Low-degree gravity change from GPS data of COSMIC and GRACE satellite missions

► Kinematic orbits of COSMIC satellites and GRACE satellites are determined to cm accuracy using GPS. ► Dynamic orbits (with a static gravity field) of the 8 satellites are determined using GEODYN II. ► Monthly gravity harmonic coefficients to degree 5 are determined from orbit perturbations. ► GPS-derived zonal coefficients are consistent with the SLR and GRACE KBR results.