XM Radio has patented a “Method and system for providing geographic specific services in a satellite communications network” (#US6347216) and the National Association of Broadcasters is very upset. They are expecting XM Radio to honor their pledge to stay out of the local radio programming business. But the technology covered by the patent allows them to determine a listener’s location with local repeaters and, presumably, offer local information and compete directly with broadcast radio. XM Radio says it still plans to offer only nationally syndicated programming. I’d venture a guess that local traffic and weather would be a nice future addition. (Note: the US Patent Office’s online database is down at the moment, so I used the database at Delphion, IBM’s intellectual property spinoff company)

Here is a PDF of the NAB’s official complaint to the FCC (854KB) which also has the complete patent attached to it. The FCC allowed XM to install the repeaters, something the NAB fought against.

How Stuff Works has detailed explanations of all three satellite radio providers and their technology. XM Radio has two Boeing satellites, named “Rock” and “Roll”, in parallel geostationary orbit. Sirius has three Loral satellites in “an inclined elliptical satellite constellation.” WorldSpace has a satellite over Africa, Asia, and plans for one to cover Central and South America.