(I'm not sure if this is actually a software issue)

I just tried to fly my DJI Spark a while ago, and it didn't tell me anything about the RTH altitude that I have as default. Then, while i was on the air flying my drone, it suddenly went to ATTI Mode and started going on the opposite direction from where I was, luckily i could get my drone back to me safe. When I saw my cellphone, I noticed that it only had 10 satellites on a place where I had allready flown on the past with more than 18 satellites. I don't know what could be the problem. The last time I flew my drone at this exact location was on October 28th, so I can't understand how it could change in such a short period of time.

Any help would be nice. Thanks!

How many satellites does the spark need to see to keep flying in GPS mode?
Do think that 10 would be enough....or ?

cheers Hans

JJBspark Posted at 2017-11-12 11:29
How many satellites does the spark need to see to keep flying in GPS mode?
Do think that 10 would be enough....or ?

I'm not so sure, but I usually try to fly it with more than 10, but this time the maximum number of satellites that i got was 10. On my phone it said that it wasn't flying with GPS.

JJBspark Posted at 2017-11-12 11:29
How many satellites does the spark need to see to keep flying in GPS mode?
Do think that 10 would be enough....or ?

I would recommend you take the GPS signal as reference. Even if there are over 10 satellites, the compass can be affected by interference with weak GPS signal. In this case, do not fly your drone.  

How about the GPS signal? Please ensure that your drone fly in a wide place without interference and most channels in the wifi image are green. I think something bothered your compass. Here are some advice on flight environment.

The GPS satellites are in medium orbit.  The satellites over you change constantly as they travel by your location.  I think you need three satellites for a ground location and four satellites for a location above the ground as far as navigation goes.

DJI Elektra Posted at 2017-11-12 18:29
How about the GPS signal? Please ensure that your drone fly in a wide place without interference and most channels in the wifi image are green. I think something bothered your compass. Here are some advice on flight environment.

Hi Elektra,

There must be a minimum of satellites to calculate the position (4). Ofcourse those received signals should be strong enough and steady. Can imagine that the software needs, lets say 6 for security, satellites to enter GPS mode and less than 6 to go into ATTI mode. Can you be more specific?

Don`t understand your saying about the need of a lot green wifi channels. In an other post you wrote that in the wifi AUTO mode the spark will choose the best signal and during flight will not change to an other signal. That means that 1 green wifi signal (thus the best one) is enough to connect and fly the Spark.

Cheers
Hans

JJBspark Posted at 2017-11-12 23:50
Hi Elektra,

There must be a minimum of satellites to calculate the position (4). Ofcourse those received signals should be strong enough and steady. Can imagine that the software needs, lets say 6 for security, satellites to enter GPS mode and less than 6 to go into ATTI mode. Can you be more specific?

For your first question, usually, the drone needs at least 6 satellites to record the home point. Speaking of green channel, if you enter the wifi setting and most of the channels are red, it means that the signal is unstable and there is interference.

Keep in mind that GPS/GLONASS satellites are in orbit and are constantly moving, so the number of available satellites visible from your location can be potentially changing all of the time.  I mention this to clarify that just because you had 18 satellites last month when you flew, doesn't mean you can expect that same number the next time.  In fact, had you flown a couple hours later, the number of satellites available in that same location on that same day likely would have been different.  

DJI's drones such as the Spark utilizes a combination of GPS and GLONASS satellites.  

GPS = US based positioning system
GLONASS = Russian based positioning system

Here is a site you can use to predict the number of satellites available based on your position for a given day:
http://satpredictor2.deere.com/lookup

Note that one of the variables they use in their predictions is an elevation mask.  This is the angle from the horizon for satellites in which GPS devices essentially can't use.  Note that your location will be affected by objects on your horizon such as mountains, buildings, trees, etc.

Also, I think many of us would be interested to learn from your experience.  Would it be possible to upload your Flight Record to the following site and then post the resulting URL here?

http://www.phantomhelp.com/LogViewer/Upload/

Kloo Gee Posted at 2017-11-13 06:14
Keep in mind that GPS/GLONASS satellites are in orbit and are constantly moving, so the number of available satellites visible from your location can be potentially changing all of the time.  I mention this to clarify that just because you had 18 satellites last month when you flew, doesn't mean you can expect that same number the next time.  In fact, had you flown a couple hours later, the number of satellites available in that same location on that same day likely would have been different.  

DJI's drones such as the Spark utilizes a combination of GPS and GLONASS satellites.  

Informative, thanks!  I live in the Smoky Mountains of Western NC.  So I almost always am surrounded by higher peaks. (some 6000 ft. +)  Very seldom can  I access more than 7 satellites for GPS on my Spark or on my P4.  Your post explains this very well.

mtnlandpix Posted at 2017-11-13 06:57
Informative, thanks!  I live in the Smoky Mountains of Western NC.  So I almost always am surrounded by higher peaks. (some 6000 ft. +)  Very seldom can  I access more than 7 satellites for GPS on my Spark or on my P4.  Your post explains this very well.

Eek, only 7 satellites regularly is a bit rough!  Does it go into GPS mode?  If so, does it stay there or does it flip to ATTI mode regularly?

No it goes into GPS mode and records the home point.  However, it usually takes about 1 to 2 minutes to access enough birds to go into GPS mode.  I have never had a problem going into Atti mode after the drones become airborne.  They usually pick up another bird or two when they gain a bit of altitude.  The only real issue is using up battery life while waiting for GPS mode.

JJBspark Posted at 2017-11-12 23:50
Hi Elektra,

There must be a minimum of satellites to calculate the position (4). Ofcourse those received signals should be strong enough and steady. Can imagine that the software needs, lets say 6 for security, satellites to enter GPS mode and less than 6 to go into ATTI mode. Can you be more specific?

Note that your receiver picks up both glonass and gps, you need 6 satellites to fly so to be safe and to insure you at least 6 of either gps or glonass then safe flying starts at 11 satellites.

Kloo Gee Posted at 2017-11-13 06:14
Keep in mind that GPS/GLONASS satellites are in orbit and are constantly moving, so the number of available satellites visible from your location can be potentially changing all of the time.  I mention this to clarify that just because you had 18 satellites last month when you flew, doesn't mean you can expect that same number the next time.  In fact, had you flown a couple hours later, the number of satellites available in that same location on that same day likely would have been different.  

DJI's drones such as the Spark utilizes a combination of GPS and GLONASS satellites.  

I'll try... I've never done that

Kloo Gee Posted at 2017-11-13 06:14
Keep in mind that GPS/GLONASS satellites are in orbit and are constantly moving, so the number of available satellites visible from your location can be potentially changing all of the time.  I mention this to clarify that just because you had 18 satellites last month when you flew, doesn't mean you can expect that same number the next time.  In fact, had you flown a couple hours later, the number of satellites available in that same location on that same day likely would have been different.  

DJI's drones such as the Spark utilizes a combination of GPS and GLONASS satellites.  

http://www.phantomhelp.com/LogViewer/1NW9XG5VWYQZW5PMHVDD/

not sure if this was what you meant... but this is how I flew that day...