Figure 2.

The figure (a) depicts the ego and target vehicle driving in an Earth-fixed navigation frame $[x^n,y^n]$. A ranging sensor in the ego vehicle is able to detect the target vehicle, whose position is given in an ego vehicle coordinate frame $[x^l,y^l]$. The figure (b) shows how a geometric model of the target vehicle can be constructed from the ranging sensor measurement data. Using a tracking algorithm, the future location of the target vehicle can be predicted.