Radio Technical Commission for Maritime Services

1. Radio Technical Commission for Maritime Services The State and Status Special Committee – 104 20 March, 2014 NOAA March 2014 NOAA / NGS RTN Webinar Kendall Ferguson Hemisphere GNSS, Senior Principal Design Engineer RTCM, SC-104 Chair & Board of Directors Stafford, VA USA

2. Presentation Outline • Question Often Asked • Why is RTCM, an apparent maritime-based organization, involved in carrier-based real-time GNSS provider networks? • Existing Standards: State and Work In Progress • The current standards • Work in progress • New work on the horizon • Summary

3. Two Main Message Standards • RTCM 2.3 (RTCM 10402.3) • Codephase Differential Corrections • Primarily L1-Only, GPS-Only (though there is some support for GLONASS) • For SOLAS applications • Message format developed with primary communication link layer in mind • MF/LF Band at 25-300 bps • Typical Accuracies < 1 m • Yes, RTCM 18-21 support carrier applications but these are not SOLAS • RTCM 3.2 (RTCM 10403.2) • Carrier and Code Differential Corrections for High-Precision • For RTK, Network RTK, and PPP-type applications • Recently modernized with, so called Multiple Signals Messages (MSM), for generic inclusion of new constellations and signals • MSM Currently supports GPS, GLONASS, Galileo, QZSS, BeiDou, SBAS • Though some work still in progress for newer constellations and signals • Message structure designed with OSI 7-layer architecture in mind

4. Standards Work In Progress • RTCM 10402.3 (i.e., Version 2.3)  Version 2.4 • Multi-GNSS/Multi-Frequency (i.e., DGNSS). • Via new generic messaging approaches (e.g., Type 41 and 42). • Potential for 2 dm 2 σ (at max broadcast range). • Supports Legacy Message Interleave (e.g., Type 1 and 9). • Recommending Retirement of Types 18-21 • RTCM 10401.2 (i.e., RSIM 1.2)  RSIM 1.3 • Defining Reference Station (RS), Integrity Monitor (IM), Control Station (CS) and Transmitter (TR) Performance, Functions, and Messaging for SOLAS DGNSS Applications. • Modernizing from L1 GPS only to Multi-GNSS/Multi-Frequency • Adding further Alarm Attributes to Aid in Monitoring and Reporting of Alarm Conditions • Reduce Load on Control Station Operators • Speed System/Component Failure Detection and Recovery

5. Standards Work In Progress (continued) • RTCM 3.2 • Version 3.2 Published February 1, 2013 • Mostly to collect the numerous revisions to Version 3.1 • These 3.1 updates include: • First Multiple Signals Messages (MSM) • First State Space Representation (SSR) Messages • MAC and FKP Messages • Amendment 1 (Published July 12, 2013) • Added BeiDou Multiple Signals Messages (MSM) • Added Galileo F/Nav Ephemeris Message • Amendment 2 (Published Nov 7, 2013) • Added QZSS Multiple Signals Messages (MSM) • Added QZSS Ephemeris Message

6. Standards Work In Progress (continued) • RTCM 3.2 (Work In Progress) • State Space Representation (SSR), a message for PPP-type uses • Phase I: already in published 3.2 • Phase II: adding additional models such as TEC (in progress) • Phase III: carrier based clocks (in early development states) • Coordinate Transformation Messages improvements underway • Network RTK Approaches (i.e., Non-Physical Reference, MAC, and FKP) • Currently GPS and GLONASS only • Committee currently deliberating adding other constellations and signals • Navigation Data Frame (NDF) messages under deliberation • Carries raw navigation data frames from various satellites: • GPS, GLONASS, BeiDou, QZSS, and SBAS.

7. Standards Work In Progress (continued) • Network Transport of RTCM via Internet Protocol (Ntrip) • Ntrip Version 2.0, with Amendment 1 • Published on June 28, 2011 • Widely used in industry carrying not only RTCM data but numerous other data (even beyond proprietary GNSS receiver data) • Supporting TCP/IP, UDP, and SSL • Work In Progress • Sourcing the Station Log Files • Offering suggested source table meta-names to aid in more automation of stream selections.

8. RINEX Working Group • RINEX and SC-104 Tighter Relationship (~2 yrs ago) • RINEX and RTCM essentially deal with same ‘observables’ • The independent committees now jointly develop solutions • Example: Phase alignment • Ensure RINEX can be created from RTCM 3.x • Joint decision to only further development of 3.x • Example: RINEX 3.02 supports BeiDou; version 2.x does not. • BKG developing open source for RTCM 3 and RINEX converters • http://software.rtcm-ntrip.org/ • teqc equivalent in the plans • RINEX 3.03 current being considered • Several issues with 3.02 raised by community that may require 3.03 • Any version beyond 3.02 will likely undergo RTCM-type interoperability testing

9. NMEA Working Group • NMEA and SC-104 Tighter Relationship • RTCM SC-104 Standards messages traditionally from Reference Receiver / Network sent to User • Community requesting standardized messages for high precision work carrying end solutions reaching a wider range of other applications, systems and devices • Formed an NMEA Working Group (WG) within SC-104 • Will be developing messages that essentially carry solution results to other applications, systems and devices • Will likely be developing messages targeted at Network management side • Receiver Controls: e.g., reset commands, elevation masks, etc. • These will be developed under NMEA-0183, 2000, and the new OneNet • WG Formed Sept 2013, thus no progress yet to report

10. Thank You • Thank You • RTCM SC-104 Participation • Questions