Competing in All Fields: Technologies for Multi-Orbit Architectures

Fueled by strategic direction and an impending near-peer conflict, the Pentagon is creating resilient transport diversity across multiple constellations. Projects like the Army’s Multi-Orbit Modem, the Space Force Commercial Satellite Communications Office's contracts for multi-orbit, multi-band satellite capabilities, and SES’s Secure Integrated Multi-Orbit Networking (SIMON) are investing in multi-orbit diversification.

Similarly, commercial sectors — like aviation and maritime — are equally driving adoption, seeking higher bandwidth and greater resiliency through multi-orbit solutions. Airlines are racing to meet passengers' expectations for streaming, driving a surge in flexible, high-capacity in-flight connectivity, and maritime operators are scaling up data use for navigation, IoT sensors, and crew welfare. Both verticals are seeking faster, more affordable links through the combined strengths of Low-Earth Orbit (LEO) for speed and Geostationary Orbit (GEO) for reliability.

While the new investment strategy of the future is to diversify orbits, the technical reality of ground systems is anything but simple. Diversifying using multi-orbit networks involves managing a portfolio of frequencies, satellite locations across different orbital planes, networks with different waveforms, and traffic through multiple satellite networks. These complexities are changing the way terminals and gateways will function.

Sending and receiving multi-orbit signals is like playing tennis, golf, and baseball all at the same time — each ball (i.e., signal/frequency) flying with its own physics, trajectory, and communication protocol. For multi-orbit applications, marrying frequency diversity with satellite tracking is akin to awkwardly carrying a racket, a club, and a bat. For example, parabolic antennas can only track one satellite at a time. Therefore, supporting multiple simultaneous satellite connections using parabolics requires an antenna for each satellite, each one dedicated to a different constellation.

Electronically steered arrays (ESAs) emit multiple beams to point at several satellites across several orbits in the same antenna. However, even when an ESA can juggle multiple simultaneous satellite beams, multi-frequency is still challenging. Fortunately, companies are starting to narrow this gap. Kymeta recently demonstrated simultaneous Ku- and Ka-beams on the same antenna, while All.Space is promising the Hydra KuKa antenna with a Ku- and Ka-band multi-beam architecture.

Much like a 1950s telephone operator manually patching circuits to complete calls, antenna output signals require routing of intermediate frequencies (IFs) for modem processing. Using analog cabling to handle multiple orbital signals creates a complex network of wires and analog processing equipment, which must be hardwired to the corresponding modem, making transport increasingly complex and inflexible. Especially in multi-orbit, the task of transporting signals for processing requires a new approach.

IF signals should behave more like streaming video, replacing fixed cabling with a flexible IP fabric. This approach requires digitizers, such as the the SENTRY RFoIP, to convert IF into Digital IF Interoperability (DIFI) IP streams. DIFI enables rerouting through any data path, dynamically linking modems with transmission systems without the constraints of hardwires. Instead of managing a maze of dedicated analog connections, operators can utilize a common IP-based fabric to support multiple frequencies and orbital paths, thereby reducing hardware complexity and enabling the seamless, flexible, and scalable integration of multiple satellite networks.

Like the racket, club and bat, multi-orbit IF streams each require a dedicated modem appliance to provide the waveform processing. Today, modem appliances rely on separate proprietary hardware, which complicates logistics, slows migration, and limits flexibility. For the DoW, reliance on siloed proprietary hardware has long plagued gateway operations, particularly in managing multiple hardware logistical paths. For aircraft, replacing hardware is an expensive and logistical nightmare due to safety regulations.

Like a magic multi-sport tool that transforms into a racket, club, or bat on demand, modems should be deployed as applications on common hardware, allowing multi-orbit solutions to support a network-agnostic solution and future network compatibilities. The Waveform Architecture for Virtualized Ecosystems (WAVE) defines agile waveform processing, leveraging standardized compute platforms — such as Amazon EC2 F2 instances — to process DIFI streams.

Leveraging field-programmable gate array (FPGAs) F2 instances enable modem vendors to continue delivering spectrally efficient designs while gaining the scale of the cloud. This approach eliminates dependence on proprietary hardware, establishes a scalable vendor-agnostic infrastructure, reduces gateway footprints, and provides a migration path for modem vendors to support multi-orbit systems.

WAVE equips the multi-sport (orbit) problem with one adaptive tool, but winning requires more than equipment— it takes strategy. Sending traffic across multi-orbit links requires aggregating links to deliver higher throughput or steering data onto the link that best matches the traffic requirements (i.e., latency). Software-defined wide area networking (SD-WAN) provides these playbooks for orchestrating traffic across multi-orbit links. Through SD-WAN systems, such as XipLink’s XipOS, multi-orbit systems can dynamically match traffic to latency requirements, combine links for increased throughput, or duplicate data flows for assured resilience.

Just as investors diversify their portfolios to weather volatility and capture opportunity, the satcom industry is diversifying orbits. What was once a fragmented ecosystem of proprietary appliances is becoming a cohesive, interoperable framework. Multi-access antenna systems provide the RF connections, DIFI unlocks flexible transport fabric, WAVE provides agile network access through modem applications, and SD-WAN manages multi-network traffic.

Together, these elements are creating a new generation of ground infrastructure capable of delivering resilient, scalable connectivity that aligns with the strategic and commercial demands of the future. VS

Dr. Juan Deaton is the WAVE Consortium's Executive Director, providing strategic technical guidance to the board while championing industry partnerships to drive satcom standards forward. He also serves as Chief Alignment Officer at Alignment Consulting and Engineering.