I have been reading about fly aways and loss of a GPS signal and wonder if anyone has tried to switch the GPS off when this happens to take full control of the H? I have an older quad and anytime I lost a GPS signal all I did was switch to manual mode and safely brought the quad back in. Is this even possible with the H?
GPS loss question
- Thread starter Raydee38
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PatR
Premium Pilot
That has been discussed and found to work as long as the only issue is GPS. Losing GPS in and of itself a non issue because the system essentially reverts to a type of Angle mode not being augmented with GPS. The aircraft is guided by the operator and providing the operator understands how to fly there's no problem. The operator that tries to use RTH once GPS has been lost is another story. They are telling the aircraft to go to a place it cannot find, somewhere will it go?
Next thing is getting to the GPS electronic on/off switch quickly. It's likely many are not all that familiar with their ST-16 screen and will be slow to turn the GPS off or fumble around seeking the correct function button to push.
Realistically I doubt loss of GPS is the cause of fly aways. My suspicion has them caused by a code conflict with the compass, and the compass has proven to be less robust than it should be.
Next thing is getting to the GPS electronic on/off switch quickly. It's likely many are not all that familiar with their ST-16 screen and will be slow to turn the GPS off or fumble around seeking the correct function button to push.
Realistically I doubt loss of GPS is the cause of fly aways. My suspicion has them caused by a code conflict with the compass, and the compass has proven to be less robust than it should be.
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I had a flyaway flying without GPS, my H suddenly went from about 1m to 60m full speed and then started drifting away with the wind, I had a bit of control for a moment and lost it again and the H went downwind.
Before this I had compass warnings and it happened right after a low voltage warning. Now I have my balance charger working and I will get new batteries and take good care of them. No more flying till I get the voltage warning, at least not intended...
Before this I had compass warnings and it happened right after a low voltage warning. Now I have my balance charger working and I will get new batteries and take good care of them. No more flying till I get the voltage warning, at least not intended...
PatR
Premium Pilot
A little additional support for my suspicion the compass unit is the root cause of fly away's, not the GPS unit.
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rdonson
Premium Pilot
I don't know. I consulted with @Steve Carr on my flyaway. The telemetry showed a loss of GPS when it took off for a tree and I had no control and no time to turn GPS off. I've since replaced the GPS module as I have no other ideas/options and I'm not looking forward to another flyaway.
The big question for me is WHERE IS THE COMPASS? Is it a replaceable part? Is it part of the GPS module?
I'm also hoping that the ARM processor chips in the TH and the ST16 are powerful enough to do everything asked of them.
The big question for me is WHERE IS THE COMPASS? Is it a replaceable part? Is it part of the GPS module?
I'm also hoping that the ARM processor chips in the TH and the ST16 are powerful enough to do everything asked of them.
rdonson
Premium Pilot
Thanks, @Steve Carr !!!! I certainly feel better now. I've had no issues since replacing the GPS module and I'll continue to keep my fingers crossed.
rdonson
Premium Pilot
@Steve Carr @PatR I'm still curious though about the shield that sticks to the top of the upper shell above the GPS module. What purpose does that serve?
The main reason is to stop electrical interference from getting to the GPS module from the circuits and motors. You also find all of the wiring bundles have been twisted to reduce interference. I'm considering doubling up on the shield the next time I open it up provided there is room to do so.
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rdonson
Premium Pilot
Steve, I understand the desire to reduce or eliminate electrical interference but I’m curious how to accomplish that without diminishing GPS signals or interfering with the compass.
When I replaced my GPS module it sure seemed like there was plenty of room available to double up on the shield.
When I replaced my GPS module it sure seemed like there was plenty of room available to double up on the shield.
If I can find the same type being used on the H it would be my preference.
I planned to simply double up on the foam foil covering the underside of the top shell. The GPS antenna is located directly under the flat area and of coarse the compass is located there as well. Perhaps it won't have any affect on the GPS, but it's possible it may benefit the compass. I suspect that @PatR may be correct in thinking the compass may actually cause more problems than the GPS.
In any case, it's an easy test and can't hurt to check it out.
Johnno has been experimenting with placing the GPS/compass unit outside the shell and isolating it better against interference.
Seems he has had good results in GPS stability and smoother, more stable, flying characteristics.
Seems he has had good results in GPS stability and smoother, more stable, flying characteristics.
rdonson
Premium Pilot
When I purchased a new upper shell for the H it came with a new shield that needed to be installed. I’d bet that Terrestrial Imaging would sell you a new upper shell with a shield or perhaps just the shield.
Had a flight today and the Gps had a drop out and then the compass calibration warning massage came up So just re-calibrated and it settled down as good as gold which was a bit odd as i only did it two days ago .
Me thinks i mite just do it every time
Now as to the Shielding idea you can get sticky copper sheet only a 10th of a mm thick which is ideal for shielding .i used the same on an old gopro to cut down on interference and no real noticeable weight on Walkira quads worked a teat
Me thinks i mite just do it every time
Now as to the Shielding idea you can get sticky copper sheet only a 10th of a mm thick which is ideal for shielding .i used the same on an old gopro to cut down on interference and no real noticeable weight on Walkira quads worked a teat
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Yes sure Good old Amazon
https://www.amazon.co.uk/gp/aw/d/B0...lding+tape&dpPl=1&dpID=41MVNYbkQYL&ref=plSrch
rdonson
Premium Pilot
Thanks! A quick look shows it available on Amazon US for $8.73.
https://www.amazon.com/Andoer-Coppe...pID=41MVNYbkQYL&preST=_SY300_QL70_&dpSrc=srch
https://www.amazon.com/Andoer-Coppe...pID=41MVNYbkQYL&preST=_SY300_QL70_&dpSrc=srch
PatR
Premium Pilot
Copper foil is not used for just a noise or RF shield, it's also used at the same time as a ground plane which can improve reception and positional accuracy. Such use is very common on government grade UAV's.
Bear in mind GPS is more for maintaining a position and relaying positional information for navigational purposes. Remove GPS from the equation and an aircraft will still fly just fine as long as command and control communications are maintained. We don't even need a compass to maintain aircraft control, although once the compass is removed from a system there's nothing for an auto pilot to use to maintain heading guidance.
Bear in mind GPS is more for maintaining a position and relaying positional information for navigational purposes. Remove GPS from the equation and an aircraft will still fly just fine as long as command and control communications are maintained. We don't even need a compass to maintain aircraft control, although once the compass is removed from a system there's nothing for an auto pilot to use to maintain heading guidance.
Good point. As I've thought about shielding I've become more interested in the compass than the GPS. The compass warnings seem to occur lower than 30' and when raising and lowering the gear. When reviewing telemetry, error code 32 is common even though the duration is short of a warning. It would be interesting to see if additional shielding would reduce the number of 32 errors.
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