OneMatt
lvl.3
Flight distance : 155984 ft
Canada
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Charles Adams Posted at 2017-8-28 12:25
Hi DJI Susan, I'm hoping you can clear up something for me.
Page 12 of the manual says to "Please be vigilant when operating the spark in the following situations:" and then lists one of the situations as "Flying over water or transparent surfaces".
As I recall from my P3A, the issue has to do with the VPS and how it reacts to the reflections.
Spark VPS uses cameras to determine position and height. When a surface such as water is wavy, the reflections will confuse the position camera with motion, so it won't know how to hold a position. Similar, the waves and reflected light may create the illusion of gaining or losing altitude, causing it to potentially dunk into the water.
When a surface is transparent, it cannot see that surface to adequately determine height, and may get confused. Example: perfectly flat water on a pool, it may see through the water and decide the bottom of the pool is the ground, leading to splashdown.
Same reason why they advise against flying over snowy surfaces, as they lack contrast for the VPS to determine anything.
If you are flying above whatever the VPS max altitude is (8M? 30M?) the Spark uses GPS and barometer for position and altitude. Those sensors alone however are not very precise, so if you are 2M above the water, and the VPS is confused enough to revert to GPS/Baro, you may have a crash. |
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