Field-assembled modular phased array SATCOM terminal

Abstract

A field-assembled satellite communications terminal has a plurality of individual modular aperture blocks. Each aperture block includes an electrically operated antenna aperture and a plurality of interconnection ports for power and data communications between the plurality of aperture blocks. The plurality of interconnection ports are removably connectable by an end user in the field. The terminal also has a signal processing system that receives, processes, and generates signals to and from the apertures. The aperture blocks are connected together in the field and self-configure to form an electrically operated antenna.

Description

[Technical Field]

[0001] The present disclosure relates to a manpack or portable VSAT satellite communications terminal that includes an antenna, a modem, and support equipment.

[0002] [Related Applications] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 004929, filed April 3, 2020, on the contents of which the present application relies, the contents of which are incorporated herein by reference in their entirety. [Background technology]

[0003] Communications satellites provide connectivity to fixed, mobile, permanent, and temporary sites worldwide via a number of frequency bands and services. The VSAT (Very Small Aperture Terminal) service class, offered in the X, Ku, and Ka frequency bands, is used for civil, commercial, and defense applications that require worldwide connectivity and high bandwidth from a moderate aperture size. Alternative lower frequency band (UHF, L-, S-, C-) services are applied for uses requiring much lower bandwidth, except where extremely large antennas can be used.

[0004] Communication with a satellite requires a terminal that includes an antenna, a modem, and associated amplifiers, mixers, and other RF or microwave components. Terminals are differentiated primarily by their antennas, whether they are fixed or steerable, mechanical or electronic.

[0005] For defense and civilian applications where intermittent and on-the-fly communications are required in remote locations, a particular class of terminals known as "manpacks" are designed to be easily transported, assembled, operated, and disassembled by a very small group of individuals. Manpack terminals can be considered a subset of the Comms-on-the-Halt antenna class, but specifically antennas that can be transported on foot by one or two individuals. Weight, power consumption, volume, and ease of use are key differentiators in this market segment. In particular, the ability to travel with the antenna on an airplane as carry-on or checked baggage is highly valued.

[0006] For VSAT frequencies, parabolic reflector antennas are nearly universal among manpack solutions. The most common approach is a parabolic dish that is broken into pieces. The pieces clip together, and a central foldable frame holds the feed antenna, sub-reflector, amplifier, modem, battery, and other equipment to form the correct shape. See, for example, the Hawkeye III Lite, a 1.2M Tri-band VSAT, www.L3Harris.com. Size and weight determine whether a terminal is considered a manpack or a larger flyaway terminal intended for transport by truck or plane rather than by individual. A variety exists that are inflatable spheres containing a reflector and feed. See, for example, Expeditionary SATCOM, Cubic, www.cubic.com. Some models have motorized automatic pointing, while others require an experienced or semi-experienced user to align the reflector with the desired satellite. Fully integrated, pre-set and pre-configured modems are very common because end users are interested in fast setup and teardown of communications without the need for configuration and complicated wiring or setup.

[0007] Flat panel antennas (e.g., Digisat International's Paradigm Communications Swarm 45 (45 cm) flat panel Ka-band satellite terminal) are an alternative to parabolic reflectors as the primary antenna for SATCOM terminals. These terminals can be smaller and, in some cases, lighter than parabolic antennas, but are not typically used for very large aperture sizes and very high performance applications.

[0008] Conventional phased array or electronically scanned antennas are rarely used in manpack configurations, primarily due to their high power consumption relative to performance and the aperture size limitations imposed on integrated antennas designed for one-person portability. In other applications, phased arrays offer many advantages, including near-instantaneous scanning and tracking capabilities with greater reliability due to the lack of moving parts. To achieve high performance, a large aperture size is required, which also increases power requirements. Summary of the Invention

[0009] A field-assembled, electronically scanned phased array for VSAT satellite communications includes a set of independent, identical, freestanding aperture blocks that self-configure and calibrate to mechanically or magnetically interlock in the field with limited or no exposed contacts to form a single phased array or other electrically operated antenna aperture. Each block contains control, power, antenna segments, signal processing, and interfaces so that any combination of blocks, from a single block to many (unspecified number), can be tiled together to form a functioning satcom terminal. Different implementations can include an integrated modem and battery, or have a single externally connected block that provides these and other capabilities for the entire assembled terminal.

[0010] The overall antenna aperture, which combines the antenna apertures from each assembled aperture block, has gain and performance proportional to its size. That is, the more blocks, the greater the antenna gain and the higher the achievable performance. As many available blocks as possible are combined on-the-fly in the field to form a functioning communications terminal with automatic configuration, satellite tracking, and connection initialization. This communications terminal can then be quickly disassembled and split for transport. Compared to the traditional case where a single individual carries communications equipment, communications capabilities are distributed among a group of individuals. Each individual block is lightweight and easily transported. This system can be used as a manpack terminal or a flyaway terminal, where the number of allocated modules determines the overall performance.

[0011] The following references cited herein are incorporated by reference in their entirety.

[0012] The accompanying drawings are incorporated into and form a part of this specification. It should be understood that these drawings illustrate only some examples of the present disclosure, and that other examples or combinations of various examples not specifically shown in the drawings may be included within the scope of the present disclosure, although not shown in the drawings. Examples will now be described in more detail by using the drawings. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 illustrates the present disclosure having a collection of free-standing electronically scanned modular antenna aperture blocks that are interconnected in the field to form a terminal. [Figure 2(a)] FIG. 12 is a side view of the interconnect structure and interface between two aperture blocks, along with magnets for physical alignment and methods for wireless data and power transfer. [Figure 2(b)] FIG. 10 is a top view of the interconnect structure and interface between two aperture blocks, along with magnets for physical alignment and a method for wireless data and power transfer. [Figure 2(c)] FIG. 10 is a side view of an alternative interconnect structure and interface between two aperture blocks with a transformer for power transfer and an optical interface for data transfer. [Figure 2(d)] FIG. 10 is a top view of an alternative interconnect structure and interface between two aperture blocks with a transformer for power transfer and an optical interface for data transfer. [Figure 2(e)] FIG. 10 is a side view of a second alternative interconnect structure and interface between two aperture blocks with conductive contacts for power and data signals. [Figure 2(f)] FIG. 10 is a top view of a second alternative interconnect structure and interface between two aperture blocks with conductive contacts for power and data signals. [Figure 3(a)] FIG. 1 is a block diagram of a single antenna aperture block. [Figure 3(b)] FIG. 10 is a block diagram of an alternative embodiment of a single antenna aperture block with associated external modem and power supply functionality. [Figure 4] FIG. 1 is a block diagram of an electronically scanned modular terminal. [Figure 5] 1A-1C illustrate representative choices of block shapes and interconnect geometries. [Figure 6] FIG. 10 shows an aperture block constructed using a lens antenna array as an electrically steered antenna aperture. [Figures 7(a)-7(d)] FIG. 10 shows arrays of different sizes constructed using the same aperture block. [Figure 8] FIG. 10 illustrates how apertures can evolve with arrays constructed from various numbers of aperture blocks. [Figure 9(a)] FIG. 1 shows an assembled terminal with accessories. [Figure 9(b)] 1 shows an assembled terminal having an external interface module block, a power block, and a modem block. [Figure 10]FIG. 1 is a workflow diagram illustrating the setup and operation of a terminal. [Figure 11] FIG. 1 illustrates a measurement system for measuring the relative position and alignment between two aperture blocks for on-the-fly calibration purposes. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present disclosure includes a field-assembled satellite communications terminal targeted for manpack or flyaway applications where portability, ease of use, and robustness are critical, although other applications may also be provided. As shown in FIG. 1, the satellite communications terminal 101 includes a plurality of interconnected individual aperture blocks 103. The aperture blocks 103 include a first block 103a, a second block 103b, a third block 103c, and a fourth block 103d. However, any suitable number of blocks 103 may be utilized. Generally, each individual block 103 in the array 101 is identical and interconnected with its neighbors in a modular fashion, ranging from a single block to multiple blocks, with possible rotation between adjacent blocks to form a larger array of interconnected blocks of any size to form the satellite communications terminal. Each modular block can operate independently when properly connected to power and a local data communications channel (i.e., Ethernet, modem) with the end user; however, the more modular blocks interconnected, the greater the capabilities of the combined terminal. In this illustration, each block 103 is substantially square or rectangular, with four sides having edges and an aperture 105 located in the center of the block 103. Different block shapes are possible.

[0015] One important feature of the present disclosure is that individual modular blocks 103 are assembled into the terminal 101 on-demand by the end user in the field (e.g., without requiring special tools or training at the time of use), and the assembled blocks, regardless of the number of blocks used, then self-calibrate and initialize themselves to communicate with the satellite. Received signals from the satellite and transmitted signals from each aperture block to the satellite are transferred between blocks as digitized waveforms, comprising digital samples of the waveform, at either RF frequencies, intermediate frequencies (IF), or baseband, to reduce DSP requirements. This differs from other phased arrays, which are described as consisting of modular subarrays that are assembled into an array, assembled and calibrated in a factory or during installation on a mobile platform, but are not repeatedly disassembled and reassembled into a functioning terminal by the end user at various times and configurations. While self-calibration, which corrects for time-dependent changes to thermal or frequency response, is common in existing phased arrays, this standard capability (also called Built-In Test [BIT]) does not support the continued operation of a terminal when it is disassembled into component modules, transported, and then reassembled in a different shape and configuration when needed. The exchange of digitally sampled waveform data simplifies the calibration process because digital communication removes sensitivity to phase and amplitude variations at each block connection, which can vary from assembly to assembly. Once digitized, waveforms can be transferred between field-assembled modular blocks without distortion or signal loss.

[0016] A key feature of each block 103 is a phased array antenna aperture 105 or other electrically operated antenna aperture. This aperture is recessed inside the block 103 but resides on top of the block 103 to allow free radiation into the upper hemisphere. When the blocks are interconnected for operation in the field, the antenna apertures 105 of each block 103 are active and work together to form a larger, combined or aggregated antenna aperture with gain and overall antenna performance commensurate with the size of the combined or aggregated antenna aperture. Various numbers of blocks 103 can be assembled into an array. The blocks are interconnected through communication power transfer ports 107, which also provide mechanical alignment and orientation between the blocks 103. The ports constrain adjacent blocks so that they are coplanar (within mechanical tolerances) and point in the same direction, thereby ensuring that all antenna apertures 105 are coplanar and point in the same direction within mechanical tolerances, allowing them to all communicate with the same target. Thus, a single aperture block 103 can be connected to additional blocks 103a and 103b via ports 107. In the illustrated embodiment, ports 107 are located in the center of each side edge of block 103. The housing or outer case of each block 103 should be hermetically sealed and resistant to environmental conditions encountered outdoors (moisture, dust, sand, mud, etc.). The housing includes an RF-transparent radome above the antenna apertures 105. Ports 107 are formed within the block housing in a manner that prevents the ingress of moisture or contaminants.

[0017] Although terminal 101 can be designed to operate in any frequency band, the preferred embodiment is for one of the common VSAT frequency bands: X-band, Ku-band, and military and commercial Ka-band. To increase operational flexibility, operation across multiple bands in the same aperture is highly desirable, for example, a single terminal operating across X-band and Ku-band, or Ku-band and Ka-band.

[0018] Each block should be capable of both transmitting and receiving satellite signals through an antenna aperture 105 in either switched half-duplex mode, or simultaneous full-duplex mode with separate antenna subsets for transmitting and receiving, or through a shared aperture. It is possible to build a terminal 101 from both, with separate aperture blocks 103 for either transmitting or receiving, but this places more constraints on assembling the blocks to form a functioning terminal, as correct ratios and placement are required.

[0019] An antenna aperture 105 that simultaneously supports multiple transmit and receive beams is highly desirable because the terminal 101 can then collectively support multiple beams, enabling connections to multiple satellites simultaneously. This may be desirable to enable more resilient communications through multiple terrestrial gateways, or to selectively route communications through two different networks with different bandwidth, latency, or data security characteristics. Additionally, emerging constellations of NGSO (Non-Geostationary Orbit) satellites, including satellites in LEO (Low-Earth Orbit), MEO (Medium-Earth Orbit), and HEO (Highly Elliptical Orbit), are beneficial in enabling seamless make-before-break handover for terminals with multiple beams from the same aperture.

[0020] Interconnect ports 107 between aperture blocks 103 are used for all data and power transfer between the different blocks. While multiple implementations are possible, including traditional ports, plugs, headers, and / or cables, any solution requiring exposed contacts or holes is prone to damage or becoming inoperable due to dirt, grease, moisture, or any number of environmental contaminants or conditions. For this reason, one embodiment of the present disclosure uses a short-range, high-speed wireless link for data transfer and inductive coupling for bulk power transfer, as shown in Figure 2, which illustrates an expanded side view (Figure 2(a)) and an expanded top view (Figure 2(b)).

[0021] In all cases, the implementation of the interconnection port 107 must be symmetrical across the geometric centerline to allow interfacing with identical ports on neighboring blocks 103. For example, a single power transformer coil 205 should be centrally positioned within the port 107, while posts 203 and holes 201 intended to interface with each other from neighboring blocks should be symmetrical about the centerline.

[0022] In one embodiment, the outer case or housing of aperture block 103 is sealed and has no holes or perforations. For alignment purposes, port 107 (including power and data transfer capabilities) includes alignment features formed by symmetrical alignment mounting holes 201 and posts 203 that align aperture blocks 103 when they are mated.

[0023] In one embodiment, as shown in FIGS. 1 and 2, the hole 201 of the port 107a is recessed inward from a side edge of the block 103. The hole 201 has a first sidewall 202, a second sidewall 204, and a bottom surface 206 formed between the first sidewall 202 and the second sidewall 204. The sidewalls 202, 204 may be angled to taper outward so that the top of the hole 201 is wider than the bottom 206 of the hole 201, allowing for easy alignment between the blocks 103. As best shown in FIG. 2(a), the hole may be circular or oval in shape, although other shapes, such as substantially square or rectangular, may also be used.

[0024] The post 203 has a mirrored geometry relative to the hole 201, allowing the post of one block 103a to engage with the hole of the second block 103b and vice versa. The post 203 protrudes outward from a side edge of the block 103. The post 203 has a first sidewall 208, a second sidewall 210, and a top surface 212 formed between the first sidewall 208 and the second sidewall 210. The post 203 forms a base at the side edge of the block 103. The sidewalls 208, 210 may be angled to taper upward so that the top surface 212 is smaller than the base. As best shown in FIG. 2(a), the post 203 may be circular or elliptical in shape to match the shape of the hole 201.

[0025] The holes 201 and posts 203 are angled and shaped to slidably interconnect and mate with respective posts 203 and holes 201 of the adjacent mating block 103, as shown in FIGURE 1. Thus, for example, the side walls 202, 204 of the hole 201 slidably receive the side walls 208, 210 of the post 203 of the adjacent mating block. When fully mated, the top surface 212 of the post 203 contacts the bottom surface 206 of the hole 201, supporting direct electrical engagement of the contacts, inductive coupling between the transmitting transformer coils, and / or wireless data transmission via adjacent transceivers in the holes 201 and posts 203, respectively.

[0026] 1, the second sidewall 204 of the hole 201 and the first sidewall 208 of the post 203 can be continuous. Thus, the post 203 of one block can slide along the first sidewall 208 and the second sidewall 204 of the hole 201 of an adjacent block to be received within the hole 201. In another embodiment, shown in FIGS. 2(a) and 2(b), the hole 201 and the post 203 can be slightly separated to form a bridge 214 therebetween.

[0027] Strong magnets 209a and 209b with appropriate polarization are aligned within holes 201 and posts 203 and cooperate to hold the module in place. Additionally, electronic components, such as short-range, high-frequency communication components such as microchips 207a, 207b (see, for example, Keyssa technology (www.Keyssa.com)®, © 2021 Keyssa, Inc.), are attached to holes 201 and posts 203, respectively, to wirelessly pass traffic between the two aperture blocks 103 via ports 107.

[0028] 2(a) and 2(b), a first magnet 209a is recessed into the bottom 206 of the hole 201 and mounted centrally on the inner surface of the bottom 206 of the hole 201 (i.e., inside the hole within the block body) so as to be substantially flush with the bottom surface 206 of the hole 201. A first electronic device or component 207a is recessed into the bottom 206 of the hole 201 and mounted adjacent to the side of the first magnet 209 on the inner surface of the bottom 206 of the hole 201 so as to be substantially flush with the bottom surface 206 of the hole 201. A second magnet 209b is mounted centrally on the outer surface of the upper portion 212 of the post portion 203 and recessed into this outer surface so as to be substantially flush with the upper surface. A second electronic component 207b is mounted adjacent to the side of the second magnet 209b and is recessed into the outer surface of the upper portion 212 of the post portion 203 so as to be substantially flush with the upper surface.

[0029] First magnet 209a and second magnet 209b are attracted to each other. Thus, when post 203 is slidably received by hole 201, magnets 209a and 209b fully retract post 203 into hole 201, fully engaging adjacent blocks with each other and exerting a magnetic attractive force that maintains the engagement of adjacent blocks. Additionally, a user can separate adjacent blocks if desired.

[0030] The first electronic component 207a and the second electronic component 207b are positioned to align with their respective mating components 207b, 207a of the adjacent block. When the adjacent blocks are fully engaged, the first electronic component 207a and the second electronic component 207b are aligned with each other and communicate via a short-range wireless channel, such as an ultra-wideband transceiver without electrical contacts or inductive or capacitive coupling. In one embodiment, the magnet 209a and / or the electronic component 207a can be recessed into the outer surface of the hole 201 so as to be substantially flush with the inner surface of the hole 201. The magnets 209a, 209b can also be positioned inside the block body and exert a magnetic force that extends through the block body into the hole or through the top of the post.

[0031] Depending on the capabilities of the chips 207, each of these chips can pass bidirectional traffic or can send data in only one direction: data is sent through the holes 201 and received through the posts 203, or vice versa. When the two aperture blocks 103 are aligned and interfaced via the holes 201 and posts 203, the magnets 209 hold them together with the proper tolerances so that the communication chips are properly aligned for proper operation. The magnets 209 and communication microchips 207 are inside a hermetically sealed block case or housing and are not visible from outside the aperture block. Magnetic coupling and data transfer occur through a magnetically and RF-transparent (polymer) housing or an RF-transparent and magnetically-transparent window in a non-transparent housing. The port 107 coexists with the aperture 105 within the sealed case or housing of the aperture block 103. The data exchanged includes low-speed control, calibration, and health information, as well as high-speed digitized waveform data for each receive and transmit beam carried by terminal 101 .

[0032] A power transfer mechanism 205, such as an inductive coupling loop or a transformer, is used to transfer power between the blocks 103 forming the terminal 101. Power transfer between the aperture blocks 103 allows for charging of embedded batteries from a single external power connection, and for providing operating power to the entire array if batteries are not included in each aperture block. The mechanism 205 can be an open coil of wire in a straight or semicircular configuration or a ferrite core with wire wrapped around it to increase the coil's transfer efficiency. The use of wireless communication and wireless power transfer between blocks increases the power requirements of the array in addition to the terminal's direct needs. Optimizing power transfer efficiency as much as possible is important to minimize power consumption and extend battery life or reduce the number of batteries required. In the illustrated embodiment, the power transfer mechanism 205 can be attached to a bridge 214 between the hole 201 and the post 203.

[0033] As an alternative alignment feature to the magnets 209 (FIGS. 2(a) and 2(b)), mechanical devices can be provided at each hole 201 and each post 203. These mechanical devices removably and securely connect the holes 201 and posts 203 to the posts 203 and holes 201 of neighboring blocks, while also providing electronic connections between the electronic components 207a and 207b. For example, one embodiment of an interconnection port 107b is shown in FIG. 2(c) (side view) and FIG. 2(d) (top view). In this implementation, one or more posts 241 replace the posts 203, and one or more slots 243 replace the holes 201, configured to mechanically align the locations of neighboring aperture blocks 103 and allow a flexible clip 245 in one aperture block to removably connect with a mating slot 247 in the other aperture block. As shown, the posts 241 can be located at opposing ends of the block 103, spaced apart from the slots 243, and can be separated by other components, such as light sources 257 and / or receivers 259, on a side edge or surface of the block. In the embodiment of FIG. 2(c), two posts 241 and two slots 243 are shown, but any suitable number can be provided. In contrast, in the embodiments of FIGS. 2(a) and 2(b), the holes 201 and posts 203 are adjacent to each other in the same area on a side edge or surface of the block 103, with no surface components disposed between them (note that the power transfer portion 205 is recessed into or below the surface). While the posts and slots are shown on opposing edges of the block 103, they can be positioned anywhere on the block, such as on the top and / or bottom. In yet another embodiment, one or more of the light sources 257 and / or optical receivers 259 can be positioned outside of their respective posts 241 and / or holes 243.

[0034] In one exemplary embodiment, a mating feature such as a catch or button 249 may be integrated with the mating slots 247 and used to engage and disengage the mechanical clip 245, allowing for detachable connection and disconnection of two aperture blocks 103. The use of mechanical clips 245 may be preferred over magnets 209 because it may make the structure more robust and rigid when connected and help protect against accidental disconnection, but requires more effort to connect and disconnect. The use of mechanical clips may increase the rigidity of the assembled terminal 101 and allow an assembled terminal 101 made up of multiple aperture blocks 103 to be placed so that it is supported only from its edges, such as when tilted at an angle by (for example) resting it on a stand or solid foundation, thus increasing the operational flexibility of the terminal.

[0035] In this embodiment, a PCB-integrated ferrite transformer coil 205b is used to transfer power in either direction between the two aperture blocks, preferably using a ferrite pot core to contain the transformer's magnetic field and increase efficiency. A PCB-integrated planar ferrite core, using traces on the PCB for the transformer's field winding, is a good solution because the resulting transformer has a very low profile, minimizing the size and mass required for a given power transfer. Circuitry integrated within interconnect port 107b monitors the transformer and indicates when a nearby block is installed and available to deliver or receive power. This circuitry then configures interconnect port 107b to either receive power through the transformer, deliver power, or neither, depending on the system requirements.

[0036] In the embodiments of Figures 2(c) and 2(d), data transfer occurs through optical devices. One or more high-speed light sources 257 are excited by circuitry to carry signals in one aperture block 103, and the resulting light is then received by one or more matching, aligned optical receivers 259 in the other aperture block. In this embodiment 107b, the light sources 257 and receivers 259 replace the high-speed data interfaces 207a and 207b in ports 107 that transfer data between blocks 103. Each aperture block has both a light source 257 that transmits data and an optical receiver 259 that receives data through interconnection port 107b. One exemplary embodiment uses an LED 255 coupled to a corresponding light conductor or light guide 256 to drive the light source 257 and a photodiode or phototransistor sensor 254 coupled to a corresponding light conductor or light guide 258 to detect the light received by the optical receiver 259. In this case, when the LED 255 and sensor 254 are mounted on a printed circuit board 253 inside the aperture block 103, light guides 256, 258 are used to couple light from the LED 255 and sensor 254 to the light source 257 and receiver 259. In other words, the light source 257 and light receiver 259 can be positioned on the end face of the block, and the LED 255 and phototransistor 254 can be located within the block and connected by guides 256, 258, respectively. By using high-speed LEDs 255 and photodiodes 254, high data transmission rates can be achieved, and additional pairs of light sources 257 and sensors 259 can be added to support even higher rates, such as may be required for wide instantaneous bandwidths or multiple simultaneous beams. The outer surfaces of the light guides 256, 258 must be at least relatively clean to transmit light, but the surfaces of the light source 257 and sensor 259 can be designed to avoid trapping dirt or other contaminants so that the surfaces can be quickly cleaned.

[0037] In another embodiment, interconnection port 107c is shown from the side in Figure 2(e) and from above in Figure 2(f). In this embodiment, alignment features such as pegs 241 and slots 243 are configured to mechanically align the location of adjacent aperture blocks 103. In that case, recessed recesses 285 in the housing are included to allow for the installation of external retaining clips or snaps that hold adjacent blocks 103 together. The advantage of external clips is easier installation and better control over the tension that can be withstood when connected.

[0038] In this embodiment, electrical contacts 283 are used to transfer power between aperture blocks at each interconnection port 107c. The advantage of direct electrical contacts is increased power transfer efficiency over transformer-based approaches, thus reducing overall power consumption and heating, as well as simplifying the design and reducing costs. However, the exposed contacts must be protected from moisture and contaminants, which can be done with an integrated cover, such as a flexible silicone lid 281, that covers the port 107. This lid can be removed for installation and replaced for storage and transport. Similar to power transfer, data signals can be carried by electrical contacts 287, 289 with the same benefits and costs. In this embodiment 107c, plugs 287 and sockets 289 replace the high-speed data interfaces 207a, 207b in the port 107 that transfer data between blocks 103.

[0039] The various options discussed for alignment and mechanical attachment between aperture blocks 103, power transfer between blocks 103, and data transfer between blocks can be applied in various combinations and are not just shown as examples here.

[0040] Figure 3(a) illustrates one embodiment of the functions and sub-components of aperture block 103, including any of the implementations shown in Figure 1 or Figures 2(a)-2(f). Aperture block 103 generally includes a plurality of interconnection ports 107 that are geometrically arranged around the periphery of the block and, where appropriate, interconnect to neighboring blocks 103 of terminal 101. The physical arrangement of blocks 103 can be uniform, with all blocks being identically arranged (as in a square), or can involve a rotation, where only some ports 107m of some blocks may interconnect with specific ports 107n on neighboring blocks 103.

[0041] The physical user interface on each block has multiple input buttons 301 and indicator lights 303 located in locations that are both physically accessible while the array is connected and operational. Location can be on one or more of the sides of the aperture block, or on the front or back, depending on the application and installation. Multiple sets of input buttons 301 and lights 303 can be located around the periphery of aperture block 103 to allow easy access in various positions and orientations. Control and configuration of blocks 103 and terminal 101 as a whole is primarily performed using external controls (such as a software application running on the end-user device or modem, or a virtual control panel running as a web application hosted on the terminal) rather than physical interfaces 301 and 303, which can be used for simple operations such as powering on and off.

[0042] Data to / from interconnection ports 107m, 107n, 107p through high-speed data interface 207 and user interfaces 301, 303 are both directly connected to communication controller 311 via transmission lines 307 and 305, respectively. Communication controller 311 may be implemented as a microcontroller or similar device responsible for managing data input to and output from block 103. Power transfer mechanism 205 of interconnection port 107 is connected to and controlled by power manager 313. Power manager 313 controls the flow of power between blocks 103 via power lines 309, manages battery 315, charges battery 315 via unregulated supply line 317 (while power is supplied from one of ports 107m, 107n, 107p), and supplies regulated power from battery 315 to the rest of the block electronic components via power line 319. The power manager can use data transferred between blocks via 207 to vary the flow of power through the power transfer mechanism 205 .

[0043] Antenna aperture 105 is a segment of a phased array or other variety of electrically steered antenna (ESA) selected for power efficiency and operational capabilities of the individual blocks receiving and generating satellite signals 304. This can be, for example, a conventional patch antenna phased array with a rectangular, triangular, or irregular lattice shape; an array based on digital or analog beamforming and phase shifting; or an array based on liquid crystal or other tunable materials. Block 103 can utilize any electrically steered antenna, but it is particularly useful to use an antenna with reduced power consumption, such as that described in U.S. Pat. No. 10,116,051, the entire contents of which are incorporated herein by reference. Advantages of this system over conventional phased array antennas include greater portability of the aperture, since the aperture can be divided into smaller pieces, thus allowing larger or smaller apertures to be constructed and operated on demand, resulting in greater flexibility in aperture application.

[0044] The state and operation of the ESA are controlled via control signals 331 by antenna control logic 327 running on a data processor 325 (e.g., implemented as an FPGA (Field-Programmable Gate Array) or SoC (System on Chip)). RF or IF signals 333 (which may be digital or analog) to and from the aperture 105 are passed to a DSP processor 335, which performs filtering, processing, time and phase shifting, and data combining on the receive and transmit signals. This data combining includes combining the signals with data from neighboring blocks 103 through interconnection ports 107 and communications processor 311. The processed data 361 is then passed to the data processor 325, which processes this data according to the configuration of the array. The overall combination of components within a block is novel to a single aperture block, as are combinations where multiple blocks are combined to operate together.

[0045] The data processor 325 works closely with the orchestration processor 339 to control the operation and state of the array. While the data processor 329 handles real-time signal processing and control operations, the orchestration processor 339 is the block's main controller, managing communication flows 323, 321 between blocks 103, determining power allocation between blocks and their components, configuring the data processor 325 via 337, managing and integrating sensor data 341 from the inertial navigation unit 343 and GNSS receiver 345, storing and retrieving configuration data 355 in memory 353, coordinating the behavior and operation of the other interconnected blocks 103 with the orchestration controller 339, and finally controlling the user interface and configuration through the data port 107 or on-board interfaces 301, 303. The GNSS antenna 347 receives GNSS signals (i.e., GPS) 349 and passes those signals to the GNSS receiver 345, which provides position and time data to the orchestration processor 339, which operates the antenna controller to set the terminal's pointing direction to a given satellite based on the terminal's location and orientation.

[0046] The data processor 325 is implemented using reconfigurable hardware (such as an FPGA) so that the function and characteristics of each block can be changed by software. When the terminal 101 is assembled and operational, one of the configuration blocks 103 is automatically selected to be the master or main block, from which the other slave or secondary blocks are controlled; one is selected to operate as a modem, one is selected to operate as an antenna control unit (ACU), and so on. Only one instance of each function is needed. In some cases, a single block can operate in multiple roles simultaneously. Any blocks 103 not selected to operate in a special way operate as standard blocks. This standard block optionally receives data containing digital samples of the received waveform from neighboring aperture blocks from its port 107, processes the digital sampled waveform data together with digitally processed waveform data 361 to generate a combined sampled signal from its own DSP processor 335, and forwards the combined digitally processed waveform data from the current block 103 and neighboring blocks to another port 107.

[0047] Data received by the antenna aperture 105 is summed in a distributed fashion by all of the aperture blocks 103 before being routed and further combined by neighboring blocks 103 until the final aggregate data, representing the satellite signals received by the entire terminal 101, reaches a specific block 103 that acts as a modem (or has an interface to an external modem). Each of the blocks 103 can function in either role by loading its respective FPGA image or software image 357 from image store 351. Image store 351 contains images of all the required features and functions. Some function 327, the aperture 105 control logic, is included in every aperture block 103; the remaining unallocated capacity 329 in the data processor 325 is dynamically configured in each block during array setup based on the needs of the terminal. This unallocated capacity 329 is used to implement control processes in the main blocks, modem functions, and antenna control unit (ACU) functions in selected aperture blocks 103.

[0048] While FIG. 3( a) shows numerous features and subcomponents included in aperture block 103, there are options for some that are considered optional or are only included in different variations of the aperture block to save cost. For example, some modules may include battery unit 315, other modules may include FPGA processing block 325, and other modules may include GNSS receiver 345; in that case, the array will function as long as at least one aperture block in the array includes each of the required features. This reduces the cost of each block by reducing the number of components to be installed, but it also increases the number of aperture block variations, increasing the risk of missing essential elements when the terminal is assembled and reducing installation and configuration flexibility. For this reason, a preferred embodiment is one in which each aperture block includes all of the shown features and functions, so that aperture blocks 103 are interchangeable and any combination of blocks can be used to form a functioning terminal.

[0049] Thus, FIG. 3(a) illustrates a fully self-contained implementation in which the battery and controller are integrated to eliminate single points of failure. FIG. 3(b) illustrates a simplified option that requires dedicated external hardware (controller, modem, power supply) but reduces overall antenna cost, weight, and power. Thus, FIG. 3(b) illustrates an alternative implementation of the aperture block 103's functions and subcomponents in which components required in only a single block 103 of the terminal are moved to the external user interface block 381, modem and antenna controller block 383, and external pack 315z. In this alternative implementation, features such as the battery 315, physical user interfaces 301 and 303, inertial navigation unit 343, and GNSS receiver 345 are omitted from the terminal block 103 and instead installed externally. In this way, aperture block cost is reduced because only one aperture block 103 in the array requires, for example, a user interface or a GNSS receiver.

[0050] The external user interface block 381 then connects to the aperture block 103 via interconnect port 107 in the same manner as when two aperture blocks 103 are connected (transferring power via 205 and control and digitally sampled waveforms via 207). A communications controller or processor 311z receives and transmits signals from / to port 107z via line 307z and also interfaces with the user interface components 301z, 303z via line 305z. An orchestration processor 339z receives inputs 341z from an IMU 343z and a GNSS receiver 345z, which operates using the same antenna 347z and GNSS signals 349 as when located within the aperture block 103. The GNSS receiver 345z, IMU 343z and user interfaces 301z and 303z must be mounted directly to the aperture block 103 to ensure that the position and movement data is directly related to the antenna aperture for calibration purposes.

[0051] Additional processing capacity 325z for modem functionality, operating via data processor 329z and overall power supply 313z, may optionally be connected via cable 385 to another block 383 that may be suitable for carrying in a backpack or other convenient manner. An external or integrated high capacity battery pack 315z is also available for carrying in a similarly convenient manner.

[0052] An advantage of this alternative embodiment shown in FIG. 3(b) over the embodiment shown in FIG. 3(a) is that the mass and cost of the aperture block 103 are reduced due to common functionality being contained in a single external block 381 rather than in every aperture block 103. This allows for the use of conventional phased array or other electronically scanned antennas (such as lens array antennas) for use in manpack configurations. Separate user interfaces 301z and 303z also allow for further remote control of the assembled antenna 101. Note that any one or more of the operable components 311, 313, 325, 329, 327, and 335 can be processing devices such as processors, controllers, or ASICs. Components 311, 313, 325, 329, 327, and 335 can be separate or combined into one or more integrated processing devices. Any combination of 103, 381, 383 can be carried by a single individual in a backpack or other container, with other items 103, 381, 383 being carried by others, and the terminal being assembled when needed.

[0053] 4 illustrates how aperture blocks 103 interconnect via their ports 107 to form a representative terminal 101 with associated accessories 421, 431, 441, 451, and 461 connected using the same port 107. One of the blocks 103 can be collaboratively selected by an orchestration processor during startup to be the primary block 103m based on a set of criteria. The set of criteria can include proximity to other blocks and associated accessories to minimize data transfer complexity within the array, battery levels, etc. Alternatively, an external user interface block 381 with an associated modem block 383 can be connected.

[0054] Port 107 can be considered to have multiple internal connections or data streams, as shown in the expanded view of transfer signal 401, which can be communicated, for example, via interface 207. Port 107 can pass power 403 bidirectionally in response to commands issued by the orchestration processor 339 and power controller 313 of each of the blocks under the direction of orchestration processor 339 of primary block 103m. For example, if external power 433 is being supplied by power accessory 431, the availability of that accessory is reported to primary block 103m, which then coordinates the transfer of power from external power accessory 431 to the rest of the connected blocks 103.

[0055] Multiple parallel data streams are supported by the interconnection ports 107, particularly the communications devices 207. These can be carried over separate physical channels, contacts, or communications chips, or multiplexed into one or more underlying physical data streams. Low-speed command and control signals 405 are used for array-wide orchestration and low-rate communications and control, such as with a CAN (Controller-Area Network). A management 10 / 100 / 1000 Ethernet network 407 with dynamic routing within the connected elements is used for high-speed communications and control, including beam-pointing instructions from the antenna control unit, modem commands, and terminal internal or external control signals, as well as terminal and individual block management, programming, and configuration from an external computer. A user data 10 / 100 / 1000 Ethernet link 409 carries user traffic from the modem through the array to one or more accessories for user access. These accessories may be a local wireless access card 461 with a wifi or Bluetooth antenna 463, an Ethernet adapter accessory 451 that connects to an external Ethernet network 453, or an adapter 421 that connects to an external computer, wireless device, or other device 423 via a USB or other connection.

[0056] Finally, high speed synchronous packet line 411 carries sampled RF signal data 305 between antenna aperture 105 and DSP processor 335 in attached block 103, or completely external to the terminal through modem port 441 to pass digital data (possibly converted to an L-band IF signal) to an external modem 443 (which may be desirable in some use cases).

[0057] This flexible architecture allows for customization of the terminal size and its use by connecting different accessories. Depending on the desired application and use case, some accessory functions can be integrated into the module 103 itself (i.e., enclosed by the module housing) and sealed with a cover, with each module having a single Ethernet port providing, for example, external connectivity and data networks for management, power over Ethernet for charging, and interconnection with a computer. Whether separate accessories 421, 431, 441, 451, and 461 are used with sealed magnetic data ports 107 or whether their functionality is included in the aperture block 103 itself depends on the use case and requirements of the overall terminal system. Additional accessory types are also possible, including data storage devices, external batteries, chargers for external devices that utilize the battery inside the aperture block 103, and the like.

[0058] Embodiments of the present disclosure impose several constraints on the shape and size of the aperture blocks 103. The larger the blocks 103, the fewer blocks need to be interconnected to achieve a given communication performance, but the individual blocks are bulkier and heavier and therefore more difficult to transport. Smaller blocks 103 require more blocks to be interconnected, increasing assembly and disassembly time, but allowing more blocks to be distributed among more individuals in the group to distribute transportation, and thus making some level of communication available to more individuals in the group, regardless of how they end up separated or what subgroups they may be separated into at any given time. The shape of the blocks should be such that any number of blocks can be tiled or flush with each other to form arbitrarily large or small arrays. Because gaps, even small ones, exist between antenna apertures 105, it is desirable to support aperiodic tiling of aperture blocks, or tiling that is rotationally symmetric rather than translationally symmetric. Non-periodic and asymmetric tiling is preferred because periodic or symmetric structures can have undesirable characteristics in the sidelobes of the resulting overall antenna beam.

[0059] FIG. 5 shows three possible implementations of aperture block 103: triangular block 103x in FIG. 5(a), square block 103y in FIG. 5(b), and hexagonal block 103z in FIG. 5(c). While many triangular configurations are possible, a particularly desirable option is a triangle in which five triangular blocks 103 form a regular pentagon, with interior angles of 72 degrees, 54 degrees, and 54 degrees. This particular triangle can be tiled into regular polygons that do not have mirror symmetry and into many different irregular polygons and other shapes that primarily have rotational symmetry. This is highly desirable compared to the periodic arrays achievable when using the square 103y or hexagonal 103z options. Triangles that form regular polygons with an odd number of sides are more likely to produce a desirable tiling or tessellation than others (such as equilateral triangles, which necessarily form regular hexagons with six sides). Another option is the irregular pentagon, for which there are 15 families that allow for tiling the plane with a single shape (see Wolchover, Pentagon Tiling Proof Solves Century-Old Math Problem). However, the more complex the shape, the more difficult it becomes for the end user to tile it into a suitable, usable array. Other shapes are possible, including options that allow aperture blocks of multiple shapes to be tiled together.

[0060] If the shape of the aperture block 103 has multiple edge lengths (such as a triangle 103x), the interconnection ports 107 on the long and short edges can have different sizes or orientations to ensure that the blocks can only be assembled in a compliant manner.

[0061] Unlike conventional phased array or electrically steered antennas, the antenna aperture 105 can be implemented using a lens array, such as that described in U.S. Pat. No. 10,116,051, where substantially flat (e.g., aspherical) lenses are particularly useful for forming a phased array. FIG. 6 illustrates how an array of transmit lenses 605 and receive lenses 603 can be tiled within a triangular aperture block 601. While the lenses 603 and 605 are shown as circular, they could also be hexagonal (as in U.S. Pat. No. 10,116,051) or any other suitable shape and size. The ratio of transmit lenses to receive lenses can be varied to tailor the overall array performance. The aperture 105 can also be implemented with combined receive and transmit lenses supporting either full-duplex or half-duplex operation to optimize the gain of the terminal 101 in either mode for a given number of blocks. Advantages of lens arrays over conventional array antennas include lower power consumption and heat generation, which are important for battery-operated applications, and a significantly reduced overall component count.

[0062] Additionally, the ability to easily extend NGSO to multi-beam operation is included. Figure 7 then shows how these blocks can be tiled together to form an array of a single aperture block 701 (Figure 7(a)), an array of five aperture blocks 703 (Figure 7(b)), an array of ten aperture blocks 705 (Figure 7(c)), and an array of twenty aperture blocks 707 (Figure 7(d)).

[0063] To illustrate the level of flexibility in working with any number of aperture blocks, FIG. 8 illustrates array terminals 801-815 consisting of 1-15 elements, and array terminal 820 consisting of 20 elements. These are representative tilings; other arrangements are possible and acceptable. In general, the denser the tiling, the more practical it is. The advantage of supporting many tilings with different shapes is that any number of elements 103 can be combined to form terminal 101, and those elements can be combined in many ways that simplify assembly. Modules can be installed and function as long as they fit.

[0064] FIG. 9(a) shows an exemplary terminal 901 assembled from five triangular aperture blocks 103x into a regular pentagon. Three accessories are shown assembled on the device: power adapter 431, data cable 451, and local wireless adapter 461. This is one of many possible configurations achievable using the blocks and accessories described above (e.g., at angles of 72 degrees, 54 degrees, and 54 degrees). For clarity, accessories such as adapter 431, cable 451, and adapter 461 are external to the housing of triangular block 103, such that they couple to block 103 at port 107. However, in other embodiments, the accessories may be integrated with block 103.

[0065] 9(b) shows another embodiment of terminal assembly 951 connecting five triangular aperture blocks 103x to an external user interface block 381 connected via cable 385 to a modem block 383 and external battery 315z. The modem block 383 and external battery 315z are shown stacked on a backpack, facilitating quick setup and disassembly of the system without the need to remove these components to connect to the antenna array 951.

[0066] Figure 10 shows an operational flowchart for the terminal 101. Starting with a request to deploy a terminal 1001, the terminal is first configured (1003). Multiple aperture blocks 103 and any associated accessories (including external user interface 381 or modem block 383) are simultaneously tested, optionally have their batteries (if present) charged, and configured (1005) with the same satellite, modem, and operational settings and any required credentials that allow them to connect to the provisioned capacity on the network. Once the set of blocks is properly configured before departure for the field, any combination or subset of blocks 103 can then be combined to form an operational terminal. Any block with allocated accessories is then distributed to an end user (1007).

[0067] When an end user needs to communicate in the field (1011), the terminal is assembled and set up (1013). First, the blocks and necessary accessories must be taken and assembled into an array with documentation indicating the preferred placement to form a single connected unit on the ground or other flat surface (1015). Here, one or more of the blocks 103 are physically connected to each other by connecting mating posts and holes to form a continuous block assembly, and optionally attaching accessories to one or more of the blocks.

[0068] Once the blocks 103 are assembled and all accessories are connected (step 1015), the end user then presses the power button 301 on any one of the connected units (1017). This triggers the collaboration phase 1019 of the setup process. In this collaboration phase 1019, the set of connected blocks 103 communicate collaboratively through an ad-hoc mesh network of port connections where the blocks are assembled to determine the number, orientation, and geometry of the connected blocks, identify any of the connected accessories, and select one of the blocks to be the primary block 103m. The primary block is selected based on configurable metrics such as proximity to a modem, central location within the array, or battery charge level. This process is performed for each block 103 by the orchestration processor 339. Temporary addresses for each block 103 are mutually determined according to their location within the array to facilitate communication. For example, with reference to FIG. 9(a), block 103x can be selected as the primary block for array 901. In this case, the addresses can then be determined in a breadth-first search through all connected ports 107 of each connected block in array 901. The main block is assigned address 1, and the blocks attached to each of the ports (if any) are then assigned addresses 2, 3, and 4. In array 901, only addresses 2 and 3 are used for the left and right blocks, respectively. The remaining blocks are addressed in the same manner. Command and control signals can then be sent and received between blocks that are not directly connected through messages forwarded by the intervening aperture blocks. The status of this process, and any faults, are reported via status indicators 303.

[0069] After the primary block is selected, the primary block controls the array's communications and configuration (specifically, via the orchestration processor 339) during the calibration and initialization phase 1021. Based on previously determined geometry and orientation information, the primary block 103m establishes power, signal, and data routing paths throughout the array, simplifying the mesh network topology to a defined set of connections. The terminal 101 as a whole then self-calibrates under the control of the primary block 103m, loading calibration coefficients from storage and performing self-checks to ensure all connections are secure. Each block independently calculates its relative orientation and offset distance to its neighbors, and the terminal, under the control of the primary block 103m, uses a consensus technique to compare calculations by different blocks 103 and arrive at a single value for each interface at the terminal 101. The calculated orientation and offset are then used by a calibration routine to correct each block's phase settings and ensure accurate beamforming throughout the array.

[0070] One or more blocks are selected to operate as an antenna control unit (ACU) and modem, unless the external modem accessory 443 or external modem block 383 and external user interface 381 are installed. If installed, digitized waveforms or signals are routed to / from the external modem accessory or external modem block. The location and general orientation of the terminal relative to the Earth and satellites is determined using the INU 343 and GNSS sensors 345 in one or more of the connected blocks under the control of the orchestration processor 339 of the main block 1203m, and at least one beam is formed to connect to at least one satellite based on the configuration data loaded during the configuration phase 1003.

[0071] The beam is implemented as a bidirectional stream of digital waveform samples containing the transmit and receive signals. The transmit signals are distributed to all of the aperture blocks 103, where appropriate amplitude and phase offsets are applied before being transmitted by each respective aperture 105, and the receive signals are aggregated from all of the apertures 105 in the aperture block 103 and combined into a single sampled waveform from the entire terminal and provided to the modem. Once the satellite link is established, the external data accessories are activated and the terminal 101 enters the operational phase 1033 (1031). Satellite link establishment begins with a receive-only connection being established to locate the target satellite and verify that the expected signal is received from the satellite before the transmit link is enabled. The status of this process, and any faults, are reported via the status indicators 303.

[0072] During the operational phase (step 1033), bidirectional data is transferred over the satellite link in step 1035 through the combined aperture formed from all of the interconnected apertures 105 in each block 103 of the block assembly. During this phase, both transmit and receive waveforms are continuously streamed through the array between the satellite and the modem, subject to any implementation requirements for half-duplex operation. The beam or beams continue to track the satellite (step 1037) and report feedback to the user via the physical user interface 303 or via data links 461, 451, and 421 to the end-user device (step 1039). Tracking data and command and control signals from the main block 103m continue to be transferred between blocks to update beam pointing direction, power levels, calibration settings, and other operational information useful to the individual blocks within the terminal 101. This process continues while the terminal 101 is operational. Terminal status is reported via the status indicators 303 and also to the end-user device via the data link. The terminal constantly monitors the received signals from the satellites to use for tracking purposes, and if the received signal is lost, it must immediately disable the transmit beam until the received signal can be reacquired, as is standard for SATCOM terminal operation.

[0073] Terminal shutdown is triggered (1041) by the user either issuing a command over the data link, pressing the power button 301 on the interface of any one of the connected aperture blocks 103, or severing any one of the connections between the blocks by initiating disassembly of the terminal 101. The main block 103m then immediately disables (1045) all transmit functions of the block 103 and then powers down the entire system. The user then disassembles and stores (1047) the aperture block 103 for transport. When communication needs to be resumed (1011), the process is repeated, starting from the setup phase 1013.

[0074] If a new module 103 is added to a terminal 101 in the operational state 1033, the terminal can automatically return to the setup phase 1013 and reconfigure to a larger size, or it can wait for the user to request that the setup and recalibration process begin.

[0075] This disclosure illustrates a successful design for a manpack SATCOM terminal. This design is highly modular, with fully replaceable components. Failure of any one component does not prevent the terminal from operating; instead, only a single element is removed. Field assembly involves removing the tiles from a backpack or other carrying case, placing them all in a reasonably level location, facing the sky with the desired satellite in view, and snapping the tiles together. For operation with LEO constellations, knowledge of satellite locations is not required; only a clear view of the sky is required. Assembly can be completed in minutes. The ports 107 are adjusted to connect only when the apertures face the same direction (upward) and all edges of a triangle (for example) are meant to connect when aligned with similar edges. With an integrated battery, there is no need to find a power source to operate the terminal, and battery capacity can be scaled to meet application requirements. As environmentally sealed units with an integrated sealed housing incorporating an RF transparent radome over the aperture, they are suitable for operation in polluted environments. The port itself is large enough to allow for easy cleaning or flushing of gross debris, and the system is insensitive to surface grit, dust, and dirt.

[0076] By assembling more aperture blocks 103 together, the aperture area increases, and the preferred triangular shape 103x creates an irregular, non-periodic tiling that is preferred from an aperture perspective. This terminal 101 is suitable for both high and low throughput applications, and since more RF power, aperture area, and gain are both available for both transmit and receive modes, more blocks 103 are used to generate greater throughput.

[0077] Electronic steering of the beams is necessary to enable both high antenna gain and the elimination of moving parts. Without electronic steering, either a user or an actuator would need to physically point the aperture toward the satellite, which is undesirable and removes an important advantage of this terminal. The beam direction is determined by the orchestration controller 339 using the specific aperture 105 settings determined by the beam controller processor 327. Each beam is electronically scanned in a manner appropriate to the type of antenna aperture 105 used to implement the antenna. For example, a phased array of patch antennas has phase and amplitude settings at each patch antenna configured by the beam controller 327 to generate a beam in the desired direction according to the calibration coefficients of the specific aperture block.

[0078] When an array 101 is assembled from multiple aperture blocks 103, alignment features built into the interconnection ports 107 ensure that the blocks connect in an acceptably manner. However, the mechanical tolerances achievable during assembly may not allow for sufficiently repeatable and precise alignment (relative position and orientation) of neighboring aperture blocks 103 that the aperture array can reliably form a beam without self-calibration.

[0079] Pre-operational calibration of the array is intended to correct for relative position and orientation offsets between the aperture blocks 103 that form the array 101, as well as phase differences and mismatches in the interconnects 107 themselves. Because the array is intended for assembly and disassembly in the field without external equipment, this process must be automatic for the system to operate.

[0080] One solution is to have each of the aperture blocks lock onto a strong signal independently and measure the difference in the received signal from each block so that the phase correction for each block can be calculated to accurately form the beam. This can be done by transmitting a test signal from one or more blocks, or by listening for known satellite signals.

[0081] This method can be improved if the relative position and orientation of the aperture blocks can be estimated with high accuracy before evaluating the signal in the RF domain. Figure 11 shows a measurement method for simultaneously characterizing the relative position and orientation offset between two aperture blocks 103. Sensor 1101 can be integrated into interconnect port 107 and can be associated with a second identical sensor 1101b during operation. Sensor 1101 includes a single optical transmitter or light transmitter 1123 coupled by light guide 1121 through the housing to transmit port 1103. Light transmitter 1123 can be an infrared, UV, or visible light LED or laser diode.

[0082] The sensor includes a corresponding receive port 1105 with three optical receivers 1133 and corresponding light guides 1131. The receivers 1133 may be photodiodes or phototransistors. The receive port may have a generally concave hemispherical shape with the three light guides spaced in an equidistant pattern across its surface.

[0083] The optical transmitter is driven by a signal generator 1141 that generates a high-frequency signal with a phase of 1 degree or less at a nominal frequency for which the desired position measurement accuracy is desired. For example, to measure a distance of approximately 0.1 mm, a signal with a maximum frequency component of 1 GHz can be selected, since a 30 cm wavelength at 1 GHz results in a light propagation distance of less than 0.1 mm for a 1 degree phase shift. Multiple sinusoidal tones or other signals can be superimposed to enable greater accuracy in the absolute distance measurements made possible by the sensor 1101.

[0084] The optical sensor generates a signal corresponding to the light generated by the opposing sensor 1101b. The three received signals are compared to the output of the signal generator and the relative time delay / phase shift measured by comparator 1135. Comparator 1135 can be implemented by a phase-locked loop or similar circuit. The measured time offsets and / or phase shifts are then read by processor 1143, which compares the relative time delays between the three signals and, therefore, the three distances between transmitter 1103b and receiver 1131. Processor 1143 also adjusts signal generator 1141 to align the received signals and convert the two disparate systems into a single loop. If multiple tones are generated by generator 1141, filters or frequency diplexers can be used to separate the different tones and compare their phases separately in separate comparators 1135, or a unified comparator can process the aggregate signal.

[0085] As this process continues at both associated sensors 1101, 1101b, both sensors generate measurements of the phase offset and, therefore, the relative distance between the transmitter 1103, 1103b and the receiver 1105, 1105b. The placement and spacing of the transmitter 1103 and receiver 1105 at one sensor 1101 is known, and the path length difference / measured relative distance is then used to calculate the relative position 1107 and orientation 1109, 1109b of the two aperture blocks. This method uses processing techniques similar to those used in interferometers, relying on known base time delays in the light guides and a processing chain that allows their effects to be removed from the position calculation. This position and relative orientation can then be used by the orchestration processor 339 of block 103 to calibrate the array and support beamforming control calculations to set the phase weights of each individual aperture 105.

[0086] Note that the diagram shows ports 107 on all sides of each block. However, ports 107 may be provided on fewer than all sides of each block. Additionally, while one example of ports 107 is shown, any suitable ports may be utilized, and the blocks may be coupled together electronically and / or mechanically in any suitable manner.

[0087] It should be noted that the drawings may depict, and the specification and claims may use, geometric or related terms such as side, edge, top, bottom, plane, coplanar, parallel, perpendicular, rectangle, square, triangle, circle, polygon, pentagon, equilateral triangle, irregular polygon, etc. These terms are not intended to limit the disclosure, but are generally used for convenience to facilitate explanation based on the examples shown in the figures. Additionally, the geometric or related terms may not be precise. For example, walls may not be exactly perpendicular or parallel to one another due to, for example, surface roughness, tolerances allowed in manufacturing, etc., yet may still be considered perpendicular or parallel.

[0088] Numerous applications of the present disclosure will readily occur to those skilled in the art, and therefore, it is not desired to limit the disclosure to the disclosed examples or to the exact construction and operation shown or described. On the contrary, all suitable modifications and equivalents may be used that fall within the scope of the present disclosure.

Claims

1. a plurality of individual modular aperture blocks (103) that are removably connected to one another in the field and that operate together to form a combined electrically operated antenna, each of the plurality of individual modular aperture blocks comprising: i. an electrically operated antenna aperture (105), and ii. a plurality of interconnection ports (107) for power and data communication between the plurality of individual modular aperture blocks, the interconnection ports (107) being removably connectable by an end user in the field; a plurality of individual modular aperture blocks (103) including: a signal processing system (325) for receiving, processing and generating signals to and from said antenna aperture (105); a controller (339) in each of the plurality of individual modular aperture blocks (103) that automatically measures the relative distance and orientation between the individual modular aperture block and an adjacent individual modular aperture block and corrects the phase setting of the plurality of individual modular aperture blocks (103); A locally assembled satellite communication terminal (101) comprising:

2. 2. The terminal of claim 1, wherein the plurality of individual modular aperture blocks (103) are assembled to form a block assembly having a combined aperture formed by a plurality of the antenna apertures (105).

3. The terminal of claim 2 , wherein the combined aperture has higher gain, performance, and throughput.

4. A terminal according to any one of claims 1 to 3, wherein each of the plurality of individual modular aperture blocks includes an integrated battery and power control circuitry.

5. A terminal according to any one of claims 1 to 4, further comprising an external battery (433) for providing power through the interconnection interface.

6. The terminal of any one of claims 1 to 5, wherein the individual modular aperture blocks include a computing device (311) for inter-module communication and control.

7. A terminal according to any preceding claim, wherein one of the plurality of individual modular aperture blocks is jointly selected during configuration to act as a primary block.

8. 3. The terminal of claim 2, wherein the block assembly operates as an integrated terminal with a modem and antenna control unit instantiated as part of the processing capacity (329) and position and orientation sensors (343, 345) provided by the plurality of individual modular aperture blocks.

9. 9. The terminal of claim 2 or 8, wherein the block assembly operates as an integrated terminal with a modem, a battery, an antenna control unit, and position and orientation sensors provided by an external block.

10. The terminal of any one of claims 1 to 9, further comprising a reconfigurable processing device or FPGA included in each of the plurality of modular aperture blocks.

11. A terminal according to any preceding claim, wherein the individual modular aperture blocks are environmentally sealed within a housing.

12. The terminal of any one of claims 1 to 11, further comprising an inductive power coupling (205) for providing wireless power transfer between the plurality of individual modular aperture blocks (103).

13. The terminal of any one of claims 1 to 11, wherein the plurality of interconnection ports (107) have electrical contacts (283) for power transfer, and the terminal further comprises a removable cover for protecting the electrical contacts.

14. The terminal according to any one of claims 1 to 13, wherein the plurality of interconnection ports use short-range high-frequency wireless communication for data transfer.

15. The terminal of any one of claims 1 to 13, wherein the plurality of interconnection ports use optical data couplers for data transfer.

16. 16. The terminal of claim 1, further comprising one or more external data transfer power accessories connected to one or more of the plurality of interconnection ports in one or more of the plurality of aperture blocks.

17. A terminal according to any preceding claim, wherein the electrically steered antenna aperture is a digital phased array.

18. A terminal according to any preceding claim, wherein the electrically steered antenna aperture is an analogue phased array.

19. A terminal according to any preceding claim, wherein the electrically operated antenna aperture is a lens antenna array.

20. A terminal according to any preceding claim, wherein the electrically operated antenna aperture is a liquid crystal based antenna.

21. A terminal according to any preceding claim, wherein each of the plurality of discrete modular aperture blocks has a triangular shape with interior angles of 72 degrees, 54 degrees and 54 degrees.

22. 22. The terminal of claim 21, wherein the triangular shape has rounded corners.

23. A terminal according to any preceding claim, wherein the combined antenna aperture is self-calibrating from internally or externally transmitted RF signals.

24. The terminal of any one of claims 1 to 23, wherein the relative positions and orientations of the plurality of aperture blocks are determined for calibration by measuring optical path length differences through phase comparisons from one transmitter and at least three receivers of high frequency optical modulated signals.

25. A terminal according to any preceding claim, wherein the terminal operates as a VSAT satellite communications terminal.

26. A terminal according to any preceding claim, wherein the terminal operates in commercial and military Ka-band satcom frequencies.

27. A terminal according to any preceding claim, wherein the terminal operates on Ku Satcom frequencies.

28. A terminal according to any preceding claim, wherein the terminal operates in X-band satcom frequencies.

29. A terminal according to any preceding claim, wherein the terminal is capable of operating over multiple bands.

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