## 5 Conclusions  
A detailed analysis of GNSS carrier phase DDs in urban and flight navigation is presented. Two experiments were conducted, one using a vehicle and another using an aircraft to study the quality of the carrier phase observations. During the flight experiment, high dynamics are affecting the geodetic-grade equipment. In contrast to the open sky characteristics, peculiar in-flight navigation, the experiment carried out in the urban area was affected by obstructions and diffraction from multiple buildings and the environment was more prone to severe multipath effects. In addition to the geodetic-grade receivers, the urban experiment also included high sensitivity receivers. In order to characterise the quality of the phase observations, carrier phase DDs are analysed on a moving zero-baseline. In both the experiments, the time synchronisation of receivers needs to be considered to account for the kinematic DD bias. It is shown that not taking the kinematic DD bias into account leads to systematic errors in the range of several centimeters depending on the receiver clock biases and the velocity of the moving platform. In the urban environment, it is observed that the noise of DDs for UBX receivers (high sensitivity) is higher in comparison to the geodetic receivers. In the case of geodetic-grade receiver combination, 95% of the L1 carrier phase noises for GPS, GLONASS and Galileo are below 2, 2.8 and 1.7 mm, respectively. These values are at least two times higher with the UBX receivers. For all the systems, the noise process of the DD time series for high elevating satellites is dominated by a white phase modulation as indicated by the modified ADEV. An elevation dependency is not observed due to multipath contamination from buildings in the vicinity of the antenna. On the contrary, a C/N\({}_{0}\) dependency is observed and a corresponding weighting can be applied for geodetic-grade receivers. Interestingly, the availability of the UBX carrier phase data seems restricted compared to the geodetic receivers. There is no impact of high dynamics on the analysed DDs with geodetic-grade receivers with the data from the flight experiment. Also, there is no significant difference observed between the two selected receiver combinations, which means that different ultra-stable external oscillator  
Figure 17: DDs CDFs for L1 (a), L2 (b) and L5 (c) carrier phase observations from all the satellites of different systems with two different receiver combinations. configurations do not have any influence on the quality of the observations. For both receiver combinations, 95% of the L1 carrier phase noises for GPS, GLONASS and Galileo are below 1.4, 4.6 and 1.5 mm, respectively. All DD time series show a clear white noise process, similar to the urban case. The DDs show a clear dependency with respect to the elevation angles and the C/N\({}_{0}\) (except GLONASS DD with respect to C/N\({}_{0}\)). An elevation dependency based on an exponential function with different parameters for L1 carrier phase observations of different GNSS systems have been evaluated and listed for geodetic-grade receivers, applicable in an open-sky environment. [PERSON] along with other group members planned and performed the urban experiment. [PERSON] and [PERSON] designed and planned the flight experiment. [PERSON] analysed the urban data-set whereas [PERSON] analysed the flight data-set. [PERSON], [PERSON] and [PERSON] wrote the paper. All authors have read and agreed to the published version of the manuscript. The flight experiment has been carried out in the project VENADU II funded by the German Federal Ministry for Economic Affairs and Energy following a resolution of the German Bundestag (project number: 50 NA1705). The terrestrial data was analysed in the framework of the i.c.sens research training group funded by DFG under grant GRK2159. The authors would like to thank [PERSON], [PERSON] and [PERSON] for the help in conducting the car experiment.