Does anyone have specific information about how the Spark fixes its position using satellites?
I have read on here that it uses both GPS and Glonass satellites.
I have also read that Spark needs a minimum of 6 GPS OR 6 Glonass satellites for a satisfactory fix. I presume then, it has separate solutions for both systems and since the minimum number to establish a unique fix is 4 satellites I presume some degree of redundancy is needed.
The Spark only tells you the total number of satellites being received so logically we need to see a minimum of 11 satellites before being certain of a good position from one or the other.
What is not mentioned is the geometry of the satellites. Are they near the horizon at the time you fly, or more to one side of your AC than the other? Also they are obviously moving and changing position all the time.
What is going through my mind is, once you have taken off, is it possible/likely that you can go from a strong position fix to a bad position fix by losing a satellite due to an obstruction e.g. a building or getting a reflected (multipath) signal.
Could this explain any of the “fly aways” we read about?
Personally I check on UAV forecast to see number of satellites. I tick and untick the “show Glonass “ box to see which satellites will be available. I am surprised to find that there are times in the day when flying is not recommended. There are plenty of other sites which show the actual geometry but I am not quite that anal to check them every time I fly.
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