In the airport scene monitoring system, the common multi-point positioning system locates the target over the airport. The traditional multi-point positioning system has the drawbacks of long baseline, large time standard deviation and greater difficulty in the installation of small, medium or remote airports. In order to solve the above problems, a short baseline system is designed. By analyzing the influence factors of GDOP, on the basis of improving the accuracy of time delay estimation error, the positioning accuracy of short baseline system will be further enhanced by adding more base stations and changing the base station layout, so as to expand the effective coverage of the positioning system. The simulation result prove that this system could be well suited for small and medium-sized airports.