Up for air


You are spot on about screaming for alerting, which is more a function of
the use rather than the SAR. SAR imagery has a wide range of resolution
and coverage. The Joint Stars SAR is narrowly focused over a small
region, picked on the basis of MTI alert. This is a time sharing issue.
Too much time integrating the SAR takes away from the overall MTI mission.
And along-track resolution is strictly a function of aperture--read how
far platform moves whilst looking at a point. Joint Stars isn't really
a mapping SAR. The mapping SARs do cover a fairly wide swath and of
course a long distance. The phase history bandwidth is in the order of
200 MHz, which is why one would seek to reduce to an image before sending
to multiple recipients. Since the area covered is so large, only small
portions of the take will be of interest to a given recipient. So, even
if you had reduced to imagery, there would still be a local requirement to
sort/store tons of useless data. Even within a region of interest, most of
the area is not of special interest. From a terrain mapping point of view,
the pattern is important with local amplification. From intel point of view,
most of the terrain is empty. Even if the image resolution were very good,
building an overall situation map from a mosaic of specific recognized
entities is incredibly time consuming. Which is why the overall MTI sweep
is so important to get a general picture. Then specific details are filled
in as needed. Whether by SAR or by UAV, the FTI fills in the details--but
only when asked. This is just as well because the FTI tends to lag the
alert from MTI.

Like comment on bias. Will ruminate.

Enjoy the weekend.

Bill C.

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Subject: Re: Up for air