Polarimetric microwave radiometer can be used for remote sensing of ocean surface wind speed and direction.The global minimum of the cost function corresponds to the best estimate of the actual wind vector;but due to the level of noise it may not be the closest ambiguity to the true wind direction.The presence of these ambiguous solutions must be carefully considered in the retrieval of wind vector estimates.Expected errors in wind direction retrievals have been examined using Monte Carlo simulation analysis

as well as the maximum likelihood estimation（MLE）cost function in the presence of noise.An algorithm is proposed to obtain wind direction according to the first and second rank solutions of the first scan and the first rank solution of the second scan.The simulated results show that the algorithm can avoid ambiguous solution

and the cells near the position that along or perpendicular to spacecraft-heading vector give the largest error of retrieved wind direction.These cells can be used for cold and warm calibration

and the residual cells which give smaller direction errors can be used for wind direction remote sensing.A new scanning geometry for conical-scan is put forward.