Following a discussion on Math and this particular comment, I am wondering how a GPS receiver determines its bearing. As I understand it:
- GPS is not a directional system, thus bearing can only be inferred from receiver movement. If a receiver has obtained a fix and a valid bearing, then turns while stationary, the bearing will not reflect that until the receiver actually starts moving in that direction.
- So far I have therefore assumed that the receiver simply takes the current and previous location, assumes it has traveled in a straight line from one to the other and returns the appropriate bearing.
- Bearing will therefore suffer from errors which are linked to the positional accuracy of these two positions, as well as the distance between them.
- The error increases whenever the receiver is not traveling along a straight line – rather than the current bearing, the receiver would return the average bearing as it moved from the previous to the current position.
But the comment I got seems to indicate otherwise.
Are my assumptions correct? Or do GPS receivers have another way of determining bearing from satellite signals alone?