Though Apple did not wildly tout this, the specification sheet for the new iPhone 4s shows it can acquire signals from the U.S. GPS system, as well as its Russian rival, the Global Navigation Satellite System (GLONASS), which has been in development since 1976.
GPS and GLONASS receivers determine location by a sophisticated take on the simple triangulation principle, with signals from three satellites needed to determine latitude and longitude, and a signal from a fourth needed to determine height.
These weak signals from space can be blocked by mountains or tall buildings, so more satellites -- 24 in the GLONASS constellation and 31 GPS satellites -- means phones and receivers have a better chance to lock on to satellites, which zip around Earth in an inclined plane orbit, rising and setting like the sun.
Apple did not add GLONASS reception out of sheer generosity -- Russia will slap a 25 percent duty on GPS-equipped gadgets that cannot receive GLONASS signals this year. Nor is this the first -- Qualcomm announced a GPS/GLONASS chip set this May, along with a ZTE Corp of China phone, which also incorporated that chip set.
But, by adding GLONASS capabilities to its iPhone line, Apple probably gave the Russian GPS system the biggest de facto endorsement in its history.