Energy-based process for the detection of signals drowned in noise
AssigneeSextant Avionique
InventorDominique Pastor
Life of this patent
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Abstract
The energy-based process according to the invention for the detection of useful signals drowned in noise consists of starting from a frame of samples of a noisy signal grouped in successive frames, making a pre-classification by comparing the energies of successive samples of each frame with a determined optimum threshold and sorting samples which have a high probability of belonging to a "noise only" class into this class, and then for each of these samples detecting those that have a sufficiently high energy so that they have a high probability of belonging to a "noise+useful signal" class, this second class being defined using the first class as a reference.
Claims21
A process for detecting a transmitted useful signal drowned in noise, comprising the steps of:
- receiving a noisy signal;
- partitioning a portion of the received noisy signal into L frames of N samples;
- calculating energies of each of said L frames;
- determining an optimum threshold, s;
- preclassifying M of said L frames into a set .DELTA. by using a predetermined set of ratios, m, .alpha..sub.1 and .alpha..sub.2 which define characteristic signal-to-noise ratios of the noisy signal;
- calculating an average noise energy value, E.sub.0, from the frames in .DELTA. as determined in the preclassifying step;
- and
- detecting for each frame not in set .DELTA. if a useful signal exists by using the average noise energy value, E.sub.0.
A process for detecting a transmitted useful signal drowned in noise, comprising the steps of:
- receiving a noisy signal;
- partitioning a portion of the received noisy signal into L frames of N samples;
- calculating energies of each of said L frames;
- determining an optimum threshold, s;
- preclassifying M of said L frames into a set .DELTA. by using a predetermined set of ratios, m, .alpha..sub.1 and .alpha..sub.2 which define characteristic signal-to-noise ratios of the noisy signal;
- calculating an average noise energy value, E.sub.0, from the frames in .DELTA. as determined in the preclassifying step;
- whitening each of said L frames not in .alpha.;
- and
- detecting for each frame not in set .DELTA. if a useful signal exists by using the average noise energy value, E.sub.0.
A process for detecting a transmitted useful signal drowned in noise, comprising the steps of:
- receiving a noisy signal;
- partitioning a portion of the received noisy signal into L frames of N samples;
- calculating energies of each of said L frames;
- determining an optimum threshold, s;
- preclassifying M of said L frames into a set .DELTA. by using a predetermined set of ratios, m, .alpha..sub.1 and .alpha..sub.2 which define characteristic signal-to-noise ratios of the noisy signal;
- calculating an average noise energy value, E.sub.0, from the frames in .DELTA. as determined in the preclassifying step;
- filtering each of said L frames not in .DELTA.;
- and
- detecting for each frame not in set .DELTA. if a useful signal exists by using the average noise energy value, E.sub.0.
Dependencies are inferred from the claim text.