New multi-megabit-per-second Ku-Band satcoms-on-the-move (OTM or SOTM) products and service offerings, some employing technology originally vetted in military use, are being brought to market for commercial services. These exciting new service opportunities include live news video streaming from moving vehicles, rear-seat entertainment for cars,in-flight and in-train broadband services, as well as law enforcement and first-responder systems.
Keeping On Track
Whether for land, sea, or air, implementing antennas small, light, and low-cost enough to fit on a vehicle, train, or plane, yet still able to track a satellite while in motion poses technical challenges. Ground antennas must continuously steer and track the satellite while the vehicle, vessel, or aircraft is in fast motion, either using mechanical pointing, electronic pointing, or a combination of these.
Key antenna systems suppliers for stabilized on-the-move antennas capable of two-way services, leading maritime players SeaTel, KVH Industries, Orbit, and KNS, land-focused suppliers such as TracStar, and RaySat, aeronautical-focused players such as Rantec, Starling, AeroSat, and EMS Satcom.
A number of military systems suppliers have their sights on commercial Ku-Band on-the-move applications. For example, Starling, of Yoqneam, Isreal (whose shareholders include Isreali Defense suppliers Elbit, Rafael Development Corporation, and Elron Electronic Industries) has made a push into commercial applications with its new MIJET® line of two-way on-the-move antennas for air, rail and auto markets. Another example is ThinKom of Torrance, CA, which supplies low profile and lightweight antenna systems for military and intelligence applications at milsatcom and other frequencies, and is introducing a new commercial Ku-Band product line.
The Big Scrunch: Smaller and Lighter Antennas
The smaller the antenna diameter, the lower the receive and transmit gain, and the wider the transmit beam width – increasing the potential for adjacent satellite interference from sidelobes.
One solution to the problem of adjacent satellite inference with small Ku-band dishes is to spread the signal across a wider bandwidth. VSAT modem manufacturers, including iDirect, Hughes, and ViaSat have responded withspread spectrum products. iDirect uses DS-SS (Direct-Sequence Spread Spectrum) technology to enable transmissions to smaller on-the-move terminals. ViaSat’s ArcLight® technology also includes spreading, as does Hughes’ broadband-VSAT-for-mobile solution. For its benefits, Spread Spectrum requires more transponder bandwidth than conventionally used waveforms – which can increase a network’s recurring satellite bandwidth costs by a big margin.
Gain Improvements On The Horizon
ThinKom plans to introduce what it says will be the most efficient low-profile commercial two-way on-the-move antenna system on the market. According to ThinKom’s Chairman William Milroy, "Because of its efficiency, low sidelobes, and very narrow GEO-Plane beam width, no signal spreading is required even at Ku-Band." The company says its ThinSat300 antenna will offer 40-65% lower profile, and 4x to 10x higher spectral efficiency (Mbps/MHz) than competing OTM products. "Only 11 cm high, it can deliver comparable performance to a typical 90 cm by 35 cm parabolic (elliptical) dish," says Milroy. The product, which goes into beta trials in cars and SUVs later this year, uses a novel Variable Inclination Continuous Transverse Stub (VICTS) array technology, proven at X-, Ku, Ka-, Q-band in years of military applications. The VICTS array is under 4.5" high, consisting of two circular metal-coated plastic plates which rotate – enabling low manufacturing and materials costs, says the company.
Good Things in Small Packages
Land mobile two-way services at Ku-band have become more viable on vehicle-top systems thanks to innovation in the design of low profile, lightweight and low-power-draw amplifiers. "In many systems, the difference between a solution that will or won’t operate, or make business sense is an issue of the temperature, size, or weight," says Gary Echo, VP of Business Development for WaveStream of San Dimas, CA. "We overcome that challenge with our Ku-band technology," he says. WaveStream is delivering uplink amplifiers that are about half the size and weight of comparably rated SSPAs, while drawing about one-third less power of conventional Ku-Band SSPAs by using the company’s patented spatial-power combining technology. Its solid-state power amplifier (SSPA) and block upconverter ("BUC") technology can be found in on-the-move Ku-band systems from Tracstar, SeaTel, RaySat, ThinKom and others.
Promising New Antenna Technologies
Electronically steerable phased-array antenna technology has been used in military space applications on spacecraft and ground systems for decades. Unlike conventional "dish" reflector antennas, electronic array antennas can be "flat panel antennas" – for example 6" or less in height – which is perfect for ‘low drag’ or ‘low profile’ on-the-move systems. Until recently, these kinds of antennas have largely been the exclusive province of expensive military systems due to their high costs. ThinKom’s, Bill Milroy, explains: "People are working on low-cost phased arrays, as are we, but there are two problems. First, they are too expensive. Second, they are not very efficient. You have to use a lot of area to get the same performance."
Commtact, of Yavne, Israel, has a decade of experience in wireless on-the-move defense communications hardware but has been moving into the commercial SOTM arena. Zachi Bejerik, CTO of the antenna manufacturer agrees that phased array technology is too expensive for commercial systems. "Until phased arrays are mature, probably several more years, and until it introduces good efficiencies, we believe our reflective technology is the best in terms of performance and price." He sees the market ranging from $125K down to $40-$45K for considerable quantities of two-way terminals, with Commtact positioned in the low price range. One advantage of Commtact’s reflector and feed array approach compared to phased array-based products is that converting from Ku-Band to Ka-Band only requires replacing the feed.
But emerging satellite solutions for railroad and autos communications are nudging phased array technology into commercial systems. An example is the vehicle antenna system used by AT&T CruiseCast, a satellite-delivered in-car entertainment service that will include a lineup of 22 satellite video channels and 20 radio channels. The antenna for this service, built by RaySat, Inc. has a phased array antenna that dynamically tracks the satellite. The low-profile (12 cm high) antenna that affixes to the roof of cars, SUVs and larger vehicles, has a manufacturers adjusted price (with receiver) of $1,299. It implements mechanically steered azimuth tracking and electronically steered elevation tracking.
From Military to Commercial – Risks and Opportunities
Demand for on-the-move applications is not only driving the need for Ku-band capacity and services, it is also helping to bring some interesting and exciting new ground systems technologies from military into commercial markets. But to succeed in commercial markets, suppliers that have traditionally served defense customers will need to shift to commercially oriented thinking and behavior. This means, for example, investing in marketing, advertising, and promotion, as well as sales and distribution and support strategies. It can also mean making product investment decisions based on broader market requirements, and taking some market risk. It can also take a cultural mindset that is very different from the one to which companies from a defense customer environment with single-customer RFPs may be accustomed. But if market studies are on track, the potential for land-mobile, rail, and aeronautical on-the-move products and services should be well worth the effort.
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Since 1990, Dan Freyer has worked with leading spacecraft and ground equipment manufacturers, satellite operators, and video and IP users to grow their businesses. AdWavez Marketing (www.AdWavez.com) helps companies in the technology, broadcasting and satellite industries market their products. He can be reached at dan@adwavez.com
