Abstract: The estimation errors leading by the observation noise and the data resolution are discussed.The general formula of optimal linear estimation and its error power spectrum that considering observation noise and data resolution are given based on the frequency form of the least mean square error criterion.The example shows that the estimation results are mainly affected by measurement noises when the data resolution is high.However,the aliased errors because of discete sampling are dominated in the estimation results when the data resolution is lower at some degree.Improving the quality of observations has a little effect on the improvement of the accuracy of estimation results.The findings can be a reference for the scheme design of gravity data sampling.