What is A-GLONASS? GPS vs GLONASS

What is A-GLONASS?

A-GLONASS, Assisted GLONASS is very similar to GLONASS but A-GLONASS brings more features for smartphones. It brings features such as turn by turn navigation, real time traffic data and more. It uses the cell towers near your location to lock your location quickly with the help from your data connection. A-GLONASS also enhances the performance in chip-sets that come with GLONASS support.

Versions-

The various versions of GLONASS are

1. GLONASS – launched in 1982, the satellites launched were intended to work for weather positioning, velocity measuring and timing anywhere in the world or near-Earth space by the military and official organisations.
2. GLONASS-M – launched in 2003 add second civil code. It is important for GIS mapping receivers.
3. GLONASS-k – started in 2011 again has 3 more types namely k1, k2 and km for research. Adds third civil frequency.
4. GLONASS-K2 – will be launched after 2015 (currently in design phase)
5. GLONASS-KM – will be launched after 2025 (currently in research phase)  

GPS developed by USA has a network of 31 satellites covering this planet and has been widely used in commercial devices like mobile phones, navigators etc.
GLONASS is developed by Russia originally started by Soviet Union in 1976. This has a network of 24 satellites covering the earth.
The image shows the orbit and constellation of GLONASS (left) and GPS (right)