Estimation and analysis of the short-term variations of multi-GNSS receiver differential code biases using global ionosphere maps

Care should be taken to minimize the adverse impact of differential code biases (dcbs) on global navigation satellite systems (gnss)-derived ionospheric information determinations. for the sake of convenience, satellite and receiver dcb products provided by the international gnss service (igs) are treated as constants over a period of 24 h (li et al. (2014)). however, if dcb estimates show remarkable intra-day variability, the dcbs estimated as constants over 1-day period will partially account for ionospheric modeling error; in this case dcbs will be required to be estimated over shorter time period. therefore, it is important to further gain insight into the short-term variation characteristics of receiver dcbs. in this contribution, the igs combined global ionospheric maps and the german aerospace center (dlr)-provided satellite dcbs are used in the improved method to determine the multi-gnss receiver dcbs with an hourly time resolution. the intra-day stability of the receiver dcbs is thereby analyzed in detail. based on 1 month of data collected within the multi-gnss experiment of the igs, a good agreement within the receiver dcbs is found between the resulting receiver dcb estimates and multi-gnss dcb products from the dlr at a level of 0.24 ns for gps, 0.28 ns for glonass, 0.28 ns for bds, and 0.30 ns for galileo. although most of the receiver dcbs are relatively stable over a 1-day period, large fluctuations (more than 9 ns between two consecutive hours) within the receiver dcbs can be found. we also demonstrate the impact of the significant short-term variations in receiver dcbs on the extraction of ionospheric total electron content (tec), at a level of 12.96 tecu (tec unit). compared to daily receiver dcb estimates, the hourly dcb estimates obtained from this study can reflect the short-term variations of the dcb estimates more dedicatedly. the main conclusion is that preliminary analysis of characteristics of receiver dcb variations over short-term intervals should be finished prior to estimate daily multi-gnss receiver dcb products.