Stealth "radar"

The system presented in this paper has the purpose of airplane detection including stealth airplanes. The system is sensitive to any natural emission of energy or background noise coming from anything beyond the targeted airplane. In contrast to conventional radar that illuminates the target with microwaves, the targeted airplane does not receive any signal that it has been detected by this new system. The algorithm for computing of what is being detected considers that the airplane causes a shade on the background noise and this shade indicates the position of the airplane. The polar diagram of sensitivity of the detector may be the narrowest possible, however it does not need to be narrower than the solid angle of the airplane because it will always disturb consistently the reception of the background noise