Development of wind velocity estimation method using the airspeed
The method suggested in this paper provides estimates for the three projections of wind velocity in earth's normal coordinate system using satellite navigation systems (SNS) data, as well as on-board barometric airspeed measurements. The wind speed and its direction are assumed constant for a flight leg of 50-60 s duration. This means, that for the given time interval projections of the wind velocity values on the axis of the normal earth coordinate system are constant. Further, the object and observation models are presented, as well as the identification algorithm accuracy characteristics, obtained from the simulation data processing. The airspeed measuring error effect on the wind velocity estimation is also under discussion. The results, showing the accuracy of wind velocity estimation depending on the constant velocity measurement errors, are presented. The analysis shows that horizontal projections of wind velocities are estimated with high accuracy (relative errors of 1-3%), but a certain time interval to obtain the proper degree of identifiability is necessary. After this, the accuracy of estimating the horizontal projections of wind velocities remains at a decent level, and does not depend heavily on the increase of the speed measurement error. The wind vertical projection estimation herewith leaves something to be desired. It makes 30-40% even at zero flight speed error, and increases considerably with an increase of speed measuring error. Thus, we may conclude that the suggested method can ensure the good accuracy for estimating the wind velocities along the horizontal coordinate axes, and it is not applicable for estimating the vertical component of wind velocity.