Performance of Singapore Integrated Multiple Reference Station Network (SIMRSN) for RTK Positioning

Abstract

Conventional RTK positioning is usable, but requires the use of a local base station. It is also restricted by the effects of the de-correlate atmospheric refraction on the GPS signal, which limits the use of the RTK positioning up to distances of 10–15 km from the reference station to the user. With a multiple reference station network approach, precise RTK positioning capability may be extended for a much larger area. The Singapore Integrated Multiple Reference Station Network (SIMRSN) has been established for this purpose. Using an existing method termed linear combination method, the multiple reference station network corrections are generated for the user on an epoch by epoch, satellite-by-satellite basis. A residual-based adaptive Kalman filter is proposed to improve network correction availability. The VRS concept is used to transmit corrections to the user for RTK positioning. Field tests were conducted to demonstrate the general performance of SIMRSN. The tests confirmed that RTK positioning within a multiple reference station network can provide the user with better than 3 cm in horizontal position, the height accuracy is in the range of 1–7 cm, and the average TTF (Time To Fix) are 46 and 76 s during GLC station and LPR station tests, respectively. With this highly efficient survey technique, the user needs only to be equipped with a single GPS receiver. This reduces equipment and manpower costs compared with traditional RTK positioning using a specially set up reference station. The multiple reference station framework also paves the way for various other applications beyond the traditional surveying profession.