The positioning accuracy of the X-ray pulsar navigation depends on the angular position accuracy of the pulsars. Currently, long baseline interferometer technology provides 0.1 mas pulsar positioning accuracy, which is far away from the requirement of X-ray pulsar navigation. Using classical statistical optics, we studied the relationship between direct observation of the pulsar angular position and second-order correlation. As an application, we give a proposal to realize angular position measurement of pulsars based on X-ray intensity correlation. (C) 2018 Elsevier GmbH. All rights reserved.