While South Korean media are reporting the first stage of the rocket - known as the booster - has been moved to the launch facility, DigitalGlobe Senior Analyst Joseph Bermudez said that is not visible in this image.

"It does confirm a higher level of activity within the overall facility and significant activity at the launch pad specifically," according to Bermudez. "This activity appears consistent with preparations for a satellite launch."

The booster would be placed on top of the mobile launch platform (in the satellite image, the black square on the launch pad) that shows nothing on it when the DigitalGlobe image was taken. There is evidence of some sort of spill near the trucks sitting on the launch pad, Bermudez told CNN. Additional support equipment is visible near the mobile launch pad.

Bermudez said the North Koreans are assembling the long-range missile inside a horizontal assembly facility not far from the launch pad after it was shipped by rail from a factory outside Pyongyang.

Once the missile is assembled and tested, the stages will be moved by specialized vehicles to the launch pad and assembled, lifted by the crane and assembled on the umbilical tower, Bermudez explained.

The buildings visible to the right of the launch pad in the satellite image are storage for fuel and oxidizer, according to Bermudez. A pipeline leading to the umbilical tower is visible in the image.

The launch, expected between April 12 and April 16, is meant to coincide with the 100th anniversary of the birth of Kim Il Song, the founder of communist North Korea and the grandfather of the current North Korean leader.