**2. Advances improving satellite navigation systems**

In the first part of the book, chapters are dedicated to improving functionalities of satellite navigation systems. A focus on characteristics of GPS and Beidou satellite navigation systems

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is interesting, especially when time and coordinate systems are utilized. For improving a receiver's accuracy, a high-precision dynamic localization can be considered in conjunction with an improved dual-mode positioning algorithm of the star selection and an optimal location algorithm. In order to solve a localization problem, an interesting solution can be applied to an approximate linearization system. For possible single-mode and dual-mode systems, requested equations for the filter should be prepared. It must be expected that a satellite navigation system composition is under composition and an improved algorithm is simulated and verified by the software. A positioning method of the dual-mode location and star selection can not only guarantee a positioning accuracy, but it should also improve system efficiency. Then, a design of the dual-mode navigation and positioning system can be advantageous.-

When GPS and BeiDou satellite navigation systems are used for determining a course angle of the aircraft, then a focus on antenna orientation methods is interesting. The idea that global satellite navigation systems can not only provide the information in terms of location and time, but also the course angle of its carrier through processing of multiple antennas and specific data, can be considered. It is useful to utilize its advantages of none accumulative errors and its high orientation accuracy. For this reason, an observation model of satellite navigation systems can be established for proposing orientation methods. It must be emphases that any suggested resolution method of the carrier phase must be analyzed through a depth study. Also in this case, combined orientation and directional algorithms should have been verified in preference by the simulation program and hardware platform experiments.-
