We measure ocean tides as experienced by sea ice or ice shelves using a single GPS receiver. Such a method allows for tidal measurements to be made with the same precision regardless of its distance from a GPS base station, since such a base station is not required. Single epoch observations are shown to be accurate to about 50 mm when compared with concurrent Bottom Pressure Gauge (BPG) observations. The differences between the GPS and BPG observations are largely free from power at tidal frequencies. Furthermore, harmonic tidal analyses show that these GPS observations allow the correct determination of diurnal and semi-diurnal tidal constituents, meaning that observations of this type can be assimilated into numerical tide models.