💡 NOTE: Correlation can only be used for post-processing when working with Generation 2 instruments or the Signature series!
Correlation is a statistical measure of similar behavior between two observables, which in our case is how similar the transmitted signal is to itself at a delayed time (when the signal is received after reflection). Correlation is output in %, where 100 % means perfect correlation and 0 % means no similarity. The magnitude of the correlation is thus a quality measure of the velocity data, and as the correlation decreases so does the data accuracy. Correlation decreases with distance from the instrument and establishes the maximum usable profiling range. A commonly accepted threshold for range when considering correlation data is 50%. This is approximately where the amplitude drops to the noise floor. When this is not the case, take it as a sign that the data needs more careful analysis.
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