PRC (Pseudo-Range Correction)

A pseudo-range correction (PRC) is the per-satellite range error computed by a differential GNSS reference station and broadcast to users. The reference receiver sits on a surveyed point, so it knows the true geometric range to each satellite; it subtracts that from the measured pseudo-range to get the PRC, the combined error from satellite clock, ephemeris, and atmospheric delay. It also sends the range-rate correction (RRC) so the user can extrapolate the PRC to the moment of fix, since the correction ages between updates. The roving receiver applies PRC plus RRC times the age to each satellite before solving its position. In RTCM SC-104 these ride in Type 1 and Type 9 messages.