WHY 2 + 2 EQUALS MORE THAN 4

摘要

In 2020, with the completion of China's BeiDou-3 (aka BDS) and Europe's Galileo, the number of available global navigation satellite system (GNSS) constellations doubled. Analogously to the addition of GLONASS to GPS a quarter century earlier, but much more so, this sharp increase in the number of available satellites and frequencies greatly improved the precision of satellite-based positioning, the speed of first fix, and the confidence in the results - especially in GNSS-challenged places, such as under thick canopy and in deep urban canyons.