Abstract: Inverse positioning system(IPS)is a new type of positioning system for the resident stratosphere balloon platform. The basic principle of IPS is to calculate the position of the radiator with known positions of receivers. In this paper, the calculating model is built based on Kalman Filter method, and the algorithm is given. Since the locations of ground stations have a great influence on positioning accuracy, the selection principle of ground station location is given, and a set of locations with good performance are given after plenty of calculating and simulation. Besides, the asynchronism of clocks is a main source of error, the positioning error caused by it is analyzed, and a way of estimating is given. The transmitting error and the equipment error are also analyzed. In the end, a simulation model is built and the simulation is proceeded, the result shows that the system has higher positioning accuracy.