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On 30 Dec 2006 19:51:21 -0800, "Peter Divos" <pdivos@xxxxxxxxx> wrote:
>Hi,
>
>I heard there are some types of radar which operate passively, this
>means, they dont send any signal and dont wait for the echo, but they
>get some random electromagnetic waves from the air which are reflected
>on objects as well and it is possible get some image in exchange of
>some computation.
>I also heard of a swiss company who are using the same principle but in
>geology, seismology, oil exploration. They dont produce any signal
>(like explosion under the surface) but instead use very sensitive
>detectors and catch the random seismic noise from the earth which
>reflects as well and get the image based on this.
>
>So. I am interested in the mathematical and algorithmical part of the
>topic. Does anyone know any good references? Like keywords or book
>titles.
>
>Many thanks
>Peter
need two or more antennas. Two ears, and listen.
Localizing lighning flashes is an application
http://www.aldis.at/
The theory is basically ident, if you send a signal and wait for the
reflections, or just listen to what is coming along, acoustically or
electromagnetic.
en.wikipedia.org/wiki/Passive_radar">http://en.wikipedia.org/wiki/Passive_radar
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