Newbie - GPS / Failsafe/ Setting home

[cgcrute]

Patiently waiting for the bulk of my parts to arrive and I';ve been playing with the board. I';ve a question I can';t find answered anywhere.

I';d like to employ a failsafe for obvious reasons but cannot find any information whether you can configure it to automatically set ';home'; to be the Arming location or do you HAVE to manually set it?

Many thanks, in advance

[teslahed]

You have to use your radio with your flight controller to set return to home failsafes on multiwii.

In the multiwii config code you can set the failsafe to make your quad go to auto-level then land (wherever it is) but it will not return to home first.

You would have to set things up so that switch high is return to home off, switch low is GPS return to home, auto-level, altitude hold, magnetomer on, and your radio so that when it loses signal it defaults to signal low. I am not sure if this would be possible with your radio setup or not.

[cgcrute]

You have to use your radio with your flight controller to set return to home failsafes on multiwii.

In the multiwii config code you can set the failsafe to make your quad go to auto-level then land (wherever it is) but it will not return to home first.

You would have to set things up so that switch high is return to home off, switch low is GPS return to home, auto-level, altitude hold, magnetomer on, and your radio so that when it loses signal it defaults to signal low. I am not sure if this would be possible with your radio setup or not.

Thanks, I understand the tx/Rx failsafe bit. It';s the setting of the home location I';m curious about.

[Biffa]

As far as I can remember with the Crius, it sets home position on full GPS fix every time you power up.

[Hands0n]

The GPS_Home location is set when you Arm the flight controller.  Just remember when powering up to give sufficient time for the GPS to obtain a good 3D lock. Conventional advise is to wait three minutes before Arming and lift off.

[cgcrute]

The GPS_Home location is set when you Arm the flight controller.  Just remember when powering up to give sufficient time for the GPS to obtain a good 3D lock. Conventional advise is to wait three minutes before Arming and lift off.

Awesome, thanks for the advice. From memory you can tell if you have lock from the ';C'; light on the board can';t you? Mine seems a lot quicker than 3 minutes, or does a good lock take longer?

[Hands0n]

Yes - the C light says you have a GPS lock.  If you watch it in the GUI you may be able to see it go to 3D lock a short while after 2D. 

Also, if you have the newer CN-06v2 board it will successivly GPS lock quicker as it retains the last location before power off in its on-board memory.  I went from a CN-06v1 to a CN-06v2 and it locks on quicker and is way more accurate on the v2.

[cgcrute]

Yes - the C light says you have a GPS lock.  If you watch it in the GUI you may be able to see it go to 3D lock a short while after 2D. 

Also, if you have the newer CN-06v2 board it will successivly GPS lock quicker as it retains the last location before power off in its on-board memory.  I went from a CN-06v1 to a CN-06v2 and it locks on quicker and is way more accurate on the v2.

Mines a V2 (only arrived 2 days ago!), it';s accuracy seems incredible, it pin-pointed it';s location down to a couple of metres even though I was indoors. I';ve not tested it outdoors yet as the power components have yet to arrive so I am reliant on USB power!

[Hands0n]

If you want to have play, and you have the right cables, you should hook the CN-06v2 up to uCentre (download it from here http://www.u-blox.com/en/evaluation-tools-a-software/u-center/u-center.html ).  I saw it state that the GPS accuracy got down to 0.8 metres  - in the book it is claimed to be accurate to 2.5m, probably a conservative figure for marketing purposes.

[cgcrute]

If you want to have play, and you have the right cables, you should hook the CN-06v2 up to uCentre (download it from here http://www.u-blox.com/en/evaluation-tools-a-software/u-center/u-center.html ).  I saw it state that the GPS accuracy got down to 0.8 metres  - in the book it is claimed to be accurate to 2.5m, probably a conservative figure for marketing purposes.

Thanks, I';ll have a look although I';m guessing it will involve another lead?

[Hands0n]

Thanks, I';ll have a look although I';m guessing it will involve another lead?

Err, yeah, probably, and a TTL to USB adapter too (always worth having for a few quid spend). But yeah, it will.

[cgcrute]

Err, yeah, probably, and a TTL to USB adapter too (always worth having for a few quid spend). But yeah, it will.

Thought it may... I';ll def check it out at some point but I think my bank manager would not be pleased if I spent anything else on this build!!

Are there any useful settings that can be messed with or is it a curiosity thing? (that doesn';t rule it out btw ;-)   ).

[Hands0n]

Typically you need uCentre, cable and TTL/USB kit to reconfigure the uBlox GPS for speed and GPS strings sent to the flight controller where it is an APM or Megapirate-NG firmware.  Out of the box the GPS runs at 9600bps (the FC needs 38400bps) and a full set of GPS strings. 

The tool and cable are often useful for other purposes also where you need USB to Serial which a lot of FC accessories use.

[cgcrute]

Typically you need uCentre, cable and TTL/USB kit to reconfigure the uBlox GPS for speed and GPS strings sent to the flight controller where it is an APM or Megapirate-NG firmware.  Out of the box the GPS runs at 9600bps (the FC needs 38400bps) and a full set of GPS strings. 

The tool and cable are often useful for other purposes also where you need USB to Serial which a lot of FC accessories use.

That';s odd, mine works fine out of the box. How do I check the baud rate?

[cgcrute]

Just looked in the sketch and it';s set to 38400.

[Hands0n]

I didn';t originally have CN-06, it was some other brand of uBlox GPS so I had to get in there :-) I suppose the CN-06 is ready set up. I still had to run in that script to change the GPS data chiming to the FC. It doesn';t matter if you don';t but the additional data just takes up bandwidth.

Sent from my C6603 using Tapatalk 4

[orfordness]

My ublox from rctimer has worked straight from the pack, I';ve not adjusted anything and i';m getting 0.8m accuracy...

working on a "is not broke don';t fix it " policy!

Steve

[robshaw]

My ublox from rctimer has worked straight from the pack, I';ve not adjusted anything and i';m getting 0.8m accuracy...

working on a "is not broke don';t fix it " policy!

Steve

How are you measuring your accuracy to 0.8m?

[QuadBod]

That';s odd, mine works fine out of the box.

It will, but it';s chucking a load of extraeous data at your flight controller, which then has to pick through it all for the useful stull. You aslo risk random repositioning in flight and on RTL due to SBAS shift if the first SBAS update is recieved after take-off.

Best to configure correctly for multi-rotor use:

http://www.multi-rotor.co.uk/index.php?topic=1177.0

(Can we get that pinned at the top of the AIOP section?)