Patent Application
20250038424
This disclosure relates to a multi-beam antenna array, a satellite communications terminal comprising a multi-beam antenna array, a system comprising a plurality of satellite communications terminals, and methods of operation thereof. In certain aspects, the disclosure relates to an improved VSAT SATCOM terminal composed of an electrically-steered multi-beam lens-array radiating aperture; a containing housing, radome, and base; mounting features for installing to a fixed or mobile platform, and modular bays for the power supply and other end-user customizable hardware.
Conventional satellite communications (SATCOM) terminals are assembled or integrated from a number of different discrete components, which typically include an antenna, a block upconverter (BUC), a low-noise block (LNB) downconverter, an antenna controller (in the case of steerable antennas), and a modem. These components may be assembled in a single location, or distributed across a greater or smaller area with long cable or packet network connections between components. The combination of these components, when properly configured, is then referred to as the SATCOM terminal, functioning as a single unit for communications purposes with the modem acting as the interface for the end user. Terminals that are intended to operate while on-the-move (such as those mounted to vehicles) must include antennas that are steerable in terms of the direction they are pointed relative to the platform on which they are mounted. Steering or pointing the antenna can be done mechanically, in the case of parabolic reflectors or gimbaled flat-panel antennas, or can be performed electronically in the case of electrically-steered antennas such as phased arrays, metamaterial antennas, and lens arrays. Electrically-steered antennas have been challenged in the market due to high power consumption and cost, but offer benefits in terms of beam steering agility and speed and the potential to offer multiple beams pointed from the same antenna, something that mechanically steered apertures cannot offer.
Integrated terminals with all of the respective components combined into a single package have been constructed previously for both electrically-steered antennas and mechanically steered antennas, such as the Kymeta® U8 terminal. Terminals containing lens array antennas have been described by the present Applicant in WO 2018/167717, the full disclosure of which is incorporated herein by reference.
Viewed from a first aspect, there is provided a multi-beam antenna array, comprising:
Each antenna module may comprise at least three individually-steerable antenna elements.
More generally, each antenna module may comprise M individually-steerable antenna elements, where M is an integer greater than 1, preferably at least 3.
Each antenna module may comprise the same number of individually-steerable antenna elements.
The antenna modules may be arranged in a substantially circular or regular polygonal arrangement.
The antenna modules may be arranged in a plurality of nested, substantially concentric circles or regular polygons.
Some of the antenna modules may be configured as transmit antenna modules and a remainder of the antenna modules may be configured as receive antenna modules.
Each substantially concentric circle or polygon may comprise only transmit antenna modules or only receive antenna modules.
An outermost circle or polygon may comprise transmit antenna modules, and an innermost circle or polygon may comprise receive antenna modules. In some embodiments, the outermost circle or polygon may comprise transmit antenna modules, and the inner circles or polygons may comprise receive antenna modules.
The antenna modules may be mounted on a substrate. The substrate may be a parallel combiner slice (PCS). The substrate may be a one-piece substrate. Alternatively, the substrate may comprise a plurality N of tiled sections. The N tiled sections may have substantially the same shape as each other so as to tile together to form a shape with N-fold rotational symmetry. Each of the N tiled sections of substrate may have a substantially identical arrangement of antenna modules mounted thereon.
The antenna array may be configured such that beams formed by the individually-steerable antenna elements are steered in an analog domain. The beams can be steered by adjusting the phase, or the magnitude (amplitude), or the phase and the magnitude (amplitude) of analog signals such as waveforms.
The antenna array may be configured such that a beam formed by combining the beams formed by the individually-steerable antenna elements is steered in a digital domain. The combined beam may be steered by adjusting the phase, or the magnitude, or the phase and the magnitude, by digital signal processors. Phase adjustment may be effected by introducing time delays or time adjustments by way of a digital signal processor.
Phase adjustment can be made by way of phase shifters, which apply the same phase shift independently of the frequency of the signal. However, this can give rise to beam squint when a wide range of frequencies are being used, as for example in a wideband array. In some embodiments, it may be preferred to use true time delay to apply variable phase shifting across the spectrum of the beam that is being steered. True time delay may be implemented in both the analog and digital domains.
In some embodiments, true time delay phase adjustment is implemented in each sub-array of radiating elements.
The sub-arrays of radiating elements may be configured as evenly-spaced feeds in a circular or regular polygonal grid arrangement.
Alternatively, the sub-arrays of radiating elements may be configured as non-evenly-spaced feeds.
The radiating elements in the sub-arrays may be arranged so as to display M-fold rotational symmetry together with the antenna elements within each module. This allows for ease of manufacture and assembly.
Alternatively, the radiating elements in the sub-arrays may be arranged so as to not to display M-fold rotational symmetry together with the antenna elements within each module. A slight asymmetry may contribute to producing a smooth scanning profile at the array level together with the rotation of the antenna modules themselves relative to the array as a whole.
Each individually-steerable antenna element may be a lens antenna comprising a dielectric lens.
The radiating elements in each sub-array may be mounted on a printed circuit board (PCB) that connects to the substrate via a connector. The antenna array may further comprise front-end RF circuits or amplifiers mounted on the PCB.
The radiating elements in each sub-array may be mounted on a PCB that connects to the substrate by way of planar surface-mount solder connections. The antenna array may further comprise front-end RF circuits or amplifiers that connect to the PCB by way of planar surface-mount solder connections.
The radiating elements in each sub-array may be mounted on the substrate. The radiating elements in each sub-array may be mounted directly on the substrate. The antenna array may further comprise front-end RF circuits or amplifiers that are mounted on the substrate, optionally directly on the substrate.
The antenna array may be provided with one mixer stage channel and one digital signal processor (DSP) stage channel per sub-array per supported beam.
The antenna array may be configured such that activation of one or more radiating elements within a sub-array controls a radiation pattern of the associated antenna element within the main array.
The antenna array may further comprise control circuitry configured dynamically to activate different numbers of radiating elements within the sub-arrays according to power and performance requirements.
In some particularly preferred embodiments, M=3 and N=6.
In some embodiments, six antenna modules are provided on each tiled section of the substrate.
In the context of the present disclosure, the expression “N-fold rotational symmetry” is used to describe an arrangement of antenna modules that looks substantially the same when the main array is rotated by integral multiples of 360°/N. For example, where N=6, the arrangement of antenna modules in the main array will look substantially the same, when viewed from above, at each rotation by 60° of the array about an axis of rotation extending perpendicularly through the centre of the main array. It will be understood that manufacturing tolerances and cosmetic features are to be disregarded when determining rotational symmetry, and that minor configurational variations that have substantially no functional effect can also be disregarded.
In the context of the present disclosure, the expression “M-fold rotational symmetry” is used to describe an arrangement of antenna elements in an antenna module that looks substantially the same when the antenna module is rotated by integral multiples of 360°/M. For example, where M=3, the arrangement of antenna elements in the antenna module will look substantially the same, when viewed from above, at each rotation by 120° of the antenna module about an axis of rotation extending perpendicularly through the centre of the antenna module. It will be understood that manufacturing tolerances and cosmetic features are to be disregarded when determining rotational symmetry, and that minor configurational variations that have substantially no functional effect can also be disregarded.
Viewed from a second aspect, there is provided a satellite communications terminal comprising the multi-beam antenna array according to the first aspect.
The terminal may be configured such that the antenna modules are disposed within an antenna aperture, and the antenna aperture may be covered with a radome.
The radome may comprise a composite fiber-PTFE fabric and a ring-shaped support structure.
The terminal may further comprise a housing. The housing may include integrated handles for movement and installation. The housing may include integrated hoist points.
The housing may comprise a plurality of bays. Each bay may be configured to receive one or more electronic modules. Examples of such electronic modules include: power supplies, analog modems, digital modems, computers, cellular gateways, network switches, routers etc. The bays may be configured to allow easy field reconfiguration of the terminal by swapping electronic modules between bays, or adding new electronic components to empty bays. The bays may be provided with electrical connectors configured for pluggable engagement with corresponding electrical connectors on the electronic modules. The electrical connectors may be of an industry standard configuration, such as one or more of the various Universal Serial Bus (USB) standards, or may have a custom configuration.
Two or more terminals of the second aspect may be electrically connected with each other. There may be provided a system comprising at least one terminal of the second aspect configured as a transmit terminal, electrically connected with at least one other terminal of the second aspect configured as a receive terminal.
Viewed from a third aspect, there is provided a system comprising a plurality of satellite communications terminals according to the second aspect, each terminal having a digital waveform port, wherein:
The plurality of terminals may be rigidly mounted to a common mounting frame.
The terminals may be substantially coplanar or mounted in a substantially coplanar configuration.
Viewed from a fourth aspect, there is provided a method of operating the antenna array according to the first aspect, or the terminal according to the second aspect, or the system according to the third aspect, wherein:
Viewed from a fifth aspect, there is provided a method of operating a multi-beam, multi-link satellite communications terminal, comprising:
Viewed from a sixth aspect, there is provided a method of operating a multi-beam satellite communications terminal, comprising:
Embodiments of the present disclosure may be configured to enable full duplex connections to multiple satellites from a single terminal by way of independently steerable beams that allow both transmit and receive.
Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:
Some embodiments of the present disclosure provide a very small aperture terminal (VSAT) communications terminal comprising an antenna aperture in combination with an integrated controller, at least one bay for an integrated modem, and accompanying housing, radome, heat sink, and mounting framework. The combination of these features into a single package offers benefits against terminals that are composed of an antenna, housing, and radome and separate amplifier, controller, and modem components (as is common for many parabolic reflector-based VSAT terminals). The antenna aperture may be a hybrid analog-digital beamforming phased array, where subarrays of the aperture perform beamforming via analog phase and magnitude shifters. Signals from the set of subarrays may be digitized and combined in the digital domain along with phase, magnitude, and time shifts applied via digital signal processing. A preferred embodiment of the antenna aperture is for the antenna subarrays to be composed of electrically-steerable lens antennas that steer their beams by selection of one or more feeds, forming a focal plane excitation on the focal plane of the lens, from a collection of feeds. The lenses may be as described in US 2018/0183152 and U.S. Pat. No. 10,553,947 (the full disclosures of which are incorporated herein by reference), such as an inhomogeneous gradient-index lens, flattened or ordinary Luneburg lens, or metamaterial lens. The location of the focal plane excitation relative to the focal point of each individual lens may determine the scanning angle of the radiation pattern from the individual lens. The feeds at the appropriate position underneath all of the lenses jointly are enabled to create electrically-steered element patterns in all of the subarrays that point in the desired overall pointing direction.
For an individual lens, the minimum spacing between feeds that is dictated by the size and mutual coupling of the feeds means that there are some required scan directions where no one feed can generate a beam in the desired direction. There is the option of picking the feed that generates the beam in the closest direction to the target, but this can result in significant performance degradations, such as the case when the desired focal plane excitation is equidistant from multiple feeds. In this case, multiple feeds may be enabled underneath a single lens simultaneously and their signals summed with magnitude and phase offsets to interfere constructively in the desired direction of operation. This method may enable nearly continuous resolution of element pattern scan directions from the subarrays, rather than the discrete scanning angles achieved by switching only a single feed per lens at a time.
Lens antennas are particularly beneficial when used to form the antenna subarrays, because a lens antenna is very strong in a multibeam context. Generating multiple independent beams from a single lens antenna is performed by enabling multiple feeds simultaneously with different signals. For beams steered in different directions, completely separate feeds may be used, which minimizes the performance impact of generating multiple beams compared to conventional phased array antennas. When multiple beams are pointed close together (where close can be typically defined as within a single beamwidth of the element pattern), then an individual feed may be required to contribute optimally to multiple beams. In this case, the feeds can either be divided to continue contributing only to one beam and allow the beam shape or gain of the other beam to be decreased, or to contribute to both beams simultaneously after backing off the power level of both individual beams. In the expected use cases, beams are typically far apart from each other, such as during handover between a rising and setting satellite, or when communicating with both a geosynchronous equatorial orbit (GEO) and non-geostationary orbit (NGSO) satellite, and the case of sharing power from a single feed between multiple beams is rare and of short duration in each occurrence.
Individual antenna subarrays may be receive-only, transmit-only, or combined receive-transmit in either full- or half-duplex modes. Separating receive and transmit reduces the filtering requirements at the front-end due to the increased isolation between receive and transmit from not collocating those two functions. Reduced front-end filtering requirements may also reduce or minimize absorptive losses in the front end, which may directly impact the critical transmit equivalent isotropic radiated power (EIRP) and receive gain to noise temperature (G/T) metrics.
Independent of the size of the subarrays for beamforming purposes, one or more subarrays may be grouped for convenience in printed circuit board (PCB) design and layout, or sharing control circuitry such as microcontrollers for setting the state of the radio frequency (RF) components. Some preferred embodiments may gather lenses into groups of three to be mounted together and share common circuitry, but other numbers are possible, such as individual lenses, two, four, or six. The number in each group may be selected to enable tiling of the group of lenses. These groups of lenses, together with the associated printed circuit boards with feeds & associated RF front-end circuits and control circuitry, are collectively referred to as antenna modules.
The size of the analog subarrays may be selected based on the competing trades of instantaneous bandwidth, power consumption, and terminal cost. Subarray size may be limited by beam squint, which is a change in the direction of the steered subarray element pattern with frequency that is caused by the frequency dispersion of analog phase shifters. The larger the subarray when measured in electrical wavelengths at the operational frequency of the terminal, the more beam squint will occur. For a hybrid analog-digital array, the ultimate array steering direction is determined by the digital time delay offsets applied by the digital signal processor (DSP), and beam squint exhibits at the system level as a frequency dependence on antenna gain caused by an effective change in gain at the element patterns due to the change in steering direction. In some preferred embodiments, a single lens antenna may used as the subarray to minimize effect of beam squint, but additional lenses may be combined in the analog domain to reduce the number of required DSP channels, which reduces both power consumption and number of integrated circuits (ICs) and therefore cost. Three lenses would be a natural increase, such that a single tri-lens antenna module may be treated as a subarray, or nine lenses consisting of three tri-lens antenna modules.
It is most beneficial for one or more subarrays to be grouped onto a single antenna module, rather than multiple antenna modules to be grouped into a subarray, since all signals at the subarray level are combined in the analog domain and processing introduces noise and distortion. Once the subarray is processed into the digital domain, the data may be transferred and operated upon with much more controlled operations to minimize any further introduced distortions and noise.
Turning to the figures, in
As seen in the bottom view of
The power supply bay 111 and multi-purpose bays 113 are shown superimposed upon the central control module (CCM) 131 on the other side of the heat sink 107, with connectors 127, 129 passing through the heat sink 107 to provide power and signal connections to the contents of the bays 111, 113. The external user interface (including management & user data ethernet & serial ports, Tx mute, and status readouts) is available through the modular power bay 111, which may be replaced to change a terminal from a DC supply (such as a nominal 24V vehicular supply) to an AC supply (such as a 120 or 240 VAC mains supply). Silhouettes of the global navigation satellite system (GNSS) receiver antennas 125 and parallel combiner slice (PCS) PCBs 133 within the terminal are also illustrated. Additional features may include crane or hoist attachment points 121 and carrying handles 123.
The top of the terminal 101 with the radome removed is illustrated in
The PCS 133 is irregularly shaped to accommodate the tilings of the triangular antenna modules 141 while still achieving an optimal packing density. In this embodiment, each PCS 133 hosts six antenna modules 141, of which three antenna modules 141 are configured to operate in the transmit mode, and three in the receive mode. Different aperture sizes can be configured with more or fewer antenna modules 141 and different ratios between receive and transmit modules to vary the performance ratio between receive and transmit at the terminal level. The GNSS antennas 125 may be electrically connected to the PCS 133 or directly to the CCM 131 and mounted to the housing 105. Depending on the implementation, the signals passed from the antenna modules 141 to the PCS 133 via the connectors 145, 153 may either be digital (if the DSP ICs are mounted on the antenna module 141) or analog (if the DSP ICs are mounted on the PCS 133). An additional PCB 151 connects the six PCS 133 to share common signals and power, and each PCS 133 connects down to the CCM 131 for unique connections to each PCS 133 such as the control and high-speed digital waveform lines.
More detail of the arrangement and distribution of the receive and transmit antenna modules 141 in a preferred embodiment are shown in
Multiple potential embodiments are illustrated in
The PCS 133 is shown connecting to the CCM 131, which also connects to the power bay 111 and multi-purpose bays 113 using the connectors 127, 129 through slots in the heat sink 107. Depending on the expected levels of dissipated power and operating temperature ranges, fans 311 may be included to provide forced-air cooling across the heat sink.
This embodiment 301 is the simplest to design, as it separates the functionality of the antenna modules 141, which provide the front-end RF processing from multiple lens antennas 143 and associated feeds, from the PCS 133, which combine signals from multiple antenna modules 141, from the CCM 131, which performs the ultimate beamforming operation to combine the signals from all of the PCS 133, and hosts the terminal control and management processors and software.
A modified embodiment 331 illustrated in
A further simplification 361 illustrated in
In embodiments 331 and 361, the array plate 313 is no longer required, since the thermally active components are now directly mounted to the PCS 133. In these embodiments 331 and 361, the array plate 313 the plate is removed (which offers a mass reduction for the terminal as a whole) and the structure of the heat sink 107 adjusted to directly remove heat from the circuits mounted to the PCS 131.
Details of the preferred embodiment for the antenna module 141 are illustrated in
Although
Each of the split data streams 636 are then passed through a daisy chain of DSP stages 627, which cascade the digitized waveform 636 to additional DSP stages 627 through the digital interconnect 635, while splitting off copies of the signal 633 to be passed through configurable digital filters and time/phase/magnitude shifters 631. The time delay, typically implemented as a configurable buffer in the DSP stage combined with fine-tuning through the configurable filter, allows the physical distance between subarrays to be corrected for and therefore reduce the incidence and impact of beam squint in the array radiation pattern. The final stage of the DSP stage 627 is a digital-to-analog (DAC) converter 629 that produces a baseband or intermediate frequency (IF) analog signal from the processed waveform samples 636. Each stage includes one or more duplicate processing chains to support multiple channels of data to be processed independently, such as separate subarrays, antenna modules 141, lens antennas 143, or multiple beams associated with a single antenna module 141 or lens antenna 143. The DSP stage may be implemented as separate ICs for each stage, or may be implemented by combining multiple stages 627 and the splitter 637 into a single monolithic FPGA or SOC. The number of DSP stages and channels per DSP stage 627 are determined by the number of supported beams per subarray and the number of subarrays in the array 101.
Analog intermediate frequency (IF) signals from the DSP stages 627 are then upconverted to the target RF frequency in a mixer stage 621, which includes multiple mixers 623 and associated filters and other relevant circuitry, such as local oscillator (LO) generation, management, and amplification, clock synchronization, and configurable amplification. Mixer stages 621 may be implemented as integrated ICs, or may be composed of discrete components.
One upconverted RF signal is generated for each supported beam in each subarray of the terminal 101. The RF front-end 611 consists of a selector 620 that chooses one or more feeds 311 within a subarray to use for a given beam. The selector 620 acts as a matrix switch that allows any number of outputs to be connected to each input, as well as summing outputs to receive inputs from multiple inputs simultaneously. Any feeds 311 that are not selected by at least one beam can have their associated amplifier 615 and other circuitry 617 disabled to reduce power consumption. This process then allows an individual feed to contribute to multiple beams, by summing multiple RF inputs. The resulting signal for each feed, which may be disabled individually as necessary, is then split 619 into two components for two polarizations, which are then individually processed via a magnitude and phase shifter 617 and amplifier 615 before being passed through a filter 613 and radiated by the feed 311 through the lens 143, with the direction of the resulting signal being determined by the location of the feed 311 relative to the focal point of the lens 143. The RF front-end 611 circuits can be implemented as an integrated IC with multiple channels per IC, or can be implemented with a combination of discrete components.
Turning to
The output of the selector 670 is then passed to a mixer stage 671, which includes a downconverting mixer 673 and associated filters and other circuits, such as LO generation and management. Multiple channels may be included in the mixer stage 671, to support multiple beams.
The output of the mixer stage 671 in then processed in the DSP stage 677 by first being digitized by the analog to digital converter 679. Each channel corresponding to a beam and subarray is digitized separately and processed with phase, magnitude, and time shifters and reconfigurable filter 681. The output of each digitizing channel in the DSP stage 677 is then summed 683 with the input 685 of the DSP stage 677 to produce the output waveform 686 consisting of the sum of all of the signals of the different subarrays from a single beam of a single PCS 133. The combined waveforms 686 from each beam of each PCS 133 are then summed into a single output waveform for each beam from the terminal 101 as either a digitized waveform 691 or as an analog L-band IF waveform 693 after being passed through a DAC 689. The DSP stages, summer 687, and DAC 689 may be implemented in an integrated FPGA or SOC, or may be implemented with custom components for each stage and function.
A controller, hosted on the CCM 131, which may take the form of one or more microprocessors (potentially hosted on an FPGA or SOC), interacts with all of the components in both the transmit 601 and receive 651 subarrays. The amplifiers 615, 655, phase & magnitude shifters 617, 667, and selectors 620, 670 for different channels in the set of lenses 143 may be enabled/disabled and values configured by the controller. Depending on the number of beams in use at a moment in time, individual channels of the mixer stages 621, 671 and DSP stages 627, 677 may be enabled or disabled. For any enabled channels, the settings of the time, phase, and magnitude shifters and the reconfigurable filters are set by the controller, which will also configure the appropriate LO settings for the mixer stages 621, 671 for each enabled beam. The controller also serves as the antenna control unit (ACU) that enables both inertial and GNSS-based tracking of stationary and moving (GEO & NGSO) satellites from stationary and moving platforms, as well as the external user interface and management system for the terminal. The summer 687 and splitter 638 functionality are implemented on the CCM 131.
The waveforms 641/643, 691/693 are sourced from/provided to a modem connected to the terminal 101. Multiple modems may be connected, to allow for multiple beams to be active from the terminal 101 at once. Modems are connected to the CCM 131, which processes the digitized waveforms 641, 691, through the multi-purpose bays (MPB) 113 and associated connectors 129. The terminal 101 supports different contents of the MPB 113, which can include modems installed in card form directly to integrate the entire functionality of a communications terminal into a single box. In this case, digital or analog waveforms 641, 643/691, 693 are received from/provided to each modem within a MPB 113. Alternately, the MPB 113 can itself include external connectors, such as N-type coax, ethernet, or others, to enable connecting an external modem to the terminal. Since the digitized signals 641, 691 are available, modified or simplified versions of the modem may be used that do not include the typical initial DAC/ADC stages, reducing the power consumption of the modem.
The MPB 113 may be used for other functionality as well, not only modems. Alternate communications channels may be installed, such as additional networking ports, cellular modems for data offloading, or local WiFi. In addition, the digitized waveforms 641, 691 that can be transferred through the MPB 113 can be used to perform beamforming between multiple terminal instances 101, rather than only connect to a modem. Multiple instances of the terminal 101 may be used in different configurations and combinations, as illustrated in
Due to the difference in orientation between lenses and feeds within a single antenna module 141, some special handling is required to enable beamforming across the array.
There are multiple ways that that this can be managed for the terminal 101 overall. The simplest case is to choose the single closest feed under each lens for the desired beam direction 831, and accept that most lenses will produce element patterns that are not peaked in the desired scanning direction, thus reducing the overall array antenna gain in the desired direction. This is illustrated in
By enabling multiple feeds at once beneath a single lens, as shown in feed group 313b for feeds 832 and 834 with an appropriate calibrated magnitude and phase difference, an aggregate element pattern 837 from the lens can be produced as the weighted sum of the two feed patterns 833 and 835 to point in the desired beam steering direction 831. When this process is repeated for all of the lenses 143 in the terminal 101, the improved performance over enabling only the closest feed 311 in each lens can be significant. Additional feeds can be enabled using the same principle, with diminishing returns on improved performance for enabling more than about four feeds in most configurations. The results are even more significant in transmit mode than receive mode, since each enabled feed contributes RF power as well as improved antenna radiation patterns, thus contributing to the transmit EIRP in two ways. Which feeds and the number of feeds under each lens for a given beam are configured by the selector 620, 670 hardware by the controller on the CCM 131.
The number of feeds used under each lens for beamforming can be adjusted to tune the performance of the array. For example, in a power-optimized operational mode, the controller might select only a single feed 311 per lens 143 and accept the reduction in performance. Alternately, the controller might select four feeds 311 per lens 143 in a performance-optimized operational mode, in exchange for increased power consumption and heat generation. Different operational modes can be applied to different beams, such that a standby beam might be dynamically configured to use minimum resources (feeds, power) in a standby mode, but to automatically scale up to more resources if the link becomes busy. Intermediate and intelligent steps can be applied as well, with varying number of feeds selected per lens based on a balance of power and performance, such as only adding an additional feed if it increases the per-lens performance by a set threshold, or enabling more feeds per lens at wide scanning angles where scan losses are more severe, but operating with reduced number of feeds near boresight where gain is improved. These forms of dynamic resource allocation allow the performance and power consumption of the terminal 101 to be adjusted under software control as circumstances demand. The use of different numbers of feeds as different performance modes is a commercially valuable feature, as access to different settings can be included as software-unlocked capabilities for end-users. For example, a terminal operates ordinarily in a standard power setting with a given set of specified performance metrics. An end user, through the controller or a web interface, could request additional features, including additional beams past a default of one, to be unlocked either in an unlimited or time-limited way through a software key. The ability to boost satellite link performance by a discrete amount for a period of time could allow for more performance while traveling in a location with poor coverage to a desired satellite, or to support additional users or visitors during a short time period when the additional communication capacity is not required all of the time.
The number of feeds may be set by the controller in all cases. For each beam and lens, one or more feeds may be enabled to create the beam. The controller, by monitoring the link performance (such as the carrier to noise ratio) and the requested data traffic (instantaneous throughput, buffer lengths, TCP retransmits), can change the number of enabled feeds to better match the antenna's performance to the capacity of the link. By decreasing the number of feeds when traffic is low, power is saved. When traffic is high and the link is congested, additional feeds can be enabled to increase the EIRP & G/T of the multibeam lens array terminal and improve the communications performance, at the expense of increased power. This dynamic resource allocation feature allows power consumption and performance to be balanced by changing the number of enabled feeds under each lens for each beam.
The number of enabled feeds may also affect the beam quality. Enabling multiple feeds can improve the shape of the radiation patterns of a lens antenna even if all but one feed are enabled with significantly lower signal amplitude by being tuned to compensate for sidelobes or beam asymmetry from the dominant feed.
A block diagram of the critical components of the terminal 101 is shown in
The heat sink 107 is thermally connected, directly and indirectly, to all of the heat-generating electronic components in the system. The subsystems with the highest power density are the transmit antenna modules 141, which hold the final-stage high-power amplifiers. In this embodiment, the antenna modules 141 and the PCS 133 are mounted on both sides of an array plate 313, which acts as both structural support as well as a local heat sink for the high-power RF & digital components. The array plate 313 may be implemented as a machined or cast aluminum plate with cutouts to interface with the circuits and components, or may include heat pipes to increase thermal conductivity. In the case of embodiments 331 or 361, the array plate 313 may be removed and compensated by a more direct thermal connection directly from the heat sink 107. The array plate 313 then connects via heat pipes or other thermally conductive structures to the heat sink to transfer the heat from the circuitry to the base of the terminal 101, where the heat may be radiated from the heat sink 107 assisted where required by forced air provided by the fans 311.
RF signals received/transmitted from the antenna modules 141 are provided to/from the PCS 133 as either analog RF or IF or digital waveforms, with the mixer stage 621, 671 and DSP stage 627, 677 functionality implemented either within the antenna module 141, the PCS 133, or CCM 131. The waveforms are transferred between the various PCS 133 and CCM 131, where the signals from all of the PCS 133 are combined. The controller on the CCM 131 also controls and sets of the state of all of the electrical components of the system and configures the communications path between the MPB 113 and the CCM 131. The controller on the CCM 131 is connected to the GNSS & inertial measurement unit (IMU) sensors 913 and the optional integrated cellular modem 911 to provide either low-cost backhaul when in range of terrestrial communications coverage and back-channel terminal debugging and updates through low-bandwidth terrestrial links.
The MPB 113 is mounted to the heat sink 107 with the connector 129 passing through a slot. The contents of the MPB 113 (which may be an embedded modem card, an external modem pass-through card, a digital waveform pass-through card, or other functionality) communicate with the controller on the CCM 131 to pass power, control, management, and waveform data through the connector 129. The connector passes control, management, and user data through gigabit ethernet, digitized waveform samples through gigabit, 10-gigabit, or greater ethernet, power, and any incidental signals required by modems or other devices (such as Tx mute). The modular power supply bay 111 is also mounted to the heat sink 107 with the connector 127 passing through a slot. The connector 127 includes regulated power supply to the terminal 101, ethernet connections to support the external user interface as well as management and control and user data forwarded from internally installed modems, as well as other individuals signals such as serial ports and Tx mute lines. The modular power supply bay 111 and MPB 113 are field removable and swappable. The external user interface, including management and user data ethernet ports, indicators, and the external power supply input are provided from the modular power supply bay 111.
With multiple modems installed (or a multi-beam capable modem), the terminal 101 can support multiple independently-steerable bidirectional beams (where each beam is a transmit-receive pair) where the pointing angle in two dimensions (theta, phi or azimuth, elevation) of each of the beams is set by the antenna controller. These beams can be used for multiple links to multiple satellites in different constellations or orbits, for make-before-break handovers where the current satellite can be changed without losing the link.
There are additional use cases and commercial values for the second and further beams of the multibeam satcom terminal. In some cases, such as handover, the use of the second or further beams could be enabled and available all of the time. In other circumstances, the end user may only require a single link at most times. However, if during a short time they required additional bandwidth, the satellite service provider in concert with the antenna hardware vendor could offer access to additional beams as a service to temporarily (or permanently) increase the capacity to a single terminal. In this way, end users with requirements for single links can have access to the other capabilities of the electrically-steered terminal at a lower cost, while end-users making full use of the many-beam connectivity to establish multiple bidirectional links can access the capability of the terminal through a software unlock. In other cases, the end users of the terminal might not know or care about how many beams are used to provide the contracted bandwidth, and a service provider or satellite operator might transparently enable or disable different beams to different satellite assets in order to optimize the efficiency and/or throughput of their network. In either case, the terminals capability to establish multiple links with multiple satellites opens new options for commercializing the capability.
Numerous applications of the disclosure will readily occur to those skilled in the art. Therefore, it is not desired to limit the disclosure to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the disclosure.
Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2113903.5 | Sep 2021 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/GB2022/052371 | 9/20/2022 | WO |
