How to Use AeroPoints For the PPK Workflow

AeroPoint 1s and AeroPoint 2s are smart ground control points (GCPs) used for geotag corrections and model creation. When used with PPK or RTK enabled drones as part of the Propeller PPK workflow, they replace the need for a local base station.

Laying out AeroPoint 1s & AeroPoint 2s

AeroPoints need to collect data for the duration of your drone flight. For best practices on distributing your AeroPoints, please refer to this video tutorial and skip to the chapter "Preparation and Placement" for more information.  

Along with the videos above, the guidelines below should be followed when planning AeroPoint layout for PPK flights:

• 1–3 AeroPoints should be used for sites up to 150 acres (60 hectares)
• For best accuracy and redundancy, at least three AeroPoints are recommended.
• For each additional 50 acres (20 hectares), you need 1–2 additional AeroPoints.
• No AeroPoint should be more than .75 mi (~1.2 km) away from another AeroPoint.

In order to obtain an accurate positioning of an AeroPoint location, the following criteria must be met: 

• A clear view of the sky in all directions (avoid power lines, walls, and trees).
• Trees, buildings, power lines, or other obstacles should not obstruct them.
• To avoid interference, they should be at least 30ft (9m) away from vehicles or other large metal objects.
• Placed on a relatively flat surface (maximum 20° from horizontal) 
• Remain unmoved during data capture 

Correct AeroPoint placement

Poor AeroPoint placement

If AeroPoints are positioned poorly, this can obstruct or interfere with the signals from the GPS satellite constellations that are required to determine their position accurately. The following are some examples of poor AeroPoint placement: 

• Next to water (signal reflection off the surface) 
• Underneath, on top of, or near metal structures (signal interference) 
• AeroPoint upside-down (signal interference) 
• Underneath power lines (signal interference) 
• Next to trees and buildings (signal obstruction) 
• In deep grass or shrub (poor indication of the surface)  

The version of AeroPoints you use will determine the minimum required time to collect data to produce the most accurate survey. The requirements are slightly different if you are using a mixed fleet of AeroPoints.

The capture time required to acquire a GPS fix

AeroPoint 1s

Capture time: minimum of 45 minutes
PPK Drone Flight time: minimum of 10 minutes

AeroPoint 2s

Capture time: minimum of 10 minutes
PPK Drone Flight time using the Propeller Corrections Network: minimum of 10 minutes
PPK Drone Flight time using the Known Point Method: minimum of two minutes

Local Coordinate Systems

For sites with local coordinate systems, one of your AeroPoints needs to be placed on a point with known coordinates referenced through your coordinate system of choice. When processing data, you’ll need to provide us with a calibration file (.JXL, or .GC3) of the site. 

1. Place the AeroPoint stencil's center precisely over the known point.

2. Spray-paint the corners.

3. Place the AeroPoint on top of the painted stencil and turn it on.

Propeller Corrections Network

If you don't have known points surveyed for your site already, you can rely on the Propeller Corrections Network. This means we can provide accurate corrections for your site as long as it exists within the Network. 

Linear Flights

Flying linear projects with the PPK workflow is slightly different than normal flights. You can learn more about best practices for linear flights by reviewing our article How to Plan and Fly Corridor/Linear Projects with the P4RTK, or How to Plan a Linear Mission Using DJI Pilot 2.

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.