Although we commonly say “GPS” when referring to any satellite-based location system, the NAVSTAR Global Positioning System is just the first (and for a while, the only) satellite navigation service, or Global Navigation Satellite System (GNSS), specifically the network of American satellites providing location services. Although GPS is available and used worldwide, the fact that it’s under a single country’s control has led several other countries to work on their own satellite positioning system.

Russia’s system is called GLONASS, and was started in 1976 with the group of 24 satellites (the constellation) being completed in 1995. Much like GPS, it has a low precision (civilian) signal and a high precision (military) signal. When it was operating, it would locate horizontal position within 57-70 meters, and vertical positioning within 70 meters. With the fall of the Soviet Union, satellite location funding was quickly cut, and so the system has fallen into disrepair.  Currently, the system only works about 16 hours/day in Russia, and even less worldwide. Repairs were started in 2001 and are scheduled to be returned to service worldwide in 2009 (with the help of the Indian government in return for access to the high precision signal).

Along with assisting Russia in returning GLONASS to service, India is also working on their own satellite navigation system, The Indian Regional Navigational Satellite System (IRNSS), started in May 2006 and targeted to be finished by 2012. The goal of this system is to have a regional navigational system that’s completely under Indian control (including launching, timing, and ground control), and preferably built by Indian companies using Indian components. Its 7 satellites should provide accuracy to within 20 meters within the Indian region.

Also covering the Asian continent is Beidou, China’s navigation system. This system uses 4 satellites in geostationary orbit. This limits their coverage to the region of the world from which they are always visible, but allows for constant coverage (and roughly 10m accuracy for the civilian signal) with relatively few satellites. These satellites served as experimentation for the Chinese space program, and they have just in 2007 started launching satellites for Beidou-2 (aka Compass), which is to be a global navigation system with both geostationary and Middle-Earth Orbit satellites. No completion date has been announced for Beidou-2. China had previously (in 2003) agreed to participate in the European Union’s GNSS program, but has not made clear whether they will support the EU’s program as well as China’s.

The European Union’s next-generation GNSS is called Galileo, and is intended to provide both independence from the US-controlled GPS as well as more accurate positioning. Galileo will have two tiers of service. The free ‘Open Service’ will be accurate horizontally to 4m and vertically to 8m, while the encrypted ‘Commercial Service’ (usable only by paying a licensing fee) will be accurate to 1m, which they envision will allow usage of GNSS in new ways, such as aircraft landing via Galileo signal. The Galileo project was started in 2003 and is targeted for completion in 2013, and has been joined by numerous non-EU countries, including China, Israel, Ukraine, India, Saudi Arabia, and South Korea. The project has been plagued by cost overruns, and is currently over budget by 3.5 billion dollars, a number that is only likely to increase. The cost increases have caused several of the member countries to question their involvement in a project that was originally intended to be mostly paid for by commercial participants, but as of now it seems that the Galileo project has enough support to be completed.