Before planning a 3D mission, contact your Customer Success Engineer. This feature must be turned on before uploading your data to the platform. Since 3D missions differ from 2D missions with both data capture and data upload, your CSE will go over best practices and processing times with you.
While the Propeller Platform works best with 2D photogrammetry missions, in certain cases, a 3D photogrammetry mission produces more actionable results.
Getting Started
1. To begin, power on your controller using the GS RTK app
2. Connect to a WiFi network or hotspot to ensure base maps will load to assist with mission planning.
3. From the GS RTK main menu, tap Plan in the bottom left corner.
Planning a Double Grid Mission
1. Tap 3D Photogrammetry (Double Grid).
2. Locate your site by panning around the map and using two fingers to adjust the zoom.
3. Drop a pin to start creating your survey area by tapping on the screen on the boundary of the site.
Note: the flight path will go outside of the set site boundary.
4. Drop a minimum of three pins to produce a survey area. To move a pin, tap on it again to select it, then either use the wheel on the right or drag it around with your finger. You can delete the selected pin by tapping the trash icon or by double-tapping on the pin.
5. After completing your survey area, tap the white tab on the right side of the screen to display the mission settings.
The settings listed below are good guidelines to follow when planning 3D double grid photogrammetry missions.
| Drone Setting |
Set to |
Question to Ask Yourself |
Reason |
| Height |
260-400ft (80-120m) |
How high should I fly comparative to the takeoff point? |
The height is a balance between how quickly you would like to complete your survey (higher makes it faster) and the ground sampling distance that you need. This range satisfies this balance. |
| Speed |
Max Speed Allowable |
How fast should I fly? |
Unless you're trying to reach the required 10min mission time, increase the speed to minimize overall flight time. In low light conditions, reduce the speed and the shutter speed to ~640.
|
| Shooting Mode |
Distance Shooting |
What metric is used to capture images? |
Distance shooting allows the drone to capture images with consistent overlap. |
| Finish |
Return to Home |
What should I do after completing the mission? |
Safety and not losing your drone. Once completed, the drone will make its way back to the home point automatically.
|
| Relative Altitude (m) |
0m |
Is the terrain I want to survey at a different altitude to my home point? |
Unless the terrain that you are surveying is at a much different height than your home point, leave this as 0m. On mines and quarries, consider changing the relative altitude.
|
| Camera Setting |
Set to |
Question to Ask Yourself |
Reason |
| Photo Ratio |
3:2 |
How much of the image should I delete? |
3:2 deletes nothing, utilizing the whole sensor. Everything else deletes data.
|
| White Balance |
Set to the conditions of the day |
What conditions should I accomodate for? |
Adjust the setting to reflect current weather conditions. Setting the white balance incorrectly will result in poor stitching and/or inaccurate coloring of your model.
|
| Metering Mode |
Average |
How should the camera determine exposure? |
Average metering uses light information from the entire image and creates an average for the final exposure. This type of metering does not weight any part of the image. Sites with highly contrasting light and dark areas will benefit from an average metering mode
|
| Gimbal Angle |
-60º |
What should I point the camera at while flying? |
3D reconstructions and 3D mapping require passes from multiple angles using a -60º gimbal angle. -90º is facing straight down, 0º is horizontal facing the direction of the drone.
|
| Shutter Priority |
Enabled ~1000 |
How should the exposure be controlled? |
To avoid motion blur. Shutter priority tells the camera that a fixed shutter speed must be used. The camera can adjust the exposure with apeture and ISO. 1000 is usually a good place to start for sunny conditions. In low light conditions, reduce the shutter speed to ~800 and lower the speed.
|
| Distortion Correction |
Disabled |
Should the distortion correction be applied by the camera? |
Leaving the distortion correction off allows the photogrammetric software to undistort the images itself. The software usually does a better job. For any nonsurveying purposes, leave this enabled.
|
| Advanced Setting |
Set to |
Question to Ask Yourself |
Reason |
| Horizontal and Vertical Overlapping Rate (%) |
~75% |
How much should each of the images overlap each other? |
This provides enough overlap for if some images are missing or poor quality, while still building a contiguous model. The lower the detail on the surface below, the higher your overlap should be. If you have a large area to survery, you can look at reducing the horizontal overlap (no lower than 60%) to increase the area you can cover per battery.
|
| Margin |
Manual → 0 |
How much margin do you want to leave around the survey area? |
Provided that you have covered the entire area you would like to survey accurately, you don't need any margin. |
Note: these settings are very similar to 2D photogrammetry missions, except for the gimbal angle.
6. Tap Save and give your task a name.
Tips for Flying 3D Photogrammetry Missions
- Fly a 2D photogrammetry mission to cover the whole site first.
- Fly a 3D photogrammetry mission at roughly 15-20m lower than the 2D mission. This is to get a slightly higher ground resolution.
- Only fly the 3D mission over the areas of interest on your site. There's no need to do the whole site, i.e. don’t waste your time by flying flat areas.
- Your flight still needs to be at least 10min long to get good GPS positioning data.
After you fly the mission, upload your data to Propeller.
The most common use of 3D missions is to produce clear and detailed images of vertical features, such as a pit wall or building facade. If you have questions about when and how to use 3D missions, please contact Propeller support.
I still can't do it!
We wrote these articles to equip you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.
If you're stuck, the Propeller hardware support team may be able to help. You can contact them by emailing hardwaresupport@propelleraero.com.au.