Abstract: To achieve a stable phase center, this paper designs a simple broadband circularly polarized navigation antenna. The antenna adopts a highly symmetric cross dipole, enabling its phase center to remain stable within a small spatial region. The operating bandwidth of the antenna is further expanded by adding a parasitic substrate on the reflector plane. Simulation and test results show that the antenna has excellent bandwidth performance, with a −10 dB impedance bandwidth of 52.7% and a 3 dB axial ratio bandwidth of 47.3%, covering all frequency bands of the Global Navigation Satellite System (GNSS). The proposed antenna achieves right-hand circular polarization at the desired frequencies. Meanwhile, within the operating frequency band, the phase center of the antenna remains stable within a 100° wide beam, with the phase center variation kept below 5°.