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GPS Hold, What am i doing wrong??

Posted: Sun May 24, 2015 11:05 am
by mr_fid
Hello

This may be a simple fix or may be something fundamentally wrong with my understanding of multiwii concept!

Basically I have set up GPS hold and when I flick the switch nothing happens. In fact I am not really sure if I have ever had any mode working!!

I know there is a lot of information on this forum, but is there something I should be doing? do I need to switch on something else when I turn on GPS hold?

currently I fly with the horizontal always on, but because I have no one to compare with I am not sure how good or bad my set up is, I have to continually apply small inputs on the sticks to keep the hex in one place, is this correct? what should I expect?

I have the following setup
CRIUS AIO PRO, with 2.4, CRIUS NEO-6 GPS V3.1 when I connect to the multiwii GUI I can see the gps working and I believe its all correct.
Thanks for any help or suggestions you may have.

Re: GPS Hold, What am i doing wrong??

Posted: Sun May 24, 2015 3:03 pm
by FengShuiDrone
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Re: GPS Hold, What am i doing wrong??

Posted: Sun May 24, 2015 8:45 pm
by mr_fid
Thanks for your reply, I really appreciate the time you have taken in your response.

From your list of things the only thing I could see I had got wrong was
Your GPS baud rate will be 57600. You can type in the speed if something else is already written. So when you're finished there your GPS baud statement should look like this #define GPS_BAUD 57600.
I had changed this to 115200 the same as the SERIAL_COM_SPEED. so I corrected that and just gave it a try in the garden....... I was only about 6' up and it was hard to say if it was working, it drifted about 10' before kind of coming back? but then went a different way. I need to find a space bigger than my garden!!!! its to late here in UK! so I will try again tomorrow and try and get some video. what am I expecting? should it stay very still?

Thanks Again

Re: GPS Hold, What am i doing wrong??

Posted: Sun May 24, 2015 10:06 pm
by FengShuiDrone
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Re: GPS Hold, What am i doing wrong??

Posted: Mon May 25, 2015 9:43 am
by mr_fid
I had another go this morning in the garden (two children prevented my escape) I still don't really seem to have a lock, or put another way I flick the switch and try not to apply any corrections but end up having to take control to prevent a crash. So I am really not sure if its doing anything.

Just to clarify
What Baudrate should the GPS unit be set to? I can change it in the u-center 8.10 software. (as original it was set to 115200)
should the #define GPS_BAUD be set to the same?
And What should I set the #define SERIAL2_COM_SPEED too?

Shouldn't they all be the same?

Re: GPS Hold, What am i doing wrong??

Posted: Mon May 25, 2015 12:22 pm
by FengShuiDrone
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Re: GPS Hold, What am i doing wrong??

Posted: Mon May 25, 2015 5:48 pm
by mr_fid
Hello
Again thanks for you information. I will read carefully once kids are in bed.
However I did get some kind of GPS lock, check out the youtube clip.
https://youtu.be/JI379hG04ZA

For the whole clip I am not correcting the movement.

I am not sure how to do youtube clips on here?

Re: GPS Hold, What am i doing wrong??

Posted: Mon May 25, 2015 6:06 pm
by mr_fid
And here are some pictures to show this really simple quad! The middle picture shows the different layers with a piece of copper clad board underneath the lid and another piece under the GPS.

The damage in the last picture was caused my the quad tumbling out of the sky. I don't know why it did it?
Image
Image
Image

Re: GPS Hold, What am i doing wrong??

Posted: Mon May 25, 2015 9:16 pm
by FengShuiDrone
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Re: GPS Hold, What am i doing wrong??

Posted: Mon May 25, 2015 9:38 pm
by mr_fid
Its definitely trying, can I get this better?

When I click the GPS Hold does it also lock to Baro? and MAG? it seems like it does.
The next Youtube clip shows the view from the copter at a good height, it also shows two crashes, which I believe are due to a faulty ESC?

https://youtu.be/X6q1FSCEScc

Re: GPS Hold, What am i doing wrong??

Posted: Tue May 26, 2015 1:09 am
by FengShuiDrone
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Re: GPS Hold, What am i doing wrong??

Posted: Wed May 27, 2015 4:41 am
by pihlerm
Hi,
you have to manually enable MAG and BARO modes (see multiwii conf) together with GPS_HOLD. 2.4 multiwii can work without MAG.
I had great problems with on-board MAG because of power cables that were causing magnetic field. Direction of compass varied with throttle up to 30 degrees.
I can see from photos that your power distribution is away from the FC, anyway you should check this (hold copter firmly in you hand or strap it down, then connect with USB cable, use multiwii conf or wingui to check compass as you turn battery off and compare with powering up and throttling to different speeds).
See that your magnetic declination for your location is set correctly.

Of course there are PID settings - but these are important more in windy conditions. Also check how much your GPS wanders- with wingui for example - depends on the chip, on solar storms, weather, ..