The USA-built and maintained GPS satellite network isn't the only navigation system in the sky. There are six other satellite constellations in orbit providing navigation services. None of these is as complete and well-tested as US GPS, yet, but they are making continual progress. One of the alternatives is the Russian-built and maintained GLONASS system. There have been some consumer product applications for the GLONASS signals, with the most recent and notable being Garmin adding GLONASS capability, in addition to GPS, to its handheld eTrex line (shown in photo).
"When using GLONASS satellites and GPS, the time it takes for the receiver to 'lock on' to a position is (on average) approximately 20 percent faster than using GPS alone," states Garmin. "Furthermore, when using both GPS and GLONASS, the receiver has the ability to lock on to 24 more satellites than using GPS alone. This is particularly helpful for users who need reliable satellite navigation in challenging environments such as deep canyons or urban environments where a large portion of the sky is blocked by solid objects."
A minus is that the eTrex handhelds burn through battery a bit quicker when parsing GPS and GLONASS together. Image © Garmin