The introductory chapter (1) is about the evolution of the remote sensing technique during the last decades. Chapter 2 describes the satellite navigation etc. aboard the Swedish state icebreaker YMER on an interdisciplinary expedition performed in the High Arctic during June - September 1980. The next chapter (3) deals with the pioneering voyage of the Soviet nuclear-powered icebreaker ARKTIKA to the North Pole in August 1977, and the fact that the ship's position, in spite of frequent fog, was obtained with very high precision thanks to an advanced satellite navigation system. Chapter 4 mention the responsibilities of the Swedish Space Corporation and new satellite generations, among others a French-Swedish remote sensing satellite system, etc. The development of LORAN C into an expanded and improved aid to navigation on a worldwide scale is reported in chapter 5. The importance of visual ice reconnaissance in combination with optical viewing systems in arctic waters all the year round is dealt with in chapter 6. The last chapter is about "Underwater technology".