An Overview of Multi-Reference Station Methods for cm-Level Positioning

Over the past few years, a significant amount of research has been conducted on the formulation of carrier phase corrections in order to enhance ambiguity resolution and to increase the distances over which precise positioning can be achieved. Recently the use of a network of multiple GPS reference stations for generating carrier phase-based corrections has emerged with great promise for use in real-time environments. However, little research has been conducted on the distribution of these corrections to potential GPS users located within, and surrounding, the network coverage area. This is an integral part of real-time kinematic DGPS, and it must be adequately addressed before a practical realization of the multireference station concept is implemented. The focus of this paper is to present a comprehensive summary of some of the multiple reference station methods, with specific attention directed toward the correction generation and dissemination processes. More specifically, the various multi-reference station methodologies have been categorized according to their underlying correction generation framework, but will be discussed in terms of the correction dissemination options presented by the various authors. The for main categories of methods investigated in this paper are: (a) partial derivative algorithms, (b) linear interpolation algorithms, (c) condition adjustment algorithms, and (d) virtual reference station methodologies. © 2001 John Wiley & Sons, Inc.