Abstract
The triple-frequency linear combination with a low noise, a long wavelength, and a weak ionosphere is beneficial to effectively eliminate or weaken the common errors, advance the reliability of cycle slip detection and repair, and speed up the convergence time of fixed ambiguity. By establishing the Galileo triple-frequency carrier linear combination model, three types of linear combinations are derived: Geometry-free (GF) combinations, minimum noise (MN) combinations, and ionosphere-free (IF) combinations. The geometric relationships of these linear combinations are displayed in the form of image. The results indicate that the angle formed by the IF combinations and the MN combinations is between 75.02° and 86.01°, which also illustrates that it is more difficult to meet the carrier phase combinations with a low noise and a weak ionosphere. Moreover, to guarantee the integer cycle characteristics of ambiguity, the combination coefficient must be an integer. Galileo triple-frequency linear combination is solved utilizing the extremum method. To sum up, the sum of the coefficients of the extra wide lane (EWL) combinations and wide lane (WL) combinations is zero, and the sum of the coefficients of the narrow lane (NL) combinations is one. (0, 1, −1) is the optimal triple-frequency linear combination in Galileo. Three independent linear combinations are selected separately from the EWL, WL, and NL to jointly solve the integer ambiguity. Further, it creates a prerequisite for high-precision and real-time kinematic positioning.
Highlights
With the stable operation of Galileo and BDS systems and the promotion of the modernization and transformation of GPS and GLONASS systems, global satellite navigation system (GNSS) has developed multi-system and multi-frequency integrated positioning and navigation
The optimal triple-frequency linear combination satisfying the requirements of a low noise, a long wavelength, and a weak ionosphere is located in the wide lane area marked in Figure 6(a), and the sum of the combination coefficients Sc = a1 + a2 + a3 from the WL and the extra wide lane (EWL) is zero
In order to further verify the superiority of the linear combination observations selected in this paper, we have provided an example in the updated manuscript
Summary
With the stable operation of Galileo and BDS systems and the promotion of the modernization and transformation of GPS and GLONASS systems, global satellite navigation system (GNSS) has developed multi-system and multi-frequency integrated positioning and navigation. The multi-frequency carrier phase of the Galileo system can form triple-frequency linear combination with smaller ionospheric delay error, lower observation noise error and longer wavelength through certain linear combination.. Different linear combination coefficients correspond to different combination observation wavelength, ionospheric delay effect and noise characteristics. Among the four groups of Galileo linear combinations, when the wavelength and the minimum noise take a fixed value, the analysis in Figure 6 indicates that the ionospheric delay amplification factor in cycles increases with an increase of the Sc. when the ionospheric delay amplification factor and minimum noise take a fixed value, the wavelength decreases with an increase of the Sc. The optimal triple-frequency linear combination satisfying the requirements of a low noise, a long (a).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
