In order to realize the fast acquisition and coarse tracking of a moving object, a coarse APT demonstration system is designed for an unmanned aerial vehicle,and outdoor flight experiment s have been carried on to validate the system′s performance preliminarily.In the system,the fast acquisition is based on the calculation of the GPS coordinates.After correcting the attitude data,azimuth and elevation errors ar e reduced to 0.60° and 0.40° (1σ), respectively.And consequently,the uncertain region becomes narrower efficientl y.For the sake of resolving the contradiction between the quick responsibility and the overshooting when trackin g the dynamic object,the proportion integration differentiation (PID) algorithm of the coarse tracking has also been ameliorated by introducing segmen ted functions to simulate the nonlinear adjustment function.In outdoor flight experiments,acquisition times are less than 10s,and residual coarse tracking errors are less than 480μrad,which provides favorable conditio ns for the fine tracking subsystem to achieve the final tracking accuracy.The results verify the feasibility of this s ystem to realize fast establishments of the laser communication links.