A Comparison of Single Reference Station, Correction-Based Multiple Reference Station, and Tightly Coupled Methods using Stochastic Ionospheric Modelling

The multiple reference station approach to carrier phase-based positioning uses a network of GPS reference stations to model the correlated errors in a geographic region. This paper compares two methods for multiple reference station positioning under a low and a high level of ionosphere. The first method tested is the conventional method for multiple reference station positioning, which is usually a three-step process, namely (1) estimation of the carrier phase ambiguities in the network, (2) prediction of the measured network errors at the location of the rover, and (3) application of the corrections in a practical format. The second method is called the tightly coupled or in-receiver approach, which uses the data from the rover and integrates it with the network solution to better model the effect of the ionosphere. In this approach there are no explicit corrections. These two methods are compared with the single reference station approach for data from two days collected from the Southern Alberta Network in Canada, a medium scale network with inter-stations distance of 34 to 59 km.