Approach

The route we use in our approach consists of a sequence of waypoints. In order to generate refined instructions for navigation, it is crucial to know how close the navi-gator is to the next waypoint. Consider the example of a tourist in the process of fol-lowing a predefined route as illustrated in Figure 3. In the vicinity of the next way-point, the visual instructions will still guide the user to the next waypoint while giving an indication of where to go once that waypoint is reached. When the user has reached a waypoint, i.e., is very close to the waypoint, the given visual instruction is not refined and simply points the user in the direction of the next waypoint.

Figure 3. Example of a tourist moving from waypoint b to waypoint c and the according in-structions.

In this example, we used vicinity and closeness to describe the navigator’s location in relation to the location of the waypoint. Hence, the conclusion is that the key to provide refined instructions is to determine different stages of closeness of the naviga-tor with respect to the upcoming waypoint. Once such stages are defined, refined instructions can be given based on each stage. The remainder of this paper describes the following tasks:

1. Definition of a data model of the navigator’s location and the waypoints, including location accuracies and the waypoint’s accuracy or decision area.

2. Analysis of possible relations between a navigator’s location and the location of a waypoint.

3. Analysis of navigator’s movement towards a waypoint and definition of stages of closeness along such a trajectory.

4. Example of refinements of route instructions based on stages of closeness in 3.

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