Miscellaneous
Maritime
Informations
/
Informations
maritimes
diverses
Sailing Directions/Instructions nautiques List of Lights/Livres des feux
Radio Signals/Ouvrages de radiosignaux
Tide Tables/Annuaire des marées
Advice / Conseils
For navigation use only updated regulatory documents /
Pour la navigation n'utiliser que des documents réglementaires à jour.
GPS is more accurate than nautical charts /
Un GPS est plus précis qu'un carte marine
Web Servers / Serveurs Web
You can use the nearest or faster server / Vous pouvez utiliser le serveur le plus proche ou le plus rapide :
Caption / Légende
II-1 - Main Nautical Publications / Ouvrages nautiques principaux
II-2 - Other Nautical Documents / Autres documents nautiques
The Sun continuously emits energy into space. That energy emission by the Sun is variable and hence shapes a variable space environment which also impacts the Earth's atmosphere and magnetosphere. Here are some impacts of the sun:
GNSS positional errors
The accuracy of positioning using GPS is degraded when there are Sun stroms. For exemple when charged particles ejected from the Sun arrive at the Earth, they can cause perturbations in the geomagnetic field. These disturbances will significantly modify the ionospheric propagation of radio waves used by GPS. The GPS accuracy depends on amplitude scintillations and variation of total electron contents (TEC). These phenomena are associated with geomagnetic stroms that create disturbances in the ionosphere. The total electron contents (TEC) of the ionosphere is the electron density (number of electrons in a given volume) and the can vary considerably, both in time and space. The time of GPS signal propagation increase with TEC. More information about Space Weather.
La précision du positionnement par GPS est dégradée lors de tempêtes solaires. Par exemple lorsque des particules chargées émises par le soleil atteignent la terre, elles peuvent perturber le champ géomagnétique terrestre. Ces perturbations vont modifier de manière importantes la propagation ionosphérique des ondes radioélectriques qui sont utilisées par le GPS.
La précison du GPS depend de la scintillation d’amplitude et de la variation du contenu électronique total (TEC). Ces phénomènes sont associés aux tempêtes géomagnétiques qui créent des perturbations dans l'ionosphère. Les scintillations d'amplitude sont des fluctuations de l'amplitude du signal GPS (comme pour la lumière des étoiles). Le contenu électronique total (TEC) de l'ionosphère est la densité d'électrons (nombre d'électrons dans une région donnée) et il peut varier considérablement, dans le temps et dans l'espace. Le temps de propagation du signal GPS augmente avec le TEC. Plus d'information sur la météo de l'espace.
The Sun is an active place and solar activity changes over time. Sunspots are dark, planet-sized regions that appear on the surface of the Sun. Because sunspots are associated with increased solar activity, space weather forecasters track these features to help predict solar storms that can impact Earth. Solar activity cycles between a minimum and a maximum about every 11 years. Studying how solar activity changes throughout the entire cycle improves our understanding of how Earth is affected and improves our space-weather forecasting abilities. When solar activity is at a maximum, strong magnetic fields cause numerous sunspots and more frequent solar storms. When solar activity is at a minimum, the Sun’s magnetic field weakens and there are few to no sunspots and fewer solar storms. Sunspots can cause geomagnetic storms in Earth’s magnetosphere. During a solar maximum, when sunspot numbers are at their peak, the Sun emits more electrons and protons than usual. These charged solar particles emitted from the Sun can enter the atmosphere and can disrupt infrastructure, such as satellites, navigation, communications, and the electric power grid. Through careful counting of sunspots, solar prediction scientists determined that a solar minimum (when there are the fewest number of sunspots) occurred in December 2019. This recent solar minimum marks the beginning of Solar Cycle 25 (the current 11-year sunspot cycle). Scientists predict that Solar Cycle 25 will peak in July 2025 (+/- eight months). As Solar Cycle 25 approaches its peak, and even for several years after, Earth will likely experience increased geomagnetic storms in both the northern and southern hemispheres.
The ionosphere can be the largest source of error in GPS positioning and navigation. Furthermore, under certain conditions, amplitude fading and phase scintillation effects can cause loss of carrier lock and intermittent GPS receiver operation.
Time on your local computer
For first aid see also / Pour les premiers soins voir aussi : Medical Guides for Ships
ENC Symbols
Mariners are warned to be extra cautious and to take necessary precautionary measures when transiting the following areas:
South East Asia and Indian Sub-Continent, Africa and Red Sea, South and Central America and the Caribbean Waters.
Vessels are encouraged to send regular position reports on these areas.
Always report all actual, attempted or suspicious piracy and armed robbery incidents occurring anywhere.
Coronavirus / Coronavirus
Cyber security / Cyber sécurité
GPS vulnerability / Vulnérabilité du GPS
Security Charts / Cartes de sûreté
Mediterranean / Méditerranée
Gulf of Guinea / Golfe de Guinée
Indian Ocean / Océan Indien
Asia / Asie
