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    • 专利摘要:
    The present invention relates to a communication satellite (100) for use in a satellite constellation (10). The satellite (100) has a user-side interface (105) for receiving and transmitting wireless data, a network-side interface (110) for receiving and transmitting wireless data, a first inter-satellite interface (115) for receiving and transmitting wireless data, transmitting wireless data with a first electromagnetic wave transmitting direction (116), a second inter-satellite interface (120) for receiving and transmitting wireless data with a second wave transmitting direction (121) electromagnetic. The first direction (116) has a first transmission angle (117) relative to a direction of travel (125) of the satellite (100). The second direction (121) has a second transmission angle (122) relative to the direction (125) of the satellite. A value of the first angle (117) corresponds to a value of the second angle (122).
    公开号:FR3058861A1
    申请号:FR1760745
    申请日:2017-11-15
    公开日:2018-05-18
    发明作者:Erich Auer
    申请人:Tesat Spacecom GmbH and Co KG；
    IPC主号:
    专利说明:

    ® FRENCH REPUBLIC
    NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,058,861 (to be used only for reproduction orders) (© National registration number: 17 60745
    COURBEVOIE © Int Cl 8 : H 04 W36 / 28 (2017.01), H 04 W 84/06, H 04 B 7/185
    A1 PATENT APPLICATION
    ©) Date of filing: 15.11.17. © Applicant (s): TESAT-SPACECOM GMBH & CO. KG © Priority: 15.11.16 DE 102016121919.3. - OF. @ Inventor (s): AUER ERICH. ©) Date of public availability of the request: 18.05.18 Bulletin 18/20. ©) List of documents cited in the report preliminary research: The latter was not established on the date of publication of the request. (© References to other national documents ® Holder (s): TESAT-SPACECOM GMBH & CO. KG. related: ©) Extension request (s): (© Agent (s): LLR.
    COMMUNICATION SATELLITE FOR A CONSTELLATION OF SATELLITES.
    FR 3 058 861 - A1
    The present invention relates to a communication satellite (100) for use in a satellite constellation (10). The satellite (100) has a user side interface (105) for receiving and transmitting wireless data, a network side interface (110) for receiving and transmitting wireless data, a first inter-satellite interface (115) for receiving and wirelessly transmitting data with a first transmitting direction (116) of electromagnetic waves, a second inter-satellite interface (120) for receiving and transmitting wireless data with a second transmitting direction (121) of electromagnetic waves. The first direction (116) has a first transmission angle (117) relative to a direction of movement (125) of the satellite (100). The second direction (121) has a second transmission angle (122) relative to the direction (125) of the satellite. A value from the first angle (117) corresponds to a value from the second angle (122).
    20B
    280 km
    The invention relates generally to the technical field of data and signal transmission. The invention relates in particular to a communication satellite intended for use in a constellation of satellites, as well as to a constellation of satellites comprising a plurality of such communication satellites.
    Communication satellites are usually used as part or part of a communication path and replace all or part of a terrestrial communication network. A communication path implies here the components inserted between two communicating devices and used to transmit data between these devices. Communication satellites can also be used to connect user devices with access points to a terrestrial communication network, so that user devices can connect to the communication network.
    Communication satellites can be used to advantage in order to connect user devices to a communication network in regions of the world that are underserved in terms of infrastructure, or even unserved. This may be the case when terrestrial access to the communication network is either completely non-existent or cannot even be provided, for example in sparsely populated areas of the Earth or over large bodies of water.
    Communication satellites have at least two interfaces. A user-side interface allows signals to be received from or sent to a user device, and a network-side interface allows signals to be sent to, or received from, the communications network. Satellites generally have the advantage of rotating in orbit around the Earth and thus being able to connect virtually every point on the surface of the Earth to a communication network. However, such a satellite also requires a remote station which is connected to the terrestrial communication network.
    It can be considered that an object of the present invention is to improve the availability of the connection of a user device to a terrestrial communication network. In a first aspect, a communication satellite is provided for use in a constellation of satellites. The communications satellite includes: a user-side interface for receiving and transmitting wireless data;
    ; a network side interface for receiving and transmitting wireless data; a first inter-satellite interface for receiving and transmitting wireless data with a first direction of emission of electromagnetic waves; a second inter-satellite interface for receiving and transmitting wireless data with a second direction of emission of electromagnetic waves. The first direction of emission has a first angle of emission with respect to a direction of movement of the communication satellite. The second direction of emission has a second angle of emission with respect to the direction of travel of the communication satellite. For this purpose, a value of the first emission angle corresponds to a value of the second emission angle.
    The communication satellite can in particular be used to provide a communication infrastructure. It is particularly suitable for establishing communication links in regions of the world where the development of infrastructures with land lines is not possible or is only very difficult or does not take place for other reasons, for example for economic considerations.
    The term satellite constellation is used here to encompass a set of communication satellites (said constellation satellites), at least all of the satellites located in an orbital plane.
    The user side interface designates the link with users or user devices. A user device can be a terminal, but also a network node which concentrates the communication links of several user terminals and which transmits to the user side interface of the communication satellite. The user side interface as well as all other communication interfaces are preferably implemented so as to transmit signals wirelessly and by means of electromagnetic waves. The electromagnetic waves can for example be optical signals or radio signals.
    The network side interface designates the link with the access nodes in the terrestrial communication network (for example the Internet). These access nodes can be called gateways and are for example fixed remote stations on the surface of the Earth. The communication satellite establishes a link between the user devices and the access nodes.
    In principle, data transmission is provided from the user side interface to the network side interface, or vice versa. Thus, the communication satellite replaces a land line that may be required, or another communication link between a user device and a data or communication network.
    The first and second inter-satellite interfaces can also be called inter-satellite links (ISL). ISLs can establish links with a previous satellite and / or a next satellite in an orbit of the satellite constellation. These ISLs are configured so that their direction of emission corresponds to a fixed angle of emission, thus allowing a connection to be established with the previous satellite or with the next satellite. The configuration in which the emission angles of the two emission directions have the same value with respect to the direction of movement (flight path or tangent to the substantially circular flight path in the current position of the communication satellite) allows the use in a constellation of satellites in which several satellites revolve around the Earth in the same circular orbit plane, and provided that the distances between the satellites in the same orbit are of the same order of magnitude or have an order of magnitude substantially identical. As the distance between each satellite and its previous or next satellite is equal, the emission angle of identical value of the two transmission directions allows each satellite to establish, at each instant and at each point of the orbit, a link via ISL with both the previous satellite and the next satellite.
    According to another example and in the case of an elliptical orbit of the communication satellite around the Earth, the emission angles of the ILS can be variable over a limited angular range only in one dimension, that is to say in the orbital plane. This means that the emission angles are not fixed in this example and may vary during the lifetime of the satellite. The emission angles can in particular vary so that the first emission angle is greater than or equal to the second emission angle. The first and second inter-satellite interfaces can respectively be suspended relative to the satellite, so that they can execute a rotational movement around an axis (axis of rotation) or around a point. Suitable training devices can be provided for this purpose. The first and second inter-satellite interfaces in this example execute a rotational movement with a degree of freedom and are otherwise stationary. The rotational movement of the inter-satellite interfaces is carried out so as to compensate for a change in the relative position of two immediately neighboring satellites in the same orbit, that is to say that at least one inter-satellite interface can follow the immediately neighboring satellite as soon as the immediately neighboring satellite changes its relative position with respect to the current satellite due to the elliptical orbit. Preferably, two inter-satellite interfaces can pivot in the same direction or the same plane, so that the inter-satellite interfaces have only one degree of freedom in rotation and that the axes of rotation of the two inter-satellite interfaces are parallel.
    The user-side interface, the network-side interface, and the first and second inter-satellite interfaces can each be individually designated as the communication interface. These communication interfaces are preferably implemented for bidirectional data transmission and can include a transmission channel and a reception channel.
    It should be noted that in the context of this description, the terms communication satellite and satellite are used in a similar manner, that is to say that a reference to a satellite also always includes in particular a communication satellite .
    ISLs can be used advantageously in a constellation of satellites because they allow any link between a satellite and its immediately preceding satellite and its immediately next satellite, as well as transparent routing. The concept of transparent routing implies reorientation according to the needs of the data flow between the satellites located in the same orbit in order to establish a link with a remote station, in a transparent way for the user devices.
    The orbit of a satellite is defined by its shape (elliptical or circular), the radius or average flight altitude above the average surface of the Earth, and the angle of inclination (angle of the orbit relative to the equator).
    In the case where a satellite changes its orientation in space and in orbit, for example by a pivoting or tilting movement around a central point of the satellite, the inter-satellite interfaces can for example execute a movement of compensation in order to maintain a constant emission angle relative to the orbit.
    According to one embodiment, the first inter-satellite interface is arranged so that the first transmission angle is fixedly defined with respect to the communication satellite, and remains unchanged during the operating life of the communication satellite.
    Assuming that a plurality of communication satellites are equidistant from each other in an orbit and that the plurality of communication satellites are moving at the same speed on the same path (i.e. orbit), the value of the first transmission angle depends directly on the number of communication satellites present in an orbit. The distances between communication satellites do not vary, or hardly vary, so that the emission angle can be predefined as soon as the communication satellite is manufactured. A variation of the emission angle during the operating time is not necessary in the case of a circular orbit, so that complex monitoring of the emission angle is also not necessary. In other words, if there is no relative movement between the communication satellites in orbit, in the case of a circular orbit, then there is no need to change the emission angle. According to another embodiment, the communication satellite is implemented so as to detect the presence of a remote station for the network side interface and in the case where such a remote station is absent, pass the first inter- satellite and / or the second inter-satellite interface in the active state in order to be able to establish an outgoing communication link with a previous satellite and / or a next satellite.
    This embodiment describes the method in the case of a remote station absent or defective, as well as the way in which the communication satellite operates in such a scenario. In other words, the communication satellite establishes an outgoing communication link with a neighboring satellite, in particular with an immediately neighboring satellite in the same orbit. For this purpose, an identification number (ID) can be assigned to each communication satellite of the satellite constellation and each communication satellite can also be configured so that the IDs of the neighboring communication satellites are known. In general, each communication satellite must know its own ID as well as two other IDs, namely that of the previous satellite and that of the next satellite. ISLs can be activated as needed and are not required when a network side interface satellite has a remote station on the surface of the Earth.
    According to another embodiment, the communication satellite is implemented in the case of a remote station absent for the network side interface, so as to send the data intended for a transmission channel of the network side interface via the first inter-satellite interface or the second inter-satellite interface in the active state.
    If the remote station is absent, the data is sent via the active ISL to an immediately neighboring communication satellite. The active ISL takes over the network side interface.
    This makes it possible to provide, using communication satellites, a connection to a terrestrial communication network also in regions of the globe lacking terrestrial communication infrastructure.
    According to another embodiment, the communication satellite is used to receive, via a reception channel from at least one of the inter-satellite interfaces, an incoming request to establish a communication link with a next satellite. or a previous satellite, and to establish a communication link with the previous satellite or the next satellite, in particular with the previous satellite or the next satellite immediately neighboring on the orbit.
    This embodiment widens the functional perimeter so that the communication satellite can not only generate its outgoing data via an ISL in the case of remote stations absent on the surface of the Earth, but also in the case where a neighboring satellite has no remote station on the surface of the Earth, the neighboring satellite can transmit its outgoing data to the current communication satellite via an ISL. The communication satellite therefore receives incoming communication links.
    According to another embodiment, the communication satellite is implemented so as to deliver data which is received via the communication link of an inter-satellite interface, either via the network-side interface or via through the other inter-satellite interface.
    This embodiment describes how the data, which is received through an ISL, is processed and in particular through which output interface this data is delivered. When the communication satellite has a link with a remote station on the surface of the Earth, the data received via the ISL is then delivered by this means. Otherwise they are transmitted to the next satellite via the second ISL. This latter process is called transparent routing.
    According to another embodiment, the communication satellite is used to convert frequency bands of the communication links, so that the signals of an incoming communication link (for example via an ISL of incoming communication links) do not overlap with signals from an outgoing communication link from the communication satellite.
    This embodiment describes the allocation of resources in a communication satellite. The term resources here implies the frequency, the time or a code used. The allocation of resources is (only) relevant for inbound communication links. If a satellite only delivers data through one of its ISLs, it does so at the frequencies assigned to it. To avoid interference and overlap on the transmitting channel (whether at a distant station on the surface of the Earth or through the other ISL with another satellite), the receiving satellite data from a neighboring satellite via an ISL, on the other hand, must allocate resources on its output interface or in a signal processing channel which is upstream of the output interface.
    The allocation of resources is explained below, by way of example, using the frequencies used. These explanations are however also valid for other resources, for example time or codes or a coding process. Several frequency bands to which the satellites transmit data via the user-side interface can be allocated to the communication satellites of a constellation of satellites. The user side interface may include several transmitting and receiving devices (for example antennas), which are respectively assigned their own transmission direction. Hereinafter, the transmitting and receiving devices are called the transmitting device, it being understood that this term does not exclude bidirectional transmission (transmitting and receiving). The frequency bands are allocated to the transmitting devices so that neighboring transmitting devices use different frequency bands. After different satellites have been able to allocate the same frequency bands for their transmitting devices due to spatial separation, without creating overlaps in normal operation (each communication satellite has at least one communication link with a remote station at the surface of the Earth), overlaps can very well appear as soon as a satellite transmits this outgoing data via an ISL to a neighboring satellite. To prevent this overlap, a frequency conversion of the incoming communications link by an ISL is performed. Frequency conversion can be carried out so that the communication satellite with which the additional communication link is established via an ISL uses only part of the frequency bands allocated to it for its own use. data (i.e. the data that this current communication satellite receives on the user-side interface and which it has to process), and uses the other frequency bands for the incoming communication link via ISL. This allocation or conversion can be carried out dynamically according to bandwidth needs, certain scenarios for the manufacturing or initial configuration of the communication satellite can be prepared so that only the corresponding configuration is read and applied.
    For the allocation of the resources required for transmission, all access methods can be applied, for example frequency multiplexing (FDMA, frequency division multiple access), time multiplexing (TDMA, distribution multiple access over time) or code multiplexing (CDMA, code division multiple access), or a combination of these, to separate the transmission ranges of two satellites and avoid overlapping. What has been explained above with regard to the frequency bands can, by analogy, also be transposed to separate time intervals from each other or to different coding methods.
    According to another embodiment, the user-side interface comprises a plurality of transmitting and receiving devices, a communication cell on the surface of the Earth being able to be assigned to each transmitting and receiving device.
    The term user-side interface is used here to encompass all of the communication devices that are used to transmit data to or from a user side. It can for example be a plurality of antennas which are respectively oriented so as to cover an area of the surface of the Earth having a predefined size. Two antennas can be oriented to cover contiguous regions of the Earth’s surface, with antennas covering neighboring regions using different resources (such as frequency bands) to avoid overlap and interference. A communication satellite can for example use four different frequency bands. A grouping of cells can thus be formed on the surface of the earth, in which it is possible that no cell has a neighboring cell in which identical frequency bands are used.
    If the number of communication satellites is sufficient, it is thus possible to equip the entire surface of the Earth with cells, so that from anywhere on Earth, a communication link can be established with the communication satellite via a user device. For such a cellular system which covers the entire surface of the Earth, communication satellites can for example be provided on several orbits, several equidistant or angularly equidistant communication satellites rotating around the Earth in each orbit. The ISLs described here are used to establish the link between communication satellites located in the same orbit. It is planned that a communication satellite can establish a link, via ISL, only with its immediately preceding and / or next satellite. Thus, the direction of transmission of the inter-satellite interfaces can be fixedly defined when the distances between the satellites in an orbit do not vary or practically do not vary, that is to say when the satellites do not execute any, or practically none, relative movement with respect to each other such as for example in a circular orbit.
    It is for example possible to predict n orbits having respectively m satellites, which involves a total number of η χ m satellites. The number of satellites per orbit and the number of orbits can be chosen to cover most or all of the Earth's surface. Thus, ships on the high seas or isolated islands or even user devices in regions not served in terms of infrastructure or underserved, are connected to a communication network by means of such a constellation of satellites.
    According to another embodiment, the devices for transmitting and receiving the user-side interface are implemented in an identical manner from a structural and / or functional point of view.
    The structure of the communication satellite described here makes it possible to implement the transmission and reception channels of the user side interface in an identical manner from a structural and / or functional point of view, and which differ only in particular in resources used (frequencies, time intervals, codes). The structure of the communication satellite therefore allows a high degree of modularity, and preferably along each signal path of an interface. Each signal path can be implemented in the form of a specific module, in which a signal path implies respectively a transmission channel and a reception channel. This type of modularity allows a simple construction of the communication satellite as well as an economical use of the components on a large scale, that is to say for a constellation of satellites comprising a plurality of satellites.
    The transmission device contains, on a transmission channel, the components required for the conditioning of a signal to be transmitted until transfer to the wireless transmission interface. Conversely, the reception equipment contains, on the reception channel, the components which contain and condition the signal received on the wireless transmission interface and which are available for further processing. The transmission device and the transmission device may both in particular comprise the following components: at least one signal filter, at least one amplifier, a duplexer for transmitting the received signal to a desired component (for example for internal processing or at the user side interface or also at one of the ISLs), or to select a component from which the signal to be transmitted must be obtained (for example from the user side interface or from one of the ISL).
    A module or the concept of modularity must here be interpreted as follows: a module contains functions and / or elements and uses these functions and / or elements, and makes it possible to manufacture interchangeable units (modules) which can therefore be exchanged because they are identical from a functional and / or structural point of view, these modular units being able to be possibly adapted by defining configuration parameters, without their function and / or structure being modified.
    The structure of the communication satellite advantageously supports the use of modularized, i.e. similar, components.
    According to another embodiment, the network side interface comprises a first transmitting and receiving device and a second transmitting and receiving device, which are both implemented so as to be directed respectively to a remote station fixed to the surface of the Earth.
    The communication satellites described here can be used in particular in low Earth orbit (LEO), at an average distance of 400 km to 1400 km from the average surface of the Earth. In low Earth orbit, satellites move for example at an orbital speed by making a complete rotation around the Earth in about 90 minutes.
    To avoid connection breaks on the network side interface resulting from the high speed of the satellites, two transmitting and receiving devices are provided, the first transmitting and receiving device establishing and being able to maintain a link with the remote station. next fixed in the direction of movement of the satellite, while the second transmitting and receiving device maintains a momentary link with the current remote station. In other words, a connection with the next remote station is thus established before the connection with the current remote station is cut. These two links can also be used simultaneously for data transmission, so that the efficient available bandwidth is increased.
    This link to the remote station allows user devices connected to the user-side interface to transmit data to, or receive data from, a communication network via the network-side interface and fixed remote stations.
    According to another embodiment, a transmission angle of the first transmission and reception device of the network side interface can vary during the operating life of the communication satellite.
    In regions which are poorly served in terms of infrastructure or undeveloped, the density of fixed remote stations offering an access point to a communication network is very low. This low density of fixed remote stations can be better exploited when the transmission and reception device (or antenna) of the network-side interface can be set to a fixed remote station and remains directed towards said remote station during the movement. of the satellite into orbit at least for a limited time or for a limited trajectory while the satellite is in motion.
    Unlike the user side interface which covers an area of the Earth's surface (and in total all satellites can cover all or a large part of the Earth's surface), the network side antenna is assigned to be or become directed to one of the few fixed remote stations. Due to the movement of the communication satellite, it is necessary to follow this antenna, that is to say to adapt the current position of a satellite with respect to fixed remote stations. According to another embodiment, the communication satellite is implemented so as to use signals having different polarizations both on the network-side interface and on the first inter-satellite interface and the second inter-satellite interface.
    The bandwidth actually available can thus increase, for example be doubled. Signals can be linearly or circularly polarized. Polarization doubles the number of transmit and receive channels (and therefore the number of components required for this).
    To provide a required bandwidth, it is naturally possible, as a variant or as a complement to the use of signals having different polarizations, to also increase the number of additional resources, for example the frequency bands, within the limits of this which is possible and allowed.
    According to another embodiment, the first and second transmission and reception devices of the network-side interface as well as the transmission and reception devices of the first and second inter-satellite interfaces are implemented in an identical fashion. '' from a structural and / or functional point of view.
    In the case where a satellite establishes an ISL (outgoing) link with another satellite, it is then possible that the other satellite behaves from a functional point of view as a distant station on the surface of the Earth, or consider as such. This is naturally also valid in the opposite case of an incoming ISL link.
    The structure makes it possible to adapt the functions of the individual interfaces and a simplified structural design of the communication satellite as a whole. In addition to the structural identity, other resources (for example frequencies) than those used on the other ISL interface are however used in an ISL link of an ISL interface for the transmission and reception channels. The simple reason is that an ISL interface, from the point of view of the other ISL interface, acts functionally as the fixed remote station on the surface of the Earth, so that it receives in the frequency band in which the another satellite sends, and vice versa.
    The frequency bands of the inter-satellite interfaces and the network-side interfaces can be identical and thus be used collectively since the transmission directions of the inter-satellite interfaces and the network-side interfaces are always angularly sufficiently separated in order to avoid mutual disturbances . This reduces the total number of frequency bands used, which is a significant aspect, especially when used in satellites.
    According to another aspect, a constellation of satellites is provided in an orbit, the constellation of satellites comprising a plurality of communication satellites as described here, in which the satellites of a first group of communication satellites are located in a first orbit at the same angular distance from each other, and in which the satellites of a second group of communication satellites are located in a second orbit at the same angular distance from each other.
    The orbit may in particular be a low Earth orbit at an average altitude of 400 km to 1,400 km above the average surface of the Earth.
    The second orbit is at an angle to the first orbit not equal to 0 ° and not equal to 180 °, and so that the satellites on the two orbits do not cross. That is to say that the first orbit is different from the second orbit, that the communication satellites in the second orbit cover or fly over other regions of the surface of the Earth than the satellites placed in the first orbit orbits can however intersect at two points, for example above the Earth's poles. The two orbits may have a slightly different altitude above the Earth’s surface so that the satellites do not influence each other at the crossing points.
    The satellite constellation can naturally comprise more than two groups of communication satellites.
    Each group of communication satellites is organized in such a way that the corresponding orbit preferably describes a closed circle or an ellipse which the satellites traverse repeatedly. The circle or ellipse can be called the orbital plane. Starting from a center of the orbit (this can correspond to the center of the Earth), an opening angle between each pair of neighboring satellites (i.e. located directly one behind the other on the same orbit, so that no other satellite is interspersed in the same orbit) located in one orbit is identical or substantially identical. In other words, the distance between each neighboring satellite in an orbit is constant.
    According to one embodiment, each communication satellite of the plurality of communication satellites is implemented so as to establish a communication link via its inter-satellite interfaces exclusively with the immediately neighboring communication satellites in the same orbit.
    This of course does not mean that, by reasoning backwards, communication satellites cannot establish any communication link via the user side interface and the network side interface. This only concerns the aspect that through inter-satellite interfaces, with the exception of immediately neighboring satellites in the same orbit, no other satellite can be connected via inter-satellite interfaces.
    In the case of a circular orbit, the orientation of the antennas of the inter-satellite interface is fixedly defined.
    In the case of an elliptical orbit, the orientation of the antennas of the inter-satellite interface over a limited angular range can on the other hand be adapted only in one dimension, namely in the orbital plane.
    Below are summarized the characteristics of the communication satellites as well as the resulting advantages and characteristics for the satellite constellation.
    Given the large number of communication satellites in a complete satellite constellation, it may be a requirement that the satellites have the lowest possible take-off weight in order to be able to launch as many satellites as possible by rocket. It may also be required that satellite manufacturing costs be as low as possible in order to minimize investment costs per space segment and that the highest possible data capacity is provided for each satellite in order to maintain a capacity of data guaranteed by user device or user as high as possible (for example 50 MB / s). An uninterrupted transfer of the communication link from satellite-to-satellite user devices during overflight is advantageous, as well as high availability of services (for example by redundant satellites). The structure of the communication satellites as well as the constellation of satellites makes it possible to minimize the number of ground stations as well as to adapt to the different densities of users in different service areas. It is also possible to fill, using the satellite constellation (by means of transparent routing), missing destination points for ground stations, for example for large bodies of water such as the Pacific or Atlantic Ocean or important desert areas such as the Sahara, to allow a global and economic service. High availability of services can also be obtained in the event of failure of ground stations (flexible routing by spatial segment).
    The communication satellites described here offer a modular extension possibility for creating inter-satellite links (ISL) between constellation satellites, preferably in the same orbit. For ISL between satellites in constellation, it is possible to use for ISL with the next satellite (successor) TRX units of identical construction, which are used for gateway links (link with a remote station fixed to the ground). For ISL with the previous satellite (predecessor), the transmit and receive frequency bands must be redundant, that is to say that the modular structure thus completed also covers the extension by ISL. ISLs between satellites in an orbit allow transparent transmission (transparent routing and transfer, TRF process) of data from user devices via multiple satellites before this data is provided via a link. from the gateway to the ground station and then to the terrestrial network.
    The proposed TRF method is compatible with all access methods (frequency division multiple access (FDMA), time division multiple access (TDMA) and code division multiple access (CDMA) and their mixed forms. The application of the TRF only requires that frequency bands, time intervals or free codes be provided as well as suitable control and synchronization (frequency, time, code) at the level of the gateway links and of the ISLs concerned.
    For an angular distance a between two neighboring satellites in an orbit, the ISL antennas can be fixedly mounted relative to the predecessor and successor satellites with an emission angle β = α / 2 (angle of inclination downwards, tilt inward towards the Earth's surface relative to the circular orbit).
    The orientation of the ISL antennas fixedly mounted is fixedly coupled to the orthogonal orientation of the antennas (point beam of the user link) of the user side interface with the Earth's surface and therefore does not require any additional adjustment mechanism and no cost. additional in terms of command and control.
    It is also possible to use frequency bands of gateway links for ISLs because the two links are constantly spatially separated (solid angle 90 ° - a / 2).
    It is possible to use the same frequency bands for all the ISLs because the ISLs from one satellite to the next are respectively separated from the solid angle a. A suitable design of the ISL antenna makes it possible to ensure that their directivity is sufficient to satisfactorily remove a parasitic element under the solid angle a.
    In one example, ISLs can be provided by one satellite to the next second satellite in the same orbit. The ISLs with the next satellite are respectively spatially separated securely with the solid angle a using the previous antenna design by the ISLs with the immediately next satellite. In another example, ISLs are established with both the next-door satellite and the next second satellite.
    Interference from ISLs with other satellites outside the constellation (GEO or LEO at other flight altitudes) that use the same frequency bands can be excluded by separation of a sufficiently large solid angle in conjunction with a sufficiently large distance.
    The cost of additional hardware for the TRF process is the number of TRX units that are required for gateway links, as well as two additional fixed antennas.
    The TRF process makes it possible to reduce the density of ground stations for a constellation of satellites. This makes it possible to increase overall network coverage despite low infrastructure costs.
    The TRF process makes it possible to fill the so-called dead zones, that is to say the vast oceanic and desert zones in which no ground station is possible. The TRF process dramatically increases the overall coverage that can be achieved with a constellation of satellites. The TRF process offers above all, during the launch and development phase of the space and terrestrial segment of a constellation of satellites, an advantageous and flexible architecture which minimizes investments (terrestrial segment) and optimizes revenues (coverage).
    If the load of the constellation of satellites increases during the phase of use in specific zones (wireless access zones) up to the limit of the capacities on the user side of the individual satellites of the constellation, an extension of the terrestrial segment in these wireless access zones, it is possible to dispense with the TRF process. This scenario also offers a flexible network architecture.
    An advantageous design of the useful bandwidths of the gateway links as well as of the ISLs with respect to the sum of the bandwidths of all the user links consists in choosing the first largest by at least a factor equal to 2. It will then be It is possible, in the case of full use up to the capacity limit on the user side of the individual satellites of the constellation, to still use the TRF process because of the higher useful bandwidths of the gateway links and of the ISLs. This also allows working at full load up to the limit capacity with a lower density at ground stations due to the use of the TRF process.
    If two polarization planes (horizontal and vertical or left circular and right circular) are used for gateway links and ISLs but not for user links, it is thus possible to obtain, without additional expenditure in terms of frequency bands, the advantageous factor 2 previously described. The basis of the implementation remains, as before, the extended modular system.
    The TRF process makes it possible to switch to redundant channels in the event of failure of ground stations and thus increases the reliability of the entire system (terrestrial and space segment). The TRF process also makes it possible to switch redundant channels to satellites in the event of a TRX gateway failure and thus increases the reliability of the entire system (terrestrial and space segment). Examples of embodiments of the invention are explained below in more detail by means of the accompanying drawings. The figures are schematic and are not to scale. Identical references relate to identical or analogous elements. Other characteristics and advantages of the invention will emerge more clearly on reading the description below, made with reference to the accompanying drawings, in which:
    - Figure 1 is a schematic representation of a communication system for a communication satellite,
    FIG. 2 is a schematic representation of a communication system for a communication satellite,
    FIG. 3 is a schematic representation of a communication system for a communication satellite,
    FIG. 4 is a schematic representation of a constellation of satellites according to an exemplary embodiment,
    FIG. 5 is a schematic representation of a communication satellite according to another exemplary embodiment,
    FIG. 6 is a schematic representation of a constellation of satellites according to another exemplary embodiment,
    FIG. 7 is a schematic representation of a constellation of satellites according to another exemplary embodiment,
    FIG. 8 is a schematic representation of a communication satellite according to another exemplary embodiment,
    FIG. 9 is a schematic representation of a communication satellite according to another exemplary embodiment,
    FIG. 10 is a schematic representation of a communication satellite according to another exemplary embodiment,
    - Figure 11 is a schematic representation of a communication satellite according to another embodiment.
    FIG. 1 illustrates a communication system 102 of a communication satellite. A communication system 102 here implies the systems of a communication satellite which are provided and configured for the reception and transmission of data. Subsequently, when a reference is made to the communication satellite, a reference will in particular also be made to the communication system 102.
    The communication system 102 includes a user side interface 105. The user side interface can include several transmission and reception devices, each comprising at least one reception channel 105A and one transmission channel 105B. Both the transmit channel and the receive channel may include the usual components required for this purpose, such as amplifiers, filters, frequency distributors, etc.
    The communication system 102 further comprises a network side interface 110. The network side interface 110 may also include several transmission and reception devices each comprising a reception channel 110A and a transmission channel 110B. The same embodiments as those of the transmit channel and the receive channel of the user side interface are also applicable here.
    The user side interface 105 and the network side interface 110 can respectively be implemented so as to transmit wireless signals to a user or to another remote station. Specific frequency ranges can respectively be provided for this purpose, for example on the user side interface 105 of frequencies in the Ku band, and on the network side interface 110 for example, frequencies of the K band or of the band Ka.
    The communication system 102 is notably implemented to deliver data to the network side interface 110 which is received on the user side interface 105, or vice versa. To deliver the data received on the intended interface, a switching mechanism 103 is provided for connecting the transmission channels and the corresponding reception channels.
    FIG. 2 is a diagrammatic representation of a communication system for a communication satellite 100. Reference will be made to FIG. 1 for the details of this representation. Figure 2 shows schematically how the components of the communication system can be modularized. In this representation, modularization is carried out by means of identical functions, which means that components having the same functions are provided in the form of modules and are in principle interchangeable. This type of modularization can also be called vertical modularization.
    FIG. 3 represents, in a manner similar to FIG. 1, a possibility of modularization of the components of a communication system. Contrary to FIG. 2, a modularization is represented in FIG. 3 along the signal path, that is to say that at least part of the signal path, for example the reception channel and / or the channel is available as a module. This type of modularization can also be called horizontal modularization and has the advantages described above.
    FIG. 4 schematically presents a constellation of satellites 10 as well as part of the Earth 1. A plurality of communication satellites 100 circles the Earth in the same orbit 125. The communication satellites 100 in the same orbit 125 are preferably located at the same angular distance 30 from each other and move at the same angular speed and / or trajectory speed around the Earth, so that the angular distance 30 is also maintained during the movement of the communication satellites around of the earth.
    The angular distance 30 between two successive communication satellites is determined by an angle defined between two fictitious connecting lines 30A, 30B between the respective communication satellites and the center of the Earth.
    Orbit 125 may, in low Earth orbit, be at a distance from the Earth's surface between 400 km and 1,400 km, for example 1,000 km above the Earth's surface.
    From the point of view of each communication satellite 100, there is in the same orbit respectively a satellite immediately preceding 100A and a satellite immediately following 100B. As already described, each communication satellite 100 can establish, via the inter-satellite interface, communication links only with the immediately preceding satellite or the immediately following satellite.
    It can also be deduced from FIG. 4 that each communication satellite 100 can establish communication links with a user device 15 (via the user side interface) and with at least one, preferably two, remote stations 20A, 20B (respectively via a transmission and reception device on the network-side interface), so that the user device 15 can transmit data to and / or receive data from the remote station via the communication satellites -this.
    As the angular distance between two communication satellites which follow each other is constant, when the orbit is circular, it is possible to set a fixed angle 117 of the inter-satellite interface and to maintain it.
    For the communication satellite 100 and its inter-satellite interface with respect to the communication satellite 100B, the emission angle 117 can be described as the angle between a tangent to the orbit in the position of the communication satellite 100 and a fictitious link between the communication satellites 100 and 100B. This angle 117 is represented with the symbol β, this angle corresponding to half the angular distance 30 between two neighboring communication satellites in the same orbit.
    FIG. 5 represents a communication satellite 100 in which the transmitting and receiving devices of the user side interface 105, of the network side interface 110 and of the inter-satellite interfaces 115, 120 are shown.
    The user side interface 105 includes several transmitting and receiving devices, four of which are shown in this figure. The four transmitting and receiving devices shown are called W1, W5, W9 and W13. Each of these transmitting and receiving devices is used to establish a communication link with user devices which are located in communication cells 5 on the earth's surface 1. The communication cells are here represented in the form of alveoli. The number of transmitting and receiving devices on the user-side interface, the number of communication satellites per orbit and the number of orbits make it possible to cover the entire surface of the Earth or a major part of the terrestrial surface. with communication cells.
    The network side interface 110 comprises two transmitting and receiving devices 111, 112. The transmitting and receiving devices 111, 112 can respectively pivot individually (the possibility of pivoting is indicated by the arrows) in order to orient them towards a distant station on the surface of the Earth. Remote stations can also be called gateways and used for the transfer of communication data in a terrestrial and data communication network. The user devices which are dispersed on the surface of the Earth can thus exchange data with said terrestrial communication network via the communication satellites described or via the constellation of satellites.
    The communication satellite 100 also comprises a first inter-satellite interface 115 with a first transmission and reception device 115A, as well as a second inter-satellite interface 120 with a second transmission and reception device 120A. The transmission directions 116, 121 of the first or second transmission and reception device 115A, 120A are adjusted so that they are directly aligned with the next satellite or the previous satellite. FIG. 5 shows that the emission angle 117, 122 is defined from the direction of emission 116, 121 of the first or second transmission and reception device 115A, 120A and the orbit 125 of a tangent to each point of the orbit where the communication satellite 100 is currently located.
    This structure of the communication satellite 100 with the transmitting and receiving devices fixedly oriented on the user side interface and the adjustable transmitting and receiving devices on the network side interface makes it possible to connect the user devices to a remote station. from any point on Earth and also from mobile user devices via communication satellites, thereby establishing a communication link with a terrestrial communication network.
    In the case where a communication satellite cannot establish a link with a remote station via the network side interface, for example because no remote station is present in its area of spatial coverage, this communication satellite can when even receive data from the communication cells and transmit this data via one of its inter-satellite interfaces to the previous or next satellite. The level of coverage of the earth's surface is therefore increased with usable communication cells.
    FIG. 6 represents a constellation of satellites 10 in which the connection between the communication satellites 100 and a communication network 7 which is in particular a terrestrial communication network is represented in general and schematically. Here, for example, five communication satellites are represented, but it should not be seen as a limitation.
    By means of the user-side interfaces, the communication satellites cover the earth's surface with communication cells 5 in which there are user devices 15. A communication cell can, for example, have a range of 280 km.
    The communication satellites 100 establish a link with the fixed remote stations 20A, 20B on the surface of the Earth via the network side interface. As the satellites move in an orbit around the Earth, it is necessary to choose another distant station for the transmission of data according to the position of a satellite above the surface of the Earth. The two satellites shown on the left are exclusively connected to the remote station 20A and the two satellites shown on the right are exclusively connected to the remote station 20B, while the central satellite is connected to the two remote stations 20A, 20B. In a transition range between the transmission and reception ranges of the two remote stations 20A, 20B, the satellites are connected to the two remote stations in order to transfer the communication links from the remote station 20A to the remote station 20B, the devices users thus suffering at most a short interruption of the effective communication link with the terrestrial communication network 7, see no interruption.
    Figure 7 now shows a scenario in which at least one communication satellite (here the two satellites on the left) has no direct remote station on its network side interface. So that the communication cells of the two satellites on the left, however, are able to establish a link with the communication network 7, the two satellites on the left respectively establish an inter-satellite link 130 with their respective previous satellite. The leftmost satellite establishes a link with the satellite on its right (with the second satellite on the left), the latter also having no distant station on the network side interface and establishing again a connection with the satellite central through its inter-satellite interface.
    In other words, the data traffic is transferred to the remote station 20B from and to the two satellites on the left via the central satellite. This increases the effective coverage of the earth's surface with usable communication satellites, so that it is possible, even in regions which have no fixed remote station, to establish a link with a communication network 7.
    We now divide the bandwidth of the central satellite between a total of three communication satellites. To this end, the data from the two satellites on the left are integrated into the frequency bands of the central satellite. This may require a new allocation of transmission resources (frequencies, times and codes in particular) in order to avoid overlapping of the signals.
    In principle, all communication satellites can use the same transmission resources due to spatial separation. However, a conflict situation may arise if an inter-satellite link 130 is created. This will for example be explained by using eight frequency bands, the embodiment also applying by analogy when using identical time intervals or codes.
    In the scenario in Figure 7, both the leftmost satellite and the second left satellite on the user side interface can use the frequency bands 1 2 and 3 respectively, without any conflict. because the two satellites are separated in space. If an inter-satellite link is now created between these two satellites, a conflict may arise when the same frequency bands are used for data transmission. The frequency bands used on the inter-satellite interface must therefore be converted before they are processed or transmitted by the receiving satellite. The data which arrives on the inter-satellite interface in the frequency bands 1 2 and 3 can for example be converted on the frequency bands 4, 5 and 6 of the receiving satellite, in order to avoid a conflict with the frequency bands 1, 2 and 3 of the receiving satellite. When the receiving satellite for its part transmits the data via an inter-satellite link to its previous satellite, a conversion of resources must also be carried out in order to avoid a conflict. In this example, the frequency bands 7 and 8 still remain. In case the available bandwidth is insufficient to be able to transmit to all frequency bands, it is possible to use resource management which limits the data traffic transmitted via an inter-satellite link. In the example above, the first satellite uses three frequency bands, the second satellite also uses three frequency bands and the third satellite uses two frequency bands, which gives a total of eight frequency bands and what corresponds also in this example at the frequency band of the link with the remote station. If each satellite now needs a bandwidth of four frequency bands, the result is a need for twelve frequency bands, which is more than the eight available frequency bands. This situation requires limiting the bandwidth (i.e. the useful frequency bands) by satellite.
    FIGS. 8 to 11 are schematic representations of the communication system of a communication satellite 100 intended to explain possible scenarios in a constellation of satellites. These figures respectively represent 3058861 the user side interface, the network side interface and the inter-satellite interface with the associated transmitting and receiving devices.
    In all the representations of FIGS. 8 to 11, it is understood that the user side interface is represented without modification. The user side interface is used to establish communication links with user devices. As the user devices can be mobile and distributed over the entire surface of the Earth, the user-side interfaces are implemented so as to provide communication cells according to a predefined scheme.
    Unlike user devices, remote stations for connection to the terrestrial communication network are not available everywhere, in particular in regions not served or underserved in terms of infrastructure or in regions which cannot contain such a remote station. , such as for example large water areas where remote stations are generally not available. User devices may however be present in these regions. In order to connect these user devices to the terrestrial communication network, data traffic can be transmitted to and from these user devices via satellites (transparent routing).
    To allow this, we can imagine different scenarios in the constellation of satellites described here: the communication satellite has a direct link with a single remote station (it can be one of the two stations or the link can also be simultaneously established with two remote stations) and no inter-satellite link with a previous satellite or a next satellite is active (Figure 8); the communication satellite has no connection to a remote station and routes all of the data traffic to the previous or next satellite (Figure 9) via an inter-satellite interface; the communication satellite has a link with a remote station and one (or two) inter-satellite interface (s) with the previous satellite and / or the next satellite is (are) also active, in order to be able to route traffic data from or to the previous satellite or the next satellite via the link with the remote station (Figure 10); the communication satellite has no link with remote stations via the network side interface, but two inter-satellite links are active with both the previous and the next satellite, in order to be able to route data traffic from the previous satellite to the next satellite (or vice versa), data traffic from the own user-side interface is also transmitted via the in3058861 ter-satellite link to the previous or next satellite, depending on whether the previous satellite or the next satellite has a link with a remote station (Figure 11).
    In all the exemplary embodiments of FIGS. 8 to 11, a switching mechanism 103 is provided which routes the data from an input interface (for example from the user side interface or from an inter-satellite interface) to an output interface (for example the network side interface or the other inter-satellite interface). The switching mechanism 103 is implemented so as to allocate resources intended to avoid resource conflicts on the output interface.
    The general structure of the communication system of the communication satellite 100 will first of all be explained by means of the representation of FIG. 8. The user side interface 105 includes several transmission and reception devices, for example up to eight, two of which are shown, which are called User-TRX-1 and User-TRX-8. Each transmission and reception device comprises a transmission channel and a reception channel and the transmission and reception devices are preferably implemented in an identical manner from a structural and functional point of view. The network side interface 110 has two transmitting and receiving devices 111, 112, which are designated Alim-TRX-A and Alim-TRX-B. Each transmission and reception device comprises a transmission channel and a reception channel and the transmission and reception devices are preferably implemented in an identical manner from a structural and functional point of view. In addition, the communication satellite comprises two inter-satellite interfaces 115, 120 respectively comprising a transmitting and receiving device, which are designated Router-TRX-P and Router-TRX-S, in order to create the link with the satellite previous (Predecessor, P) and the next satellite (Successor, S). Each transmission and reception device comprises a transmission channel 119, 124 and a reception channel 118, 123 and the transmission and reception devices are preferably implemented identically from a structural point of view. and functional. Each transmit channel and each receive channel of all transmit and receive devices has a switch 140 which can put the respective channel into the active or inactive state, and can thus predetermine whether the data can be transmitted / received or not via the respective transmitting and receiving device.
    The transmitting and receiving devices of the user side interface are connected to a first side (left) of the switching mechanism 103, while the transmitting and receiving devices of the network side interface are connected to a second side (right) of the switching mechanism 103. The first side and the second side can also be called the input side and the output side, although bidirectional data transmission is possible despite these designations, that is to say the from the network side to the user side interface, and vice versa.
    A duplexer 150 is also provided for the transmitting and receiving devices of the inter-satellite interfaces. This is because inter-satellite interfaces can transmit data traffic both from the user side and from the network side. If, for example, the next satellite has no connection to a remote station, then it transmits data traffic from its user side to the current satellite, so that incoming data traffic via its inter-satellite interface arrives on the side user (left) of the switching mechanism 103, and is then transmitted by the current satellite either to a remote station or to the other inter-satellite interface. The duplexer 150 also determines for an inter-satellite interface whether this inter-satellite interface is data traffic on the user side or data traffic on the network, so that this inter-satellite interface is connected to the switching mechanism 103 from the left or the right. In FIG. 8, the network-side transmission and reception device Alim-TRX-A has a direct link with a remote station and is in the active state, as can be seen with the closed switch 140. It is also possible see that the Alim-TRX-A transmitting and receiving device is connected to the network side of the switching mechanism 103 via a duplexer. In this constellation, data traffic can be transmitted directly from the user-side interface 105 via the second transmission and reception device Alim-TRX-A to the terrestrial communication network (not shown), or can be received of it.
    The structure of the communication satellite is universally adapted to different scenarios. Thus, the data traffic is routed from the user side interface 105 to the network side interface 110, or to one of the two inter-satellite interfaces 115, 120 (or vice versa), and the data traffic can be routed from one or both inter-satellite interfaces 115, 120 to the network side interface 110, to the user side interface 105 or to another inter-satellite interface. A user device can therefore be connected to a remote station of the terrestrial communication network via a single satellite or via several satellites. This connection is transparent to the user device.
    It may however be indicated, for information only, that the communication satellite 100 can activate the first transmission and reception device 111 of the network side interface 110 in a complementary or alternative manner to the second transmission and reception device 112, as shown in Figure 6 for the central satellite. In this case, the data can be transmitted or received via the first interface or via the second interface, which increases the effective useful bandwidth. FIG. 9 shows the case where the current satellite has no connection with a remote station (the switches 140 of the two power systems are open). The connection with the remote stations of the communication network is carried out directly with the preceding satellite via the first inter-satellite interface 115. The duplexer 150 is connected so that the first inter-satellite interface 115 is connected to the network side (right) of the switching mechanism 103. Data traffic to and from the user side interface 105 is also routed via the preceding satellite.
    In this case also, an inter-satellite link can be established in a complementary or alternative way with the next satellite via the inter-satellite interface Router-TRX-S, so that each interface is directly accessible via the previous satellite and the satellite. following. For this purpose, the duplexer 150 for the Router-TRX-S interface is connected to the user side of the switching mechanism 103. The position of the duplexer 150 for the Router-TRX-S interface has no influence on the operation because switch 140 of the Router-TRX-S interface is open.
    FIG. 10 shows an exemplary embodiment in which the communication satellite 100 has a direct link with a remote station via Alim-TRX-A and also receives data traffic from the immediately preceding satellite via Router TRX-P, and routes this traffic data via Alim-TRX-A to the remote station (or vice versa). The Router-TRX-P interface is active, switch 140 is closed, and duplexer 150 routes data traffic to the user side (left) of switching mechanism 103.
    The link between this satellite and the remote station is therefore used both by the own user-side interface and by the previous satellite. In this example, the Router-TRX-S interface could also still be active in order to receive data from the next satellite and route it to the remote station via Alim-TRX-A (when the next satellite has not no direct link with a remote station).
    One can also imagine routing data traffic to and from several previous satellites via the Router-TRX-P interface (see Figure 7). Here, data traffic from and to the two satellites on the left is routed through the central satellite’s XA interface. Now, in order not to direct all the data traffic coming from the Router-TPX-P interface via Alim-TRX-A, we can imagine that part of this data traffic is routed via Router-TRX-S to the next satellite. Thus, the data traffic originating from several preceding satellites can be distributed between two or more than two neighboring satellites, when these all have an active and direct link with a remote station. This can have advantages for the effective use of the available bandwidth.
    FIG. 11 presents a scenario in which the current communication satellite 100 has no direct link with a remote station and receives data traffic both on the own user-side interface and from the previous satellite via the router interface. -TRX-P. The Router-TRX-P interface is connected to the user side (left) of the switching mechanism 103 through duplexer 150. All of the data traffic is routed to the Router-TRX-S interface on the user side (right) of the switching mechanism 103.
    In Figure 11, the current communications satellite therefore routes data traffic from its own user-side interface to the next satellite, and also serves as a transparent transition station for data traffic to and from at least one previous satellite.
    In total, it can be seen that the user side interface is constantly oriented towards the user side of the switching mechanism 103, the network side interface is constantly oriented towards the network side of the switching mechanism 103, and each of the two inter-satellite interfaces can be selectively oriented to both the network side and the user side. As a result, both at least one preceding satellite and at least one following satellite can be connected either to the network side (as a variant or in addition to the network side interface) or to the user side (in addition to the interface user side) of the switching mechanism 103 of the current satellite.
    A communication satellite as described here and in the constellation of satellites as described here can thus improve the availability of access to a communication network on a global scale, since communication satellites can route data traffic from transparently to a user device.
    Communication satellites can exchange suitable control information, so that each communication satellite is informed of the status of the respective direct neighbor. This control information can indicate via a satellite whether there is a direct link to a remote station, the total bandwidth that remains available and the amount that has yet to be allocated. When a satellite only has a direct link (i.e. via at least one additional satellite) with a remote station, it is possible to determine the number of intermediate stations (satellites) present up to the remote station, so that each satellite can choose the shortest route to a remote station when it itself has no direct link to a remote station.
    It should also be clarified that the terms including or including do not exclude any other element or stage and articles one or one do not exclude any plurality. In addition, it should be noted that the characteristics or steps which have been described with reference to one of the exemplary embodiments described above, can also be used in combination with other characteristics or stages of other exemplary embodiments. described above. The references contained in the claims should not be considered as limiting.
    1 Earth 5 Communication units 7 Communication network 10 Constellation of satellites 15 User device 20A, 20B Remote station 30 Angular distance 30A, 30B Dummy line to the center of the Earth 100 Communication satellite 100A Previous satellite 100B Next satellite 102 Communication system 103 Switching mechanism 105 User side interface 105A Receiving channel 105B Channel of emission 106 Transmitting and receiving device 110 Network side interface 110A Receiving channel 110B Channel of emission 111 First transmission and reception device 112 Second transmission and reception device 115 First inter-satellite interface 115A Transmitting and receiving device 116 First show direction 117 First angle of emission 118 Receiving channel 119 Channel of emission 120 Second inter-satellite interface 120A Transmitting and receiving device 121 Second program direction 122 Second angle of emission 123 Receiving channel 124 Channel of emission 125 Direction of movement, orbit
    130
    140
    150
    Inter-satellite link
    Switch
    Duplexer
    权利要求:
    Claims (15)
    [1" id="c-fr-0001]
    1. Communication satellite (100) for use in a constellation of satellites (10), the communication satellite (100) comprising:
    a user side interface (105) for receiving and transmitting wireless data, a network side interface (110) for receiving and transmitting wireless data, a first inter-satellite interface (115) for receiving and transmitting wireless data transmission with a first transmission direction (116) of electromagnetic waves, a second inter-satellite interface (120) for reception and wireless data transmission with a second transmission direction (121) d electromagnetic wave, characterized in that the first direction of emission (116) has a first angle of emission (117) with respect to a direction of movement (125) of the communication satellite (100), the second direction of emission (121) has a second emission angle (122) relative to the direction of movement (125) of the communication satellite (100), and a value of the first emission angle corresponds to a value of sec emission angle.
    [2" id="c-fr-0002]
    2. Communication satellite (100) according to claim 1, characterized in that the first inter-satellite interface (115) is arranged so that the first transmission angle (117) is fixedly defined relative to the satellite communication and cannot vary during the operating life of the communication satellite (100).
    [3" id="c-fr-0003]
    3. Communication satellite (100) according to claim 1 or 2, characterized in that the communication satellite (100) is implemented so as to detect the presence of a remote station (20A, 20B) for the interface network side (110) and, if no remote station is present, switch the first inter-satellite interface (115) and / or the second inter-satellite interface (120) to the active state, in order to be able to establish an outgoing communication link with a previous satellite (100A) and / or a next satellite (100B).
    [4" id="c-fr-0004]
    4. Communication satellite (100) according to claim 3, characterized in that the communication satellite (100) is implemented so as to send, in the absence of a remote station for the network side interface (110) , the data intended for a transmission channel of the network side interface (105) via the first inter-satellite interface (115) or the second inter-satellite interface (120) which has entered the active state .
    [5" id="c-fr-0005]
    5. Communication satellite (100) according to one of the preceding claims, characterized in that the communication satellite (100) is implemented so as to receive, via a transmission channel (118, 123) from at least one of the inter-satellite interfaces (115, 120), an incoming request to establish a communication link with a previous satellite (100A) or a next satellite (100B), and to establish a communication link with the previous satellite (100A ) or the next satellite (100B).
    [6" id="c-fr-0006]
    6. Communication satellite (100) according to claim 5, characterized in that the communication satellite (100) is implemented so as to deliver the data which have been received via the incoming communication link of an inter- satellites (115; 120), either through the network side interface (105) or through the other inter-satellite interface (120; 115).
    [7" id="c-fr-0007]
    7. Communication satellite (100) according to claim 5 or 6, characterized in that the communication satellite (100) is implemented so as to convert the frequency bands of the incoming communication link, so that the signals of the incoming communication link is not superimposed on the signals of an outgoing communication link from the communication satellite (100).
    [8" id="c-fr-0008]
    8. Communication satellite (100) according to one of the preceding claims, characterized in that the user side interface (105) comprises a plurality of transmission and reception devices (106), a communication cell (5) on the surface of the Earth that can be associated with each transmitting and receiving device.
    [9" id="c-fr-0009]
    9. Communication satellite (100) according to claim 8, characterized in that the transmission and reception devices (106) of the user side interface (105) are identical from a structural and / or functional point of view. .
    [10" id="c-fr-0010]
    10. Communication satellite (100) according to one of the preceding claims, characterized in that the network side interface (110) comprises a first transmission and reception device (111) and a second transmission and reception device reception (112), both implemented to be directed respectively to a fixed remote station (20A, 20B) on the surface of the Earth.
    [11" id="c-fr-0011]
    11. Communication satellite (100) according to claim 10, characterized in that a transmission angle (117) of the first transmission and reception device (111) of the user side interface (110) can be changed during the operating life of the communication satellite (100).
    [12" id="c-fr-0012]
    12. Communication satellite (100) according to one of the preceding claims, characterized in that the communication satellite (100) is implemented so as to use, both on the network side interface (110) and on the first inter-satellite interface (115) and the second inter-satellite interface (120), signals having different polarizations.
    [13" id="c-fr-0013]
    13. Communication satellite (100) according to one of claims 10 to 12, characterized in that the first and second transmission and reception devices (111, 112) of the network side interface (110) as well as the transmitting and receiving devices (115A, 120A) of the first and second inter-satellite interfaces (115, 120) are identical from a structural and / or functional point of view.
    [14" id="c-fr-0014]
    14. Constellation of satellites (10) in an orbit, comprising:
    a plurality of communication satellites (100) according to one of the preceding claims, characterized in that a first group of communication satellites (100) are placed in a first orbit at an angular distance (30) equal to each other , a second group of communication satellites (100) are placed in a second orbit at an angular distance (30) equal to each other.
    [15" id="c-fr-0015]
    15. Constellation of satellites (10) according to claim 14, characterized in that each communication satellite (100) of the plurality of communication satellites is implemented so as to establish, via its inter-satellite interface (115, 120 ), a communication link exclusively with the immediately neighboring communication satellites (100A, 100B) in the same orbit.
    1/8
    102
    105B
    110A
    HPA-U
    103
    LNA-F
    Oc,XOc »—D “| -” OC.'v
    Ku band
    105Α
    -XXOc,OC.“X.oc.
    LNA-1
    Ί
    7 "- 7 Z —► Z -U; / 3 105 110 -1 Z 7 Z —► 7
    <l ·
    oc.
    HPA • 110B
    LNA-1
    Band K or Ka
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    同族专利:
    公开号 | 公开日
    DE102016121919B4|2018-10-31|
    FR3058861B1|2021-03-19|
    US10404357B2|2019-09-03|
    US20180138968A1|2018-05-17|
    DE102016121919A1|2018-05-17|
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    法律状态:
    2019-11-20| PLFP| Fee payment|Year of fee payment: 3 |
    2020-11-20| PLFP| Fee payment|Year of fee payment: 4 |
    2021-11-22| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102016121919.3A|DE102016121919B4|2016-11-15|2016-11-15|Communications satellite for a satellite constellation|
    DE102016121919.3|2016-11-15|
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