## 4 Results and Analysis of the Flight Test
### Flight Test Results  
The purpose of the flight test is to connect the real-time communication link of image information, assess the communication anti-interference ability and shooting vibration resistance of equipment in aircraft maneuvering state, and verify the engineering applicability of the system. Therefore, the main assessment includes imaging quality, image concatenation, and real-time data transmission.  
In the flight test, the aircraft carried mobile communication equipment and image stabilization platform with a reliable working time of more than 2 h and conducted effective maneuvers at the flight test site. The results show that the image stabilization platform has good image stabilization ability and captured clear images in high-frequency fuselage vibration environments greater than 13 Hz. The communication link has a bandwidth of no less than 2 Mbps and a packet loss rate of no more than 1% in a 13 Hz propeller interference environment. In addition, the aircraft performed small-scale maneuvering flights, with periodic tilting vibrations applied in pitch and roll directions, and then the imaging quality was evaluated. The shooting object of the flight test site is weeds on the ground. Based on the actual size estimation of weeds, with clear leaf contours, the resolution of the image obtained in the flight altitude of 325.3 m is less than 1 cm (Figure 6), which meets the emergency observation requirements. Table 5 shows that the stability accuracy of the equipment under airborne conditions meets the usage requirements.  
During the flight test, satellite data transmission was carried out on the captured images of the image stabilization platform using the mobile Communication system. The aircraft hovered in four directions, with each direction separated by 90\({}^{\circ}\), to analyze the impact of the relative positions of the antenna, fuselage, and satellite on communication quality. The ground receiving station located in Beijing received data and analyzed them. The results show that mobile communication equipment has a transmission rate of the bandwidth of 2 Mbps in 114 received packets, without data loss. Considering the use of  
Figure 6: Ground weeds captured in the flight test site of Chongqing Tuohang Technology Co., Ltd.  
image compression function (not less than 16 times), it can transmit 1080P real-time video and high-resolution images of not less than 32 Mbps in real-time in the later stage.  
The images collected during the Nanpingba Island flight test at altitudes of 250 m and 450 m were concatenated, and the results are shown in Figure 7a,d. Figure 7b,c are enlarged partial views of Figure 7a, from which the situation of farmland and small boats by the river can be clearly captured. Figure 7e is a frame from Figure 7d, from which the conditions of the houses and roads can be clearly seen. From the image quality and continuity of splicing, it can be seen that under the condition of 2 Mbps bandwidth, the packet loss rate is 0%, the transmission is very stable, the imaging and splicing effects are good, the ground buildings are clearly visible, and the landscapes on the ground can be effectively identified. These pieces of information are all of concern in disaster relief. After receiving image information, the Beijing ground station compared the timestamp of the image with the receiving time, with a time delay of no more than 2 s. The above data indicate that in the event of natural disasters, the aerial remote sensing combined with real-time satellite transmission can be used to emergency observation with mature and reliable engineering technology and application conditions.