AN EFFICIENT DUAL AND TRIPLE FREQUENCY PREPROCESSING METHOD FOR GALILEO AND GPS SIGNALS

Data preprocessing is a mandatory stage for most of GNSS applications. In the frame of space weather and precise point positioning applications, the Geomati cs Unit of the University of Liege has purchased two Septentrio PolaRx3eG receivers which allow tracking GPS L1/L5 and Galileo E1/E5a signals. In order to fully exploit these new data, we develo ped a preprocessing method extending existing techniques. Our preprocessing method consists of three consecut ive steps. The first step is devoted to the compensatio n of receiver clock slips affecting code pseudorange and carrier-phase measurements. The second step covers cycle slips detection and the third step assesses d ata quality in terms of noise essentially affecting cod e pseudorange measurements.