A new method for sea wave detection by using a speed log meter

We present two different methods for measuring waves from the information provided by the speed log meter onboard. The first method processes data in the time domain, and is based in the measurement of the standard deviation of the voltage signal period at the transducer output. The second method is based in the measurement of the -3dB bandwidth of the frequency peaks in the spectral domain. Our results show a Lorentzian widening of the spectrum due to the effect of waves similar to the effect of jitter in electrical oscillators. As a predictable phenomenon, this work can lead to the design of new low-cost wave measurement systems and enhanced autopilot systems.