Data Quality of AeroPoint Surveys

After an AeroPoint survey is processed, you can see information on the data quality of the capture for each AeroPoint used in the survey in the flight details. Flight details are accessed by clicking on an individual flight in your AeroPoints dashboard.

Each AeroPoint used in the survey will have an expandable details section. Under the QUALITY heading, there are four metrics that Propeller uses to determine the AeroPoint's data quality for that survey. 


Data points

This is the number of satellite observation logs that contain the recorded positions of the AeroPoint over the duration of the survey. Only one data point will be used when processing using the Known Point Method.

Points used

Not every data point is always used, so the Points used show the number of data points used with high certainty to determine the AeroPoint's global position.

Baseline distance 

Baseline distance is the distance between the AeroPoint and the correction source, whether you use the Propeller Corrections Network or the AeroPoint used to correct other AeroPoints.

Data variance

This measures how close or far the individual points are to the median of the set of points in an observation. 

The smaller the variance, the more accurate the results are. A large variance usually indicates something wrong with the observation (for example, the AeroPoint was disturbed during the observation or obstructed from viewing enough satellites). 

Suppose you are not receiving high-quality data (such as a low-quality fix on the AeroPoint). In that case, there are some methods you can use to improve the quality, such as collecting the AeroPoints in reverse order, leaving them out for a longer period before and after your drone flight, and ensuring that there are no metal objects within 30ft (about 9m) of the AeroPoint while it is capturing data. 

What Does a Low-quality Fix Mean for AeroPoint Surveys?

AeroPoints need a clear view of the sky above 15 degrees to guarantee good results. If this isn't the problem, the failures you see are most likely due to placing AeroPoints near obstructions such as trees or buildings or accidentally moving the AeroPoints during the survey.

Suppose you are certain that this has not happened. In that case, we can attribute the error to other sources, such as atmospheric conditions (effect of the ionosphere and tropospheric refraction, which may cause the distance to deviate from its true value); satellite geometry at the time of the AeroPoint survey (position dilution of precision); and other external factors which are out of our control. 

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 team may be able to help. You can contact our support team by clicking the support tab on the top-right pane of your user portal.