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Table of Contents
What You Will Learn
- The Importance of BVLOS Operations and how it enhances operations’ efficiency.
- What are the limitations of VLOS Drones
- What is the Functionality of SATCOM
- What are the benefits of SATCOM for drone operations.
- What are the drawbacks of SATCOM
- What are the alternative Solutions such as multi-link cellular communications as an alternative for long-range and BVLOS operations.
Military and civilian UAS (unmanned aerial systems) alike are becoming increasingly reliant on BVLOS (beyond visual line of sight) operations, which allow the aircraft to travel great distances from their operators or base stations. BVLOS flights enable drones to perform more efficiently and effectively, as the operator no longer needs to relocate when their drone travels outside the line of sight, and to cover greater areas and distances in a single flight.
Many VLOS drones use communications and data links that depend on line-of-sight RF (radio frequency) transmissions, requiring a clear unobstructed view between the aircraft and ground control station. Even if an operator is authorized to fly BVLOS, these links may be unsuitable for such purposes, as the range of the link will be limited by the curvature of the Earth as well as other obstacles that may cause blockages in the horizontal direction. While this range can be extended by using a taller antenna, eventually a practical limit will still be reached.
What is SATCOM and how does it work?
One method that is used to circumvent the aforementioned limitation of line-of-sight RF links is SATCOM (satellite communications). SATCOM uses direct transmission between Earth-based devices or stations and strategically-placed satellites, which may be in geostationary orbit, low Earth orbit (LEO), medium Earth orbit (MEO), or high Earth orbit (HEO). Signals are broadcast to a satellite, which then redirects, bonds, and amplifies the strength of the signal and retransmits it to the intended destination.
SATCOM transmission may be one-way, in which uplink and downlink occur between the satellite and different earth receivers, or two-way with a separate uplink and downlink, in which bidirectional communications can be established between a satellite and a single device. SATCOM uses a number of different frequencies, each of which provides different data rates and levels of resilience to environmental factors such as atmospheric conditions.
What are the benefts of SATCOM for drones?
SATCOM allows for long-distance communication with UAVs, enabling command and control over thousands of miles. However, real-time piloting is limited due to latency in satellite connectivity, making it unsuitable for precision maneuvers or live drone operation. Beyond control signals, SATCOM can also transit data collected by UAVs including:
- High-resolution imagery
- Live or recorded video
- Telemetry and sensor data
Depending on the network and the orbits of the satellites, SATCOM can potentially provide coverage almost anywhere on the globe, and with High Earth orbit (HEO) this can even include the polar regions. This makes the SATCOM ideal for operations in areas without reliable communication infrastructure, such as:
- Remote or rural environments
- Conflict zones
- Natural disaster areas
Depending on the network and the orbits of the satellites, SATCOM can potentially provide coverage almost anywhere on the globe, and with High Earth orbit (HEO) this can even include the polar regions. This makes the technology ideal for drones operating in remote regions, and areas with no existing communication infrastructure or in disaster zones where infrastructure has been destroyed.
SATCOM’s reach can potentially span nearly the entire planet, with the extent of coverage determined by the specific satellite network and orbital configurations.
Real-world applications of SATCOM
SATCOM is used for a wide variety of both civilian and military drone applications, including:
- ISR (intelligence, surveillance, and reconnaissance) – gathering critical information that will enhance situational awareness and enable more effective decision-making for military forces
- Remote drone delivery – SATCOM has been used by drones to deliver critical cargo such as vaccines and medical supplies to islands, rural areas, and other remote regions
Mapping, surveying and environmental monitoring – these use cases may require drones to gather data across vast geographical areas, thus requiring an over-the-horizon communication capability such as SATCOM
Recent industry trends underscore this hybrid connectivity approach. Drone systems are increasingly combining LTE/5G cellular links and SATCOM broadband into a unified, secure way. For instance, in regions such as India, this combined strategy is proving vital for enabling long-distance drone operations where terrestrial infrastructure is limited.
The disadvantages of SATCOM
While SATCOM enables BVLOS operations and can enhance capabilities beyond those of standard unlicensed RF datalinks, although due to its latency it is not the perfect solution for all drone applications. UAV SATCOM terminals tend to be bulky and heavy, and can significantly impact the SWaP (size, weight and power) budget of an aircraft, and thus its effective range and flight time. While advances in technology have managed to miniaturize the SATCOM terminal somewhat, the smallest drones will still not be able to take advantage of them. Accessing the highest possible data rates also requires larger terminals and antennas, meaning that applications such as real-time high-definition video streaming can only be carried out by larger UAVs.
SATCOM equipment and services are also expensive. The data costs for short-burst messaging may be viable for small businesses, but the bandwidth required for high-capacity streaming can run into thousands of dollars or more per month, putting it outside the reach of anyone other than large enterprises and governments. In addition, SatCom’s high latency precludes it from becoming a serious provider of connectivity for unmanned flights.
SATCOM services are expensive and suffer from high latency, lower bandwidth, and a high SWAP budget.
Multi-link cellular communications – an alternative option for long-range and BVLOS drones
Multi-link cellular communication utilizing 4G and 5G networks provides an alternative solution for long-range and BVLOS drone connectivity. Like SATCOM, it also allows drones to operate almost anywhere in the world, as long as they are within range of a relevant cell tower.
Cellular services, in particular 5G, provide high-bandwidth and low-latency throughput that is ideal for supporting streaming video and real-time command and control, with far lower data costs than SATCOM. Cellular modems are also inexpensive, lightweight and compact, and can easily fit within the SWaP budget of even the smallest UAV.
For some drone platforms, a combined SATCOM and cellular communications system may be highly suitable for ensuring that a backup is available should the primary communications link go down.
Multi-link cellular communication leverages multiple 4G and 5G networks to enable long-distance and beyond visual line of sight (BVLOS) drone operations globally, provided the drones remain within the coverage area of applicable cellular towers.
Elsight’s Halo – a leading connectivity solution leveraging multi-link cellular communications
The Elsight Halo is a compact, lightweight and low-power solution that allows drone operators and OEMs to take full advantage of the power of cellular communications. The versatile and carrier-agnostic platform aggregates up to four unique cellular (LTE and 5G) datalinks from multiple providers along with SatComm and RF technologies.
These multiple datalinks can be used to ensure critical redundancy for BVLOS drones passing over large geographical areas and through dynamic communications environments, such as high mountains. Halo’s proprietary algorithms continuously prioritizes all available connections to provide the optimized bond for any moment.
Halo’s state-of-the-art capabilities is its secure cellular bonding technology, which takes advantage of maximum throughput for bandwidth-intensive applications such as real-time video and data streaming.
Contact us to find out more about how Halo can enable cost-effective and SWaP-friendly BVLOS operations and how it manages a SatCom link.
FAQs
1. How does SATCOM latency affect real-time drone control, and which missions is it suitable for?
SATCOM latency is typically higher than terrestrial LTE or 5G networks’ latency, especially with GEO satellites, which can affect flight control and data streaming. However, SATCOM is well-suited for long range BVLOS missions, such as maritime surveillance, defense, offshore inspection, disaster response, and remote area operations where coverage is unavailable or unreliable. Hybrid systems combining SATCOM with cellular links help balance latency, reliability, and coverage.
2. What are the size, weight, and power (SWaP) requirements for SATCOM terminals on UAVs?
Traditional SATCOM terminals can add significant size, weight, and power requirements to smaller UAV platforms, potentially reducing payload capacity and flight endurance. Newer SATCOM solutions and hybrid communication platforms are becoming smaller and more power efficient, making integration easier for commercial and public safety drones.
3. When should I choose SATCOM, multilink cellular, or a hybrid solution for BVLOS operations?
SATCOM is typically preferred for remote, offshore, maritime, or sparsely populated regions where cellular coverage is unavailable. Multilink cellular solutions are often ideal for urban, suburban, and many commercial BVLOS operations due to lower latency and lower operating costs. Hybrid architectures combining LTE, 5G, RF, and SATCOM provide the highest resilience and operational flexibility by maintaining connectivity across changing environments and network conditions.
4. How much do SATCOM equipment and data services typically cost for drone operations?
SATCOM systems generally entail higher hardware and recurring data service costs than cellular connectivity, particularly for high-bandwidth video streaming applications. Costs vary depending on the satellite provider, bandwidth requirements, coverage area, and terminal size. Many operators use hybrid communication architectures to reduce overall operational costs by primarily relying on cellular networks, with SATCOM as backup or for remote mission segments.
5. Are there regulatory or certification requirements to use SATCOM for BVLOS flights?
Yes. BVLOS operations using SATCOM must still comply with aviation authority requirements, such as those from FAA, EASA, or local aviation authorities governing command and control reliability, Remote ID, risk mitigation, and operational safety. Operators may also need approvals for satellite spectrum use and telecommunications regulations, depending on the country and satellite provider. Demonstrating resilient and redundant communications is often a key factor in securing BVLOS operational approvals.
Related Resources
- https://www.inmarsat.com/en/insights/corporate/2023/a-straightforward-introduction-to-satellite-communications.html – a comprehensive introduction to satellite communications, by leading SATCOM provider Inmarsat
- https://www.elsight.com/5g-solutions-with-elsight/ – the advantages of 5G cellular communications for BVLOS drones
