R-Mode Baltic Maritime signals of opportunity for terrestrial positioning

CIRM Annual Conference 2019 Vouliagmeni, Greece

Tobias Ehlers, BSH Federal Maritime & Hydrographic Agency

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Safe, reliable and resilient navigation • Gap-analysis of the IMO eNavigation

Strategy Need for a backup for GNSS • Immunity against jamming • Resistance against spoofing

R(anging)-Mode Baltic

Ehlers | BSH | R-Mode Baltic

Compelling need ?

Requirements for new technologies ? • GNSS independent systems • Usage of alternative, complementary frequencies • Jamming prove hi-power signals • Economically reasonable !

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Usage of existing infrastructure: • IALA-Beacon D-GNSS transmitter in the

MF-Band (300kHz) • AIS/ VDES base stations, VHF-Band

R(anging)-Mode Baltic

Ehlers | BSH | R-Mode Baltic

Technology – “Signals of opportunity”

R-Mode Signal

DGNSS-Data Signal

How does it work ? 300kHz IALA Beacon-Signal: 2 additional continuous wave (CW) signals, in-phase at the transmitting antenna, frequency devision of approx. 450Hz, phase deviation increases with distance Problem: Ambiguity at approx. 6km distance Solution: CW1-CW2 600km intermediate wave length. Requirement: Time synchronisation 10ns for 10meters position accuracy

Channelwidth 500Hz

AIS/ VDES-Signals: Special AIS/VDES message with digital code information (-> like GNSS C/A ) Requirement: Time synchronisation 10ns for 10meter position accuracy Problem: AIS Msg. 26 over 3 or 5 slots for 10m accuracy, range ~30km high AIS channel load -> VDES VDES: VHF Data Exchange System – Shore to ship

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R(anging)-Mode Baltic

Ehlers | BSH | R-Mode Baltic

Range measurements from ACCSEAS- Project 2017

Problem: Sky-wave propagation during night-times has severe impact on phase deviations MF-R-Mode only !

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R(anging)-Mode Baltic

Ehlers | BSH | R-Mode Baltic

Availability – “Signals of opportunity” Coverage prediction, 25 available DGNSS- Beacon stations in the Baltic Sea

Coverage predictions based on ITU-R ground conductivity charts and Sky-wave worst- case vector models (Cramer-Rao, Nakagami-Rice) provided by GLA (UK)

Estimated accuracy based on coverage and HDOP predictions for the Baltic Sea

Night-time hours, 95% accuracy [m] Day-time hours, 95% accuracy [m]

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R(anging)-Mode Baltic

Ehlers | BSH | R-Mode Baltic

Challenges

• Sky-wave • Method of mitigating the sky-wave error by „d-R-Mode“-

RTCM-Message • Software-based R-Mode signal distribution model (SF)

• Time synchronisation issues • Without GNSS (preferred) • Self-sychronisation – Sites are not all in range of each

other Possible future solution • (Usage of GPS and atomic clocks for hold-over in case of

GPS outage – Only for R-Mode demonstrator) • Future use of Galileo PRS

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R(anging)-Mode Baltic

Ehlers | BSH | R-Mode Baltic

Goals

• Installation of the test-bed until end of 2019

• Availability of R-Mode receivers until end of 2019

• Proof of concept, R-Mode as suitable positioning service

• 10 meter accuracy (IMO requirement) • Promotion of the R-Mode technology

Provide safe and resilient navigation services including reliable, GNSS cross-referenced integrity information at an economically reasonable level.

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Project partner

Contact R-Mode Baltic – Facts & Figures • EU-Interreg Baltic funding • Total Budget: ~3.500.000EURO • Duration 3 years • Project Lead: German Aerospace

Center (DLR) • 12 Project Partners • Final Demonstration October 2020

http://r-mode-baltic.eu

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Project partner

Contact

Tobias Ehlers tobias.ehlers@bsh.de Federal Maritime & Hydrographic Agency (BSH)

Thanks for your attention http://r-mode-baltic.eu

Announcement IALA Workshop on Ranging Mode

When: 9th – 12th September 2019 Where: IALA Headquarter, Saint Germain en Laye, France Topics:

– Overview of recent world-wide R-Mode activities

– Implementation aspects of R-Mode on AIS/VDES

– Implementation aspects of R-Mode on MF radio beacons

– The way forward: R-Mode roadmap

Contact: S. Gewies (Stefan.Gewies@dlr.de) or M. Hoppe (Michael.Hoppe@wsv.bund.de)