This paper analyzed the reason caused GPS signal unlocking and cycle slip in the GPS carrier phase measurement in accordance with the moving feature of aerial small targets. And explained the key technique of solving the measurement difficulty problem is how to realized ambiguity resolution on-the-fly (AROF) rapidly. Based on expatiating the advantage and disadvantage of some AROF methods, it applied a new method of AROF. This method integrated some advantages of other methods, utilized all kinds of observation messages, and determined specific algorithm according to specific condition in resolution. It realized the real-time resolution, increased the accuracy and reduced search time.