The present study selects one station as the base station because only single-differenced satellite FCB and the IFCBs between satellites make sense. This base station conforms to the following assumptions:

(1) The receiver FCB of base station is 0.

(2) The IFCBs of each satellite that can be observed at the base station is 0.

(3) The summation of the IFCBs of all satellites at the non-base station is 0