AeroPoints use data from several global navigation satellite systems (GNSS) to establish their position, including the GPS, GLONASS, and Galileo systems.
Obstructions near AeroPoints placed on the ground, such as fences, buildings, or vehicles, can block or reflect GNSS signals causing low-quality data that is difficult to process into accurate position data.
The latest version of the AeroPoints mobile app (version 1.5 for iOS and version 2.6 for Android) now includes a tool to check the quality of captured data in real-time to ensure Propeller can process it with high accuracy.
AeroPoints must be running firmware version 73 or higher to use the signal quality tool. The app works for AeroPoints running older firmware, but the signal quality feature is not available.
AeroPoints running firmware version 73 or higher now show the signal quality as an icon on the main list view.
Signal quality data, like all AeroPoints data shown in the app, is streamed over Bluetooth from the AeroPoint. Your mobile device must be in range of the AeroPoint (generally around 10m/30ft).
The compass rotation of the quality chart relies on the mobile device’s magnetometer. Nearby magnets or large metal objects can influence this. For an accurate compass heading, keep your device away from magnetic materials.
Using the Tool
Before capturing data, the AeroPoint will first measure the quality of the satellite data. This usually takes approximately 30 seconds.
Once the AeroPoint has detected enough satellites to confirm the data meets Propeller’s quality requirements, the satellite icon will turn green and no further action is needed.
If the data does not meet Propeller’s quality threshold, the icon will turn red, and a warning banner will appear.
Tap the warning banner to open the GNSS quality check tool. It displays a 360 degree measure of signal quality from the AeroPoint’s position. The chart will rotate as you move by using the compass in your mobile device to help you understand which areas have obstructions and which areas do not.
The chart updates approximately every five seconds, so improvements in GNSS quality show in real-time.
Once the AeroPoint has been moved, and the signal quality displays GOOD, restart data capture.
To restart the capture:
Ensure that you are in the area with GOOD GNSS signal.
Press the power button once to stop the current capture.
Press the button again to start a new capture.
The signal quality tool will appear at the top of the SURVEY tab of the AeroPoint detail view, if the data is low quality:
The signal quality tool can always be accessed from the AeroPoint’s DETAILS:
Using Skyplot View
The SWITCH TO SKYPLOT VIEW button underneath the signal quality chart opens an advanced mode showing each satellite's location in the sky and its signal quality. In addition, you can filter the satellites by constellation (GPS, GLONASS, or Galileo).
The skyplot view does not rotate with your mobile device’s movement.
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 firstname.lastname@example.org.