The regional estimates of the GPS satellite and receiver differential code biases

The Differential Code Biases (DCB), which are also termed hardware delay biases, are the frequency-dependent time delays of the satellite and receiver. Possible sources of these delays are antennas and cables, as well as different filters used in receivers and satellites. These instrumental delays affect both code and carrier measurements. These biases for satellites and some IGS stations tend to be obtained from the Center for Orbit Determination in Europe (CODE) as daily or monthly constants, which are based on the global ionospheric total electron content (TEC) modeling in the solar-geomagnetic frame. These biases are not provided for regional and local network receivers, and need to be computed by the user. In this study, the regional approach by the spherical Slepian function was used to estimate the GPS satellite and receiver DCBs. Validations using real data showed that this method has significant potential and the ability to yield reliable results, even for a single station DCB estimate.