Assisted-GPS for a portable biometric monitoring device is provided. The portable biometric monitoring device may obtain updated ephemeris data from an associated secondary device via a short-range, low-power communication protocol. The secondary device may be a computing device such as a smartphone, tablet, or laptop. Various rules may control when the ephemeris data is updated. The ephemeris data may be used in the calculation of the global position of the portable biometric monitoring device. Additionally, the portable biometric monitoring device may communicate downloaded position fixing data to the associated secondary device. The associated secondary device may then calculate the global position from the position fixing data.