Problem with AQ M4 and GPS

Info and discussion about the autonomous Micro FC, suitable for nanos, micros and mini multirotors

Problem with AQ M4 and GPS

Postby aqv88888 » Wed Jan 20, 2016 5:14 pm

After a few minutes flight time with AQ M4 the copter sets strongly to the side and drifts away. The drift is too fast to control against. The horizontal accuracy is about 1.5. The problem sometimes occurs after 15 minutes, sometimes after 8 minutes.
On the picture can be seen that the M4 is about 1cm under the shield of the antenna.

In normal flight mode this behavior is never occurred.

Has anyone experienced a similar case?
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aqv88888
 
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Re: Problem with AQ M4 and GPS

Postby LPR » Wed Jan 20, 2016 6:41 pm

When it comes to GPS antennas, size matters. I find in need a GPS hacc of better than .800 to be sure I'll have good control in GPS controlled flight modes.

The small antenna your using will have a hard time getting that accuracy. You may have some interference from a telemetry radio or a wifi module that's causing your problems. A 35mm GPS antenna with a ground that is 3 times as big as the antenna will get you very good GPS reception but it's heavy.

Larry
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Re: Problem with AQ M4 and GPS

Postby aqv88888 » Wed Jan 20, 2016 7:10 pm

Thanks! - You're right, the large antennas are heavy. But I will try it.

Is there a way that M4 adjust so that the M4 is switched for example to manual flight mode, when GPS problems occurs?
In no case should they react so extremely.
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Re: Problem with AQ M4 and GPS

Postby LPR » Wed Jan 20, 2016 7:35 pm

Well with GPS if garbage is coming out of the GPS receiver you get garbage for control.

There's supposed to be a filter to keep the GPS from jumping very far but if the signal is poor the distance the GPS positioning is off may not be very far but it keeps changing and causing your copter to tilt in one direction and then in another.

My large quad with a M4 will have problems with a GPS controlled flight mode if I try to fly as soon as a get to a hacc of .6. If I wait another minute the quad will fly well.

If you fly on a day with bad GPS you will have control problems so you should always be ready to switch to manual flight mode. A few multicopters have the ability of switching to camera stabilization when GPS is not good. I hope we get that functionality added to the AQ flight controllers.

Larry
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Re: Problem with AQ M4 and GPS

Postby Max » Thu Jan 21, 2016 1:13 am

I've found that putting as much distance between the GPS antenna and the AQ/rest of the electronics (especially my FrSky telemetry Rx) as possible/practical makes the most improvement. Followed by a groundplane, which helps, but not as much as distance. I've used a 25mm patch on a 250mm M4 build which was worse than a simple dipole... until I moved it up as far as the cable would reach. I think the main reason the dipoles work as well as they do is that they tend to sit higher up just by design.

My 2c anyway.

-Max
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Re: Problem with AQ M4 and GPS

Postby aqv88888 » Thu Jan 21, 2016 9:00 am

Thanks, people!

@Larray:
Would it not be a solution to automatically jump to the manual mode when GPS is not good enough?
As it is now, it's dangerous near ground ;)

I'm going to do the next few days the changes to the GPS antenna.
Then I will report at this point.

Werner
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Re: Problem with AQ M4 and GPS

Postby aqv88888 » Thu Feb 11, 2016 2:27 pm

I have experimented with 12 mm and 25 mm ceramic antenna and a simple dipole with and without shielding plate.
The statement of Max I can absolutely confirm. A greater distance of the antenna from the electronics results better values in HA (less than 0.5). With shields I did not receive such values.

Werner
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Re: Problem with AQ M4 and GPS

Postby WoSchu » Fri Feb 12, 2016 10:09 am

After a few minutes flight time with AQ M4 the copter sets strongly to the side and drifts away. The drift is too fast to control against. The horizontal accuracy is about 1.5. The problem sometimes occurs after 15 minutes, sometimes after 8 minutes.
On the picture can be seen that the M4 is about 1cm under the shield of the antenna.

In normal flight mode this behavior is never occurred.


I've that problem also ...

Can I desactivate GPS in "Altitude/Position hold" - Mode ?
So that only "Altitude hold" is activ.
I'm also flying Microkpter-Systems and in that FC I only can activate "Altitude hold" (using the barometic sensor), without activating GPS ...
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Re: Problem with AQ M4 and GPS

Postby Simson » Fri Feb 12, 2016 11:44 am

If I remember right, that would be possible with the latest firmware, but unfortunately it's not yet released.

Here you can read more about unreleased firmwares:

http://autoquad.org/wiki/wiki/whats-new ... e-changes/
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Re: Problem with AQ M4 and GPS

Postby WoSchu » Fri Feb 12, 2016 1:54 pm

but unfortunately it's not yet released


Do You know, what time it will be released?
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