Reliable Robot Localization

Introduction

I.1. Underwater challenges

“On peut braver les lois humaines, mais non résister aux lois naturelles.”

We may brave human laws, but we cannot resist natural ones.

Twenty Thousand Leagues Under the Sea, Jules Verne

I.1.1. In the vastness of the unknown

95%. This striking figure, stated¹ by the American National Oceanic and Atmospheric Administration (NOAA), tells us how little we know about oceans: about 95% of this underwater realm remains unseen by human eyes. Yet, it covers two-thirds of the Earth’s surface. It is even said that we know the Moon’s surface better than our oceans’ depths. Nevertheless, marine technologies have changed dramatically over the last 100 years, discovering ways to explore bodies of water that previously would have been unimaginable.

We could say that the underwater exploration started with the Challenger Expedition (1872, Figure I.1) by probing the depths from the surface with lead lines. The Challenger Deep, which is the deepest known point on Earth², was discovered during this expedition. Yet, it was not until the start of the 1960s that this spot was visited by humans, during the dive of the manned submersible Trieste (Figure I.2). Ever since, the place has been reached by very few expeditions, mainly unmanned descents.

Figure I.1. The HMS Challenger, a British corvette that took part in the first global marine research expedition: ...