## 2 Experiment Description
### Aerial Experiment
#### 2.2.2 Flight Test Details  
The flight experiment was carried out on 7 th October 2019 around the surrounding area of Dortmund airport in Germany using a modified twin-engine Cessna 404 TITAN aircraft (Figure 2b). The experiment lasted for a duration of about three hours. GPS, GLONASS and Galileo pseudorange, carrier phase and Doppler measurements were recorded on all the receivers, except JVD 0346, which recorded only GPS and GLONASS observations. The recorded observation RINEX specifiers on L1, L2 and L5 frequencies for different GNSS systems were exactly the same as stated for the geodetic receiver in Table 2.  
The sampling rate was set to 10 Hz for all the receivers. In the course of the experiment, an identical set of flight manoeuvres were performed at two different ellipsoidal heights, particularly at a lower height level of about 650 m and at an upper height level of about 2800 m. A single set of these manoeuvres comprised of a straight and level flight followed by flight turns with varying roll angles. The first straight and level flight starts moving from east to west and then back to east, followed by a straight and level flight line again from south to north and then back to south. After these flight paths, flight turns with high dynamics were conducted. At first, two flight turns with maximum roll angles of up to \(\pm\) 25\({}^{\circ}\) were performed, followed by two flight turns with maximum roll angles up to \(\pm\) 58\({}^{\circ}\). It must be noted that higher the roll angle, the steeper the flight turn. All the flight manoeuvre operations carried out at a lower altitude (\(\approx\) 650 m) are referred to as phase 1 of the flight experiment. A similar set of manoeuvres were conducted at an upper altitude (\(\approx\) 2800 m); it is referred to as phase 2 of the flight experiment. Figure 4a,c show the complete flight trajectory path in phase 1 and phase 2, respectively. There are four distinct points marked with different labels on each flight path in phase 1 and phase 2. The information of all the marked points on both the trajectories are summarised in Table 3 along with the corresponding approximate GPS time. Moreover, flight turns which involved high dynamics in phase 1 and phase 2 are depicted in Figure 4b,d, respectively. The flight dynamics (attitude and total acceleration) recorded by the IGI's IMU are shown in Figure 5. The black dashed lines in Figure 5 corresponds to the different marked points in the flight trajectories (cf., Figure 4). The flight dynamics include roll angles up to \(\pm\) 59\({}^{\circ}\) and pitch angles in the range of \(\pm\) 10\({}^{\circ}\). The flight dynamics are the highest towards the end of both the dynamic manoeuvres (i.e., point D and G) where the flight is accelerating at magnitudes greater than 2 g and turning with the highest roll angles. The phases where the pitch angles are seen increasing steadily refer to the take-off phase and flight ascend phase to a higher altitude. On the contrary, the phases in which pitch angles are seen decreasing steadily refer to flight descend phase to a lower altitude and the landing phase. The phases wherein the yaw angles are constant refer to straight and level flight phases; the dynamics during these phases are not very high. Figure 3: (**a**) Measurement devices placed within a camera sensor pod. (**b**) Photogrammetery mount within the aircraft on which the sensor pod is fixed. Figure 4: Airborne trajectory at heights of about 650 and 2800 m in (**a**) and (**c**), respectively. Dynamic manoeuvre segments corresponding to the different heights in (**b**) and (**d**), respectively. For details of the marked points, cf. Table 3. Map presentations taken from [26].