•Satellite clock bias
–Modeling by applying coefficients in the broadcast message using polynomial
ẟj(t) = a0 + a1(t - t0) + a2(t - t0)
where ẟj(t) is the satellite clock bias for epoch t
t0 is satellite clock reference epoch
a0,a1,a2,t0 are part of the broadcast message
•Receiver clock bias
–To compensate by using Code pseudorange model and Carrier Phase-Shift Measurements