Smart robust wind sensor using a simple optimization procedure

An effective wind sensor consisting of merely three temperature-dependent resistors is described. The sensing elements are placed under a known angle to each other around a cylindrical flow body in its asymmetrical flow field. Based on sensor models obtained by pre-operation measurements, the wind velocity as well as the wind direction are calculated from output voltages by an optimization procedure. Besides the measurement result itself, also its quality follows directly from the optimization output giving a tool to monitor on-line the sensor's state. As a further improvement, by periodic excitation of the sensor, measuring the thermal impedance of the device the various sources of influence like the ambient temperature and rain drops can be separated. A prototype sensor has been developed and evaluated with satisfactory results: The accuracies of wind velocity and direction estimation are below 5% and 2deg, resp

I. Introduction

Wind sensors are needed for a large variety of every day applications, including metrology, aviation, transport safety and wind power industry. Generally, low-cost, small-sized, robust, maintenance-free and autonomous sensors are desired. Using robust PTC (positive temperature coefficient) elements, many disadvantages of wide-spread anemometers with mechanically moving parts or thermal flow meters [1], [2] can be avoided [3], [4]. PTC elements are available in many different types at very low cost. They are very sensitive to changes of the thermal resistance against the surrounding medium and have a low response time.