We have been concerned about the accuracy of the wind sensor that we have been using on the Kitefoiler, an Airmar PB200 ultrasonic anemometer. Today we took this sensor to Crown Beach, along with our old standby, a Maretron WS100 (also ultrasonic), and a handheld mechanical anemometer. In summary, the new Airmar sensor was found to report wind speeds that were 23% higher than the other two sensors, which tended to be in good agreement with each other.
We will do further testing to determine if the wind direction relative to the sensor makes a difference, if the sensor is dirty, and if it is broken or operating outside of its specified accuracy range. The graph shows the measured correspondence between the two sensors in blue. The red line shows the ideal correspondence, while the green cloud shows the result of scaling the Airmar output for best fit with the Maretron. Note that some of the divergence will be due to varying filter parameters, sensor positions, and local air turbulence, so some difference is to be expected, but the systematic rightward-shift in the plot is a concern.
As a side note, we needed to update the logger software to handle multiple NMEA 2000 wind sensors. This turned out to be straightforward and the modification will make it easier to handle multiple instances of other N2K sensors in the future.Return to News