Bootstrapping with Multi-frequency Mixed Code Carrier Linear Combinations and Partial Integer Decorrelation in the Presence of Biases

Carrier phase measurements are extremely accurate but ambiguous. The reliability of integer ambiguity resolution is improving with Galileo which uses a Binary Offset Carrier (BOC) modulation, large signal bandwidths of up to 50 MHz and additional carrier frequencies. In this paper, a group of multi-frequency mixed code carrier linear combinations is derived which preserves geometry, eliminates the ionospheric delay and maximizes the ratio between wavelength and noise standard deviation of the combination. Moreover, a partial integer decorrelation is suggested to improve the robustness of ambiguity resolution over biases due to orbital errors, satellite clock offsets, and multipath. The proposed group of multi-frequency mixed code carrier linear combinations is characterized by a wavelength of more than 3 m, which makes this group of combinations an interesting candidate for both Wide Area Real Time Kinematics (RTK) and Precise Point Positioning.