Think tanks and NGOs in the U.S. have increasingly been monitoring North Korea through satellite pictures. Since access to the isolated communist country is tightly restricted, commercial satellite pictures are virtually the only way to obtain hard data.
The Committee for Human Rights in North Korea, an NGO based in the U.S., analyzed pictures taken by a commercial satellite image provider which it said confirms that a notorious labor camp in Chongjin, North Hamgyong Province has been expanded.
The size of the camp increased 72 percent from 580 sq. m to 1,000 sq. m over recent years, according to the group, suggesting that the camp, which earlier had an estimated 5,000 inmates, now houses a lot more people. The number of guard posts also doubled compared to 2003.
38 North, a website operated by the U.S.-Korea Institute at Johns Hopkins University, had warned of an impending rocket launch based on analysis of commercial satellite images before even the U.S. and South Korean intelligence agencies found out about it.
38 North also regularly reports on movements at the nuclear test site in Punggye-ri through satellite images.
The high-definition satellite images used for monitoring North Korea have come mostly from U.S. firm DigitalGlobe, which long dominated the market along with GeoEye until the two merged early this year.
DigitalGlobe owns the QuickBird satellite which captures 60 cm of landscape per pixel, and WorldView 1 and 2, which can capture 50 cm per pixel. The price of images varies according to quality, but one high-definition satellite picture covering 121 sq. km is said to be around US$5,000-7,000.