Design And Test Of An Offshore Shipboard Wind Measurement Device

The speed and direction of true wind is the basis of various marine operations,which is important for ship shipping,marine searching and rescuing,taking-off and landing of carrierborne aircrafts,typhoon prevention,etc.The accuracy of common anemometer is normally affected by the space motion of the ship.In this scenario,it is effective way to use ship attitude,ship speed and heading data to compensate relative wind to compute the true wind.Therefore,accurate measurements of the real-time synchronous data of relative wind,ship attitude,ship speed and heading are premise of true wind measurement,and it is also a key issue that needs to be urgently solved.For the purpose of obtaining accurate real-time data required for true wind computation under offshore shipboard conditions,this paper carry out a research on a shipboard wind measurement device based on real-time operating system ?C/OS-? and multisensor collaborative collection.The main research contents are as follows:According to the characteristics of the offshore shipboard environment and the required measurement elements,a set of measuring scheme by using collaborative collection multisensor hardware is designed.In this scheme,a 3 axis anemometer is used to measure relative wind,a gyroscope,an acceleration sensor and a magnetic sensor complementarily to measure the ship's attitude,and a GPS module to measure the speed and heading of the ship;Suitable and lowcost sensors,controller module,wireless transmission module and power modules are selected and the circuit of shipboard wind measurement device is rationally designed.The external mechanical structure of the shipboard wind measurement device is designed for waterproof and anti-corrosion.The shipboard wind measurement device is successfully built.In order to realize the real-time measurement of the data required for ocean true wind computation,the software of shipboard wind measurement device is designed and coded.The software is composed of the middle layer software,the system layer software based on ?C/OS? and the application layer software.The middle layer software is used for keeping the shipboard wind measurement device in working state before the system layer software runs;using the system layer software,the measurement work of the shipboard wind measurement device is divided into many tasks.To ensure that the tasks can be completed in real-time and in a certain order,create an event flags are created and the Round-Robin function is used by the system layer software;the application layer software is used for coding the corresponding implementation code for each task divided by the system layer software,so that the shipboard wind measurement device has specific functions such as the multi-sensor measurement,ship attitude computation,data packaging and transmission,etc.This research carries out the wireless communication quality test,attitude measurement comparison test,true wind sway simulation wind tunnel test and real ship test to the shipboard wind measurement device.The test results showed that wireless communication is stable,ship attitude computation and relative wind measurement is accurate and reliable.The shipboard wind measurement device is able to measure for a long time in the marine environment.Using the true wind sway simulation wind tunnel test data,the effect of ship sway on the measurement of the shipboard wind measurement device is analyzed in detail.A data processing method based on the rotation matrix is proposed,which can effectively eliminate the effect of ship sway on the ocean true wind measurement.