Vectrino Correlation

In a time series signal "correlation" is simply a measure of "self-similarity" other wise known as "auto-correlation".

Is the correlation referred to in the VECTRINO data simply an "auto correlation" of the return signal on which the velocity is based?.

If this is correct then we can use the VECTRINO correlations for  generating "cross correlation of signals" and generate phase, frequency, and coherence spectrum.

Hi there,

In the case of "coherent" Doppler systems, we compare two signals.  The "correlation" parameter is a measure of how well the two signals compare.  Since we are comparing two different things, we talk about the covariance and correlation and not auto-correlation, which by definition is 1 at lag zero.

In general, the covariance function is complex - mathematically speaking. In math class we often referred to the real and imaginary part of the complex function but in electrical engineering we usually refer to the amplitude and phase - which just is another representation of complex functions - because it is more appropriate for the problems we are trying to solve.

There are usually section about the autocovariance method (for determining phase shift) in signal processing books used in graduate school.  The same method (with variations) is used to solve many different problems:  

- Kinematic GPS positioning
- Short base line underwater positioning
- Direction finders in acoustic releases
- Directional estimates of surface waves

I am not quite ready to write the text book yet.  Maybe some day  " />'>

Best regards, Atle Lohrmann

Hi Alte,

Could you please mention any spcific book on signal procesing which would help us to understand the mahematics behind the 'correlation' used in the Vectrino. An easily written book would be helpful for us who don't not have Electrical Engg. background.