Evaluation of Network Topologies for Post-Mission Multiple Reference Station Positioning

In recent years the use of multiple reference stations for real-time kinematic (RTK) positioning has been shown to overcome limitations in the standard single baseline carrier phase differential positioning approach. In the single baseline approach, the rover position error becomes larger the further the separation from a reference station mostly due to the decorrelation of atmospheric errors. Multiple reference stations situated around the rover receiver can reduce rover-reference distances relative to the single reference station approach to achieve the same accuracy. This paper applies the in-receiver (otherwise known as the tightly coupled) multiple reference station approach, which includes the rover’s measurements in a large positioning adjustment. Different baseline configurations between reference receivers and the rover receiver, called topologies, are implemented in this paper to determine their effects on the rover position accuracy. Four network topologies are compared in this paper: a star, line, radial, and shortest baseline topologies using simulated and field data. Tests show that the rover position error and ambiguity resolution performance is a function of the baseline lengths in the various topologies with the exception of the star topology. The star topology has many baselines connected directly to the rover, which better average baseline measurement errors. In general, the differences between the topologies are usually less than one centimeter (RMS position error).