Developing Regional Precise Positioning Services Using the Current and Future Gnss Receivers

This paper presents an overview of technical developments within the CRCSI-funded research on "Delivering Precise Positioning Services in Regional Areas" undertaken by the authors since mid-2007. The research aims to address the technical and business issues that currently constrain GPS-based local area RTK precise positioning services so as to operate in future across larger regional areas, and therefore support services in agriculture, mining, utilities, surveying, construction, and others. Selected research findings to be presented in this paper cover the following aspects. (1) An overall technical framework has been proposed to transition the current RTK services to future larger scale coverage. The framework enables mixed use of different reference GNSS receiver types, dualor triple-frequency, single or multiple systems, to provide RTK correction services to users equipped with any type of GNSS receivers. (2) Research on data processing algorithms appropriate for triple-frequency GNSS signals has demonstrated some key performance benefits of using triple carrier signals for reliable RTK positioning over long distances. (3) A server-based RTK software platform is being developed to allow for user positioning computations at server nodes instead of on the user's device. (4) An optimal deployment scheme for reference stations across a larger-scale network has been suggested, given restrictions such as inter-station distances, candidates for reference locations, and operational modes. For instance, inter-station distances between triple-frequency receivers can be extended to 150km, doubling the distances between dualfrequency receivers in existing RTK network designs.