## 5 Experiments
### Experiment to Evaluate Maximum Detectable Motion Blur  
The objective is to ascertain whether RCM can be discerned in a compact fixed-wing UAV that is traversing the atmosphere under the influence of anticipated motion blur. As previously outlined in Section 4.3, the degree of motion blur increased in proportion to the angular velocity imparted to the camera. In the course of our experiments, we utilized a high-precision rotary table that was capable of maintaining a constant angular velocity to simulate the angular velocity exerted by a small fixed-wing UAV on a ground station detection system. The ground station detection system was positioned on the high-precision rotary table. The maximum angular velocity at which the ground station detection system was unable to detect the RCM was determined, and the marker detection performance in  
Figure 14: Relationship between the angular difference in the detected angle \(\theta_{s}\) and the actual drive angle \(\theta_{t}\). The blue markers represent the raw data output from the sensor, while the red markers represent the results after correction with A = 1.607.  
Figure 15: Result of deviation vs. drive angle.  
the presence of motion blur was evaluated using Equation (9). The experimental system is illustrated in Figure 16. The color markers were installed with a drawing size of 15 pixels, taking the operating environment into account.  
Figure 17 shows the RCM detection probability for the angular velocity from the experiment with the UAV. Based on the experimental results shown in Figure 17, all frames in which the RCM was drawn were detectable up to an angular velocity of 155 [deg./s], and half of the frames were undetectable at angular velocities of 160 [deg./s] or higher. Therefore, the proposed method was capable of detecting the RCM up to an angular velocity of 155 [deg./s]. Based on these results, the strength of motion blur was calculated using Equation (10). The formula is shown in Equation (14).  
\[\mathrm{R}=\frac{\omega\times E}{\theta}=\frac{155\times 0.003}{26.5}=0.0175\ [\cdot] \tag{14}\]  
The calculation results show that the marker detection performance of the proposed method against motion blur is 0.0175 [-], which exceeds the required performance of 0.0120 [-].  
Based on the experimental results shown in Figure 17, additional experiments were conducted to confirm the effect of the variation in exposure time, as indicated in Equation (14), on motion blur tolerance. In these experiments, the same configuration of equipment was used to measure motion blur resistance when the camera exposure time was set to 0.006 [s] and 0.009 [s]. The relationship between the maximum angular velocity at which the RCM could be detected and each exposure time is shown in Figure 18a, and the motion blur intensity at each time is summarized in Figure 18b.  
In Figure 18, the blue markers represent the results of the experiment shown in Figure 17, while the orange markers represent the results of the additional experiment. The results of the additional experiment indicate that the RCM can be detected up to a maximum angular velocity of 90 [deg./s] when the exposure time is 0.006 [s] and up to  
Figure 16: Experimental system to evaluate the maximum motion blur at which the RCM can be detected.  
Figure 17: Result of RCM detection rate per angular velocity.  
60 [deg./s] when the exposure time is 0.009 [s]. This shows that as the exposure time increases, the maximum angular velocity at which the RCM can be detected decreases, narrowing the sensor's applicable range. On the other hand, the motion blur intensity at each exposure time setting remained consistent at 0.0204 [-] in both cases. In other words, the motion blur intensity generated in the image at each exposure time setting was the same, indicating that motion blur tolerance does not change with exposure time variation in the proposed method.