R-Mode Baltic - Status info for Helcom AIS EWG30 Helcom AIS EWG30 Marek Dziewicki, MOG Stefan Gewies, DLR, Michael Hoppe, WSV Helsinki 2019
Outline • R-Mode concept • R-Mode testbed plan for the Baltic Sea • Signal-of-opportunity coverage predictions for the Southern Baltic Sea • R-Mode user & service requirements on a backup system • Ongoing R-Mode Baltic activities • Conclusions R-Mode Baltic – status info for AIS EWG30 Chart 2
R(anging)-Mode Idea - Signals-of-Opportunity Concept • Add ranging capability to existing Time maritime: DGPS radio beacons MF (300 kHz) and AIS VHF (162 MHz) • Synchronized stations provide signals with well known time and phase dependency. • Range estimation based on time of arrival (TOA) and phase. • Positioning using method of trilateration Feasibility studies and ongoing tests confirmed this approach R-Mode Baltic – status info for AIS EWG30 Chart 3
General Tasks of WP 3.1 Baseline and Priorities Document was created to: • deliver R-Mode system justification – why, what for, how ? • perform an analysis and evaluation of international legal documents treating about maritime radionavigation systems in the light of e-Navigation strategy looking for back-up to GNSS (IMO, IALA, ITU, IEC, RTCM, EMRF)…. • review of Terrestrial Radionavigation Systems ( TRS ) and their ranging • review of Terrestrial Radionavigation Systems ( TRS ) and their ranging methods, historical and contemporary (from Decca to GSM, UMTS, LTE networks) • review impact from other Projects: ACCSEAS, MF R-Mode or AIS+VDES (Germany, Netherlands, UK, Canada, China, Korea ) • define service and user requirements also taking into account VDES R-Mode Baltic – status info for AIS EWG30 Chart 4
General Tasks of WP 3.1 Baseline and Priorities • Identify sources of possible errors and mitigation methods (positioning, timing, ambiguity algorithms, propagation, spoofing, jamming) • Combine services: MF ( MSK+2CW radiobeacon) and VHF (AIS, VDES) • Develop general specification of new components for the R-Mode positioning system (MF modulator, AIS BS time slots combination, sources of time and frequency). R-Mode Baltic – status info for AIS EWG30 Chart 5
Types of alternative R-Nav system Definitions in IALA Recommendation R-129 • A redundant system provides the same functionality as the primary system, allowing a seamless transition with no change in procedures. • A backup system ensures continuation of the navigation application, but not necessarily with the full functionality of the primary system and may necessitate some changes in procedures by the user. R-Mode R-Mode • A contingency system allows safe completion of a manoeuvre, but may not be adequate for long-term use. • GNSS independent time synchronisation • GNSS dependent time synchronisation R-Mode Baltic – status info for AIS EWG30 Chart 6
Signal of MF Beacon as source for R-Mode ranging Approach : • Spectrum of F +/- CW To solve ambiguity - add two 2 continuous wave (CW) signals 225 Hz beside main F carrier of legacy MSK signal . First results (measured) • Range : <10 m day ; <50 m night Challenges Challenges • Mitigate skywave induced fading • Accurate estimation of beat signal Standard DGNSS (MSK) bandwidth is +/- 250Hz E-layer night R-Mode Baltic – status info for AIS EWG30 Chart 7
Signals of AIS as source for R-Mode ranging Approach: Range estimation using bit edge of AIS message transmitted from base station - GMSK signal Challenges: Challenges: • Design AIS message with sufficient length and autocorrelation (#26) • Additional channel load (VDL) Lower boundary for range stdev. 5 slot AIS R-Mode Baltic – status info for AIS EWG30 Chart 8
R-Mode Baltic: Goals of the Project First testbed for R-Mode with two signal types MF , VHF Build a testbed for R-Mode System that offers: Sweden • use of R-Mode enabled IALA beacons AIS Base • use of R-Mode enabled AIS base stations Station • Baltic first test for both signal types • Baltic first test for both signal types IALA Beacon Beacon • transnational synchronized network • prototypes of adapted BS and new onboard R-Mode receiver • preliminary model of global system ? Show R-Mode is able to meet maritime user requirements for a Germany Poland positioning and timing backup system. R-Mode Baltic – status info for AIS EWG30 Chart 9
R-Mode testbed implementation • Selection of testbed area based on • Requirements based on IMO def of backup system • Detailed coverage prediction, which considers disturbances of signal propagation and station geometry (HDOP) • Up to 6 radio beacons and 4 AIS base stations will be equipped with R-Mode enabled signal generators • Monitor stations will be used to monitor the proper work of the R-Mode transmitter sites • Perform static and dynamic measurements for position validation The testbed will be available from 2020. R-Mode Baltic – status info for AIS EWG30 Chart 10
Coverage of the Baltic Sea with MF radio beacon signals Based on given nominal range Number of available sites Number of available sites Sufficient (>3) number of beacons for positioning in wide areas of the Southern Baltic Sea R-Mode Baltic – status info for AIS EWG30 Chart 11
Coverage of the Baltic Sea with VHF AIS signals Based on geometrical range (vessel: 10 m antenna height) Number of available sites Number of available sites Insufficient (<4) number of stations for positioning in wide areas of the Southern Baltic Sea R-Mode Baltic – status info for AIS EWG30 Chart 12
Coverage of the Baltic Sea with VHF and MF signals Considers not disturbances of signal propagation Number of available sites Number of available sites Sufficient number of available signals (>3) for positioning in the Southern Baltic Sea – R-Mode based positioning requires both signals-of-opportunity R-Mode Baltic – status info for AIS EWG30 Chart 13
Minimum user requirement on a backup system IALA R-129 based on IMO Resolution A.915(22) System level parameters Service level parameters Absolute Integrity Accuracy Availability Continuity Fix Maritime Alert Time to Integrity % per 30 % over 15 Coverage interval region Horizonta limit Alarm Risk (per days minutes (seconds) l (meters) (meters) (seconds) 3 hours) Not covered by MF or VHF transmitter signals Ocean 1000 2500 60 99 N/A² Global 60 Coastal 100 250 30 99 N/A² Regional 15 Port R-Mode service area approach and 10 25 10 99 99,97 Regional 2 restricted waters Not reachable Port 1 2.5 10 99 99,97 Local 1 Inland 10 25 10 99 99,97 Regional 2 Waterways R-Mode Baltic – status info for AIS EWG30 Chart 14
Summary of ongoing project activities • Compatibly tests of radio beacons for R-Mode, MF modulator update (Nov. 2018) • Detailed coverage prediction for R-Mode on MF radio beacons in the Baltic Sea (May 2019) • AIS/VDES: proposal for implementation of R-Mode (until Sep. 2019) • Radio beacon: proposal for implementation of R-Mode (until Sep. 2019) • Development of concept for R-Mode stations timing (until Sep. 2019) • Concept development for R-Mode onboard receiver • Test-bed plan ( June 2019) R-Mode Baltic – status info for AIS EWG30 Chart 15
Next or just started project activities • R-Mode onboard receiver development • R-Mode VDES land base station development, (transmitter and signal tests ) • Testbed implementation preparation R-Mode Baltic – status info for AIS EWG30 Chart 16
Conclusions • R-Mode has the potential to support navigation in coastal regions, port approaches and inland waterways • IALA R-129 provides user requirements for R-Mode system development, • Both MF and VHF, require base station upgrade to R-Mode to enable positioning in the Southern Baltic Sea • Both for MF and VHF (also VDES) optional signal tests are in progress • Project R-Mode Baltic team will perform fundamental developments and build up a first testbed that can utilise both signals-of-opportunity • IALA will help to develop and standardise R-Mode system • R-Mode affects standards and guidelines of IMO, IALA, IEC and RTCM R-Mode Baltic – status info for AIS EWG30 Chart 17
Thank you for your attention marekdz@umgdy.gov.pl R-Mode Baltic – status info for AIS EWG30 Chart 18
Project partner Project partner Contact Stefan Gewies Stefan Gewies Project Manager DLR Institute of Communications and Navigation E-mail: Stefan.Gewies@dlr.de www.r-mode-baltic.eu Chart 19
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