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BDS-3 has been providing initial service from December 2018. BDS entered the stage of simultaneous service with 2 generations of satellites: BDS-2 and BDS-3. There are three different orbit for BDS satellites including GEO, IGSO and MEO, and 4 open service signals including B1I, B2I, B3I, B1C and B2a. Compared with BDS-2, the on-board payload of the BDS-3 has been redesigned, and the parameters of signals are designed to be better, especially in multipath mitigation. In order to verify the performance of BDS-3 signals in terms of multipath errors, we use data from the “international GNSS Monitoring and Assessment System (iGMAS)” multi-GNSS observation stations to analyze the multipath errors of BDS-2 and BDS-3. The results show that the pseudorange multipath error of BDS-2 has a systematic bias that varies with the elevation angle, and the performance of B3I signals is better than B1I for BDS-2 satellites. While B1I, B3I, B1C, and B2a signals of BDS-3 satellites have pseudorange multipath errors with zero mean characteristic, and BDS-3 B1I, B3I signals multipath error is significantly better than BDS-2. The B3I and B2a signals have better performance than B1I and B1C for BDS-3 satellites.

Utilization of frequency-division multiple access (FDMA) leads to GLONASS pseudorange and carrier phase observations suffering from variable levels inter-frequency bias (IFB). The bias related with carrier phase can be absorbed by ambiguities. However, the unequal code inter-frequency bias (cIFB) will degrade the accuracy of pseudorange observations, which will affect positioning accuracy and convergence of precise point positioning (PPP) when including GLONASS satellites. Based on observations made on un-differenced (UD) ionospheric-free combinations, GLONASS cIFB parameters are estimated as a constant to achieve GLONASS cIFB real-time self-calibration on a single station. A total of 23 stations, with different manufacturing backgrounds, are used to analyze the characteristics of GLONASS cIFB and its relationship with variable receiver hardware. The results show that there is an obvious common trend in cIFBs estimated using broadcast ephemeris for all of the different manufacturers, and there are unequal GLONASS inter-satellite cIFB that match brand manufacture. In addition, a particularly good consistency is found between self-calibrated receiver-dependent GLONASS cIFB and the IFB products of the German Research Centre for Geosciences (GFZ). Via a comparative experiment, it is also found that the algorithm of cIFB real-time self-calibration not only corrects receiver-dependent cIFB, but can moreover eliminate satellite-dependent cIFB, providing more stable results and further improving global navigation satellite system (GNSS) point positioning accuracy. The root mean square (RMS) improvements of single GLONASS standard point positioning (SPP) reach up to 54.18 and 53.80% in horizontal and vertical direction, respectively. The study’s GLONASS cIFB self-estimation can realize good self-consistency between cIFB and stations, working to further promote convergence efficiency relative to GPS + GLONASS PPP. An average improvement percentage of 19.03% is observed, realizing a near-consistent accuracy with GPS + GLONASS fusion PPP.