Measure Ground Control

Introduction

Measure Ground Control (MGC) is an application in which there is everything from Airspace to flight operations to mission creation and data management. A benefit of Measure over DJI GSP is that one person can create flights and assign them to different pilots.

Methods

Airspace

MGC integrates airspace authorization with Airmap a LAANC provider. I checked out a variety of areas to see what the grid altitudes are and other rules and advisories.

Figure 1. MGC Airspace Rules and Advisories for 132 Andrew Place, West Lafayette

I checked to see what airspace my apartment was in and there is the class D airspace from LAF, and a school nearby. I am in a LAANC zero grid. I also looked at two of our flying sites, Purdue Wildlife Area and Martell Forrest.

Figure 2. MGC Airspace view of Martell Forrest

Figure 3. MGC Airspace view of Purdue Wildlife area

Both Martell forest and PWA are outside the KLAF class D airspace, so they are class G airspace, and a LAANC approval is not needed to fly there.

Next I looked at McCormick Woods, which is just north of the Purdue University Airport.

Figure 4. MGC airspace view of McCormick Woods, in a 200' grid

The maximum altitude I could request with LAANC is 200 Feet AGL, this is because it is within that grid and proximity of the airport.

LAANC allows a uas operator to get authorizations to fly in airspace that is not class G. An application called airmap needs to be installed on your device to get the application. The information from airmap can help with planning, to know if you can operate at an altitude that you want to for a mapping mission. It can help after the mission as airmap logs your LAANC request, so you have a log of when you flew/were authorized to fly.

Below is an Airmap flight plan for flying the Purdue Turf Farm, to demonstrate what that would look like.

Figure 5. Airmap Flight plan area for Purdue Turf farm

Figure 6. Airmap Flight plan details for the flight planned in figure 5.

Platform and Sensor Settings

MGC allows you to set all the platform and sensor settings on the MGC app instead of using multiple applications to plan your flight. This reduces the chance that something can be completed wrong. Like flying a flight with a narrow-angle lens on a wide-angled flight plan. The resulting data would not have enough overlap and the flight would have to be re-flown. Having the sensor integrated into the mission settings reduces the chances that this happens.

The aircraft systems that have the main impact on the flight characteristics of the data are the Gimbal, IMU, and Compass. Each of these relates to the safety of the operation, as they ensure that the drone is in a functional and operational state. Also completing these tasks on a regular schedule can improve the quality of the data collected, as, without regular calibrations, the resulting data can have an increasing error over time. M600 aircraft is particularly bad with this as they are cumbersome to calibrate, and susceptible to yaw biases of +/- 5 degrees.

Fly

The fly screen in MGC is used for manually controlled flight operations. The layout of the fly screen is similar to DJI go/go4 the camera settings on the right side of the screen can be used to adjust aperture, iso, shutter speed, and ev balance. You can also check the amount of space left on the sd and internal storage if applicable. The sd card and internal storage can also be formatted, and the operator can choose where they want to save their data. The fly screen can be useful when trying to dial in-camera settings before flying a mission, as you do not have to take off in DJI go adjust camera settings then switch to another app like DJI GSP/pilot to fly the mission.

Flight Plan

One neat feature of the logged flight plans in MGC is that you can look up locations and find previously completed flights at that location. This can help as when trying to study an area change over time you want repeatable flight paths, and recalling previous flights is a good way to make that happen. We were next tasked with developing various flight plans, which are shown in figures 7-23.

o Mavic 2 Pro at 60 meters

Figure 8. Mavic pro 2 Misson at PWA taking 57 minutes and 32 seconds, capturing 760 images

o Mavic 2 Pro at 80 meters

Figure 9. Mavic pro 2 Misson at PWA taking 32 minutes and 25 seconds, capturing 434 images

o Mavic 2 Pro at 122 meters

Figure 10. Mavic pro 2 Misson at PWA taking 14 minutes and 36 seconds, capturing 186 images

o Zenmuse XT2 (13mm) at 80 meters

Figure 11. Zenmuse XT2 Misson at PWA taking 20 minutes and 58 seconds, capturing 902 images

o Zenmuse X7 16mm at 60m

Figure 12. Zenmuse X7 Misson at PWA taking 58 minutes and 59 seconds, capturing 781 images

o Zenmuse X7 24mm at 60m

Figure 13. Zenmuse X7 Misson at PWA taking 2 hours 0 minutes and 16 seconds, capturing 1698 images

o Zenmuse X7 35mm at 60m

Figure 13. Zenmuse X7 Misson at PWA taking 4 hours 14 minutes and 1 second, capturing 3585 images

• We are now going to do a mission where we change the gimbal direction and turn on the crosshatch.

o Zenmuse XT2 (13mm) at 60 meters. Gimble angle to 50 degrees and Crosshatch on.

Figure 14. Zenmuse XT2 Misson at PWA capturing the entire field with crosshatch and the gimbal at -50 degrees

Altitude and focal length are the greatest contributors to the length of time that a mapping mission will take. Altitude relates to the mission lines with increasing the flight height, the lines spread further apart. This is because the camera is able to see more of the subject when higher up so it needs fewer passes to collect the needed overlap. This increases the distance between the flight lines. Focal length also relates in a similar way, as a lower focal length, let's say 16mm, has a much wider field of view than a 35mm lens. This allows the camera to capture a wider area in an image at the same height. So using a lower focal length has a shorter flight time as it is able to capture more of the field at the same height so it requires fewer passes with the same amount of overlap. A caution to using wide-angle lenses is that they can distort the image and fly high can reduce the resolution. The sensor settings and the flight plan are a balancing act to produce the ideal quality data in a reasonable time. Someone would engage in a flight with a gimbal at an angle and the flight lines in a crosshatch pattern to collect a better data set for generating 3d models of structures. A standard NADIR flight would end up missing images from the walls of the structure or things under overhangs. Running the gimbal at an angle allows for these to be seen, and running in a crosshatch captures data that wouldn’t be seen with a regular line. Without the crosshatch sequence, you would only capture images of 2 sides of the structure, not all four.

Next we were tasked with making a flight that had

o 6 Waypoints (Each at 60 meters unless specified)

o Waypoint 1 60 meters’

o Waypoint 1 to 2 15 mph

o Waypoint 3 Start Video

o Waypoint 4 Stop Video, rise to 80 meters

o Waypoint 5 Rotate Drone

o Waypoint 6 Capture Photo 360 panorama, drop to 60 meters.

o Make sure drone returns to home after all waypoints.