The artificial satellite system has three operational components space segment, user and ground segments).
The ground segment enables the management of a spacecraft, and the distribution of payload data and telemetry among interested parties on the ground. The primary elements of a ground segment are Ground (or Earth) stations, which provide radio interfaces with spacecraft; Mission control (or operations) centers, from which spacecraft are managed; Ground networks, which connect the other ground elements to one another; Remote terminals, used by support personnel; Spacecraft integration and test facilities and Launch facilities.
In order to communicate with satellites, ground stations are necessary. Located in various parts of the world, they support different types of satellites, depending on their inclination and orbit. For example, polar-orbiting satellites need to connect with ground stations in the poles (e.g. Inuvik or Kiruna in the North Pole and Punta Arenas or Dongara at the South Pole), which provides rather long duration passes, enabling an increased amount of data downloaded.
The ground stations are made of one or more antennas, that enable satellite operators to
communicate with the satellite, sending telecommands and downlinking telemetries (e.g. mission data, satellite status).
A trend in future space missions is on-demand, 24/7 access to orbiting satellites. For extremely low-cost, experimental space missions, this type of access coverage is not affordable. First, it is cost-prohibitive for these small missions to build their own ground stations let alone an entire network that provides global coverage. Industry ground stations capable of megabit per second downlinks have extensive specialized hardware components and, on average, cost several hundred thousand dollars.
The model “as a Service” “as a Service” (aaS) initially stems from the IT industry, and more specifically from cloud computing. Software as a Service (SaaS) is a well-known example of
“aaS” model, where infrastructure and hard, middle, and software are handled by cloud service providers and made available to customers over the Internet, on a “pay-as-you-go” basis. “aaS” offers various benefits to the customers, as it helps them minimize upfront investment while avoiding operation, maintenance, and other ownership costs. Customers can thus transform their
capital expenditure (CAPEX) into operational expenditure (OPEX). Considering such benefits, “aaS” has recently become widely spread even beyond the IT world, and into the ground segment industry.
In order to support increasing data volumes, the antenna systems and/or demodulation hardware get bigger and more complex. This drives the cost per contact. For missions that have a higher demand or have to meet certain timeliness requirements the only way out it to use more antenna systems at appropriate locations. At the same time missions are no longer willing to pay for dedicated ground station infrastructure. All these pieces along with the increasing interface complexity have severe consequences for ground station service providers: On one hand building up and maintaining antenna systems and their associated infrastructure is getting more expensive. On the other hand funding is decreasing.
In order to fill in the gap between supply and demand, new GS services providers entered market, with the objective to offer New Space satellite operators a simple, elastic and cost-effective way to communicate with their satellite: GSaaS was born. Borrowing concepts and methods of IaaS and cloud computing, GSaaS abstracts GS infrastructure.
Flexible ground station network
GSaaS is a suitable solution for both satellite operators that already have ground stations (looking for complementary solution for punctual support or backup), and the ones that do not (looking for a reliable solution to ensure satellite contact). It offers GS services depending on the satellite operator’s needs, providing on-demand but also reserved contacts.
To meet the needs of an ever-expanding variety and number of spacecrafts, a flexible ground station network is needed. This includes flexibility in band, location, processing, antenna size, business model, and data.
Many of the characteristics of flexibility have to do with the amount and type of data you need to bring down from your spacecraft. Often, that can change throughout the life of the spacecraft, mission, and constellation. Early in a mission, UHF (Ultra High Frequency) may work best for communicating with your spacecraft while you are trying to acquire it post-launch and getting it into a healthy operating condition. When you start looking at bringing more data down as your mission matures, bands like S & X will allow you to do that. Having a network that can scale and shift as your data needs do allows you to move more quickly.
Another aspect of increased data downloads is location. Having only a single downlink point can limit the amount of data you can bring down. Polar locations are an excellent addition to a ground solution for sun-synchronous orbits, but still require around 90 minutes (about 1 and a half hours) between each pass, with only about 10 minutes of downlink time. Having multiple downlink points allows more total downlink time and can lower overall latency.
Antenna size also plays a key role because different missions require different gain. While you may get away with a smaller antenna for a LEO (Low Earth Orbit) mission, a CIS-lunar mission will require a larger antenna aperture. How and where you process and distribute your data upon receiving it at the ground station can have both cost and quality implications. Backhaul from remote locations can come with significant additional cost, so being able to process data at the terrestrial edge can help significantly. Power and storage limitations onboard the spacecraft may require terrestrial edge processing to get the most value out of your data. Data at the edge can also be routed to the cloud or processed in an appliance first.
Other factors that require flexibility beyond data are having schedule and business model flexibility. Whether you are using your own ground station or a provider, having redundancy or backup options can prove valuable if a planned ground station is not available to bring down your data. From a business model standpoint, one size does not fit all. If the amount of data you need to bring down changes over time, having a network that can scale both up and down with your needs to conserve costs will be important.
When it comes to satellite mission types, most GSaaS users are EO and Internet of Things (IoT) satellite operators. There are also technology satellites such as In orbit Demonstration (IoD) and In orbit Validation (IoV). EO satellites usually need to download as much data as possible and depending on their business, they look for near-real-time images. They however do not necessarily need low latency (i.e. maximum time between satellite data acquisition and reception by the user). For example, Eumetsat EO satellites in LEO have a latency of 30 minutes, which is enough to provide adequate services to their customers.
As compared to EO satellite operators, IoT satellite operator’s priority is more about number of
contacts, and they look for low latency (down to 15mn for Astrocast for example). They thus tend to select highly reliable GS that ensure satellite connection in a timely manner.
The need for GSaaS also depends on the orbit type. Indeed, as compared to GEO satellite operators that usually need few ground stations located in their targeted region to perform their mission, LEO satellite operators look for a global coverage.
Virtual Ground Station
Organizations can virtualize the ground segment by converting analog radio frequency waveforms to digital radio frequency streams (or vice-versa) as close as possible to the ground station antenna. Once analog radio frequency (RF) data is digitized, i.e. converted from an analog radio frequency signal to a digital form, it can be simply distributed to other locations over long distances with no data loss or signal degradation, or stored for later processing. This provides additional flexibility when considering the geographical placement of teams and components.
A virtual ground station is a software representation of a real life ground station. It is equipped with virtual equipement as a transceiver, an antenna and a rotor controller. Virtual equipment offers the same services its real life counter part offers. For example, the virtual transceiver can be turned on or off and its mode and frequency can be set. Like a ground station equipped with a tracking application, the virtual ground station offers services to start and stop tracking sessions. In addition, it has an owner and it knows where it’s located in terms of latitude, longitude, and
A virtual ground station can be used by any client with a computer attached to the Internet which
augments the degree of accessibility. Besides, a virtual ground station and its clients don’t have
to be collocated. A client can access a satellite as long as a remote virtual ground station has
access to it.
As the costs to put spacecraft into orbit decrease, traditional and NewSpace companies are working hard to reduce the timelines from mission design to launch. A software-based approach enables vendors of digital signal processing (DSP) solutions to build modular products and react more quickly to the needs of satellite operators, as building and distributing software is much simpler than doing the same with hardware
However, networking one single ground station isn’t enough. The true benefit of this solution comes from networking many ground stations from all around the world. This enables a user to track a satellite no matter where it is, as long as there is a ground station in its footprint.
Furthermore, with a sufficient number of networked ground stations, it is even possible to address another problem related to LEO satcom services: the intermittent nature of the services. In effect, on average, Satcom services are only available a few times a day and usually for a maximum of approximately 15 minutes. Thus, even when an uninterrupted download of a file
requires less than one hour, it can take several hours of elapsed time to download using a LEO satellite. In other words, several passes may be required to download a single file from an LEO satellite. One way to improve this situation is to consecutively use many different remote ground stations forming an extended tracking session.
Virtualization of ground segments can help scale, improve reliability, distribute and store data, avoid costly hardware refresh cycles, and innovate and adapt to change more quickly. With the cloud, you can deploy virtual servers that are tailored to your needs with a single API call or a few clicks of a mouse. In addition, the ability to manage your virtual server resources as code increases the possibilities to automate implementation and configuration steps, reducing the manual effort required to handle hundreds or thousands of satellite contacts.
Virtualization makes it simple to build reliable architectures, plus it increases the ability to recover from failure automatically. For example, you can launch several Amazon Elastic Compute Cloud (Amazon EC2) instances using a single API call to provision redundant signal processing paths in a virtualized ground segment with ease. In the cloud, replacing a virtualized function that exhibits anomalous behaviour can be as simple as terminating an underlying instance and replacing it with a new one. The cloud also improves reliability by integrating automated failover functions directly into control planes.
Ground station virtualization challenges
However, the implementation of this concept has many challenges because of the lack of flexibility of the current ground stations (GS) whose aim is to enable communication between ground users and space assets. In addition to the RF equipment needed for communication, ground stations traditionally have a suite of support systems for mission-specific data handling needs such as demultiplexing of data streams, encryption functions, data compression, time tagging, data storage, data quality measurements, and spacecraft ranging. This has led to challenges in multi-mission support due to highly specialized mission-specific equipment and a lack of flexibility for the end-users.
Additionally, the complexity of space systems is increasing and with it the possibility for systems errors and failures. Rising levels of automation introduce more software code and more computer hardware. The global distribution of space system components requires extensive networking. Increasing levels of international collaboration and peer-to peer space systems result in complex interfaces and interactions that are difficult to model.
With the adoption of terrestrial networking standards for end-to-end communication between space and ground systems, the core function of a ground station is simplifying and becoming similar to that of a standard Internet router. Therefore, the fundamental purpose of a ground station is evolving to become more simple; it is to bridge space and terrestrial networks and route packets appropriately.
Despite these similarities with Internet routers, there are some basic differences between them and ground stations. Due to the tracking constraints and narrow beamwidths of the RF links, communication channels tend to be circuit-switched; a ground station is scheduled for a particular time interval to exclusively maintain a communication channel with a single satellite. The bidirectional pointing requirements for high-speed communicational channels and slow
antenna slew rates prevent rapid multiplexing between multiple satellites. In contrast, the physical networks for routers are fixed and don’t require reconfiguration for each packet
stream. Therefore, while ground station resources remain scarce, this circuit-switched induced bottleneck requires efficient scheduling to enable multiple mission support.
The complexity of ground stations is currently significantly greater than Internet routers. In fact, ground stations usually contain a router in addition to all the equipment needed to support ground to space communication links. This increased complexity lowers the mean time to failure
and potentially increases the mean time to repair. Hardware repairs are manually intensive and regular inspections are needed. To bound costs, architectures must manage this complexity by decreasing failure detection and recovery times.
Similarly, there is a widespread movement toward rapid prototyping and deploying inexpensive space missions by using commercial-off-the-shelf (COTS) components. Another challenge is the the integration of non-mission critical components whose behaviors were not fully understood and typically designed for lighter workloads into mission-critical system service. Hardware fails (such as power supplies and disk drives) and software locks up or fails to free resources forcing system reboots.
Also, ground stations require real-time (or near real time) control of resources to maintain satellite contact channels. Telemetry feedback is used to adjust antenna pointing angles and receiver frequencies to maximize received signal strength. In contrast, routers simply manage queues without the complexity of hardware feedback control.
Networking globally distributed ground stations, enable the development of commodity services for these ground station networks, and provides high-availability techniques that enable reliable systems from unreliable components.
Satellite service and gateways, from Internet of Things (IoT) gateways to GSaaS providers, need to be extensively tested. These systems often employ virtual machines (VM) operating on general-purpose CPU host systems, which while more versatile, can be slower than dedicated systems. However, the performance of VMs is improving as the CPU technology evolves, and thus needs to be continually updated as technology advances. As well, research is being carried out to provide services to users for employing their needs in pre-developed infrastructures.
For instance, the Southwest Research Institute and its partners modeled and simulated overhead persistent infrared (OPIR), electro-optical/infrared (EO/IR), and synthetic aperture radar (SAR) data streams, transported them through space and ground networks, and processed them on the Amazon Web Services (AWS) cloud, and distributed the results to tactical users. Furthermore, ground station prototypes developed by Northrop Grumman will integrate software and hardware to offer access to commercial and military space systems’ multi-domain actionable intelligence. Additional prototyping involves that from IoT requiring global navigation satellite system (GNSS) signals and satellite communications in areas where terrestrial networks are not available. Hence, the need for satellite IoT gateways arises.
Ground Station Virtualization Architecture
The model is hierarchical and layered according to levels of autonomy; lower levels capture hardware devices and higher levels capture autonomous ground station services.
Ground station virtualization is used to decouple ownership of an antenna system from its operation. This enables multiple OEs to use the same underlying physical system. As the antenna system can only point to one satellite at a time so sharing of this asset has to be organized by time.
The virtual hardware level captures the fundamental capabilities of low-level ground station components and enables generic commanding of heterogeneous hardware. This is a master/slave control paradigm where the ground station exposes lower level control interfaces for all hardware.
The session level (SL) captures typical automation services of a single ground station installation. Users task a ground station to maintain a contact session with a satellite and employ local automation services of the station to perform routine component control during the pass. At the heart of this level is the session object which the ground station “executes” on a reserved set of hardware over a specific interval of time to maintain communication with a target satellite.
The session level captures typical automation tasks and services of a single ground station installation. Users define a session, which tasks these automation services over a specific time interval to maintain communication channels. A communication channel definition includes one or more pipelines (transmit, receive, or transceive) and associated data processing services. Session level services employ the virtual hardware level primitives to control lower level
ground station resources.
SL services automate typical ground station services such as antenna tracking, Doppler shift radio frequency correction, satellite ranging, and position estimation. These services employ hardware-level primitives to control lower-level ground station resources.
The scheduling service accepts reservations for the use of ground station systems. Ground requests are processed through terrestrial networks. Space requests are received through low resource utilization pipelines (such as simple omnidirectional antennas). Until stations are no longer a scarce resource, schedule will be a critical function. Resource availability and user access priority are taken into account during the scheduling of sessions.
The station controller automates the execution of satellite contact sessions. It monitors scheduled contact session requests, configures ground station hardware to support the requested communication channels, and enables requested automation and data processing services. It performs real-time control of station hardware to maintain and optimize communication channels during a satellite pass. Antennas are tracked, radios tuned, and link parameters (such as FEC levels and bit rates) adjusted to account for variable bit error rates. The controller also manages health monitor output and recovers from failures automatically or alerts on non-recoverable errors.
The station is monitored for proper operation by health monitor systems. These consist of sensors, both software and hardware, logging resources for storing telemetry, and health assessment functions for detecting failures and performance degradations. The estimator determines the target satellite position, antenna pointing angles, and Doppler correction factors. Possible sources for this information include pipeline ranging systems, satellite provided GPS data, or calculated values from orbital element sets.
The state management service stores session descriptions and their schedules, session products which contain GS telemetry and communication channel bit logs, a cache of satellite configuration information (pipeline frequencies, data processing needs, etc.), user access information, etc. The remote access server authenticate remote users and provides secure, encrypted ground station control. It controls access to the scheduling services, the data processing services, and also enables access to communication channels and low level virtual hardware commanding.
Processing bits on the ground side of the pipeline is handled by the data processing services. Networking and communication services include bit synchronization, forward error correction (FEC), and link and network level protocol management.
Radio signals are received from the satellite (downlink) or transmitted to the satellite (uplink) by the ground station’s antenna system. When receiving data, the analog RF is amplified to compensate for path loss, digitized into a digital intermediate frequency (DigIF) stream, then passed on for demodulation and decoding. The key component which enables the translation between analogue and digital is the digitizer. When transmitting data, DigIF is received from the modulation and encoding stage, converted to an analog RF signal, amplified, and then transmitted to the satellite.
The hardware level (HL) captures the fundamental capabilities of low-level ground station hardware and enables generic commanding of heterogeneous hardware components. Device-specific commanding protocols have been abstracted away to present a standard interface to ground station hardware (comparable to device drivers found in computer operating systems).
Researchers have modeled the ground station dedicated hardware to support ground to space communication links, which we all hardware pipelines. These consist of hardware associated with antennas, low noise receive amplifiers (LNA), output power amplifiers, radios, modems, and multiplexing hardware for flexible configurations. Pipelines also perform ranging functions to measure satellite distances and positions.
Software Defined Radio
Software Defined Radio is essentially a transceiver with complex embedded processing capabilities and a flexible/reconfigurable platform for changing radio parameters via software. SDR is also a relatively new technology increasingly being incorporated into ground stations. SDR lets ground stations accommodate variable demand by beam-hopping (such as that incorporated into the new DVB-S2X standard), adjusting coverage, and targeting high-capacity regions.
Moreover, SDRs are capable of processing the much greater downlink/uplink data requirements due to their RF to IP communications, which use 10/40/100 Gbps Ethernet connections to packetize data over to a host system or network.
SDRs are a core component of the architectures that virtualize the ground segment. SDRs package complex digital signal processing (DSP) algorithms, previously available only in specialized hardware, into software that can be hosted in the Cloud.
Conventional satellite RF systems have multiple limitations, including traditional designs that lack flexibility and are constrained by commercial equipment standards that govern communication subsystem design. Furthermore, these systems have high development, insurance, repair, and maintenance costs; regular monitoring time-periods; and environmental interference.
By integrating SDR into ground stations, numerous performance advantages are realized. This includes high independent channel counts with MIMO (multi-in-multi-out) capabilities for uplinking and downlinking multiple satellites. MIMO SDRs allow a ground station to concurrently connect with several satellites, regardless of their applications, where one channel might be used for navigation, another for research. Additionally, SDRs offer flexibility, upgradability, reconfigurability, and interoperability in the operation of ground stations, prolonging the useful life of devices and keeping up with new protocols and processes. An example would be of processes and parameters such as modulation and demodulation, coding methods, and data rates, easily being reconfigured. It’s even possible for legacy ground stations to be easily upgraded and repurposed.
Since nanosats are becoming more affordable, academic research programs often have their own satellite project/ground station projects. When establishing such a ground station, the options are to “build your own” or go with a commercial off-the-shelf (COTS) system. Using low-cost COTS SDRs allows for prototyping ground stations via GNU Radio for implementing link layers, modulation schemes, etc.
Ground operators can virtualize RF functions and digitize RF signals close to the antenna with an SDR. Therefore, many ground stations offer “as a service” using SDRs and virtual machines to decrease the complexity of specialized hardware, offer general application-level support, and increase the accessibility of satellite operation for smaller operations. Hence, instead of developing their ground segment, companies may use GSaaS to get the command, control, and data linkages they require. This allows businesses to experiment with multiple communications protocols utilizing a pay-as-you-go consumption model, reducing development, maintenance, leasing, constructing, or running operational expenses for ground stations. Services like modulation and demodulation, bit synchronization, and forward error correction, which once required massive racks of specialist equipment, are now operated on off-the-shelf computers with high-speed internet.
The network level (NL) captures the services of a federated ground station network (FGN). AFGN is a collection of autonomous, globally distributed ground stations with network services such as authentication, resource discovery, and scheduling. The underlying motivation for such a network is the sharing of geographically diverse, heterogeneous ground stations and the synergy of cooperating ground station teams to enhance satellite contact sessions.
The network level captures the services of a ground station network. These networks provided increased capabilities over single ground station installations and are federated from stations under different administrative domains. Link intermittency is reduced and temporal coverage is increased as globally distributed ground stations with overlapping contact windows handoff satellite contact session.
The registry service accepts registrations from ground stations offering their capabilities to the network. This registry service enables users to locate available ground station resources. Full scheduling authority rests with the ground stations.
The virtual ground station service composes distributed ground stations and presents a virtual single interface to station end users. This service enables peer ground station cooperation and masks failovers and handoffs without explicit user knowledge. Autonomy can be handled centrally with stations acting as slaves or distributed among them where they act as peers.
These three layers capture the core services of a ground station network and present different interfaces to users based on autonomy levels. At the virtual hardware level, users have full control of station hardware. At the session level, a station is tasked to automatically track a satellite and provide network data connections between ground and space assets. At the network level, teams of stations are tasked to maintain extended contacts, to optimize links, and provide redundancy in the presence of failures
A virtualization layer is introduced to facilitate the operation of the physical antenna system. The virtualization layer has two types of interfaces :
- A management interface that is used for the coordination/scheduling of the physical antenna system
- Low level antenna specific interface at TCP/IP level. i.e. the devices that make up the antenna system can be directly accessed using their native protocols. This includes the Antenna Control Unit (ACU), programmable Up- and Downconverters, HPAs, as well as the base band units.
Modern base band units such as AMERGINT’s satTRAC, Zodiac’s Cortex CRT/HDR family or Kongsberg’s DFEP allow to access the data at TCP/IP level. Furthermore they are highly configurable in terms of modulation scheme, bitrate and coding. These two attributes allow to re-use the base bands in a multi-mission world. As the baseband units are fairly expensive the reuse is essential to reduce cost. Most ground stations have redundant base bands. In such a case the external OE can fully make use of this redundancy, too.
The general idea is to allow network access to the physical antenna system only one from operating entity at a time. The principle idea is that shared devices are dynamically assigned to the network in which they are used. The associated logical network structure thus dynamically changes. The antenna owner controls the “position” of the switch by means of the schedule. Once switched to an external operating entity itself has no longer the ability to connect/interfere/capture traffic between the external OE and the physical system. Technically this is realized by use of Software Defined Networking.
An enforcement element consists of a SDN switch and a SDN controller. The SDN switch is a commercial of the shelf product that can be readily ordered. The SDN controller is a critical piece of software. It has to be programmed such that the resulting flow tables at the switch will allow one entity to access the shared devices at a time. From a functional perspective the SDN combination provides classical firewall functions. However, the price is much lower and packet
processing happens at line speed
New technologies are expected to have an influence on the GSaaS market, especially as it could enable GSaaS suppliers adapt their service offering to answer their customer needs. These technologies notably encompass optical communications, Flat Panel Antennas (FPA) or
Artificial Intelligence (AI).
Optical communications and intersatellite laser links
As compared traditional RF communications, optical communications present various benefits such as substantially higher data rates, increased security in data transmission but also the absence of interferences or the absence of spectrum licensing required. However, optical communications between Earth and space are dependent on weather conditions, as optical beams performance can be negatively affected by atmospheric turbulences.
In order to avoid such challenges while benefiting from all benefits, optical communications are
increasingly used for inter-satellite links in space. It consists in having GEO satellites acting as relays, communicating with user satellites with laser links. Such technology provides many benefits:
Satellites can push the data collected directly to the GEO node, that is constantly connected to the
ground. This enables almost constant satellite coverage, even when it is beyond the line of sight.
Such system also enables satellite operators to limit the number of ground stations needed,
– Depending on the Laser Communication Terminals (LCT), data rates can be very high (up to 1.8
– Inter-satellite links offer capacity to communicate with satellites for a longer period, which is key especially for satellites in LEO that have low and short contact windows.
Intersatellite laser links are currently notably provided by Airbus in the frame of “Space Data Highway”, offering data rates up to 1.8 Gbits/s. However, to benefit from such performance, satellite operators need to carry onboard their satellite an LCT that is relatively heavy, and that must be integrated in the spacecraft design from the start. Consequently, only relatively large satellites (more than 500kg) are currently able to integrate such LCTs in the future. In order to enable small satellites to communicate using laser links, lighter LCTs weighting up to 15kg are being designed, and are currently being tested by SpaceX for their Starlink constellation for
Pentagon officials often complain that the nation’s current satellite ground architecture is stymied by stovepiped, custom-built proprietary ground systems. While historically most satellite systems have been built with their own unique ground service platform, the Air Force has long wanted to move to a common platform for multiple families of satellites called Enterprise Ground Services. While EGS may have to be tweaked to work with the unique mission parameters of any satellite system, the idea is for all of the Air Force’s satellite systems to start from a common suite of command and control ground services.
Not only is this expected to save money in the long run since they won’t have to develop a new ground services architecture for each new satellite system, but the Air Force also hopes that transitioning to EGS will make it easier for satellite operators to move from system to system without having to learn an entirely new platform.
Kratos to demonstrate virtualised SATCOM ground system for US Army
The US Army’s Combat Capabilities Development Command (DEVCOM) awarded a contract to Kratos Defense & Security Solutions to demonstrate military satellite communications (SatCom) modernisation in July 2023. The company has been tasked to build a virtualised SatCom ground system based on Kratos’ OpenSpace Platform.
The platform has an open architecture that supports multiple satellites and payloads. The cloud-enabled, IP and network-centric platform delivers faster operations.
The contract will be funded through the Network Command, Control, Communication, and Intelligence Cross-Functional Team (N-CFT) of the Army’s Future Command. Kratos’ solution will support the government’s modernisation strategy to streamline gateway and remote terminal capabilities. This will reduce life-cycle costs and support dynamic space operations.
The solution is expected to support future military SatCom networks with the ability to configure services spontaneously and spin up and spin down resources for multi-mission support. Kratos Space Technology vice-president Chris Badgett said: “A strategic goal of the military is to operate an integrated SatCom enterprise, which increases assured SatCom access for the warfighter and improves the effectiveness of the infrastructure by enhancing resilience.
References and resources also include: