OK, as I have mentioned in other threads, I am messing around with open source Arduino microcontrollers and sensors with an eye to creating simple, inexpensive DIY electronic instruments. I have settled on a compass as my first project, with the added benefit that I can mount it on the dashboard of my truck for useful testing.
As I understand it, there are three types of magnetic bearing (setting aside the Southern hemisphere for the moment, sorry Ozzies)--true North meaning that it points to the geographic pole and therefore aligns with the charts, magnetic North meaning that it points predictably East or West of true North according to geographic variation in the Earth's magnetic field, and your actual compass indication, which is affected not only by the geographic variation but also by metal and electrical items in your aircraft.
Aircraft compasses, as I understand it, generally point to magnetic North, with variations due to the installation in your aircraft corrected as much as possible with little magnets and then what you can't correct is marked on a compass card. You choose your magnetic heading (what you'll follow) for the geographic declination to take you on the true heading you want to follow on the chart. My questions for the group are...
First, would it be useful to offer the option to set the geographic declination and therefore show either magnetic or true North as you choose? That would then be indicated on the compass face in some way ("m" or "t" or "mag" or "tru" or something like that).
Second, and I am not sure how to do this but I don't think it would be too hard, would it be useful to digitally correct the variation due to installation? What I mean is incorporating the corrections that would normally be marked on a compass card into the softward and then mathematically interpolating to do the correction for you.
If there is anything else I am missing, don't hesitate to say so.
Cheers,
Matthew
As I understand it, there are three types of magnetic bearing (setting aside the Southern hemisphere for the moment, sorry Ozzies)--true North meaning that it points to the geographic pole and therefore aligns with the charts, magnetic North meaning that it points predictably East or West of true North according to geographic variation in the Earth's magnetic field, and your actual compass indication, which is affected not only by the geographic variation but also by metal and electrical items in your aircraft.
Aircraft compasses, as I understand it, generally point to magnetic North, with variations due to the installation in your aircraft corrected as much as possible with little magnets and then what you can't correct is marked on a compass card. You choose your magnetic heading (what you'll follow) for the geographic declination to take you on the true heading you want to follow on the chart. My questions for the group are...
First, would it be useful to offer the option to set the geographic declination and therefore show either magnetic or true North as you choose? That would then be indicated on the compass face in some way ("m" or "t" or "mag" or "tru" or something like that).
Second, and I am not sure how to do this but I don't think it would be too hard, would it be useful to digitally correct the variation due to installation? What I mean is incorporating the corrections that would normally be marked on a compass card into the softward and then mathematically interpolating to do the correction for you.
If there is anything else I am missing, don't hesitate to say so.
Cheers,
Matthew
