Western intelligence agencies are a bit embarrassed that they were not able to predict the exact day that North Korea recently launched a long-range rocket. Even though North Korea announced the two week period during which the launch would take place last December, and several nations had photo satellites flying over the launch site regularly, the actual launch came as a surprise. The North Koreans apparently took advantage of the regular schedules of these spy satellites to move equipment around the launch site at the right time to conceal just how close the rocket was to takeoff. Many intel analysts had not seen this sort of thing at all (if they were young) and the older ones had not seen it done to this degree since the 1980s, when the Soviet Union was still around and using their maskirovka (“masking”) agency to carry out large scale deceptions of photo satellites. The Russians taught the North Koreans many things, and maskirovka was apparently part of the curriculum.
In addition to concealing weapons, their performance, and movements the Soviets also used satellite deception to mislead the west on how their troops would operate in the field. Several times a year the Soviets would hold large scale maneuvers. Each of these exercises would involve many divisions, plus hundreds of aircraft and helicopters. Satellite photos of these maneuvers were thought to reveal tactics the Soviets were going to use in future wars. But the Soviets knew when American satellites were coming over and sometimes arranged displays of tactics they had no intention of using. Naturally, this made it more difficult for the Western intelligence analysts to figure out exactly what the Soviets were planning. This, of course, was the sort of confusion the Soviets wanted to create with these little deceptions.
The Soviets used more of these "false demonstrations" to confuse those in the West who were using satellite photos to figure out what Soviet industry was producing in the way of weapons. Again, because the satellites could not take photos around the clock but only when their orbit brought them over a specific location, the Soviets would arrange special events when they knew an American satellite was overhead. For a factory they could ask all workers to leave at a certain time, stay away for an hour or so, and then return, or go out of sight and then return so that it appeared that shifts were changing. Since production at a plant varies with the number of shifts there are, or how long the shifts last, these "schedule deceptions" would mess up any weapons production calculations based on satellite photos. To carry the deception further, the weapons shipped out of the factory would go on covered rail cars. Some would be real weapons while others would be nothing but empty rail cars with the usual covering. To deceive metal mass sensors the rail cars carrying dummy weapons would have an appropriate mass of metal under the cover. All of this doesn't work all the time, but it doesn't have to. If deceptions are partially successful, they work. All you have to do is deceive your opponent part of the time to keep him guessing. And guesses are not as good as facts. Western intelligence got a reminder of this recently from the North Koreans.