Taking UAS Data in the Field

Introduction:

There are multiple steps to taking good UAS data and it is important that each one of them is completed to maintain data integrity and consistency.   This lab will discuss the process of taking UAS data from mission planning to the actual flight.

Process:

Before leaving to the field it is important to make a mission plan and make sure all items that are needed are charged and ready to go.  The mission plan will allow for an efficient use of time and background knowledge of the area.  These flights are to be used as example data and minimal mission planning occurred.  Three flights took place at a community garden in Eau Claire Wi.  Two flights were done with a DJI Phantom 3 Advanced and one practice flight was done with a DJI Inspire 1 Pro.

Before any flights occurred, GCP's were placed in the garden and located with a highly accurate GPS.  The GPS is mounted on a tripod and positioned directly in the center of the GCP.

The tripod has a leveling bubble that was put in the center before taking the coordinates.  This was done so the coordinates were exactly in the center of the GCP.  These coordinates are recorded in a table format to be used during data processing.

After all the GCP's locations were recorded it was time to fly.

Flight one with the Phantom took imagery of the garden with GCP's in place.  The Pix4D capture app was used to plan and fly this mission.  The shape of where to fly, and flight settings are entered on the app and the mission is ready to go.  The remote pilot-in-command took off and brought the UAS up to a safe altitude.  The mission was then started on the app and the UAS rose to the proper altitude and began flying the proper pattern.  When the mission was done, the UAS returned to the position it took off from and automatically landed.

Flight 2 was a flight done over the cars parked on the road to create a 3d image.  This was done by changing the angle of the camera in the mission planning software.  The oblique imagery allows for 3d maps to be created.  The same process was used to take off and fly the mission as the first flight.

The 3rd flight was done with the Inspire and was just to let student manually maneuver the UAS in flight.  It was manually taken off and then the controller was passed around to let students familiarize themselves with flying.  After many hours using flight simulator, flying a real UAS felt very natural.  The Inspire is an impressive drone with removable cameras that allow the user to take a variety of data.

The data taken was put into Pix4D

Making GCP's

Introduction:

Ground controls points are panels that are set on the ground of a site that is going to be flown with a UAS.  These panels are marked with a highly accurate GPS and the point locations are then put into the image processing software.  The points are then matched with the imagery and optimized.  This weeks the class physically created GCP panels from scratch.

Process:

The process started with cutting equally sized squares from sheets of black polyurethane.  These squares were then painted to have a two tone look with an easily identifiable center.  The GCP's were also numbered and painted on accordingly.  This process went very fast with around 14 people helping.    

The first step after cutting the sheets of polyurethane was to use a stencil to spray paint a pattern that allows for the middle to be easily identifiable.  This is important when processing the data.

A high visibility pink paint was used to break up the black surface.  A high visibility yellow paint was then used to number each GCP.  This will come in handy when tying the imagery down in the processing.

In the end the 16 GCP's were created.  The image below shows the finished product.

GCP's are important tools to tie down imagery to where is actually is on the earth.  Creating GCP's is easy, cheap and allows for highly accurate data. It is a necessary step to do when taking UAS data.