If you have limited AeroPoints, flying larger sites can be challenging without a base and rover system to mark additional ground control. AeroPoints can obtain survey-grade positional data as smart ground control, simultaneously serving as a base station and control target and utilizing Propeller’s PPK solution to correct data after it’s been collected.
Find a suitable location
First, you must find suitable locations on your site with a clear view of the sky. These positions should be in locations that will not be easily disturbed or disrupted by future site activities.
The “15 Degree Rule” should be considered when assessing a location’s suitability as a ground control point.
These locations should also be at least 50 feet away from buildings, vehicles, metallic interference, or surrounding terrain. The taller the buildng or object, the further away your AeroPoints will need to be.
💡 Tip: Use the AeroPoints app to check GNSS signal quality after placing your AeroPoints |
Mark the ground
Once these control point locations are identified, use the stencil included with your AeroPoints to mark the ground (in the middle and outer perimeter of the stencil) with bright, contrasting paint. You may also use another permanent marker that will be easily visible from the sky when flying your site.
Collect location information
Once the paint is dry, place an AeroPoint precisely over the marked location and press the button once to turn it on to collect data.
Leave the AeroPoint in place and undisturbed for:
- AeroPoint 2s: at least 10 minutes
- AeroPoint 1s: at least 45 minutes
- Mixed fleet comprised of both AeroPoint 1s and 2s: at least 45 minutes
The longer this is left out to collect data (recommend at least 1 hour or more), the better the point will be for future surveys.
AeroPoints will enter sleep mode after they have reached the maximum capture time and will no longer be collecting data.
Maximum capture time
| AeroPoint 1s: | 5 hours |
| AeroPoint 2s: | 8 hours |
Repeat these steps for each additional location that you would like to create a permanent ground control point. For example, if you would like to create five permanent ground control points across your site, you will need to repeat this process at five different locations across your site. If you have multiple AeroPoints, you can perform these steps simultaneously at different locations.
Upload AeroPoint data
Once all AeroPoint data is collected, upload your data to the Propeller Platform.
Log in to the platform and navigate to your AeroPoints Dashboard.
For each AeroPoint survey that uploaded data, click the PROCESS NOW button.
Select Propeller Corrections Network.
Once processing is complete, download the CSV (simple) file for future use during full site surveys. If you uploaded multiple AeroPoint surveys and processed them separately, download multiple CSV (simple) files, then combine them into a single file.
The Z values are measured from the top of the AeroPoints, so to understand the correct height of the ground underneath the AeroPoint, you can subtract the thickness of the AeroPoint from the survey report's height data.
To do this, reduce the NAD83 (2011) Height (m)— usually column G, and NAVD88 Height (m)— usually column J, values for each AeroPoint.
Reduce by: |
|
AeroPoint 1s |
0.032 m |
AeroPoint 2s |
0.026 m |
After these changes, the CSV can then be used in the future for full site surveys.
Data collection using established ground control points
When you're ready to fly a survey with your new supplemental control points, lay out your AeroPoints and ensure that your permanent ground control points are clear and visible and that there is adequate spacing between your AeroPoints and the permanent controls across your site. You are now ready to conduct your survey.
ℹ️ Note: Once the paint at your marked locations begins to fade, you will need to refresh the paint to ensure they are still cleary visible in the photos during your survey. |
Upload survey data
Upload your new flight data to the portal and select AeroPoints + CSV when choosing your ground control method.
Select the appropriate AeroPoint survey and upload the CSV file you created for your site.
To help our team quickly identify the permanent markers during processing, add a note in the comments section that includes a brief description of the target, such as color and shape, if different from the AeroPoint stencil.
You can complete the remainder of the dataset upload process as normal.
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 our support team by emailing hardwaresupport@propelleraero.com.au.
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