The US government announced the launch of an upgraded GPS signal, called L2C. The signal is specially designed to benefit mobile phone users. According to the government, L2C is transmitted with a higher effective power, which will enable the handsets to receive more accurate location even in urban regions and indoors, where GPS is normally weak. The upgraded signal also requires less energy to be received, which makes it very suitable for small, battery-powered devices such as cellphones. Although L2C is already available, most of the current devices will need an upgrade in order to be able to take advantage of the new signal's benefits.
Source: RCR Wireless News