I am looking for techniques and methods to detect very small linear magnetic movement caused by a bar magnet. Imagine a bar magnet that can produce yaw and pitch but with extremely low frequency and within few degrees outlined below. I have ability to locate this device conveniently far or close.

My design parameters are as follows:

Yaw angle can change -4 to +4 degrees
Pitch angle can change -1 to +1 degrees
Temp: 32F to 110F
Variation will happen over period of hours.

I have no sense of strength of magnet involved. However, I can place sensing device far or close as required.

I'm looking for suggestions to help me accomplish this task.