The discussions in the United States among LightSquared, the Federal Communications Commission (FCC), the Global Positioning System (GPS) industry, Department of Defence (DoD), Department of Transportation (DoT) and users about the division of spectrum in the L-band should not be seen as just an internal US affair. The strength of both the camps, Telecom providers and the GPS industry indicate that this battle may easily expand to other parts of the world. For many, this battle was a surprise, particularly for a peaceful world like navigation, where discussions are more gentlemen like and either focused on which GNSS systems is the best, or on the backup of GNSS which is so vulnerable and where society cannot function anymore without GNSS. All this changed abruptly when LightSquared published plans to install 40,000 transmitters in a band adjacent to L1 band used by GPS. This led to numerous protests in the GPS industry and among its users as what has been published in many magazines. It is for us to see whether it is telecom versus GPS, or is there a sensible cooperation in reach?

The bottom line is that the LightSquared signals interfere with GPS, and LightSquared should not be allowed to proceed until the interference problems are resolved. To understand this perspective, some background is useful. The spectrum allocated to GPS for its L1 signal is from 1559 MHz to 1591 MHZ. This spectrum is shared by other Global Navigation Satellite Systems such as the EU’s Galileo, China’s Compass, and shortly also by Russia’s GLONASS, which uses the 1598 MHz to 1605 MHz band for its present signals. Basically, GNSS signals occupy the 1559 MHz – 1605 MHz band.

A precise digital map is needed to perform lane recognition using carrier-based GNSS position information.