A Motion Description Language for Robotic Reconnaissance of Unknown Fields

In this paper, we present two motion primitives that allow a mobile sensor to explore the features of an unknown scalar field. The first motion primitive is designed to follow and to map level contours (contours with constant value of the field). The second one steers the sensor to ascend or alternatively descend the field gradient and, as a result, to localize its extremum points. Both of these primitives are defined in terms of the geometric characteristics of the potential function and their performance is analyzed for different ranges of the parameters describing the geometry. The two motion primitives constitute a suitable library for rapid information acquisition aimed at the mapping of unknown fields. The motion control primitives developed below will provide the foundation of a theory of control for information acquisition in the exploration of unknown fields by means of mobile point sensors. This theory is treated in a companion paper.