Selex Sistemi Integrati (SSI) is developing Passive Air Surveillance Radar. It is referred to as a “bi-static system”, that is, one in which the receiver is widely separated from “non-cooperative” transmitters.
In other words, it does not have its own transmitter. Instead, it uses regular FM radio transmissions that bounce of an object. It can also use digital TV transmission or even cell phone frequencies to detect the target.
Obviously, this would make this system very hard to detect and destroy. Multiple antennas can give 3d coordinates.
The following link will take you to “Defense Technology International” article. Click on “inside” to read the rest of this very interesting magazine.
Selex Sistemi Integrati (in english, though linking to it in Italian was very tempting):
At first this seemed like a very original and off the wall idea, but then it was recalled that both Marconi and Tesla had noted that radio beams could be reflected and received. Indeed, what is now called radar was early on an irritating static reflection.
What goes around comes around, or is that merely a passive reflection.
Tesla, in August 1917, gave the following:
For instance, by their [standing electromagnetic waves] use we may produce at will, from a sending station, an electrical effect in any particular region of the globe; [with which] we may determine the relative position or course of a moving object, such as a vessel at sea, the distance traversed by the same, or its speed.
Marconi in a 1922 paper he wrote:
- I also described tests carried out in transmitting a beam of reflected waves across country . . . and pointed out the possibility of the utility of such a system if applied to lighthouses and lightships, so as to enable vessels in foggy weather to locate dangerous points around the coasts…
Oh, did the top photo of rather spindly radar look familiar? Perhaps “Chain Home” came to mind.
Or perhaps you were picturing the German Bf 110G-4 night fighter, ya?