From the introduction:
So. This is an odder one for you, Jumper. Anno Domini- A.D., aka your old Earth. This series is the only one in the Gundam franchise to be set during ‘real-life’- all the others are on their own. I think you’ll find this world a lot more…homely, than most of the other Gundam universes- after all, Earth is still how it is, no colonies dropped on Sydney, no Gundam Fights tearing it to shreds, there’s still war in the Middle East, etc. So, this world has the Mivonsky Particle replacement being GN Particles- green dust-like particles that have a wide variety of applications and uses, and have made modern Mobile Suits what they are.