A wind vane is used to sense both the speed and direction of the apparent wind; this can then be used to calculate the true wind speed and direction. Wind vanes are only supported for Rover sailing vehicles. All wind vane parameters can be found by searching for the prefix WNDVN.
For best results wind sensors should be mounted as high as possible away from any part of the vehicle that may disturb the air flow around the vane
Some wind sensors can be used to sense both the wind speed and direction. In this case both WNDVN_TYPE and WNDVN_SPEED_TYPE should be set to the same value. If a sensor reports both speed and direction it is still possible to use only the speed or direction by setting the WNDVN_TYPE or WNDVN_SPEED_TYPE to a alternative sensor. Note that any change to the _TYPE parameters will require a re-boot to take effect
Wind direction can be directly sensed through the use of an analogue voltage input. However it is also possible to use a fixed wind direction, this is not recommended for long term use, but will allow testing of sailboats without the need for specialist sensors. The wind vane type can be selected with WNDVN_TYPE. The wind direction is filtered using a low pass filter, the frequency of this filter can be set using WNDVN_DIR_FILT. If the wind direction is oscillating this frequency can be reduced. This will reduce the effect of fast oscillating wind shifts but will also reduce the response time to a change in wind direction.
If a wind speed sensor is also fitted the WNDVN_SPEED_MIN speed can be set. At wind speeds less than this the direction reading will be ignored, this allows the vane to be ignored when it may be stuck or inaccurate due to a temporary drop in wind. Keep in mind that if the wind is consistently less than this value the vehicle will have no new information about wind direction.
A wind speed sensor is not absolutely required to get a sailing vehicle to work well. If one is not fitted apparent wind effects are ignored, for vehicles that move slowly in comparison to the wind speed this will have little effect however, if possible, it is always better to have a wind speed sensor. The wind speed sensor type can be changed with WNDVN_SPEED_TYPE. The wind speed is filtered using a low pass filter, the frequency of this filter can be set using WNDVN_SPEED_FILT.