112
S. Montebugnoli
not seen in the previous processing phase. Of course, if found, these will have to be
validated with further observations as requested by the IPDP.
11.1.2 Present
The search for a radio carrier, as an alien signal, didn’t give any results till now, then
a change of search paradigm needs to be introduced. It is a common opinion in the
SETI community it would be worthwhile to search for unintentional signals in the
case the aliens spread out radio emission in the Galaxy as part of their planet service
transmissions. In this case, we cannot efficiently receive and decode it because of
the unknowledge of the modulation scheme. In this case, it is not possible to design
a suitable detector to handle correctly such an unknown signal. We could say that
“it is hard to find something when it is not clear what we are looking for.” We need
a mathematical tool able to flag out any weak modulated signal buried in the noise
of the analyzed radio band. As already widely demonstrated by Claudio Maccone
[2], the Karhunen Loewe Transform could be very suitable to give information about
the presence of any signals present in the band under control; anyhow, these are
composed [3, 4]. A crucial aspect of the KLT that needs to be more investigated is
sensitivity. If the S/N ratio of the signal to be analyzed is low, the eigenvalues of
the eigenvectors, that form the covariance matrix, are close to zero, and it could be
challenging to obtain the detection. Many papers have already been published on the
argument [5, 6].
11.1.3 Future
The communications channel between the possible alien radio transmitter and the
Earth-based receiver (radio telescope) generally is constituted by an unimaginable
distance (many hundreds, thousands, or more of light-years). An eventual alien modulated signal, after such a long flight, would reach the receiver antenna as a noise. The
challenge at the post-processing level is then how to understand if a small part of
the total system noise is due to a weak modulated signal sent by ET or not. Maybe
we need to face an in-depth investigation of the possible use of the Entropy concept.
Some hypotheses on the use of entropy in the SETI program have already been
advanced.
11.2 Some Considerations
Researchers have at their disposal a lot of almost similar mathematical transforms
as Fourier, Wavelet, Curvelet, Brushlet, Contourlet, Wave Atom, Haar, and so on,
S. Montebugnoli
not seen in the previous processing phase. Of course, if found, these will have to be
validated with further observations as requested by the IPDP.
11.1.2 Present
The search for a radio carrier, as an alien signal, didn’t give any results till now, then
a change of search paradigm needs to be introduced. It is a common opinion in the
SETI community it would be worthwhile to search for unintentional signals in the
case the aliens spread out radio emission in the Galaxy as part of their planet service
transmissions. In this case, we cannot efficiently receive and decode it because of
the unknowledge of the modulation scheme. In this case, it is not possible to design
a suitable detector to handle correctly such an unknown signal. We could say that
“it is hard to find something when it is not clear what we are looking for.” We need
a mathematical tool able to flag out any weak modulated signal buried in the noise
of the analyzed radio band. As already widely demonstrated by Claudio Maccone
[2], the Karhunen Loewe Transform could be very suitable to give information about
the presence of any signals present in the band under control; anyhow, these are
composed [3, 4]. A crucial aspect of the KLT that needs to be more investigated is
sensitivity. If the S/N ratio of the signal to be analyzed is low, the eigenvalues of
the eigenvectors, that form the covariance matrix, are close to zero, and it could be
challenging to obtain the detection. Many papers have already been published on the
argument [5, 6].
11.1.3 Future
The communications channel between the possible alien radio transmitter and the
Earth-based receiver (radio telescope) generally is constituted by an unimaginable
distance (many hundreds, thousands, or more of light-years). An eventual alien modulated signal, after such a long flight, would reach the receiver antenna as a noise. The
challenge at the post-processing level is then how to understand if a small part of
the total system noise is due to a weak modulated signal sent by ET or not. Maybe
we need to face an in-depth investigation of the possible use of the Entropy concept.
Some hypotheses on the use of entropy in the SETI program have already been
advanced.
11.2 Some Considerations
Researchers have at their disposal a lot of almost similar mathematical transforms
as Fourier, Wavelet, Curvelet, Brushlet, Contourlet, Wave Atom, Haar, and so on,