Using Google earth, thought I would give you a visual sense of how Russia established its military bases in Ukraine. This one is near the Ukrainian town of Krasnyi Luch (see last image for map). From April 2015 – Sept 2016, what you see is its gradual development, from simple earth compound, to large, permanent base.
Close to the border, it’s home to a large combat unit. Made up of several hundred military vehicles, inc tanks, artillery and armoured fighting vehicles, it’s a formidable force. I’ve added a Feb 2018, OSCE drone image, showing Russian Grad rockets at the base.
This unit can be used to either advance further into Ukraine, or attempt to repel any Ukrainian advance. Equipped with sleeping and canteen facilities, Russia uses these border bases as invasion, transit camps. With the remote Ukrainian border crossing of Marynivka, only 20 km away, it’s extremely easy for Russian units to enter and exit Ukraine via it.