Fraunhofer Center for Maritime Logistics and Services
Fraunhofer Center for Maritime Logistics and Services

Astronomical Navigation as an Alternative to GNSS at Sea

© Fraunhofer CML

MoNaMe – Modern Navigation Methods for Autonomous Alternative Absolute Positioning

MoNaMe is an ESA-funded research project focused on GNSS-independent, absolute positioning at sea using astronomical navigation (astronavigation/celestial navigation)

Project Description

Project Description and Background

The maritime shipping industry faces a critical challenge: Modern navigation systems rely heavily on GNSS, the Global Navigation Satellite System—a system that is increasingly threatened by cyberattacks such as jamming and spoofing. What happens if the signal fails or is tampered with? The ESA-funded research project MoNaMe (Modern Navigation Methods for Autonomous Alternative Absolute Positioning) offers a promising solution: looking back to the stars—using state-of-the-art technology.

Background and Concept of MoNaMe

  • GNSS is vulnerable to jamming (signal interference) and spoofing (manipulated position data)
  • Astronavigation provides an independent, global reference based on star positions
  • Sky imaging: An 8-camera array captures the star field
  • Identification: Pattern matching assigns stars to the star catalog
  • Determining Angles: Right ascension and declination—the celestial equivalents of longitude and latitude—are calculated
  • Position solution: An altitude-based method calculates the ship’s absolute position—without an external course reference
  • Stabilization: Gimbal keeps the sensor array horizontal, adaptively adjusting to sea state

Contributions of Fraunhofer CML to the project

A particular challenge was the development and construction of an active gimbal. This gimbal compensates for the ship’s roll and pitch movements in real time and keeps the camera array level at all times—a fundamental requirement for reliable image acquisition at sea. The system also responds intelligently to changing sea conditions: In rough weather, the integral gain is automatically reduced to prevent overcompensation. A particularly innovative feature: The elevation-based positioning method requires no external course reference whatsoever. At a glance:

  • GNSS-free, absolute positioning
  • Robust image acquisition via an active gimbal
  • Adaptive control to prevent overcompensation
  • End-to-end validation from simulation to live operation.
  • Project Status
  • Proof of concept successful; findings are being incorporated into further at-sea trials on “Elly” (Trondheim)

Research Partners

Partners: SINTEF (Norway), TeleOrbit GmbH (Germany), Fraunhofer CML

Funding Agency

ESA NAVISP-EL1-078 “AUTONOMOUS ALTERNATIVE ABSOLUTE NAVIGATION (AAAN) TECHNOLOGIES FOR MARITIME EXPRO+