The next generation Global Navigation Satellite Systems (GNSS), such as modernized GPS and Galileo systems, offer three and more carriers for civilian use. With respect to the current GPS two-frequency signals, additional frequencies can bring significant benefits to GNSS technological advancements and applications. Direct features include the ability in providing aviation and other transportation users with continuous, accurate three-dimensional position information, especially precision-approach navigation worldwide and redundancy in the event of either international or unintentional electromagnetic interference or jamming. The full potential of the three and more frequencies for professional positioning and scientific communities, however, are yet to be exploited. The Working Group¡¯s work will focus on the development of the efficient approaches to carrier phase ambiguity resolutions with three and multiple GNSS signals, namely Three Carrier Ambiguity Resolution (TCAR), or generally, Multiple Carrier Ambiguity Resolution (MCAR). The effort will improve real time kinematic positioning (RTK) performance over long ranges in particular, but extend TCAR/MCAR to other precise applications as well, in local, regional and global scales, including atmospheric soundings and geodynamics.

• To follow the technical advances in multiple frequencies related GNSS technologies and applications, and identify their benefits and potentials.
• To develop and report on efficient techniques for ambiguity estimations and resolutions using three and more GNSS carrier-phase signals.
• To improve real time kinematic (RTK) positioning performance with techniques including TCAR/MCAR over baselines from tens of kilometres and beyond. Methods for mitigation of multipath and troposphere effects on positioning accuracy will be developed.
• To encourage the development of MCAR-based technologies for local, regional and global scale precise applications, including ionospheric and tropospheric soundings, GNSS orbit determination and geodynamics.
• To support generation and provision of multiple frequency data for experimental studies shared among the members.
• To report the progress of research, development and commercialization of TCAR/MCAR related technologies.

Conduct the research and development in collaborative efforts among members and their associates. Organize seminars and workshops including the theme of multiple carrier signals, MCAR methods and applications. Set up a Work Group website for providing a focus for MCAR research and applications with the relevant links. Develop and update the reference list for MCAR research and applications. Select reprehensive publications from members and edit proceedings and research monographs on the theme and in relevant areas.