Patent Publication Number: US-11398682-B2

Title: Hosted, compact, large-aperture, multi-reflector antenna system deployable with high-dissipation feed

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims benefit of U.S. Provisional Application No. 63/005,135, filed Apr. 3, 2020, which is incorporated herein by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     FIELD OF THE INVENTION 
     The present invention generally relates to satellite communication and, more particularly, relates to a hosted, compact, east-west, large-aperture, multi-reflector antenna system deployable with high-dissipation feed. 
     BACKGROUND 
     Existing satellite antenna systems are commonly specific to a satellite (bus) design and are not designed to be hosted by other satellite types and/or designs. For example, the mechanical design of the antenna system and the satellite are performed in an integrated design cycle, and the antenna system lacks any payload component, such as an electronically steered antenna (ESA), to be easily hosted. In such an antenna system, antenna pointing can be degraded by the thermal distortions due to lack or insufficiency of thermal management system. 
     SUMMARY 
     According to various aspects of the subject technology, methods and systems are disclosed for providing a hosted multi-reflector antenna system. The disclosed hosted multi-reflector antenna system has a number of advantageous features such as compactness, east-west orientation and large aperture, and is deployable with a high-dissipation feed, as further described herein. 
     In one or more aspects, a hosted multi-reflector antenna system includes a primary reflector, a subreflector, a feed structure and an anti-jam housing. The feed structure includes an electronically steered antenna (ESA). The subreflector directs a reflected beam of the primary reflector onto the ESA, and the anti-jam housing encloses the subreflector and the ESA. The antenna system is mechanically and thermally independent of a host space vehicle, accommodates thermal dissipation of the feed structure, and maintain precise antenna alignment. 
     In other aspects, a method of providing a hosted multi-reflector antenna system includes coupling a primary reflector via a number of booms and joint structures to an optical bench. The method further includes positioning an anti-jam housing comprising a low coefficient of thermal expansion (CTE) composite structure on the optical bench and coupling a feed structure including an ESA to a first wall of the anti-jam housing. A subreflector is coupled to a second wall of the anti-jam housing opposite the first wall to direct a reflected beam of the primary reflector onto the ESA. The hosted multi-reflector antenna system is mechanically and thermally independent of a host space vehicle, accommodates a thermal dissipation of the feed structure and maintains a precise antenna system alignment. 
     In yet other aspects, a compact hosted large aperture multi-reflector antenna system includes a primary reflector coupled via a number of booms and joint structures to an optical bench. The antenna system further includes a high-dissipation feed structure including an ESA, a subreflector that directs a reflected beam of the primary reflector onto the ESA, and an anti jam housing consisting of a low CTE composite structure and one or more aluminum radiators. The anti-jam housing encloses the subreflector and the ESA. The antenna system is mechanically and thermally independent of a host space vehicle, and the low CTE composite structure preserves an antenna system alignment by reducing the thermal elastic distortion (TED) resulting from high thermal dissipation of the high-dissipation feed structure. 
     The foregoing has outlined rather broadly the features of the present disclosure so that the following detailed description can be better understood. Additional features and advantages of the disclosure, which form the subject of the claims, will be described hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions to be taken in conjunction with the accompanying drawings describing specific aspects of the disclosure, wherein: 
         FIG. 1  is a schematic diagram illustrating an example of a hosted multi-reflector antenna system, according to certain aspects of the disclosure. 
         FIG. 2A  is a schematic diagram illustrating a view from a bus panel of an example of a hosted multi-reflector antenna system, according to certain aspects of the disclosure. 
         FIG. 2B  is a schematic diagram illustrating a perspective view of an example of a hosted multi-reflector antenna system in a stowed configuration, according to certain aspects of the disclosure. 
         FIG. 3  is a schematic diagram illustrating various views of an example of a hosted multi-reflector antenna system in stowed configuration inside of a compact generic stowed volume, according to certain aspects of the disclosure. 
         FIG. 4  is a schematic diagram illustrating views of an example of a hosted multi-reflector antenna system in a stowed configuration and isolated from bus distortions, according to certain aspects of the disclosure. 
         FIG. 5  is a schematic diagram illustrating perspective views of an example of a hosted multi-reflector antenna system of the subject technology hosted on two different satellites. 
         FIG. 6  is a schematic diagram illustrating the structure of an anti-jam housing and a thermal subsystem of an example of a hosted multi-reflector antenna system, according to certain aspects of the disclosure. 
         FIG. 7  is a schematic diagram illustrating a heat-dissipation mechanism in a thermal subsystem of an example of a hosted multi-reflector antenna system, according to certain aspects of the disclosure. 
         FIG. 8  is a schematic diagram illustrating various views of a heat-dissipation mechanism in a thermal subsystem of an example of a hosted multi-reflector antenna system and the way it is kinematically decoupled from the structural subsystem, according to certain aspects of the disclosure. 
         FIG. 9  is a flow diagram illustrating an example of a method of providing a hosted multi-reflector antenna system of the subject technology. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology can be practiced. The appended drawings are incorporated herein and constitute a part of this detailed description, which includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be clear and apparent to those skilled in the art that the subject technology is not limited to the specific details set forth herein and can be practiced using one or more implementations. In one or more instances, well-known structures and components are shown in block-diagram form in order to avoid obscuring the concepts of the subject technology. 
     In some aspects of the present technology, methods and configurations are disclosed for providing a hosted multi-reflector antenna system. The hosted multi-reflector antenna system of the subject technology is a compact, east-west (E/W) oriented, and large-aperture antenna system that is deployable with a high-dissipation feed. Accommodation of features such as compactness, E/W orientation and large aperture in a hosted deployable multi-reflector antenna system with a high payload dissipation can be difficult due to a number of challenges. For example, the hosted payload design interdependency with a host space vehicle (e.g., a satellite, also referred to as a “bus”) drives cost, complexity and risk. Further, mechanical interfaces may vary depending on the host space vehicle, which can have an unknown bus distortion and an unknown thermal interface. The other challenges include precise alignment, for instance, of a laser inter-satellite link (ISD, a telescope, and so on, and antenna mechanical alignments. Furthermore, integrated thermal designs are difficult to achieve. Such thermal challenges complicate antenna and payload design due to a number of factors such as the high thermal power (e.g., ˜250 watts) that can distort antenna optics, electronically steered antennas&#39; (ESAs&#39;), requirement of low temperatures for better performance and longer life, and anti jam housing (faraday cage) that can complicate heat rejection. 
     The existing antenna systems lack any payload component, such as an ESA, to be easily hosted. In the existing antenna systems, antenna pointing can be degraded by the bus thermal distortions due to lack or insufficiency of thermal management system. 
       FIG. 1  is a schematic diagram illustrating an example of a hosted multi-reflector antenna system  100 , according to certain aspects of the disclosure. The example hosted multi-reflector antenna system  100  (hereinafter, antenna system  100 ) is a compact, E/W oriented, and large aperture antenna system that can handle thermal dissipation of a high-dissipation feed (e.g., ˜250 watts). The antenna system  100  includes a number of antenna elements such as a primary reflector  102 , an aperture (iris)  103 , a subreflector  104  and an ESA  106 , that is part of a feed structure  110 . An anti-jam housing  108  encloses the subreflector  104 , the feed structure  110  and the ESA  106 . 
     The primary reflector  102  focuses a beam  105  into the aperture  103  that is also at a focal point of the subreflector  104 , which converts the received beam into a parallel beam directed at the ESA  106 . The beam  105  is, for example, a communication link between a host space vehicle (e.g., a space vehicle, such as a satellite) and a terrestrial station such as a satellite gateway or user terminal. The antenna system  100  is designed to be mechanically and thermally independent of the host space vehicle so that it can be mounted on different host space vehicle. The antenna system  100  can readily accommodate the thermal dissipation of the feed stricture  110  of a high-dissipation feed, and is able to maintain the precise antenna alignment between the antenna elements such as the primary reflector  102 , the subreflector  104 , the aperture  103 , and the ESA  106 , as discussed in more detail herein. 
     The anti-jam housing  108  includes a composite structure and a thermal radiator layer that enable the antenna system  100  to handle the thermal dissipation of the feed structure  110 . The anti-jam housing  108  is mounted on an optical bench  116  that also supports the primary reflector  102  via a reflector-support structure, including a number of (e.g., three) booms  114  ( 114 - 1 ,  114 - 2  and  114 - 3 ) and joint structures  118  ( 118 - 1 ,  118 - 2  and  118 - 3 ). The optical bench  116  is decoupled from the host space vehicle to reduce any thermal elastic distortion (TED) from the host space vehicle so that the alignment between the primary reflector  102  and the subreflector  104  can be preserved and not disturbed by the TED of the host space vehicle. The optical bench further accommodates kinematic mounts (not shown in  FIG. 1 , for simplicity) that are used to couple the antenna system  100  to the host space vehicle. The system  100  also includes locking fixtures  120  (e.g.,  120 - 1 ,  120 - 2 ,  120 - 3  and  120 - 4  (not visible in  FIG. 1 )), which can lock components of the antenna system  100 , when not in use, in a stowed configuration. The locking fixture  120 - 1  is mounted on the anti jam housing  108  and the locking fixtures  120 - 2 ,  120 - 3  and  120 - 4  (shown in  FIG. 2B ) are mounted on the optical bench  116  and a bus panel of the host space vehicle, respectively, via fixtures  115 ,  117 - 1 , and  117 - 2  (not visible in  FIG. 1 ). 
       FIG. 2A  is a schematic diagram illustrating a view  200 A from a bus panel of an example of a hosted multi-reflector antenna system  210 , according to certain aspects of the disclosure. The view  200 A shows the hosted multi-reflector antenna system  210  (hereinafter, antenna system  210 ) from a bus panel of a host space vehicle (i.e. looking outboard from the host space vehicle) and depicts a front view of the primary reflector  102 , as it is folded back on to the locking fixtures  120  of  FIG. 1 , and a back view of the optical bench  116 . The antenna system  210  is the same antenna system  100  of  FIG. 1  in a folded configuration. Attached to the optical bench  116  are a hard mount  212  and three radial flexures  214  that are used to couple the antenna system  210  to the bus panel of a host space vehicle. The hard-mount  212  and three radial fixtures  214 , while attaching the antenna system  210  to the host space vehicle, thermally decouple the antenna system  210  from the host space vehicle so that the TED of the host space vehicle is prevented from affecting the alignment of the antenna system  210 . 
       FIG. 2B  is a schematic diagram illustrating a perspective view  200 B of an example of a hosted multi-reflector antenna system  210  in a stowed configuration, according to certain aspects of the disclosure. The antenna system  210  is the same antenna system  100  of  FIG. 1  in a folded configuration, with the booms  114  folded and locked to the locking fixture  120 - 2 , and the primary reflector  102  is locked to the locking fixtures  120 - 1 ,  120 - 3  and  120 - 4 . The locking fixtures  120 - 3  and  120 - 4  are supported by fixtures  117 - 1  and  117 - 2 , respectively, which is coupled to the bus panel of the host space vehicle. The antenna system in the stowed configuration has a compact volume as shown by the dimensions in  FIG. 3  below. 
       FIG. 3  is a schematic diagram illustrating various views  300 ,  302 ,  304  and  306  of an example of a hosted multi-reflector antenna system  310  in a stowed configuration, according to certain aspects of the disclosure. The view  300  shows the compact volume of hosted multi-reflector antenna system  310  (hereinafter, antenna system  310 ), which is the same as the antenna system  100  of  FIG. 1  in a stowed configuration, and clearly depicts folding of the primary reflector. 
     The view  302  is a top view that shows the antenna system  310  in the stowed configuration and depicts a dimension D 1  (e.g., about 104 inches) of the primary reflector  312 , which allows an aperture size ranging from 90 to 100 inches for the primary reflector  312 . 
     The view  304  is a side view of the antenna system  310  in the stowed configuration, and depicts dimensions D 2  (e.g., about 102 inches) and D 3  (e.g., 45 inches) of the antenna system  310 . 
     The view  306  is a side view of the antenna system  310  in the stowed configuration, and depicts dimension D 4  (e.g., about 28.5 inches) of the antenna system  310 . The dimensions D 1 , D 2 , D 3  and D 4  of the antenna system  310  support the claim of a compact volume in the stowed configuration of the antenna system of the subject technology, which is one of the advantageous features of the disclosed antenna system. 
       FIG. 4  is a schematic diagram illustrating views  400  and  402  of an example of a hosted multi-reflector antenna system  410  in a stowed configuration and isolated from bus distortions, according to certain aspects of the disclosure. The view  400  shows the hosted multi-reflector antenna system  410  (hereinafter, antenna system  410 ) in a stowed configuration. The view  400  depicts a low CTE composite structure  412  and a thermal subsystem  414 , which include an aluminum radiator, the subreflector  106 , the fixtures  117  and radial flexures  214 . The low CTE composite structure  412  and the thermal subsystem  414  can accommodate high thermal dissipation of the high-dissipation feed structure  110  of  FIG. 1 . 
     The view  402  shows the antenna system  410  in a stowed configuration and coupled (e.g., bolted in) to a host space vehicle (e.g., satellite)  420 . The view  402  depicts the antenna system  410 , as coupled to a bus panel  422  of the host space vehicle  420  via the fixtures  117 , the hard mount  212 , and the radial flexures  214 , which mechanically and thermally isolate the primary reflector  102  and the optical bench, respectively, from the TED of the host space vehicle  420 . 
       FIG. 5  is a schematic diagram illustrating perspective views  500  and  502  of an example of a hosted multi-reflector antenna system  510  of the subject technology hosted on two different satellites. In the perspective view  500 , the hosted multi-reflector antenna system  510  (hereinafter, antenna system  510 ) is mounted on a host space vehicle (e.g., satellite)  520 . The perspective view  500  also reveals a composite structure  512  that supports an aluminum thermal subsystem (i.e. radiators)  514  of the antenna system  510 , which is crucial in eliminating TED and maintaining the alignment of the antenna elements, as described above. 
     In the perspective view  502 , the antenna system  510  is mounted on a host space vehicle (e.g., satellite)  530 , which is different from the host space vehicle  520 . The antenna system  510  is designed to be mechanically and thermally independent of the host space vehicle so that it can be mounted on different host space vehicles such as the host space vehicles  520  and  530 . The antenna system  510  is equipped to readily accommodate the thermal dissipation of a high-dissipation feed and to be able to maintain the precise antenna alignment, as discussed above. 
       FIG. 6  is a schematic diagram illustrating the structure of an anti-jam housing  600  and a thermal subsystem  602  of an example of a hosted multi-reflector antenna system, according to certain aspects of the disclosure. The anti-jam housing  600  is mounted on the optical bench  116  and includes the aperture  103 , the subreflector  106 , and a composite structure  612  that supports aluminum thermal radiators  620  and is internally coated with a radio-frequency (RF) absorber  614 . The anti-jam housing  600  excludes the feed structure  110 . The subreflector  106  is mounted to a first wall  615  of the anti-jam housing  600  via a coupling structure  616 . The feed structure  110 , including the ESA  630 , is kinematically mounted on a wall  625  of the anti-jam housing  600  and the respective ESA mounting access holes are covered via closeout panels  627 . 
     The thermal subsystem  602  includes a thermally conductive ESA mounting plate  632  over which the ESA  630  is mounted, and it is able to transfer high thermal power (e.g., about 250 watts) generated by the ESA  630  to the aluminum thermal radiators  620  via thermally conductive heat pipes  622 . The thermal subsystem  602  can dissipate the high thermal power generated by the ESA  630  and excludes wall  625 . 
       FIG. 7  is a schematic diagram illustrating a heat-dissipation mechanism in a thermal subsystem  700  of an example of a hosted multi-reflector antenna system, according to certain aspects of the disclosure. The thermal subsystem  700  includes the thermally conductive ESA mounting plate  632  over which the ESA  630  is mounted and the thermally conductive radiator  620 . The heat transferred from the ESA mounting plate  632  flows into the aluminum radiator  620  and dissipates to the environment. The ESA mounting plate  632  and the aluminum radiator  620  are coupled to the composite structure  710  via ESA flexures  720  and radiator flexures  712 , respectively. 
       FIG. 8  is a schematic diagram illustrating various views  800 ,  802  and  804  of a heat-dissipation mechanism in the thermal subsystem of an example of a hosted multi-reflector antenna system, according to certain aspects of the disclosure. The view  800  is a top view of the thermal subsystem  700  of  FIG. 7  and shows the aluminum ESA mounting plate  632 , the composite structure  710 , the heat pipes  622 , the aluminum radiator  620 , an ESA hard-mount  810 - 1  and ESA flexures  720 . The ESA hard-mount  810 - 1  and the ESA flexures  720  are used to mount the ESA mounting plate  632  on the composite structure  710 , while keeping them mechanically decoupled, so that thermal expansion  812  of the aluminum ESA mounting plate  632  is not transferred to the composite structure  710 . The front-view  802  is similar to the thermal subsystem  700  of  FIG. 7 . The side-view  804  shows the ESA  630 , the radiator hard-mount  810 - 2  and the radiator flexures  712 . 
       FIG. 9  is a flow diagram illustrating an example of a method  900  of providing a hosted multi-reflector antenna system (e.g.,  100  of  FIG. 1 ) of the subject technology. The method  900  includes coupling a primary reflector (e.g.,  102  of  FIG. 1 ) via a number of booms (e.g.,  114  of  FIG. 1 ) and joint structures (e.g.,  118  of  FIG. 1 ) to an optical bench (e.g.,  116  of  FIG. 1 ) ( 910 ). The method further includes positioning an anti-jam housing (e.g.,  108  of  FIG. 1 ) comprising a low CTE composite structure (e.g.,  410  of  FIG. 4 ) on the optical bench ( 920 ), and coupling a feed structure (e.g.,  110  of  FIG. 1 ) including an ESA (e.g.,  106  of  FIG. 1 ) to a first wall (e.g.,  615  of  FIG. 6 ) of the anti-jam housing ( 930 ). A subreflector (e.g.,  104  of  FIG. 1 ) is coupled to a second wall (e.g.,  625  of  FIG. 6 ) of the anti-jam housing opposite the first wall to direct a reflected beam of the primary reflector onto the ESA ( 940 ). The hosted multi-reflector antenna system is configured to be mechanically and thermally independent of a host space vehicle (e.g.,  420  of  FIG. 4 ) to accommodate thermal dissipation of the feed structure (e.g., via  632  of  FIG. 6 ) and to maintain a precise antenna system alignment (e.g., alignment of  102 ,  104  and  106  of  FIG. 1 ) ( 950 ). 
     In some aspects, the subject technology may be used in various markets, including, for example, and without limitation, the satellite systems and communications systems markets. 
     Those of skill in the art would appreciate that the various illustrative blocks, modules, elements, components, methods, and algorithms described herein may be implemented as electronic hardware, computer software, or combinations of both. To illustrate this interchangeability of hardware and software, various illustrative blocks, modules, elements, components, methods, and algorithms have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application. Various components and blocks may be arranged differently (e.g., arranged in a different order, or partitioned in a different way), all without departing from the scope of the subject technology. 
     It is understood that any specific order or hierarchy of blocks in the processes disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes may be rearranged, or that all illustrated blocks may be performed. Any of the blocks may be performed simultaneously. In one or more implementations, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single hardware and software product or packaged into multiple hardware and software products. 
     The description of the subject technology is provided to enable any person skilled in the art to practice the various aspects described herein. While the subject technology has been particularly described with reference to the various figures and aspects, it should be understood that these are for illustration purposes only and should not be taken as limiting the scope of the subject technology. 
     A reference to an element in the singular is not intended to mean “one and only one” unless specifically stated, but rather “one or more.” The term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and intended to be encompassed by the subject technology. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the above description. 
     Although the invention has been described with reference to the disclosed aspects, one having ordinary skill in the art will readily appreciate that these aspects are only illustrative of the invention. It should be understood that various modifications can be made without departing from the spirit of the invention. The particular aspects disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative aspects disclosed above may be altered, combined, or modified, and all such variations are considered within the scope and spirit of the present invention. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and operations. All numbers and ranges disclosed above can vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any subrange falling within the broader range is specifically disclosed. Also, the terms in the claims have their plain, ordinary meanings unless otherwise explicitly and clearly defined by the patentee. If there is any conflict in the usage of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definition that is consistent with this specification should be adopted.