The powerful technologies of today and tomorrow emerge from the digital revolution - namely, computing ('DSP') and storage. Cell phones, satellite TV, and indoor wireless networking - are beneficiaries, and represent large commercial markets. A challenge remains, however, in sending high data rate signals to mobile, vehicular users with small antennas. This next generation 'On-Star' system, combining in-car entertainment and 'telematics', is set to take center stage in the automobile market. In the tactical mobile world, wide area terrestrial communication is usually not an option. Applying these same technologies in the SATCOM world, however, may have a significant impact in: (1) reducing the cost of the mobile terminal (2) providing improved immunity to detection, and (3) providing improved high data rates, especially on the downlink. Cost reduction, lower power transmitters, and lower profile 'tracking' antennas may benefit from this transfer. This effort will explore the use of commercial 'spread spectrum' technology (especially modems) to achieve these objectives for both existing satellite platforms and new systems. The effects on other elements of the system (satellite, tracking antenna') will also be evaluated. Based on the study results, the commercialization plan will be refined and a second implementation phase proposed.
Benefits: The potential benefits of a successful application of high volume, advanced commercial spread spectrum technology to satellite communications include the following: (1) The terminals rf power can be distributed over a wider bandwidth, reducing the probability of detection ('LPI') (2) The terminal antenna size can be reduced, since typically adjacent satellite interference governs the minimum antenna size, making mobile platforms more attractive ('low profile') (3) If spread spectrum can be successfully implemented on the downlink (or 'forward channel' in terrestrial terms), then the size of the receiving antenna can be dramatically reduced, especially in high data rate situations. (4) If operation at high efficiency in the satellite amplifiers can be combined with spot beam technology, then higher frequency operation with greatly improved performance can be achieved, especially in a jamming environment ('AJ'). The translation of these technologies into the commercial world will allow communication of video entertainment and high speed Internet to the family car with an antenna no bigger than a sun-roof. Satellite broadcast remains the only viable means of providing a multi-channel video package to the car, combined with delivery of games, popular web sites, local news, weather and sports. There are 140 million vehicles on the road just in the US, with over 25M 'family' vehicles (SUVs and mini-vans). This segment of the auto market represents the fastest growing one, with buyers in the high end of the disposable income range, typically eager to install entertainment, safety, and information technology in the car. Currently over half of the new car buyers surveyed say they intend to buy a new video system with their next car purchase ' the size of the antenna representing the greatest technical challenge to meeting this demand from the market place. The market for these systems in the automobile could be much larger than satellite TV in terms of number of subscribers (service revenue) and revenue from equipment sales (hardware).
Keywords: Satellite, Spread-Spectrum, Antenna , Communications, Anti-Jam, Modem
