GPS acquisition - Smart mode

[robnmi]

Hello TYH owners!

I possible have a similar GPS issue you are chatting here in this thread, but the drone is a bit different.

See the pictures attached!

It is a Yuneec Typhoon H on an F550 frame. I have built this only for fun, becase i had several spare parts and i was curious if this thing can fly again.
So, last year i tried with no camera and battery bottom mount. It flew well that time.

After a year i assembled a camera from scratch and mounted to this monster. A mounted the battery up but i think the gravity center is too high so i expected some misbehaviour!

On the first flight of this TYPHOONSTEIN creature was not a big succes. I made the compass cali, got green GPS lock and took off.
I hoovered in 2 meters high and i noticed the bird is drifting and does not hold its position. Hmm. I could manage this by hand. But when i pushed front then back the right stick it contoniusly flew back and i was unable to stop. So i hit the RED button.
Some props gone, but the frame unharmed! Fortunately i took off the CGO3+ camera before test flight.

So my asking is for you, what could cause this?
- GPS accuracy?
- GPS module shielding? There is a little piece of the original on the mount under the GPS.
- high center of gravity because of the high mounted battery?

Another remark: when i use angle mode on the ground i got GREEN GPS lock, when i switch to SMART GPS lost and says ACQUIRING...
Switcing to ANGLE brings back GREEN GPS lock, SMART loses GPS again...

Please tell me your opinions.

RoB from Hungary

p.s.: The log from this flight is displayed here: UAV Toolbox - Yuneec ST-16

 

[Steve Carr]

A problem with GPS would ordinarily affect both Angle and Smart modes. In your case perhaps it's actually related to the compass rather than GPS since both are mounted on the GPS module. Smart mode needs to know the true compass heading of the aircraft in order for the right stick to work properly. With that in mind, it appears the location of the GPS module may be too close the the screws and motor wire harness. The compass is located on the bottom of that board. Is it possible to raise the module higher for testing?

 

[robnmi]

Thank you for the idea Steve!

The mount for the GPS module is a little plastic priece, but the stand itself is an aluminium rod with metal screws at the ends. So i will try to remove theese and try again with proper shielding or raising much higher the GPS.

I will also get the battery back to bottom...

 

[Steve Carr]

Don't use any steel screws near the module. The original screws in the GPS module are brass. So brass or alum is fine. Steel is not.

 

[robnmi]

Don't use any steel screws near the module. The original screws in the GPS module are brass. So brass or alum is fine. Steel is not.

Well, i thought the black shielding tape will help, but not... will remove the steel screw, and use only double sided tape.
Thank you for the advice!

 

[robnmi]

I think a found the explanation of the crash. Why did the drone moving backwards and not reacting to any stick input?

I put in the GPS module the arrow facing forward! But it means the back of the drone, it is turned by 180 in the firmware....

It is SURE! It was my fault!

I watched my video from last year made after assmebling and testing... And then.. i put in the right way! And flew well

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[Steve Carr]

i put in the right way! And flew well

Good find.