I believe one of our research establishments was experimenting with a multistatic radar system based on cellphone tower transmissions and did a very good job of tracking one of the first (if not the first...) 'stealth' aircraft that the US sent over this way. Certain persons were rather annoyed when they promptly reported the track of the 'untrackable' aircraft on the internet. I have played with multistatic systems on auroras and it's remarkable how much data you can get.
Paul Reeves G8GJA -----Original Message----- From: Jim Lux [mailto:[email protected]] Sent: 16 December 2011 01:30 To: [email protected] Subject: Re: [time-nuts] "The GPS navigation is the weakest point," On 12/15/11 4:53 PM, Bob Camp wrote: > Hi > > Radar bounces off the flat sides very nicely .... > You are right, it does, but it doesn't bounce BACK towards the observer, which is what you care about. Consider a flat plate at a 45 degree angle from you. All the radar energy bounces to the side. Turns out that it's diffraction from the edges of those sides that's the limiting aspect. The first stealth planes (e.g. F-117) were all flat surfaces because you could actually calculate the reflections and make sure you didn't inadvertently create a corner reflector. This is one reason that bistatic radar (transmitter and receiver in different places) is interesting. You can detect things that have very low monostatic radar cross section (RCS). (also, radar transmitters are easy to shoot at, because they're like a big beacon saying "here I am"... so put out a bunch of transmitters and one receiver and have the expensive signal processing and operators at the receiver, which is entirely passive). Even better, you can use something benign as an illuminator... Many of us have used a TV station as a passive illuminator for a bistatic radar, using your analog TV set as the detector. Later, as computational horsepower increased, they could make nice swoopy surfaces with low RCS, and what's more to the point, low bistatic RCS. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. This email, including any attachment, is a confidential communication intended solely for the use of the individual or entity to whom it is addressed. It contains information which is private and may be proprietary or covered by legal professional privilege. If you have received this email in error, please notify the sender upon receipt, and immediately delete it from your system. Anything contained in this email that is not connected with the businesses of this company is neither endorsed by nor is the liability of this company. Whilst we have taken reasonable precautions to ensure that any attachment to this email has been swept for viruses, we cannot accept liability for any damage sustained as a result of software viruses, and would advise that you carry out your own virus checks before opening any attachment. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
