Field Activity #3: Using a multi-rotor to gather imagery/Using mission planning software.

Introduction

This week, we utilized the information that we learned in last week's field activity and flew automated missions using a multi-rotor UAS. This field activity helped us gain more experience planning missions with the Mission Planner software, engaging in pre-flight checks before every mission, updating flight logs, and staying engaged at a certain position (pilot in command, pilot at the controls and spotter) while the mission is taking place.

Study Area

For this field activity we chose to return to the Eau Claire Soccer Park in Eau Claire, Wisconsin. This complex provides us with spacious field with a minimum public presence during the late afternoon/early evening before soccer games begin. A wide open field with minimal people is important when flying multi-rotor UAS missions especially in the event of a malfunction or crash it is important no one is injured. Our survey mission was flown over a concession/restroom building that is located at the center of the park. The skies were overcast with light winds from the South.

Figure 1: Study area for this field activity. The mission was carried out in approximately same region as is outlined by the red box and North is indicated by the red arrow in the bottom right hand corner.

Methods

Upon arriving at the study area, the computer containing Mission Planner was booted up and the modem was attached. The modem was then attached to the Wonder Pole and raised into the air to its full length. For these missions we used the Matrix multi-rotor UAS. The Matrix was removed from it's container and assembled. The mission plan was created, a flight log was started and the pre-flight check was done. After the pre-flight checks, the mission was run. Each mission took about 6-7 minutes to complete and the data was saved to the sensor for later review. Two additional and identical runs were made with a Cannon SX260 camera with CDHK installed, the first with an RGB camera and the second with a near IR camera. A timer was set on both cameras to specify a time interval for image gathering, but could only be an estimate since the cameras were not linked to the Matrix hardware. After these missions were run, a post flight check was completed and the base station was dissembled.

Figure 2: Matrix multi rotor UAS

Results and Discussion

Three image gathering methods were used in our survey. The first method used was gathering image data from the sensor that was already mounted on the Matrix multi-rotor. This sensor was programmed to take images based on the mission planner software which takes into account the field of view allowing for acceptable amounts of overlap between successive pictures and passes. Two types of images were taken, one in full color RGB and one which was monochromatic. Below you can see that both Figure 3 and Figure 4 were products of the sensor imagery since both the images produced are nearly identical in position and orientation. The accuracy and overlap can be visualized in Figure 5 where I overlayed three photos to show photos one after another and in a separate pass. These images were so easy to overlap that I was able to do it in a Word document. This attests to the UAS's ability to maintain a very consistent altitude as described by the programming.

Figure 3: RGB photo capture from sensor mounted on the Matrix

Figure 4: Monochromatic photo capture from sensor mounted on Matrix

Figure 5: An overlay photo showing the overlap of the imagery collected by the sensor of the Matix. The blue box depicts the original picture depicted in figure 3, the red box depicts the next picture taken by the sensor and the green box  at the bottom shows the overlap of the photos taken in the next row pass.

The photos taken with the Canon SX260 cameras were not as accurate as the sensor imagery, but this is because they ran on their own platform instead of being programmed with the mision planning software. Since we had to use a simple "photo per time interval" approach, the overlap here was not as good. However, we were still able to gather some imagery as seen below in figures 6 and 7 with the near infrared and RGB cameras respectively.

Figure 6: Near IR imagery from Cannon SX260 camera
mounted on Matrix multi-rotor in place of first sensor

Figure 7: RGB imagery from Cannon SX260 camera 

mounted on Matrix multi-rotor in place of first sensor

Conclusion

This field activity allowed us to use a hands on approach to mission planning and carrying out a mission while reinforcing the concepts of maintaining a flight log and carrying out a pre-flight check. The RGB and monochromatic imagery that we collected with the sensor hardware connected with the software of the Matrix multi rotor turned out to be better than the camera imagery being taken from its own,separate platform. The imagery from the sensor apparatus was also able to show us just how accurate the altitude of the UAS is when it is running autonomously.