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GCRI · Espace et observation de la Terre

Communications et navigation

Satellite communications connect remote areas, ships, aircraft and disaster zones, and navigation satellites provide the position and timing that transport, telecom, finance and power grids depend on. Large new constellations are changing both. This page sets out how satellite communication and navigation services work, how society’s dependence on them can be mapped, and what evidence serves the regulators and operators who plan for their loss.

01Registre

Communications and navigation on the record.

02La question

Communications and navigation: how the risk develops.

GNSS, satcom and dependency. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.

Mécanisme

Constellations change connectivity

Large low Earth orbit constellations offer lower latency broadband, extending coverage but concentrating it with a few operators.

Mécanisme

Timing is a hidden dependency

Telecom networks, power grid measurement and financial systèmes use satellite time signals. Many users do not know they depend on them.

Mécanisme

Navigation underpins transport

Aviation, shipping, road logistics and agriculture rely on satellite positioning, with augmentation systems for higher accuracy and integrity.

Mécanisme

Backups are often missing

Alternative positioning and timing, such as terrestrial systems or holdover clocks, are unevenly deployed, so outages can cascade.

03Méthodes et preuves

How communications and navigation is modelled, measured and tested.

Le modèle, ses hypothèses, ses données et son incertitude, sous la forme qu'un scientifique ou un ingénieur vérifierait. Les structures suivent des méthodes publiées. Les valeurs représentées sont illustratives, ce ne sont pas des résultats.

Chaîne d'observation de la Terre

How a satellite or sensor record becomes evidence on communications and navigation, and where each step adds uncertainty.

  1. 01 · Acquérirorbite, capteur et revisiteIncertitude : lacunes dues aux nuages et à l'orbite
  2. 02 · Étalonnerradiométrique et géométriqueIncertitude : dérive des capteurs
  3. 03 · Corrigeratmosphère et reliefIncertitude : hypothèses sur les aérosols et la pente
  4. 04 · Récupérer ou classerla variable ou la classeIncertitude : erreur du modèle et de l'entraînement
  5. 05 · Validerpar rapport à la réalité de terrainIncertitude : plan et taille de l'échantillon
  6. 06 · Publieravec barres d'erreur et filiationIncertitude : énoncée, jamais masquée
Chaîne de traitement au sens des données prêtes pour l'analyse du CEOS ; chaque étape consigne son incertitude avant qu'un chiffre ne soit tracé. Une structure générique, non des résultats.
Principes directeurs FAIR · GO FAIR et FORCE11W3C PROV · World Wide Web ConsortiumOrientations sur le traitement cohérent des incertitudes · GIECCEOS Analysis Ready Data · Comité sur les satellites d'observation de la Terre
04À travers les domaines

Satellite communication and navigation reach every domain.

Findings are designed for the série Systèmes stratégiques. Spectrum is governed by the ITU Radio Regulations; the Global Centre for Risk and Innovation (GCRI) recommends no provider.

  • Interference and outage records.
  • Connectivity studies in remote areas.
05Indicateurs

Ce qui est mesuré, et avec quelle qualité.

Chaque indicateur porte son unité, sa périodicité, le type de source qui le sous-tend et l'étiquette de preuve que porterait une valeur. Aucune valeur n'est affichée : un programme les fournit sous sa propre autorité.

IndicateurUnitéFréquenceType de sourceÉtiquette
Population covered by satellite broadbandpercent of populationannuelRegulator and operator dataESTIMÉ
Critical sectors using GNSS timingcount of sectorspar évaluationDependency studiesESTIMÉ
Timing holdover capabilityhoursper systemOperator documentationDÉCLARÉ
Satellite broadband subscribersnombreannuelRegulator statisticsStatistiques publiées
Satellite-based augmentation coveragestatus by regionpar évaluationAugmentation system documentationStatistiques publiées
Navigation outages and degradationscount and durationannuelService noticesStatistiques publiées
06Sources

D'où proviennent les données probantes.

Jeux de données publics et registres institutionnels nommés, chacun avec sa catégorie de licence. Les sources fournies dans le cadre d'accords ne sont utilisées que selon leurs conditions et ne sont jamais republiées.

SourcesCe qu'elle apporteCatégorie de licence
ITU satellite network filings and Radio RegulationsSpectrum and orbit filingsPublic, ITU terms
GNSS service performance reports (GPS, Galileo, GLONASS, BeiDou)Service performance and noticesPublic, terms per provider
Government studies of GNSS dependence, such as the UK and US economic impact studiesSectors depending on positioning and timingPublic records, licence per government
National telecom regulator statisticsSatellite broadband adoptionPublic records, licence per regulator
ICAO and IMO documentation on navigationNavigation requirements in aviation and shippingPublic, terms per organisation
07Décisions

Qui décide, et à quoi servent les données probantes.

Space and Earth Observation prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.

Qui décideLa questionDonnées probantes servies par cette page
Telecom and transport regulatorsWhat backup timing and navigation to requireDependency maps; backup reviews
Infrastructures critiques operatorsHow long they can operate without satellite timingHoldover evidence
Governments planning connectivityWhere satellite broadband fills gapsConnectivity gap analyses

Résultats que produit ce thème

  • Dependency maps of positioning and timing
  • Backup capability reviews
  • Connectivity gap analyses including satellite options
  • Evidence notes for resilience planning
08Questions essentielles

Ce que se demandent les experts.

Specialists in navigation and satellite communications ask how dependent systèmes are and how they fail.

  • Which sectors rely on satellite timing and positioning, and do they know it?
  • How vulnerable are receivers to jamming, spoofing and interference?
  • What alternative time and position sources exist, and are they in use?
  • How do satellite communications support emergency response and remote areas, and how resilient are they?
  • How does the growth of large communications constellations change dependency and risk?
09Mécanismes et facteurs

Weak signals, wide dependence.

Navigation satellites broadcast signals that receivers use to calculate position and time. The signals are very weak by the time they reach the ground, which makes them easy to drown out with jamming or imitate with spoofing. Beyond navigation for transport and agriculture, the timing function is embedded in telecommunications networks, electricity grid synchronisation and the time-stamping of financial transactions, often without operators being aware of it.

Satellite communications carry data, voice and broadband to ships, aircraft, remote communities and disaster zones where terrestrial networks are absent or damaged. They are themselves exposed to interference, ground-segment faults and space weather. Resilience comes from diversity: multiple constellations, terrestrial backups, holdover clocks that maintain time during outages, and receivers that detect anomalies.

10Méthodes et données

Comment les données probantes sont construites, et où elles s'arrêtent.

  1. 01

    Dependency surveys

    Identifying where timing and positioning are used in critical services. Embedded dependencies are often undocumented.

  2. 02

    Interference monitoring

    Detecting jamming and spoofing through receiver networks and communications and network technology. Coverage of monitoring is limited.

  3. 03

    Tests de résilience

    Testing how systèmes behave when signals are lost or falsified. Live testing is constrained by regulation and safety.

  4. 04

    Signal and orbit physics

    Modelling signal propagation and errors, grounded in physique. Atmospheric effects vary in ways that are hard to predict locally.

12Where this page’s references

Where this page’s references lead.

Les organismes et documents à l'aune desquels cette page se lit. Les statuts et éditions changent ; chaque lien mène à l'organisme émetteur.

13Questions

Questions et réponses.

What is GNSS?
Global navigation satellite systems, such as GPS, Galileo, GLONASS and BeiDou, which provide positioning, navigation and timing worldwide.
Why do power grids and banks depend on satellites?
Because many of their systems use satellite time signals to synchronise measurements across sites and to timestamp transactions.
What is a low Earth orbit constellation?
A large group of satellites orbiting relatively close to Earth, used to provide low-latency communications coverage.
Why does finance depend on satellite navigation?
Many systems use satellite-derived time to stamp and order transactions precisely. Loss of that time source, without a backup, can disrupt synchronisation.
What is spoofing?
Broadcasting false navigation signals so that receivers compute a wrong position or time. Unlike jamming, it can go unnoticed without detection measures.
Are there alternatives to satellite timing?
Yes. Terrestrial time distribution, atomic clocks with holdover and multiple constellations can provide resilience. Their adoption varies widely.
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