Android smartphones manufactured after 2016 provide GNSS raw measurement data including carrier phase measurements. Accordingly, research on precise navigation using smartphone is being actively conducted. In order to perform precise navigation, the user’s position must be determined as one point which is Antenna Reference Point (ARP). However, since there is a difference between a position where a GNSS signal is actually received and the position of an ARP, antenna calibration is necessary. Phase Center Offset (PCO) and Phase Center Variation (PCV) must be compensated for antenna calibration, but unlike expensive receivers, PCO and PCV are not provided in smartphones. Therefore, in this study, antenna calibration was performed by estimating the PCO and PCV of the smartphone for precise navigation of the smartphone. We propose a method of estimating PCO and PCV for antenna calibration by collecting carrier phase measurements for long term in various attitudes each. Through double difference with reference station measurements located close to the smartphone. We estimate the bias for the smartphone body frame by analyzing the double differenced residual error. Through this, PCO, which is the distance between the ARP and the mean point of signal reception points, is estimated, and PCV is estimated by modeling the signal reception points positions along each direction with Spherical Harmonics (SH).