Hi Phil,

I thought the rest of the membership would be interested in what you are doing, so here are excerpts from the note you sent to me:


I would like to speak with you about your wind estimation techniques. I like the DCM method that you described on this forum. We have been using a more "brute force" method in which we program our airframe to fly in a helical pattern with a constant air speed. Then using the GPS data, we can back out what the horizontal wind speed and direction must have been.

Before I go to far, I should mention something about myself. I am a professor in meteorology at the University of Oklahoma. We have been developing an instrumented airplane with an autopilot in order to make measurements of the boundary layer. I am also deeply involved in atmospheric radar technology and we would like to use the plane in cooperation with our radar studies. We are calling our platform the SMARTSonde (Small Multi-function Autonomous Research and Teaching Sonde).

For the SMARTSonde project we are using the paparazzi system and have the plane equipped with pressure, temperature, and humidity sensors. We also have a pitot tube and an ozone sensor. Since I came to this project with virtually no experience with RC airplanes or autopilots, it has been a tough learning curve - with lots of crashes. We still have much to learn!

Anyway, we have the good fortune of having an RC airfield right across the road from my office in the National Weather Center in Norman. Also, the Norman National Weather Service office launches rawinsondes (OUN) twice daily from the weather center, so we have a good opportunity to compare our wind data from the SMARTSonde with the sounding data.

Anyway, we have the good fortune of having an RC airfield right across the road from my office in the National Weather Center in Norman. Also, the Norman National Weather Service office launches rawinsondes (OUN) twice daily from the weather center, so we have a good opportunity to compare our wind data from the SMARTSonde with the sounding data.

We are going to try and implement your method on our plane. Here are some questions:
- Do you know if this method is original to you or is this something commonly used in aeronautics?
- If we have trouble implementing it, would you be willing to give us a hand (via email)?
- Is this something that you might be interested in collaborating with us on? I must admit that I would feel a bit guilty using your method (especially if it is unique to you) and not citing your method because it is not published.

Hi Phillip,
I have no idea if the method I published for wind estimation has been published anywhere else. I think the idea is obvious, but who know.
If you have trouble implementing it, let me know, I will give you a hand.
I will help you any way that I can, no need to feel guilty. My happiest days are when I find that someone is using my ideas, with or without citation.

Best regards,
Bill

Hi Phillip,

This is one more response to the email you sent me asking about wind estimation in the Paparazzi system. I am posting it here in open forum, in case anyone else can answer your question.

You asked me if it is possible to use the paparazzi system to do wind estimation. I answered that you would need either 3 gyros, or a pitot tube, plus GPS, to get airspeed, and then wind speed vector.

As a follow up to that, it seems to me that I have seen postings from paparazzi pilots who sometimes mention they are using wind compensation, so it would seem that they have wind estimation. So, it would seem to me that the paparazzi system probably has a wind estimation option built into the system, that requires the use of either a pitot tube, or 3 gyros.

So, maybe the capability is already built into the Paparazzi system, all you need to do is enable it.

Best regards,
Bill Premerlani