In this paper, the practical applications of the pseudolite are explained with the basic concept of the pseudolite. Many researches have been developed to improve the performance of the GPS. Most of those researches need the extra equipments. But without the extra equipments, the performance of GPS can be improved only with the change in the software in GPS system. In this paper, the pseudolite and the integrated navigation system including GPS as well as pseudolite only with navigation system for the demand of more precise navigation system are introduced. Also, the advantage of the pseudolite is confirmed by some simulations.