Estimating Wind Speed with a GPS

On Wednesday, April 26, 2000 at 9:00:00 PM UTC-10, Eric Greenwell wrote:
An alternative method I've used takes one circle. During one circle,

-note the maximum GPS ground speed
-note the minimum GPS ground speed
-wind speed = (max - min)/2

Eric Greenwell

Eric:

I use your approach as well. During the circle run, I focus on GPS ground speeds and approximate direction where the max or min ground speed was observed. I then fly the direction where I thought I had the minimum ground speed. This is my guess at the head wind direction. I then vary my heading left or right to hone in on a better indication of the actual wind direction (It has the lowest ground speed).

When heading out to land, as I approach the LZ area, I will vary my course to find the minimum ground speed direction. That direction is the true wind direction at that moment. If it varies significantly from previous info, then it is concerning. I then am looking much harder at all the wind indicators on the ground that I can find. Question is there an active thermal in the LZ area, or did the wind just shift? Either way you know more by checking.