On 3/8/11 4:24 AM, Pieter ten Pierick wrote:
Hi,
GPS phased arrays aren't new, nor is it necessary to physically steer
the antennae within the aray:
http://www.navsys.com/papers/0005004.pdf
But would such a system help with the LNA overload due to a local
transmitter?
I would expect that using separately steered antennas with good
directivity could prevent this out-of-band LNA overload?
As long as your phasing is done before the one-bit ADC, you can place a
null on the offending interference source. This has been used for
adaptive interference cancellers for decades (for cosited transmitters
and receivers). A friend worked for American Nucleonics back in the 80s
when they were starting to implement digital control loops (but the
cancellation was still done with analog techniques) for this application.
You *might* be able to do it even after the sampler, if the interfering
signal isn't too strong. At a guess, if the total noise power at the
input to the sampler were within about 10dB of the interfering signal,
you'd probably be ok. When the interfering signal gets up to 10-20 dB
over the noise power, it starts to really dominate.
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