[Visesh Lal]

Good day all, I am new to the hobby, only just started trying to set up the GPS so I apologies for my nube-ness, and I have looked around a bit on the forum and did not see any existing discussion on my pblm.... if it exists and I missed it, again, apologies. 

I am using the Revo board and a YKS Ublox Upgraded NEO-7M High Precision GPS module. Everything sets up fine, the GPS unit is recognized, picks up satellites, set home position...although no map shows up the coordinates seem to make sense.

But, when I select position hold in one of the flight modes, the cc3d will not arm,I see the leds responding to the mode swich changes on the transmitter, but it will not arm, and when I select Navigation INS13, everything on my tricopter freezes, the servo which normally responds when unarmed, does not.... Anyone else have similar issues.. or am I missing something, I followed the setup as described on librepilots's site. Thanks for any help!

[Mateusz]

To begin with, CC3D has no navigation capabilities. You must be talking about Revolution board, it's a different hardware.

Software won't allow to arm in any GPS flight mode for safety reasons. Of course its not completely foolproof, but it's not a toy that works plug & play.

You have to read and learn how to set it up, and calibrate properly. It matters how you build copter, and how you configure and calibrate. If your health alarms are not green all the time (temporary orange is not good, must be green all time), horizon is not flat and attitude scopes have any sign of oscillations it won't fly. Well it will do something but you don't want to hurt yourself or anyone.

Also GPS must be first left to charge super-capacitor, powered for ~15min at clear sky to update almanac before first flight. It lasts then for 5-6h after disconnecting battery. Most GPS units dont use battery but super-capacitor. So doing that before first flight each session is needed. Otherwise it may have poor perception and pick too few usable sats.

I suggest to read Wiki, and learn first basics, start slow with basic Complementary mode, flying it, then trying by small steps more advanced modes, far from people/buildings, but knowing what you do. Be sure your failsafe works and powering off radio drops copter down. Not being able to arm is a safety feature.

[Visesh Lal]

Appreciate the response, I have been digging up on forums and YouTube. I setup the gps unit itself, went through all the configs as per the Librepilot guides, but still nothing... I am picking up all the satellites, but when I select go to home the coordinates look off.. No map comes up... And when I calibrate the board the attitude indicator and animation of the craft is just going mad. Once I reset everything without any gps settings it works fine... Well my digging and trials continue, I'll be sure to post my results... Thanks much...

[Major Tom]

http://m.banggood.com/Mini-Ublox-Neo-6M-GPS-For-CC3D-Revolution-Flight-Controller-wBuilt-in-Compass-p-1022655.html

I bought this neo-6m with a single serial plug from BG. It says it has a built it compass. It is configured for revo and does aquire sats but the mag alarm goes red.

Is it one without the mag attached to the cables? I haven't found much for info about how these particular units are wired. 

[Mateusz]

Neo-6M sounds good, it has only GPS sats, but maybe thats even better, you dont have spikes when jumping between different systems. It has good mast which wont rotate and looks small, maybe rode could be longer, but nice.

You must have 4 wires for serial (GPS) which are TX, RX, GND and VCC. Usually Magnetometer has 2 wires SCL (clock) and SDA(data) and is powered already from the GPS. So at least 6 wires. Does I2C communication occur (green status) with AuxMag ?

Did you calibrate it ? LibrePilot uses 3D Mag, which means it is also used to determine if aircraft is up or downward orientation.
Another thing is AuxMag must agree with Accelerometer on flight controller. So you must rotate it correctly by setting AuxMagBoard orientation. OP GPS v9 has by default correct orientation 0,0,0 but other Mags may be oriented differently.

[Major Tom]

The Neo-6m has only 4 wires going into the main serial port: red, black, blue, and orange. So I'm guessing it either doesn't have an internal magnetometer as advertised, or it's not wired? I'm confused.

I did go through the ACC, Mag, and level calibration. This board flies like a dream compared to my old KK2. I get great performance in complementary, but when I select INS13 I get SATs and the GPS alarm goes green, but the mag alarm goes green or orange. 

I have my S500 quad plugged into GCS now( inside) I have 9 sats. No color in my I2C alarm. Green on ATTI, STAB, GPS. But NOW my MAG alarm is flashing Orange to Green, sometimes settling on green - sometimes green when disarmed; and sporadically orange when armed and motors spinning.  I'm getting a subtle wobble in yaw and roll in my Flight Data Graphics of maybe 3 degrees, but my Compass Graphic seems to point to the correct directions as I rotate on yaw axis. The orange alarm when armed has me thinking the onboard mag is in use and not the external mag in the GPS.

I set velocity roam as mode 2 and went out briefly to give it a try, but as soon as I armed and took off( in attitude mode before switching on velocity roam the flight seemed off, pitching to the rear. Which seems consistent with mag/ACC interference.

Also, I just noticed that my quadcopter graphic on my map seems to be roaming around my front yard maybe 15-20 meters from its true position.

I really appreciate your response; I'm not sure what any of this means. Any idea what could be going on here?

[hwh]

If there are only 4 wires coming from that gps then you're not using a mag sensor in it if it has one.  Some people who've purchased gps units that have only 4 wires but say they have a compass have soldered two more wires to the gps and gotten the compass to work.  Some have found that the gps they purchased, despite the markings, didn't have the mag chip in it.  If you open the gps case and post a picture of the board inside someone here can tell you which you have.

The only readily available gps units that use one cable but still have a mag sensor are the DJI Naza gps units and their clones.

I don't see anywhere what version of the software you're using. The I2C external mag and Naza ones are only supported in the next branch of the code, the released 15.09 doesn't support them.  The only external mag supported in 15.09 and earlier is the Platinum (aka v9) gps and it's no longer made.

[Major Tom]

Thank you for the information.

I'm using the 15.09 release of gcs. I'll open up my neo-6m when I get a chance.

I'm wondering if there are any tricks to optimizing performance while using this configuration( gps + onboard mag). My quad is not small, so I might be able to reduce interference. But the unstable characteristics while using attitude mode in Ins13 troubles me.

[Mateusz]

Thank you for the information.

I'm using the 15.09 release of gcs. I'll open up my neo-6m when I get a chance.

I'm wondering if there are any tricks to optimizing performance while using this configuration( gps + onboard mag). My quad is not small, so I might be able to reduce interference. But the unstable characteristics while using attitude mode in Ins13 troubles me.

• If in doubts post a photo, but pretty easy to locate mag on pcb. It may have pads exposed or even routed tracks from mag to connector, but connector just has 4 wires.
• Mag must be green all the time, even single jump to orange is not good. Because mag calibration collects samples through the whole process, I found it better to press button 5 times, and on the last calibration step, just slowly turn aircraft in all directions and all possible rotations. This results in more accurate calibration.

Also your GPS must have up to date almanac before first flight, let it collect sats and recharge super-capacitor.  It's also good to check if baro is within reasonable range. Some Revo clones had problem with baro, but fixable easily.

[Major Tom]

Neo-6M sounds good, it has only GPS sats, but maybe thats even better, you dont have spikes when jumping between different systems. It has good mast which wont rotate and looks small, maybe rode could be longer, but nice.

You must have 4 wires for serial (GPS) which are TX, RX, GND and VCC. Usually Magnetometer has 2 wires SCL (clock) and SDA(data) and is powered already from the GPS. So at least 6 wires. Does I2C communication occur (green status) with AuxMag ?

Did you calibrate it ? LibrePilot uses 3D Mag, which means it is also used to determine if aircraft is up or downward orientation.
Another thing is AuxMag must agree with Accelerometer on flight controller. So you must rotate it correctly by setting AuxMagBoard orientation. OP GPS v9 has by default correct orientation 0,0,0 but other Mags may be oriented differently.

I opened up my Neo-6m with compass from BG. I am unable to identify the mag chip on the board. Hopefully someone here can help with that. I do see the pin out on the serial port on the gps has six pins but only four are utilized. It looks like the two unused are labeled "L" and "A." Seems to me that those two must be SCL and SDA. I guess I just need to plug in some wires and find an appropriate plug for I2C when external Mag support becomes a thing in Librepilot.

I finally had a sunny day to experiment with Ins13 a little more. I ran another Mag calibration using the "click 5 times, then rotate on all axis, return to level, then save" method. The Mag alarm stays green now, and after letting the quad sit under battery power for a few minutes before plugging in usb to my PC, I aquire 10 Sats and am able to arm. However, with INS13 enabled I cannot achieve stable flight in attitude mode without constantly fighting drift. It's even more erratic in velocity roam mode.

My Baro seems good in altitude vario, so I'm not sure if that is a problem.

I'm curious, if and when a mag experiences interference, will the mag alarm always react? It's been stable green while motors are running. I have my ESCs mounted on the arms and a solid 2 inches between the bottom of my revo board and my power harness and battery.

[Mateusz]

From the picture A983... Is the mag chip. So you have it. You are right about LA pins, just connector has no wires coming out from it two pads close to it might be also connected to L A pins, you can check with multimeter continuity. If that is the case you can easily solder two wires to thise pads or buy cable with 6 wires and connector.

First it is unlikely that your mag is oriented the same way as OP GPS v9, so you need to set its orientation in GCS. Second, you must calibrate with mags Both, but for use set AuxOnly. I would use internal mag just for reference to see if your aux mag is oriented correct. But then I would switch to using only aux mag. Calibration must be performed outdoors, far from metalic elements. Outdoors over oplink is important.

In the next branch there is mag wizard showing agreement between internal mag and aux, as well as percentage of error/disagreement. Its very helpful.

Both mag and gps can never ever happen to jump into orange.

The battery in your gps is super capacitor. It lasts 5-6h usually after charging up for ~15min. So before first flight give gps that time to fetch almanac since it may be outdated. Is it 10 sats used or in view ? In view its not saying how many sats are used. Maybe none ? Is gps also always green ? To get a lock only 1s of gps and mag being green is needed but if it jumps to orange later on you will still have lock, I doubt thats suitable for flying.

[rubberducky]

Hello,
i finished my revo setup with gps, mag and oplink, there is no alarm, all is green.

Now i want to fly with position hold and RTH, but i does not work.

I think i forget something in the configuration, but i cant find the problem.

Is here anyone who can help me?
Can anyone make some snapshots of a working gps

Thank you
jürgen from germany

[TheOtherCliff]

It is very important that you have green mag both on the ground and when flying, and that if you are using aux mag, and that you understand and set the mag "board orientation" correctly.  See the wiki article.

High current wiring pairs (and triplets) need to be twisted together.  Battery to battery connector, battery connector to PDB, PDB to ESC, ESC to motor.

RTH (we call it RTB) is an advanced topic.  Avoid it until you get other GPS flight (VelocityRoam mode) working.  Take off in Attitude mode and switch to VelocityRoam mode.  Stick in the middle it should be the same as PositionHold.  Be ready to quickly switch back to Attitude if your GPS mode starts flying away.  Be ready for it !!!

It will not arm until you have set "Home Location".  It will not arm until the GPS and mag are both green.

It helps a lot to have telemetry so you can see what these are when flying.  A laptop with an OpLink telemetry module plugged in the USB will do this.