Collect GCP with my smartpohone

I ran some tests with Garmin 62sc and my smartphone, surprisingly my smarphone was more accurate than the garmin, about 1 - 2 meters standard error, is it better not to use GCP or use my smartphone to collect it?

It would be better to use GCP’s, but the problem you are going to run into with any GNSS collection that is not localized is that you are going to report either ellipsoid, geoid or orthometric height values. None of which are relevant to true ground.

Localization is a process that ties GNSS (lat/lon) values to a cartesian (flat plane X/Y/Z) coordinate system, but uses the elevation value derived from an on-the-ground vertical benchmark.

How are you verifying that you are getting 1-2 meter accuracy? The best thing you could do with a phone is to use an app that does observation averaging. If you let it sit there for at least 5 minutes then you will get meter accuracy. It’s very doubtful you will get anything better than that without PPK or RTK corrections.

If you are only really concerned with map to map relative accuracy (lining up) then check out this thread. Otherwise you are going to need another solution to get better GCP’s.


Used Gaia GPS (android app, IDK about IOS),collecteced the points using terrrain referrences (using garmin and smarphone) and exported to google earth to compare it.

Obs: I’m not seeking to perfect accuracy, just wanna get better results with GCP and smartphone, our company are main focus in envirommental studies, does not need tha accuracy

What do you mean by terrain references? Note that Google Earth reports orthometric heights at a 1m (at best) resolution. It is not ground-leveled with benchmarks.

Even though the phone point (precision) won’t be better than what is derived from the drone GPS and processing algorithms what meter accurate GCP’s will do is keep the surface from warping. As I explain in that other thread you can derive GCP’s from the first map flown and then all maps afterwards will be perfectly relative which suffices for most use-cases where people want to monitor movement, but starting with some kind of GCP values will be even better. All you have to do is put down some markers and locate them after processing. Even though the drone is reporting ellipsoid heights the fact that the drone is using a barometer the processing models according to +/- ground values based on your home point.

I did not understand, its better not use my phone to collect GCPs?

1 Like

Your phone will be better than just using information off of Google Earth or the first map as I mentioned in the other thread. Will follow that thread for the actual scenario.

1 Like