| Military operations over the last several years have demonstrated the need for high bandwidth beyond line-of-sight communications to and from widely dispersed and mobile platforms for a variety of reasons. Such communications to platforms such as large naval ships has existed for many years, but up until recently only relatively low bandwidth communications was available to platforms such as aircraft (manned fixed and rotary-wing as well as unmanned), ground vehicles and smaller ships. Because of this recognized need, many organizations within and outside the defense establishment and industry have proposed many different approaches to provide this capability, but most have focused on ground vehicles or to a lesser extent fixed wing aircraft, and most have focused on Ku-band satellite communications at least for near term. Communications to helicopters has been limited to traditional low-rate methods such as UHF SATCOM and more recently bonded channel INMARSAT GAN service, primarily because of the lack of sufficient real estate on the aircraft and the intermittent blockage caused to higher frequency transmissions by the passing of the rotor blades over any antenna placed below the rotors. While INMARSAT BGAN service would offer higher data rates compared to either UHF or INMARSAT GAN service, a version of the BGAN waveform for airborne use in general (and rotary wing in particular) has not yet been approved, and even then its’ data rate and overall capacity within a beam is still limited and expensive. However, minor modifications to ViaSat’s ArcLight communications-on-the-move waveform have been made that allow the system to operate in the presence of the intermittent blockage caused by the passing of the rotors over the satellite antenna. These modifications take advantage of the ArcLight’s locally-controlled, asynchronous bursting on the return link (aircraft-to-satellite) in order to avoid rotor blockage. Complimentary modification of the forward link (satellite-to-aircraft) waveform similarly allows all data to be unaffected by the intermittent rotor blockage experienced at Ku-band frequencies. Furthermore, this modified waveform will allow ground vehicles to operate on the same network simultaneously with the helicopters, without any loss of performance compared to the original unmodified waveform based system, all the while meeting FCC and ITU guidelines. Measured performance during flight testing on UH-60 aircraft is included. |
| Don Wilcoxson (S’86-M’89) received the B.S.E.E. (with distinction) and M.S.E.E. degrees from Purdue University in 1988 and 1989, respectively, and the S.M.E.E.C.S and Electrical Engineer (E.E.) degrees from the Massachusetts Institute of Technology in 1996.
From 1989-1993 he served as a U.S. Air Force officer at the Air Force Electronic Warfare Center, San Antonio, TX performing simulation, analysis, and testing of current and future communications, radar, and navigational equipment. During 1993-1996 he was a teaching and research assistant with MIT’s Laboratory of Information Decision Systems and MIT Lincoln Laboratory, and performed research in a variety of communication areas, including frequency-hopping systems, phase noise effects, and cellular wireless systems. From 1996-1998, he was with TRW Space and Electronics in Redondo Beach, CA and led research and development activities for regenerative satellite communications systems. During 1998-2001, he was with ITT Aerospace and Communications where he led simulation and development activities for a DARPA-funded ad-hoc networking spread-spectrum radio program. Since 2001, he has been with ViaSat and has led systems engineering activities on a variety of commercial and military satellite communication projects. He holds 14 U.S. patents in the area of satellite communications and has several more patents pending in the U.S., Europe, and Japan.
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