Wind Shear Detection for Small and Improvised Airfields
News Flash: the Sony netbook computer (Sony VAIO VPC-W121AX/W) used for this project has failed after less than three months and Sony refuses to fix it under warranty. This will cause some minor disruption while I replace that unreliable flimsy Sony junk with something better.
Update: with the purchase of a new HP computer, the project is back on track.
Why Do It?
Wind shear has caused countless aviation accidents over the years. Just within the USA, hundreds of fatalities have been attributed to wind shear aviation accidents in recent decades. The world's largest airports have invested in hugely expensive RADAR and LASER wind shear detections systems and some large aircraft have on-board wind shear detection systems. While this is good for passengers at those airports and on those airplanes, it still leaves the overwhelming majority of air crews unprotected.
The objective of this project is to provide life-saving wind shear detection capability to pilots of small airplanes operating at airfields where there is not and will not be multi-million dollar RADAR systems.
What's Wind Shear, Anyhow?
Wind shear is a sudden shift of wind velocity or direction. It's a natural phenomenon most frequently encountered in the vicinity of thunderstorms but can exist even when there are no visual cues that wind shear may be present. According to NASA, severe wind shear is defined as a horizontal velocity change of at least 15 meter per second over a distance of one to four kilometers or a vertical wind speed change of greater than 500 feet per minute. Yes, the units are inconsistent. The definitions are NASA's.
Redundant Array of Inexpensive Sensors (RAIS)
Wind shear will be detected by gathering wind vectors and several different locations on and around the target airport, exchanging data between all collecting nodes via a mesh network, and then having each node independently decide if it has detected wind shear. The system is, thus, inherently fault tolerant and will continue to operate as long as the mesh remains operational at least in part.
Each sensor node consists of standard off the shelf anemometers connected to inexpensive Linux-based computers. Each node also includes a GPS so position and wind vector data can be exchanged between nodes. Use of 802.11s mesh networking standard WiFi allows the network to establish itself autonomously and run without a central router. It is the mesh networking and lack of a central router that makes the network inherently fault tolerant.
Civil Air Patrol cadets testing the RAIS system on Whiteman Airport, Pacoima, CA. Host computers are XOs from the OLPC foundation running Linux.
Project Lead Investigator and Contact
Dr. Mehler, rmehler (at) csun (dot) edu
This project is made possible by grants from the Wolf Aviation Fund and the OLPC Foundation.
For more information on using XO computers from the OLPC Foundation, click here.