Category:GNSS-Denied Navigation

GNSS (Navstar GPS (USA), GLONASS (RU), Beidou (CN), Galileo (EU)) might encounter jamming or spoofing. See https://gpsjam.org/ for daily maps of interference.
This page lists some alternative (marine) navigation strategies:

cross bearings

• https://de.wikipedia.org/wiki/Kreuzpeilung

dead reckoning

• https://en.wikipedia.org/wiki/Dead_reckoning

celestial navigation

• https://en.wikipedia.org/wiki/Celestial_navigation

radio direction finding

• https://en.wikipedia.org/wiki/Direction_finding

R(anging)-Mode

• https://en.wikipedia.org/wiki/Trilateration

R-Mode is a land based GNSS backup.

MF (medium frequency)

Testbed at baltic sea made use of 7 DGPS-stations.

• https://www.r-mode-baltic.eu/
• https://interreg-baltic.eu/project-posts/ormobass/important-step-towards-r-mode-standardization/
  • https://www.iala.int/product/g1187-medium-frequency-r-mode-signal-structure-and-navigation-message/

VHF (very high frequency)

Testbed at baltic sea made use of 4 AIS base-stations.

• https://www.r-mode-baltic.eu/