Differential Compassing Helps Human–Robot Teams Navigate in Magnetically Disturbed Environments

In this paper, the authors describe a sensing method, called differential compassing, which can be applied to pursue leader/follower behaviors in the field of service robotics. Differential compassing is applied to integrate proximity/range sensing in robot systems, the operation of which can involve a hands-free interaction mode, where the robot (the follower) reacts to the movements of a walking user (the leader), so as to maintain close proximity to him. Differential compassing exploits two compasses, one of them on the leader and the other one on the follower. The simple idea behind this approach is that, if a magnetic disturbance affect the two compasses, one compass will be more influenced than the other, but heading errors may have similar magnitude