" type (Fig. 2), a conventional antenna array (Fig. 3), "pseudo-frame antennas" with one or more contours of the frames (Fig. 4), and many others. In FIG. 2-4 currently inactive AE sessions are conditionally not shown.

 In order to ensure the maximum flow of information received from the object and / or transmitted to the object by means of active AE data, their structure must be oriented in the direction to the object, for example, with the configuration plane of FIG. 2-4 perpendicular to this direction (or close to it). Obviously, this problem in the present invention is solved by the selection and activation (with simultaneous phase synchronization) of certain AEs in certain ligaments - without any mechanical (disturbing motion) effect on the system.

 However, it should be noted that mechanical manipulations are not generally excluded: for example, if a vehicle with a small number of elements is used. Suppose, in particular, that there are only four ligaments "at the ends of the Mills cross" in FIG. 2, and in each ligament - one AE. Such a system, in principle, is sufficient for the implementation of a radio interferometer (for example, for astro- and geophysical studies) with the same resolution as in the case of many AEs. But only then should AE be performed in the form of pointed antennas (reflectors), which should be rotated (relative to the attached platforms of the bundles or together with them) in the desired direction. In addition, in order to change the orientation of the entire interferometer, AE (platforms) should be moved along the cable cables of the bundles. All this leads to noticeable perturbations of the movement of the ligaments, which, however, can be effectively counteracted (see [2], pp. 41–52).

 In FIG. 5 schematically depicts a communication session between an active AE system formed in region 7 (where there are many ligaments 1 with AE 2; see Fig. 1) and ground item 8. The “lattice” of the AE is oriented toward this point, providing maximum spatial resolution signals received from him and transmitted to him. In turn, ground station 8 may have a multi-antenna receiving / transmitting system (Fig. 6). This system, in particular, can carry out scanning - either due to rotations as a whole (all antennas are mounted on a common rotary frame), or due to rotations of each antenna. Perhaps electronic scanning. For the present invention, however, the first scanning option is preferred, as illustrated by the following estimates.

Technically easily achievable lengths of ligaments 1 in low orbits (300 ... 500 km) are 1.. .10 km. In the vicinity of 7 (Fig. 5), these ligaments can be maximally removed from the reference point of the vehicle’s orbit also at distances of the order of 1. . 10 km (and even significantly more, but this is not always reasonable). Thus, large resolution can be achieved at the available vehicle bases (~ 1 - 10 km): for example, for the extreme radio bands F, G (λ ~ mm) - of the order of 10 ^-6 . If point 8 is removed from the orbital system 7 ~ 1000 km, then its antennas located at intervals of ~ 1 m will be radio-distinguishable with the perpendicular arrangement of their frame to the line of sight. On a relatively small frame ~ 10 mx 10 m, which is easy to rotate, 100 antennas will fit. Thus, 100 communication channels can be served simultaneously (using traditional platforms, only one). In correlation processing of signals with the same geometric resolution, the number of antennas per unit area (i.e. channels) can be further increased.

 In FIG. 7 is a diagram illustrating AE switching using an external plasma. As is known, during the movement of bundles with conducting sections of cables in a geomagnetic field, an electric field of ~ 200 V / km is induced in the latter (in low orbits close to the geomagnetic equator; see [2], p. 62). When the terminal PCs operate in the emitter (3) and collector (4) modes (with respect to electrons), the AE 2 circuit is switched on in the near-Earth plasma and the currents 9 and 10 occur in the conducting part of the ligament and plasma, respectively. The currents 10 are due to plasma disturbances propagating along geomagnetic lines of force (B).

Similarly, when a PC is switched from emitter to collector mode (3 ---> 3 ₁ ) and vice versa (4 ---> 4 ₁ ), the currents in the circuit change direction. The coordination of the currents 9 in the bundles is provided by the corresponding PC modes: for example, the current 9 in the bundle 1 '' is parallel to the current 9 between the PCs 3 ₁ and 4 ₁ , since the upper and lower PCs of these bundles work in the same modes, etc.

 If the circuit switching (PC modes) is such that the currents 9 flow in the direction of the induced electric field, then there is energy generation in the circuit (and concomitant inhibition of the orbital motion of the bundle); otherwise, the on-board voltage source, which is opposite to the induced one, must be switched on, and the bundle switches to the energy consumption mode (with the accompanying acceleration of its orbital motion). The resistance of the plasma portions of the chains depends on the characteristics of the regions of increased plasma concentration created by the PC, and is characterized by spatio-temporal instability, which requires constant regulation of the PC.

 The electrophysical processes in a magnetized plasma associated with the operation of a PC and responsible for the characteristics of AE 2 circuits have not been fully studied. In the case of the proposed vehicle with many interacting PCs at relatively close distances, additional qualitative features may appear, including favorable ones, for efficient circuit switching. In any case, the described switching of the AE circuits (Fig. 7) provides energy coupling of the elements of the vehicle and the correction of their relative motion and position (by a corresponding combination of motor and generator modes in the bundles).

 Thus, as follows from the above description, the present invention is based on the use of elements known and tested in technology (including those tested in flight conditions), and therefore is industrially applicable.

 Described and other possible embodiments of the invention correspond to its essence, defined by the following formula.

Claims (7)

 1. A space system for the implementation of information exchange, containing a gravitationally stabilized linear bunch of antenna elements (AE), made in the form of receivers / emitters with different radiation patterns, means of phase synchronization AE, combined with a control system and / or control of the relative motion of the AE, characterized the fact that it is equipped with additional similar AE bundles located in a given neighborhood of the reference point of the cable system (TS), moving along a circular near Earth orbit and phase synchronization means, and said control system and / or monitoring are respectively formed to perform phase synchronization, management and / or control the movement of any of the selected plurality of AE of the total.  2. The system according to claim 1, characterized in that the centers of mass of the said AE bundles are placed near a plane turned to the orbit plane of the vehicle reference point around the tangent to this orbit by an angle of 60 °, and the centers of mass of the AE bundles are given free circular motion relative to the reference point The vehicle is parallel to the indicated plane with an angular velocity equal to the orbital angular velocity of this reference point.  3. The system according to p. 1 or 2, characterized in that it contains conductive sections between the AE and adjustable plasma contactors located on the bundles and connected to their conductive sections.  4. A method of implementing information exchange, including the deployment and gravitational stabilization in orbit of a bundle of antenna elements (AEs) made in the form of receivers / emitters with different radiation patterns, commissioning a certain number of AEs, controlling and / or monitoring the relative motion of the AEs, and phase AE synchronization in the mode of reception and / or radiation of signals, characterized in that additional bundles of AE are deployed and gravitationally stabilized in orbit, which are placed in a given neighborhood of supports At each point of the cable system (TS) moving in a close to circular near-Earth orbit, a set of AEs with a spatial configuration is selected in each information exchange session, providing a maximum flow of information received from the source and / or transmitted to the consumer via AE data, performing the indicated control and / or control over the relative motion of these AEs and their phase synchronization.  5. The method according to claim 4, characterized in that the centers of mass of the said AE bundles are placed near a plane turned to the orbit plane of the vehicle reference point around the tangent to this orbit by an angle of 60 °, and the centers of mass of the AE bundles are given circular free movement relative to the reference point TS parallel to the specified plane about the angular velocity equal to the orbital angular velocity of this reference point.  6. The method according to claim 4 or 5, characterized in that the AE of the selected set is switched by means of electrical circuits formed by the conductive sections of the bundles between these AEs and the electrically conductive areas of the external plasma, into which plasma contactors are placed, placed on the bundles and connected to said conductive plots.  7. The method according to claim 6, characterized in that during said switching, the currents in the mentioned circuits are coordinated by transferring some bundles to the energy-generating mode, and others to the energy consumption mode, while regulating the operating parameters of the plasma contactors.

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