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.
note: Galileo is now hardened by authentication (OSNMA) https://insidegnss.com/osnma-necessary-but-not-sufficient-for-gnss-security/
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
• GNSS-Denied Navigation using Direction of Arrival from Low-Cost Software Defined Radios and Signals of Opportunity

R(anging)-Mode

R-Mode is intended to become a ground based GNSS backup.

• https://www.navigation-mac.fr/r-mode-futur-systeme-de-positionnement-alternatif/?lang=en
• https://en.wikipedia.org/wiki/Trilateration

MF (medium frequency)

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

• https://www.r-mode-baltic.eu/
  • https://www.r-mode-baltic.eu/wp-content/uploads/2022/11/Final_report_R-Mode_Baltic2_v1.0.pdf
• 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/
• https://www.iala.int/technical/positioning-navigation-and-timing/world-dgnss-stations-list/
• R-Mode: An Alternative to Global Navigation Satellite Systems for Terrestrial Navigation at Medium Frequencies

equipment

• RTL-SDR

VHF (very high frequency)

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

• https://www.r-mode-baltic.eu/
• AIS R-Mode Trilateration for GPS Positioning and Timing Insurance
• ...