Of course they have agents watching the base, on the base, high over head, under it ~ they can tell you everything that goes on.
Really? The Norks have agents everywhere and you are using that as justification for just putting the information out on the Internet?
Open source intel, which would include the Internet, is the largest source of collection against the United States. Probably because of the commonality of your opinions.
For numerous reasons satellites are not the all seeing eye that you suppose them to be. Nor do the Norks have any satellites of their own. Although the Russians and Chinese may share intel with the Norks, I guarantee you that they do it selectively.
Beyond newscasts and the Internet, the Norks independent intel collection against the United States is about nil.