Assessment of Multi-constellation RTK Solutions During Differential Correction Data Outages

The Real Time Kinematic (RTK) positioning mode uses differential phase measurements to achieve centimetre level accuracy for various applications. Much of the research in RTK has been done using live data from GPS and GLONASS. However, in case of Galileo and BeiDou signals, limited work has been done since the satellites have only recently became operational and have started transmitting live data. A multi-constellation RTK methodology that uses single differenced pseudorange, phase and doppler measurements from four GNSS is presented. An assessment of RTK solutions using GPS/Galileo, GPS/GLONASS/Galileo and GPS/BeiDou is provided. Differential correction data outages are discussed. A methodology of measurement time differencing is introduced and position solutions are obtained during correction outages using fixed ambiguity positions as initial estimates. The position accuracy performance over various correction outage periods, ranging from 10 s to tens of minutes, ranges from a few centimetres to metres.