status and RFI tweaks

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Profile David Anderson
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Message 1969074 - Posted: 7 Dec 2018, 8:53:57 UTC
Last modified: 7 Dec 2018, 8:54:57 UTC

At a high level, here's where we're at:
we're working on creating "birdies" that are accurate simulations of the types of signals that S@h is designed to detect. In particular, we can simulate birdies that are "faint": low transmission power, and/or far away. This lets us evolve and refine our algorithms for detecting ET signals - i.e. the multiplet detection and scoring algorithms - to detect faint signals better. It will also let us make quantitative statements about the sensitivity of our search. BTW, as far as we know, no other SETI project has used this technique.

Eric and I had a very productive meeting today, and figured out a couple of potentially huge improvements to the multiplet finding algorithm, and in particular for non-barycentric multiplets. My next post will describe this.

Progress since my last post involves two tweaks to RFI removal:

In the drifting algorithm, rather than thresholding the separate probabilities of upper and lower triangles, we now look at the product of the probabilities of opposite triangles. This helps remove signals at the start and end of periods of drifting RFI.

In the multi-beam algorithm, we realized that what matters is the angular separation of signals, not whether they appear in non-adjacent beams. When the telescope is moving, signals in non-adjacent beams may in fact be coincident on the sky, and signals in the same beam may be non-coincident. I need to think of a new name for the algorithm, I guess.

-- David
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Message boards : Nebula : status and RFI tweaks


 
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