-When using clocks from Broadcast Ephemeris (with or without applied corrections) or clocks from SP3 files, it may beimportant to understand that they are not corrected for the 2nd-order relativistic effect. The 2nd-order relativistic effect is a periodic time correction defined as -2 (R * V) / c^2 and includes the scalar product of satellite position and velocity divided by the speed of light raised to the second power. +When using clocks from Broadcast Ephemeris (with or without applied corrections) or clocks from SP3 files, it may beimportant to understand that they are not corrected for the 2nd-order relativistic effect. The 2nd-order relativistic effect is a periodic time correction defined as -2 (R * V) / c^2 where R * V is the scalar product of the satellite position and velocity and c is the speed of light.