A transformative cross dipole circular polarized antenna is introduced.The conventional cross dipole antenna is ameliorated to widen the operating band so that the antenna can operate on both L1 and L2 bands of GPS.The antenna mainly consists of metal material which makes it easily satisfy the space environment requirement.The stability of phase center is very high and less than 2mm in the main lobe.The simulation and measured results are given to show the practicability and feasibility of the design.The methods of the phase center measuring and data processing are also studied in this paper.