Technology
Making Better Satellite Terminals
As fixed satellite services (FSS) continue to invade territory once occupied by mobile satellite services (MSS), MSS providers need to find ways to decrease their cost-per-bit. They can’t compete with the quantity of spectrum owned by FSS, so they need other options. In a recent cover story for Via Satellite magazine, Inmarsat CTO Ruy Pinto said that his company is focused on making cheaper and more reliable mobile satellite terminals.
Better terminals, by improving data speeds and lowering costs, could help MSS to gain more traction against FSS. The keys to making better terminals include picking the right frequency bands, improving components and innovative new construction.
Frequency Bands
When MSS providers want to deliver high-bandwidth functions like video and broadband, then the Ku-band and C-band may be the best choices. However, many applications, like SCADA and fleet tracking, don’t rely on high-bandwidth visual communications. L-band technology is far more cost-effective for low-bandwidth applications. In fact, L-band can deliver these services for one-third the cost of Ku-band or C-band.
MSS providers can concentrate on marketing low-cost L-band deployments to companies that maintain a number of mobile assets including offshore supply vessels and trucks. This strategy is cost-effective because these assets only require general pointing to pick up L-band signals. Also, lower-frequency L-band signals are less susceptible to rain fade and other weather-related disruptions.
Some solutions are making mobile satellite terminals flexible. For instance, some terminals can operate in different bands with the change of just a few parts. For example, very small aperture terminals (VSAT) can switch to the Ku-band when rain fade and other environmental factors impair the terminal’s performance in Ka-band. Knowing which band works best in different situations and delivering the flexibility to switch as needed could significantly improve end user satisfaction with mobile terminals.
Better Components
Better components, including modems, antennas and power, will power the next generation of mobile terminals. Modems, for example, are continuously featuring improvements in higher-order coding, modulation and military-specific technologies, such as anti-jamming. Adaptive coding and modulation, for example, can adjust data rates according to weather conditions.
Cutting antenna size is also important for building a better terminal. One concern about smaller antennas is that they require stronger satellite signals in order to function. However, antennas with better side-lobe characteristics and better gain-to-noise-temperature ratios can help manufacturers to build smaller and lighter terminals. At the same time, these antennas can function with narrow satellite beams. Other new technologies include software-driven antennas and beam-forming antennas that take advantage of meta materials instead of mechanical motors.
Multi-mode wireless devices within terminals allow them to receive information in the most effective and reliable way. These devices allow terminals to switch from satellite to wireless to cellular depending on the most available communications medium. Command and control terminals used during a natural disaster, for example, would experience far fewer service interruptions.
Innovative Construction
Earlier this year, GATR Technologies launched an inflatable X-band satellite terminal. These inflatable satellites, when deployed, grab additional military bandwidth from the Wideband Global SATCOM network. Inflatable construction cuts size by 80 percent while delivering the same type of performance as a rigid antenna. Measuring at 1.8 and 2.4 meters, these terminals can be easily carried and deployed by military units working in remote areas.
Other manufacturers are integrating smartphone apps to help accurately aim VSATs and to achieve the desired terminal performance. An app called Satmotion Pocket VSAT Pointing & Lineup Tool for Auto Commissioning VSAT Installations assists with both the initial installation and continuous fine-tuning of the VSAT connection. Upon deployment, Satmotion displays a map with a line to the satellite so that VSAT users have a direct line of reference on-site. Once the link is set, continuous monitoring ensures that the terminal is receiving its signal from both the right satellite and service.
The Future of MSS
Many providers plan to integrate satellite technology into terrestrial devices like smart meters. Still others want to come up with ways to embed satellite technology into everyday smartphones. In the traditional MSS market, however, smaller, more reliable and better performing terminals are key to lowering data costs and fending off FSS intrusion. The key is to focus on the end user’s experience. Inmarsat’s Pinto said this of consumers: “They simply want a service that works. Whoever succeeds in providing this end-to-end experience is going to be successful.”
About the Author: Steve Manley is the president of Globalcom Satellite Communications (http://www.globalcomsatphone.