How is heading calculated by GPS?
This is a simple question that I would have rather chatted with someone about but here it is:
How is heading calculated? I can't figure it out visually.
If the heading is calculated in regards to the Earth's Geographic North, does that mean a top view of the Earth? So when you are standing on top of the surface of the Earth somewhere, how can you get a heading direction on a digital device? What are the calculations? Does it involve the sphere at all or does the device ignore the existence of the sphere and simply keep in mind a simple coordinate eg. 90.000 N and 0.000 W?
I don't know why I can't seem to grasp the concept of heading mathematically...
Edit: I think I figured it out. You are treated as a point, on the surface; north is always directly above you figuratively- you may deviate from this point 360 degrees potentially, that's as you as a point on the surface of the Earth.
Answer
Precisly a GPS receiver does not calculate heading.
heading is the direction where you are looking to.
The more correct term is course or course over ground.
But modern APIs often intermix heading, course and bearing.
heading and course is the same for a vehicle, But not for a ship (due drift).
But the main point is that one could think a GPS chip calculates the course/heading by evaluiating old and new position. But this is not true. This would be by far to inaccurate.
GPS receiver use Doppler Shift for speed and probably also for heading calculation.
And yes course and heading is the angle clockwise measured from geographical north (0°)