Detecting a GPS receiver

Is it possible to build a device that detects the demodulator clock in a
GPS receiver from a distance of 1 - 2 metres (required), 5 metres
(desired)? I would imagine that a high gain antenna would make it
possible (without detecting actual GPS since it is 'in the noise').

Are there other aspects about a GPS receiver that would make them
detectable at that distance?

Would it tend to false positive on other near clocks/harmonics
(computers operate in the L1 region too). Would a narrow enough filter
prevent that?

With all the indiscriminate tracking (by police - re: USSC case, and
possibly other people trying to track someone) there could be quite a
market for such a detector. Find it and remove it. Better yet attach
it to a city bus.

And it would be legal (vice a jammer).

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SNICKER
or to paraphrase P.T. Barnum - You could detect some of the
receivers
some of the time, but not all the receivers all of the time.

Alan Browne wrote:

On 2011-11-20 15:47 , Richard Owlett wrote:

Unhelpful attitude, wrong attribution and you top post.

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OK, bottom posted.

There is not any way to guarantee detection of a properly shielded GPS
receiver by its emissions.

Isaac

On 2011-11-20 23:40 , isw wrote:

I doubt most GPS receivers are properly shielded. But even so, their
own antennas are transparent at the frequency of interest so something
has to be leaking out.

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