Labroides
Core User of DJI
Flight distance : 9991457 ft
Australia
Offline
|
pedro05 Posted at 2018-6-25 05:46
GPS altitude is the altitude supplied by GPS without adding or subtracting anything - Well, how do you know? I am asking the question because I want to hear from DJI.
I checked another jpeg, which I took at home on another day before the drone had taken off. It has RelativeAltitude 0.0, GPSAltitude 3.0, actual altitude above sea level 50m. I would accept a GPS error of 50m in altitude, but not one of 120m. Hence I think my suggestion is more likely to be true. But I can check this by going to a realy high place and taking a photo on the ground.
Well, how do you know? I am asking the question because I want to hear from DJI.
Good luck waiting for DJI to answer, it's unlikely to happen.
The moderators here don't have the knowledge to answer and no-one else from DJI will.
Even if they did, the answer is as likely to be wrong as correct
How do I know???
I've had over 20 years using GPS professionally, and I'm a professional drone photographer.
I answer hundreds of enquiries here to help users like you but if you you think you know better ......
I've given you accurate information and a way to check it.
Check photos taken on the same point on a number of different days and you'll find the altitudes are all over the place.
You can't work out what's behind it from only one or two.
Whether you believe me makes no difference to me.
And if you're still skeptical and want something from another source, here's what Garmin have to say about GPS altitude:
Here's what Garmin have to say about GPS altitude accuracy and why GPS altitude data is useless.
How accurate is the GPS elevation reading?
GPS heights are based on an ellipsoid (a mathematical representation of the earth's shape), while USGS map elevations are based on a vertical datum tied to the geoid (or what is commonly called mean sea level). Basically, these are two different systems, although they have a relationship that has been modeled.
The main source of error has to do with the arrangement of the satellite configurations during fix determinations. The earth blocks out satellites needed to get a good quality vertical measurement. Once the vertical datum is taken into account, the accuracy permitted by geometry considerations remains less than that of horizontal positions. It is not uncommon for satellite heights to be off from map elevations by +/- 400 ft. Use these values with caution when navigating.
|
|