I thought I lost another Phantom

Learn to fly in Atti mode. When that happens just switch modes and keep in line of sight. Calibrate the compass in an open area. I fly my f550 in front of my condo unit from time to time and had issues with it in gps mode. I had to reach up and grab it once because I had no stick input then quickly switched to Atti mode to control it. It happens pretty quickly but if you realise it's drifting away, switch to Atti to disable the compass.
 
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Forgot to mention I have those issues every time I fly in front of my condo unit in gps mode but never in an open area. I have yet to fly my p3 in front of my unit because I know there's interference there.
 
Unlikely. What you're describing is GPS drift. It's a much bigger problem for absolute positioning.
http://www.gps.gov/systems/gps/performance/accuracy/

I stand by what I said. The GPS system is not entirely stable and it does experience natural, random fluctuations.

The government used to intentionally introduce random errors into the signal. Here is something from the gps.gov website:

What About Selective Availability (SA)?
During the 1990s, GPS employed a feature called Selective Availability that degraded civilian accuracy on a global basis.

In May 2000, at the direction of President Bill Clinton, the U.S. government ended its use of Selective Availability in order to make GPS more responsive to civil and commercial users worldwide.

The United States has no intent to ever use SA again.
 
http://www.gps.gov/systems/gps/performance/accuracy/

I stand by what I said. The GPS system is not entirely stable and it does experience natural, random fluctuations.

The government used to intentionally introduce random errors into the signal. Here is something from the gps.gov website:

What About Selective Availability (SA)?
During the 1990s, GPS employed a feature called Selective Availability that degraded civilian accuracy on a global basis.

In May 2000, at the direction of President Bill Clinton, the U.S. government ended its use of Selective Availability in order to make GPS more responsive to civil and commercial users worldwide.

The United States has no intent to ever use SA again.

Let's state some facts. With GPS, here's what causes horizontal drift and how the Phantom deals with it:
  • LOW SV COUNT: The number of locked SVs falls below a lower limit. The Phantom switches to ATTI for this reason.
  • GPS JUMP: Acquisition or loss of one or more low azimuth SVs with a low overall SV count resulting in a position "jump". The Phantom mitigates this by "fusing" its calculated position with IMU data. Doubtful anything more than 20ft is possible.
  • GPS DRIFT: Atmospheric anomalies cause changes in transit time from the SV to the receiver. This is gradual (takes place over several minutes) and is mostly corrected by ground based D-GPS corrections. The Phantom is barely influenced by this except when flying by absolute reference (e.g. waypoints).
As for SA, it was turned off in 2000. No idea how it is relevant to this discussion. The gov't doesn't introduce errors on purpose save for limited testing done in the desert at pre-announced times.
 
Thx for pointing me to your thread. There are many theories here but not any real analysis. Take your mobile device, extract the data, and let's see what really happened.

There are still problems with the flight stabilization algorithm which dji has not admitted to. The more real analysis we post, the more likely someone will look at these. I have not received yet any official (or even non official) response from dji on my issue, and im really curious to see the logs of your flight. I can help analyzing if you want to post your csv file.
 
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You're scaring me lol. I plan on flying in the same area but probably taking off from Eakins oval or somewhere along the Parkway. With all the apartment buildings there, there must be a hell of a lot of wifi signals :(
 
Again, Wi-Fi signals do not cause your Phantom to go out of control. Wi-Fi signals will cause a degradation of the overall signal quality which means your range will be shorter before you hit RTH.

When your Phantom is circling out of control as is the case with the OP, it is called TBE and it is because either the compass was calibrated incorrectly or it was exposed to something metallic at takeoff. Either way, it is not a flyaway. It is user error. And it is 100% avoidable.
 
Some examples:

nyc-flatiron.jpg

Can I ask how you find wind shifts between the tall buildings in the NYC skyscraper valley affects your flights, if at all?

Sorry for the brief hijack just saw pic of ares I'll be flying in and was curious.
 
Again, Wi-Fi signals do not cause your Phantom to go out of control. Wi-Fi signals will cause a degradation of the overall signal quality which means your range will be shorter before you hit RTH.

When your Phantom is circling out of control as is the case with the OP, it is called TBE and it is because either the compass was calibrated incorrectly or it was exposed to something metallic at takeoff. Either way, it is not a flyaway. It is user error. And it is 100% avoidable.

So if you were going to be flying in such an environment, would you calibrate your compass there or somewhere else?

What do you have to look for in that kind of environment?
 
So if you were going to be flying in such an environment, would you calibrate your compass there or somewhere else?

What do you have to look for in that kind of environment?

Don't calibrate in an urban environment. That's a recipe for disaster. You need to calibrate in the middle of a field with zero metallic anything nearby.

When you take off in an urban environment, a case is helpful to get it away from potential sources of interference in the pavement. And you should use an app that can measure μT. If you see fluctuations as you get close to the ground, find another spot.

Can I ask how you find wind shifts between the tall buildings in the NYC skyscraper valley affects your flights, if at all?

Sorry for the brief hijack just saw pic of ares I'll be flying in and was curious.

Wind is one of many factors. Flying in urban environments is really tricky. You need to build up to it.
 
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