What drives the length of time it takes for the Spark to connect to GPS Satellites?
I took a flight 2 days ago and it took several minutes to establish a stable GPS connection. It had been in ATTI mode for a few minutes, then it finally found 7 satellites went into GPS mode. At that point the software was telling me it was OK to take off but I hesitated because the signal strength was only at 2 bars. After another minute or so it finally picked up 10 satellites and signal strength increased to 4 bars, so I felt better about flying. Battery strength was down to 88% at takeoff. Weather conditions were clear, temperature was in the mid 40s. I took another flight the next day, and connected to 10 satellites almost immediately. Weather conditions were the same.

I usually get 12 satellites within a minute...you can go to an app called UAV Forecast that will tell you how many satellites are available for your specific location and time.

Rustic17 Posted at 2018-3-12 14:35
I usually get 12 satellites within a minute...you can go to an app called UAV Forecast that will tell you how many satellites are available for your specific location and time.

Thanks for mentioning the UAV Forecast app. I checked it prior to the flight and there were 13 satellites available each day and the kp index was 2.

What is the Kp index and what numbers are good?

Rustic17 Posted at 2018-3-12 15:17
What is the Kp index and what numbers are good?

From the UAV Forecast app Help page: "The Kp index measures geomagnetic disruption caused by solar activity on a scale from  0 (calm) to 9 (major storm). Anything at or below 3 or 4 is usually safe for flying. The higher the Kp index, the more likely you are to have difficulties getting a GPS lock."

Time and distance from last flight plays a large factor in GPS connection times. Check out a couple of the following pages for more specific details.

http://ozzmaker.com/take-long-get-gps-fix/
http://www.gps-basics.com/faq/q0113.shtml

Kloo Gee Posted at 2018-3-12 18:28
Time and distance from last flight plays a large factor in GPS connection times. Check out a couple of the following pages for more specific details.

http://ozzmaker.com/take-long-get-gps-fix/

Interesting!

Thanks for the links. I'll check them out.

I thought anytime you restart your drone it will have to reacquire the satellites since your drone is restarting Why would time and distance have a effect on this since the drone has been powered off or restarted even if you replace batteries?

dji TO88 Posted at 2018-3-12 18:55
I thought anytime you restart your drone it will have to reacquire the satellites since your drone is restarting Why would time and distance have a effect on this since the drone has been powered off or restarted even if you replace batteries?

Did you read through the links I provided?  The second one actually provides a better explanation than the first one.

It has a section titled "Saving Time by Predicting which Satellites are Nearby" and "Saving Time by using Recent Ephemeris Data".

Also for clarification, this is a GPS behavior thing that is not specific to DJI or even to drones in general.

I had the an identical situation just yesterday. What kind of environment were you try to fly?

mattinhk Posted at 2018-3-12 19:39
I had the an identical situation just yesterday. What kind of environment were you try to fly?

I was in my back yard, which has plenty of open space. I've not traveled anywhere far with the Spark yet, but hadn't had it out in about 2 weeks, so the information in Kloo Gee's links made sense to me.