Lost GPS connection, H started "jerking around"

[Texy]

My grandson and I were out on a walk and had the H flying in Watch Me mode just for fun. Suddenly I get a low battery warning and a lost GPS message and the H started to freak out a little bit, almost doing a herky-jerky spiral or something. It was only about ten feet off the ground at the time. It rescued itself and I landed it to change the battery, but I would have power cycled it even if it didn't need a battery. We had just gone under a large tree, but prior to that we had acquired 13 satellites, so I don't think that was it. Also, my Zerotech Dobby could not acquire enough sats for autonomous flight yesterday. Something going on with GPS over Texas maybe?

 

[ricmitch]

https://www.navcen.uscg.gov/pdf/gps/gpsnotices/GPS_Interference.pdf

 

[PatR]

In addition, pay more attention to the battery level to avoid entering the low voltage warning mode. Land and change batteries before that. That battery warning is telling you the battery has reached a dangerously low level that needs attention NOW. It's not a warning function to establish how long you can fly.

Depending on what maneuvering was necessary to maintain "Watch Me" the battery may have been too low to provide the current required for the maneuvers. Various components and systems in the H have their own voltage/current minimum requirements and it is possible for one or more of them to be starved of power and render them unreliable.

 

[JulesTEO]

M... but prior to that we had acquired 13 satellites, so I don't think that was it.

I feel 13 sats is too low for a safe GPS flight.

Personally, when flying in GPS mode I won't take off until the unit has at least 18 sats. 20 is the ideal, and the most I'm willing to do (expectant of possible GPS loss) is 17 sats.

If the unit doesn't lock to the minimum of 17 after a few minutes I reboot until it reaches said numbers.

Greetings!

 

[Texy]

What do you do after more than 20 minutes of waiting and you still only get 13?

I fly with GPS turned off sometimes for the speed. It's really fast. Like almost 60 MPH fast.

 

[PatR]

If I waited for a 17 or 18 satellite GPS solution I would be changing batteries before ever leaving the ground. In 14 months of flying the H I don't recall ever seeing the number 20 on the screen except as an altitude.

 

[JulesTEO]

What do you do after more than 20 minutes of waiting and you still only get 13?

I fly with GPS turned off sometimes for the speed. It's really fast. Like almost 60 MPH fast.

If my units don't show enough sats after 5 - 7 minutes then that's about as many as they will show at that moment. I then restart the aircraft. Usually it takes no more than 5 minutes to reach 17+ but I've heard people who never get to such high numbers, I honestly wouldn't know why that would happen. (I mean, we are all on planet earth, arent we? )

 

[Shadowolf]

I take off with 10 but I also don't rely on gps. But I have to say today I got 20 sats. But I was at a lake wide open.

 

[Texy]

I'll be honest, I'm not that concerned about GPS when I fly unless I'm using features that require it. CCC, RTH, etc. require it, but I don't use those the vast majority of the time. I'm almost always flying manually. Is there really a reason to change this behavior? If so, then even slight cloud cover will ruin my day.

 

[FlushVision]

If I waited for a 17 or 18 satellite GPS solution I would be changing batteries before ever leaving the ground. In 14 months of flying the H I don't recall ever seeing the number 20 on the screen except as an altitude.

I regularly get 18 satellites almost as soon as the camera connects but keep in mind that on the EU firmware the connection time isn't fast. Indeed, seeing 20 satellites for me is not uncommon. I can't recall an instance where I've not managed to see 16 satellites by the time I'm ready to press the red button.

I've no good idea why some pilots have difficulty seeing satellites apart from mask(shadow) issues. Could it be the difference between EU and the American firmware? Could it be where you are on the planet? I can't answer this. A subject for another thread?

 

[Rayray]

If I waited for a 17 or 18 satellite GPS solution I would be changing batteries before ever leaving the ground. In 14 months of flying the H I don't recall ever seeing the number 20 on the screen except as an altitude.

You are joking, right?

 

[PatR]

Not at all. 14-17 is average across 2 states with 2 H systems and not concerned about that at all.

Flying GPS assisted auto pilots in UAV's since 2005 I've learned that having a great many satellites in view is not nearly as important as having 6 or so in view for a long time. More satellites refines the position fix but there still remains some level of positional error that persists while the vehicle is continuously moving. My need of GPS likely differs most of the time from what others want though. Primarily,I need to to locate my H if I lose it and for RTH to function if I ever need it. Unless geo tagging is necessary for some other commercial function I'm not concerned about satellite counts until they fall to <10.

 

[Rubik]

I'll be honest, I'm not that concerned about GPS when I fly unless I'm using features that require it. CCC, RTH, etc. require it, but I don't use those the vast majority of the time. I'm almost always flying manually. Is there really a reason to change this behavior? If so, then even slight cloud cover will ruin my day.

Boy, you don't live in the Pacific Northwest where cloud cover is the norm. Though, lots of sun lately. I'm glad clouds don't seem to effect GPS.