# Autopilot with Compass **URL:** \ **Category:** QGroundControl\ **Created:** [December 12, 2018, 10:45pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900 "2018-12-12T22:45:29Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![fjmenese](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@fjmenese](https://discuss.bluerobotics.com/u/fjmenese)\ **Post date:** [December 12, 2018, 10:45pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/1 "2018-12-12T22:45:29Z")
Dear Community, Do you know how can I set up an autopilot to navigate just with the compass? I want the ROV to navigate 40 seconds north and then 40 seconds south. Is this possible? Thanks ---
**Author:** ![patrickelectric](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/patrickelectric/32/2162_2.png) [@patrickelectric](https://discuss.bluerobotics.com/u/patrickelectric)\ **Post date:** [December 13, 2018, 12:11am UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/2 "2018-12-13T00:11:53Z")
Hi, Yes, this is possible, take a look in [pymavlink](https://www.ardusub.com/developers/pymavlink.html). Also, take in mind that will not be precise since you don’t have velocity and position control. ---
**Author:** ![fjmenese](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@fjmenese](https://discuss.bluerobotics.com/u/fjmenese)\ **Post date:** [December 13, 2018, 1:00am UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/3 "2018-12-13T01:00:41Z")
Dear Patrick, Thanks, I have been programing in Python, and I am able to make the ROV go forward or backwards, but I do not know how to read the compass(I do not know how it’s called in mavlink: heading or magnetometer). And then I would have to make it change direction and go forward. Please help! ---
**Author:** ![patrickelectric](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/patrickelectric/32/2162_2.png) [@patrickelectric](https://discuss.bluerobotics.com/u/patrickelectric)\ **Post date:** [December 13, 2018, 11:50am UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/4 "2018-12-13T11:50:37Z")
Hi Francisco, Take a look in **Run pyMavlink on the surface computer** / **Run pyMavlink on the companion computer** examples, in both you can see the messages **VFR\_HUD** , **AHRS2** and **AHRS3**. You can also search for mavlink messages [here](https://mavlink.io/en/messages/ardupilotmega.html). ---
**Author:** ![fjmenese](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@fjmenese](https://discuss.bluerobotics.com/u/fjmenese)\ **Post date:** [December 13, 2018, 8:33pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/5 "2018-12-13T20:33:47Z")
Thanks Patrick, Do you have an example on how to read them? I have found some for copters, but seem to be very complex. ---
**Author:** ![patrickelectric](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/patrickelectric/32/2162_2.png) [@patrickelectric](https://discuss.bluerobotics.com/u/patrickelectric)\ **Post date:** [December 13, 2018, 8:42pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/6 "2018-12-13T20:42:22Z")
Hi Francisco, Take a look in the examples available in ardusub pymavlink documentation, the examples pointed in my previous answer shows how you can access it. I would recommend to read the entire webpage and learn from each example. If you are not familiar with python, I would also recommend to study it a bit more before doing such thing. ---
**Author:** ![WaldoPepper](https://avatars.discourse-cdn.com/v4/letter/w/41988e/32.png) [@WaldoPepper](https://discuss.bluerobotics.com/u/WaldoPepper)\ **Post date:** [December 14, 2018, 1:33pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/7 "2018-12-14T13:33:54Z")
Dumb question from my side: Can I use any of the QGroundControl planning functionalities to program such kind of task? I know this approach is seriously lacking on the (no-GPS) positioning part, but will any kind of dead reckoning work? ---
**Author:** ![jwalser](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/jwalser/32/2234_2.png) [@jwalser](https://discuss.bluerobotics.com/u/jwalser)\ **Post date:** [December 14, 2018, 3:11pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/8 "2018-12-14T15:11:47Z")
There is no built in support for dead reckoning of any sort. See [here](https://www.ardusub.com/operators-manual/flight-modes.html). You will have to write a program to command the vehicle to do what you want, as @patrickelectric suggested. ---
**Author:** ![fjmenese](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@fjmenese](https://discuss.bluerobotics.com/u/fjmenese)\ **Post date:** [December 15, 2018, 12:54am UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/9 "2018-12-15T00:54:00Z")
Guys, Thanks for your help. Could it be the case that mavlink for ardu Sub does not have a human reading parameter for heading? [https://raw.githubusercontent.com/ardupilot/ardupilot/ArduSub-stable/ArduSub/Parameters.cpp](https://raw.githubusercontent.com/ardupilot/ardupilot/ArduSub-stable/ArduSub/Parameters.cpp) ---
**Author:** ![patrickelectric](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/patrickelectric/32/2162_2.png) [@patrickelectric](https://discuss.bluerobotics.com/u/patrickelectric)\ **Post date:** [December 15, 2018, 1:33pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/10 "2018-12-15T13:33:20Z")
Hi Francisco, > [@fjmenese](#): > > Could it be the case that mavlink for ardu Sub does not have a human reading parameter for heading? Sorry but your questions is not clear. Can you explain what do you want to do or accomplish ? And what is your idea of “reading parameter for heading” ? What this parameter should configure in the ROV ? ---
**Author:** ![jwalser](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/jwalser/32/2234_2.png) [@jwalser](https://discuss.bluerobotics.com/u/jwalser)\ **Post date:** [December 15, 2018, 5:39pm UTC](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/11 "2018-12-15T17:39:29Z")
> [@fjmenese](#): > > Could it be the case that mavlink for ardu Sub does not have a human reading parameter for heading? There is a difference between ‘Mavlink messages’ and ‘ArduPilot Parameters’. The parameters are settings that the user controls. The mavlink messages are what you want to look at for a heading, you can see those in the suggestion that @patrickelectric gave: > [@Autopilot with Compass](https://discuss.bluerobotics.com/t/autopilot-with-compass/3900/4): > > Hi Francisco, Take a look in Run pyMavlink on the surface computer/Run pyMavlink on the companion computer examples, in both you can see the messages VFR\_HUD, AHRS2 and AHRS3. You can also search for mavlink messages [here](https://mavlink.io/en/messages/ardupilotmega.html).