How does GPS work?

Of course, as a Nautical Specialist, I also deal with the international discussion on the advantages and disadvantages of satellite-based navigation, e-navigation and conventional terrestrial and astronomical navigation.

In my announced sequel, the second part of GPS, it is primarily about the technical and physical operational and functional limitations to which GPS is subject. These limitations, in part, have serious implications for the accuracy of GPS, and even go as far as limiting the functionality of GPS in its functions or even making it impossible. In doing so,

The vulnerability of GNSS in shore-based use is definitely different and to be regarded as much more risky than on the high seas.

How to get information for wind & current limits to be potentially encountered by thrusters – or current? - this will be described in this movie:
- Measure Drift speed, due to beam wind with no propulsion;
- Measure drift speed using full thrusters
- Estimate wind & current limits to be potentially encountered by thrusters – or current...
- Finally there is a simple formula as Rule of Thumb: the transverse drift speed is about 7-8% of wind speed!

Understanding the fundamentals of the pivot point is highly required for understanding the alteration of the courses. Pivot point is an imaginary point on the vessel which turns on a circular path on the perimeter of vessel’s turning circle when the vessel makes a turn. The knowledge about the position of the pivot point in a manoeuvring situation provides the ship handler with the information on the geometry of motion of the ship.

SWATH and SWASH are interesting technologies that allow a vessel to sail much more calmly in high waves. A stable and calm position of the ship is especially important for pilot boarding.

This video shows an introduction on the Pull-out Test-Manoeuvre and describes the procedure how to steer through this simple manoeuvre: Turning circle and then put the rudder amidships. The final rate of turn allows to identify stable and unstable conditions.

The technology group Wärtsilä will supply a complete navigational simulator upgrade for the Le Havre pilot station in France. The intention is to provide the pilot station with a totally new simulator specifically adapted to the requirements of the pilots’ operations. The order with Wärtsilä was placed in February 2020.The new unique visualisation system to be supplied is based on 14 DP projectors, comprising seven main circular and seven ground projection systems. It features a panoramic 350-degree screen.

This expert article is based on a presentation given by Capt. Pilot Sven Stemmler at the MCN's (Maritimes Cluster Norddeutschland e. V. ) event ‘On the Future of the Pilot Profession’ at Fraunhofer CML in Hamburg on 9 September 2025.

Unless you were paying attention on your last cruise, you might have missed the pilot boat bringing the pilot out to your cruise ship. Here's the story in 4K. Hey, be sure to subscribe too! Copyright © 2022 Richard L. Sites. All rights reserved. Any unauthorized reuse, copying, duplication, reproduction, or redistribution in part or in whole without written permission is strictly prohibited. To use this video for broadcast or in a commercial player contact me directly. Find me on:...