Re: Top 3 DSP/SP books

On 13 Sep, 21:38, Jerry Avins <j...@xxxxxxxx> wrote:

IIRC NORAD radar system once reported massive incoming missile
attack from "nowhere" (or more definitively 'no place')

OOOPS, moon rise

Later blamed on "computer error" related to anomalous return time
of echoes.
Might it have more with moving from a 'continuous' to 'discrete'
domain?

Don't know about NORAD, but a similar story circulated about
Soviet early warning systems:

http://www.wired.com/science/discoveries/news/2007/09/dayintech_0926

This particular story seems to have been caused by people
looking for a particular signature associated wuth ICBMs
without realizing that there might be other non-related
sources of similar signatures.

This is, of course, the perpetual Achilles heel of 'smart'
systems: They only work as long as the underlying assumptions
actually hold.

Don't be surprised if at least some of the NORAD stories
were caused by similar reasons.

The NORAD incident was a good strong return off the moon, perfectly
normal. The range counter didn't have enough bits to indicate the true
distance. Wraparound error put the distance somewhere over the North
Pole. Our "retaliatory" missiles were within a minute of being launched.

....which invalidated the implicit/hidden/forgotten
assumption that 'moon returns are irrelevant.' It was not
a 'computer error.' It was a design flaw in the system.

Rune
.

Relevant Pages

  • Re: Newtons theory of "Universal Gravitation"
    ... The Moon orbits around the Earth. ... change, its distance stays about the same, and hence its orbit must be ... named that pulling force gravity. ...
    (sci.physics)
  • Re: Moon and Mercury similarities
    ... the first one is a picture of the Moon crater Schickard made ... resemblance to much of our Moon's crater Schickard. ... distances from the Sun" ... And Saturn, at its mean distance from the sun, is slightly higher ...
    (sci.astro.amateur)
  • Re: The Farce that is Called Henri Wilson
    ... >>>to determine the distance to the Moon to the cm, Henri? ... > There are four reflectors on the ...
    (sci.physics.relativity)
  • Re: frequency adjusting only
    ... max distance threshold had to be increased to handle the Moon delay. ... And if the response is fast, the distance has not changed much either ... difference in distance during the response time of the remote computer is ... completely negligible amount. ...
    (comp.protocols.time.ntp)
  • Re: But What Does Einstein Mean - Really?
    ... Moon ... | in time to an Earth here-now. ... | A nova is seen to have occurred at a distance of 70,000 light years from ...
    (sci.physics.relativity)