Re: Can LPI be assisted by intentional noise generation?


Eunometic wrote:

The transmitter and receiver must have this algorithem and they must
also be synchronised. One way to achieve sychronisation is to give
the transmitter and receiver a very accurate clock such as an atomic
clock. (In a radar this doesn't quite matter since the transmitter and
receiver are next to each other) . Another way to achieve
synchronisation is to have a relatively short sequence (say running
over a few seconds) but then shift the sequence in the receivers untill
the two are sychronised. Once this is achieved a more elaborate Pseudo
Random sequence is used. alternatively a less accurate clock with the
sequence search over a narrow range covering the inaccuracy of the
clock.

Just one point. For MOST radar the receiver is the same as the
transmitter. The coherence time is thus dc/2 where d is the maximum
distance. Not a very great feat of memory. Quartz will easily supply
the necessary accuracy.

What you might be thinking of is the system used for bank security
where information is transmitted in synchronism. Banks do need atomic
clocks.

An aircraft needs an atomic clock for COMMUNICATION but NOT for radar.

A synthetic aperture radar where 2 or more aircraft produce a high
resolution image would also require atomic clocks. As far as I know no
one has worked on it. Maybe there is someone out there who can
contradict me.

- Ian Parker

.

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