maybe a silly question - why isn't magnetic declination calculated in code from the GPS coordinates? Is there something that prevents it? Should be more precise and it might make a difference for those with circling problems (I fly where declination is 3.5-3.3 and it's just 30 minutes away... I'm not going to change it every time I take off)
Good question, I'd like to know too?
This might be of interest...
It is possible using a lookup table, but space is limited on these devices. I am interested though... I will see how much space something like this will take up and post back here.
Good news! I have auto declination working. It produces an estimate of declination (better than nothing) which should be accurate enough for flight. It takes up 1460bytes of space. I will discuss this with the AC Dev team and see if we can get it tested and integrated in a future release.
Thanks for the suggestion!
Ok... Just had a successful test of the new automatic declination code. Marco from the dev team is also going to test it tomorrow. I'm not sure when it will hit the shelf because there are a lot of more important efforts going on right now, but consider it queued up. If you are brave enough, you can pull it from my git branch here: https://code.google.com/r/a432511-auto-declination/
Cool! Thank you :) that was pretty fast ;)
My pleasure. Please note that if you use my branch, the automatic declination is disabled by default. You would need to enable it by uncommenting the line that says #define AUTOMATIC_DECLINATION ENABLED in the APM_Config.h file. Also, by choosing to use my branch you will also be flying the beta code that has not been officially released yet (at your own risk).
If you do decide to try it out, make sure that you verify that the declination was set properly by refreshing the parameters on the configuration tab of the Mission Planner after a 3d fix is obtained. Then click the "Setup" sub-tab and view the declination where you would normally enter it manually. It should be very close to what you normally input manually.
If you are interested in testing this out without risking your copter, just upload the code (with the config file change) to your APM, zero out the declination in the Mission Planner before you get a 3d fix. The wait for the 3d fix and validate that the declination was set! Voila... you don't even have to fly it to test it.