lab_6

Operating Fixed Wing UAS and Processing UAS data

Introduction:

The demand of the UAS technology and variety are increasing as applications of this machine increase. Fixed-wing UAS is the one of the varieties. This has been used earlier than other types of UAS and it has been widely used for many other purposes. People in the research area, like to use this fixed-wing UAS because of some advantages it has. There are some advantages such as; faster, longer and further. Fixed wing has less influence with aerodynamic because of its figure is normally thin and sleek. Battery on this craft usually last longer than others. It normally has only one motor whereas multi-rotors can have more than that so it needs to be effected  by the force of gravity. Therefore, fixed-wing is made for faster structure. Fixed-wing can fly further than multi-rotors, it can map a large area in a short amount of time. Additionally it is more durable because, it is sustainable with heavy and expensive payload which  gives you good quality of the results. 

In this lab, we used the fixed-wing UAS the model of "Trimble UX5-HP".

                                           Figure 1. Trimble UX 5 - HP

Objectives:

In this lab, we have three goals, 

• Setting the GCP points on the study area to enhance the accuracy of the result.
• Fly the mission with fixed-wing UAS, Trimble UX5-HP
• Using the software(Pix4D Mapper) to post-processing the acquired data and generates point cloud, DSM and ortho-mosaic image.   

Study Area:

                                            Figure 2. Study area Map

Mission Planing Details:

There are total 8 CGPs were placed equally and widely in the quarry area. To collecting these GCPs, we have used Trimble RTK unit. This mission couldn't be used by manually, therefore, we had used mission planing software which was in the given tablet. Therefore, we had to be very careful with setting the parameter to prevent the crash event. In the mission parameters, flying height was 120 m with 70% of overlap and total 359 images are collected. Total flight time was 26 minutes. Once all the parameters are set, we can start our mission fly. 

                                         Figure 3. Mission plan of Trimble UX 5 - HP 

Post-processing:

Same as previous labs, we used software called "Pix4D Mapper".  Once you import the all the images, as an always, you need to verify your coordinate system. In this case, we used NAD83 State Plane Wisconsin South FIPS 4803 Feet (-101.86ft). The number (-101.86 ft) represents the geoid hieght above the Ellipsoid.

                                       Figure 4. Output Coordinate system setting 


Because we had placed the GCPs, we can input the points in the process. First, open the GCP/MTP Manager and import your GCP text file.

                                    Figure 5. GCP Manager

You have total 8 GCPs in your mission and each of them has to have at least 5 point selections.

                                  Figure 6. GCP Selection.

Once you adjusted all the GCP points, now you may see the GCP points in your mission page.

                                Figure 7. GCPs on the mission map.

Results:

                           

                                Figure 8. Summary & Quality check


In the results, we have 10002 key points are acquired and 350 out of 356 images are calibrated (98%).  We have 79.58% relative difference between initial and optimal camera parameters and our georeferencing of 8 GCPs had RMS error of 0.014 ft. In the results, we had 2D/3D accuracy with approximately 15cm/11cm.

                                            Figure 9. Spatial Overlap of Images

                                            Figure 10. GCP and Tie points

                                          Figure 11. 2D key points matches

                                      Figure 12. Point Cloud Densification Details

                                      Figure 13. DSM and Orthomosaic Details.

Output results:

                                           Figure 14. DSM MAP

                                           Figure 15. Ortho-mosaic Map

                                     
                                          Figure 16. Point Cloud image of quarry

Conclusion:

In conclusion, this outputs will help our next analysis which is measuring the volumetric change detection. We would expect that we can measure how much of resources were used fore mining. We are going to use Pix4D again to measure the volume of the resources and we also going to use Arc map to measure the volume. In the lab, we again, realized that importance of the having accurate GCPs to produce accurate image map. We also learned that importance of cautions for launching and landing the UAS in the irregular height of the land. Setting the parameters in the mission is very crucial and more spending time on the post-processing will give you the high accuracy of the results.    

                                          Figure 17. Launching Trimble UX 5 - HP
                                             
                               

                                         Figure 18. Great effort of Jack Radenz