January 2, 2023: Commercial photo satellites have been providing the public with regularly updated photos since 2005 when Google Earth was introduced. This free service demonstrated the usefulness of commercial satellite photos but also had some unwanted side effects. The most common problem was the use of Google Earth by criminals and terrorists. Now the problem of unwanted side effects has shown up with a new generation of commercial satellite services that use radar to provide a more abstract but more detailed image of what is on the ground. The two Sentinel radar satellites provide updated data on what is down there about once every 36 hours. Its growing number of users can filter the data in many ways to obtain a result that suits their needs which includes resource (crops, forests) monitoring and tracking forest fires and other natural disasters like earthquakes, volcanic eruptions and the like. Sentinel also became popular with users who just wanted to see all that the system could do. That’s when it was discovered that Sentinel could, using the right filters, detect Patriot air defense system radars night or day and in any weather. In hindsight, this sort of side effect was to be expected because this sort of thing has happened before with ground or aircraft based electronic transmitters.

Military equipment that depends on electronic devices has increasingly run into unexpected, and sometimes fatal, problems. This problem was first widely reported during the 1990 campaign to liberate Kuwait. It was discovered that certain combinations of airborne jammer frequencies could trigger an involuntary launch of Patriot anti-aircraft missiles as well as less catastrophic but equally unexpected events. Investigation of these incidents revealed something electronic warfare experts have been warning of for a long time. With so much exotic new gear, capable of putting out so many different signals, and in a huge number of combinations which create even more new electronic signals, there was no way to know what kind of impact this would have on existing military, and civilian, electronics. Throughout the 1990s, the problem only got worse. This became obvious as there were increased incidents of military electronics tests trashing, or playing with, nearby civilian electronic devices, especially ones that used remote control like garage door openers. The military continues seeking solutions, because it's important for military equipment, especially communications and control systems, not to suffer electronic interference.

The 2003 Iraq War saw rapid development of electronic jammers to shut down wireless detonators for roadside bombs. This brought about more unanticipated disruption of friendly electronics. Iraqi civilians are well aware of this problem, as they quickly learned that their cell phone service tended to disappear when an American military convoy approached. Other wireless gadgets went haywire in identifiable patterns. The list of items affected grew as the American jammer (mainly the Warlock series) added more frequencies to its repertoire. Warlock jammed some military equipment, including radios. This was not good. Efforts to come up with practical solutions, but none were particularly promising. As a result, the most likely source of "hostile" jamming is the force with the greatest number of transmitters.

With Sentinel, those transmissions can be monitored on a global scale and future incidents of electronic unintended side effects can be more quickly measured and monitored worldwide.