Civil GPS Service Interface Committee
International Information Subcommittee
The International Information Subcommittee (IISC) of the Civil GPS Service Interface Committee (CGSIC) convened at the Holiday Inn, Fair Oaks, in Fairfax, VA, USA, on March 29, 2000.
The original meeting minutes are below.
The IISC session of the 35th CGSIC meeting began after some administrative remarks related to future CGSIC Meetings by Captain Tom Rice. At the end of his remarks, he mentioned that Mr. Saville would be stepping down as the Chair of the IISC.
0850 OPENING REMARKS Michael Saville
Mike began by stating it has been his pleasure to serve as Chair of the IISC and he thanked all the individuals scheduled to make presentations today. After making the decision to delay his own presentation till later in the session due to technical difficulties, he introduced Mr. Denis Hains, regional chair for North America (Canada, Caribbean, Mexico).
0855 NORTH AMERICAN REGIONAL UPDATE Denis Hains
Mr. Denis Hains, vice chair of the North American region and Director, Geodetic Survey Division, Geomatics Canada, presented a North American Regional Update that focused on the 1999 activity report and the 2000 activity plan. His focus was primarily on Canada, but he also briefly mentioned that contact has been made the Caribbean and Mexico, and additional participation from these areas is being sought.
Additional 1999 activities quickly summarized by Mr. Hains were as follows:
- 1st Canadian Federal Interdepartmental GPS Coordination Meeting, June 1999;
- Canadian Active Control System (Wide Area) - GPSC and Canada-wide DGPS Program;
- 5 GPSC Test & Evaluations projects (Agriculture, Forestry, Aviation, Arctic Hydrographic & Legal Surveys)
- Precise Satellite Positioning Market Study for Canada (A. Andersen Consultant);
- Evaluation and Distribution model Study for GPSC in Canada (A. Andersen Consultant);
- Canadian involvement in Galileo through the Canadian Space Agency.
The planned activities he mentioned for the year 2000 were summarized as follows:
- 2nd Canadian Federal Interdepartmental GPS Coordination Meeting, June 2000;
- Formal contacts and meetings with Mexico and Caribbean States, Fall 2000;
- Networking with South American countries to develop a possible new Region for the IISC;
- Precise Satellite Positioning Risk Analysis Study for Canada;
- Canadian Active Control System (Wide Area) - GPSC and Canada-wide DGPS Program;
- 2 GPSC Test & Evaluations projects (Arctic Hydrographic Surveys, Geological Survey)
- Canadian involvement in Galileo through the Canadian Space Agency.
Mr. Hains concluded his presentation by illustrating the market acceptance of GPS in Canada with an advertisement for a $149 (Canadian) GPS receiver, and an article about the Casio GPS watch.
0905 INTERNATIONAL INFORMATION SUBCOMMITTEE UPDATE Mike Saville
Mr. Mike Saville, Chair of the IISC, provided an update and overview of the IISC to include its objectives, current activities, and future activities. The objectives of the organization were summarized from the March 1999 CHSIC Executive Business Plan and the September 1998 IISC Charter. Each of the excerpts from these documents highlighted the IISC's primary role as a conduit of information on GPS and its augmentations between the US Government and the international user community.
Turning to a review of on-going IISC activities, Mr. Saville first discussed the status of identifying country points of contact (CPOC) to report to the regional chairs. In Europe, Germany, France, Greece, Portugal, and Poland have identified CPOCs. In the Asia-Far East region, Japan and Hong Kong have CPOCs identified, and Australia has identified a CPOC for their region that also includes New Zealand and Indonesia. Other nations that have identified CPOCs include Canada, Israel, Saudi Arabia, and Egypt. Other nations currently without an official CPOC, such as the Czech Republic, have nevertheless been active in the IISC through activities such as hosting meetings.
Mr. Saville then briefly mentioned that the IISC web pages are under revision and any suggestions for improvement are welcome. Regarding IISC meetings, he acknowledged the recent meeting in Prague (December 1999) and upcoming meetings of the European Region (Monaco, December 2000), and Far East Region (Japan, February 2001).
Before turning to future activities Mr. Saville thanked the regional chairs, the rapporteur, and others who assist the IISC. He then listed the following subjects as potential areas of future focus for the IISC:
- Coordinated Global meetings
- International and National representation
- Institutional organizations
- ITS authorities
- Spectrum co-ordination maintenance?
- Separate IISC web site
- Obtain benefits from the exploitation of Information Society Technologies
Mr. Saville then concluded his presentation by displaying the agenda for the remainder of today's session and turned the meeting over to George Weber to give the European regional report.
0920 EUROPEAN REGIONAL UPDATE George Weber
Before beginning his formal presentation titled GPS in Europe & ITRF2000, Dr. Weber, European Regional Chair, mentioned that the 8th European IISC Meeting held in Prague and hosted by the Czech Technical University drew a much higher level of participation from Central Europe than in the past. Many of the presentations made at this meeting pointed out the challenges faced by many users of GPS due to budget constraints. He then also took the opportunity to announce that the 9th European IISC Meeting will be held this year in Monaco.
Dr. Weber began his formal presentation by stating that the geodetic reference frame used by GPS, known as WGS 84, is only accurate to 1 meter. Therefore, Europe is in the process of developing an update to the International Terrestrial Reference Frame (ITRF) known as ITRF 2000. This reference frame is being defined using many measurement techniques that include GPS and an established GPS geodetic reference station network in Europe known as EUREF.
EUREF observations for use in redefining ITRF took place from 1996 to 1999. After post-processing and modeling, these observations have resulted in root mean square (RMS) accuracy values as good as 20 millimeters.
0930 FAR EAST REGIONAL REPORT Hiroshi Nishiguchi
Mr. Nishiguchi's update on items of interest in the Far East region has very succinct. Using only one viewgraph, he introduced Mr. Simon C. W. Kwok, Geodetic Survey Section, Lands Department of Hong Kong. Mr. Kwok recently agreed to be the Hong Kong point of contact for the IISC. He then announced the 2001 IISC Far East Regional Meeting, titled GNSS Symposium 01, to be held in Japan from February 7-9, 2001.
0935 SPACEBORNE USES OF GPS John Rush
Mr. John Rush of the U.S. National Aeronautics and Space Administration (NASA) discussed the many uses of GPS that now occur in space, including the use of GPS for positioning and timing on low-earth orbiting satellites and platforms such as the Space Shuttle and the International Space Station.
H explained that the spaceborne use of GPS differs from terrestrial use in several ways. For example, high doppler rates and a changing view of the constellation from an Earth-orbiting satellite changes satellite availability based on orbital altitude. In low-earth orbit availability is very high (i.e. a recent shuttle mission continuously viewed over 20 GPS satellites); whereas in geosynchronous orbit, availability is very limited.
The benefits of GPS to space users include access to precise orbital information (as good as 5 centimeters with data post-processing) which could result in cost reductions for satellite tracking systems, and higher levels of automation for things like small satellite formation flying.
Turning to the use of GPS by satellites at a higher orbital altitude than the GPS constellation, Mr. Rush explained that this use is enabled by the fact that the aperture of the GPS satellite antenna allows the GPS signal to radiate through and beyond the limb of the Earth. Future weather satellites will be deployed with GPS receivers and equipment on-board to measure water vapor content by observing atmospheric distortion as the signal passes through the limb of the Earth.
Mr. Rush used the final portion of his presentation to discuss possible benefits to space users from an expanded number of GNSS and GNSS augmentation satellites. He believes that additional signals available from systems such as WAAS, EGNOS, MTSAT, and perhaps even Galileo, can benefit space users if both non-interference and interoperability between each constellation can be assured.
Responding to a question on the use of GPS for launch vehicles, Mr. Rush stated that the U.S. is considering increased use of GPS within the nation's launch ranges for both range tracking and for launch vehicle guidance.
0955 GLOBAL NAVIGATION SATELLITE SYSTEM: LEGAL IMPLICATIONS OF INTEROPERABILITY Ingrid Lagarrigue
Ms. Ingrid Lagarrigue, Executive Manager of Air Eurosafe, thanked Mike Saville and Rebecca Casswell for inviting her to the meeting, and then provided a summary of the legal issues she planned to discuss. These are the impact of GNSS interoperability on existing institutions, and the potential need for a new liability regime to cover global navigation satellite systems.
The working definition of interoperability used by Ms. Lagarrigue was simply the interaction of two or more systems with one another. She then hypothesized that international GNSS interoperability could be achieved by a new or existing international organization such as IMO, ICAO, ISO, and the ITU. Any one of these organizations could have a leading role in the management of interoperability between GPS, Galileo, and Glonass.
Another institutional implication of interoperability mentioned by Ms. Lagarrigue is the Harmonization of standards. She suggested that the RTCA and EuroCAE, two aviation standard setting organizations already working on MOPS for combined GPS/Glonass receivers, could be used harmonize GNSS standards. In her opinion, it remains to be seen whether or not common GNSS standards will be developed.
Turning to the impact of interoperability on liability issues, Ms. Lagarrigue stated that liability rules must be re-apportioned for GNSS because both the US and Russia, although they have pledged to provide GNSS services, currently enjoy immunity from liability tort suits. She then stade her opinion that a treaty or regime to govern GNSS liability would be an ideal solution.
Responding to a question at the conclusion of her presentation about a future in which the US would no longer enjoy sovereign immunity for GPS-based services, Ms. Lagarrigue stated that once Galileo begins operating, all GNSS service providers will have the same kind of liability because it makes no sense that one provider would be liable when another provider is not liable.
1035 GALILEO PRESENTATION TO THE CGSIC IISC -- Martine Mamlouk
Ms. Mamlouk attended the CGSIC IISC session on behalf of the European Commission (EC) Directorate General (DG) for Transport and Energy (TREN), and made it clear that she would avoid discussing the French position on Galileo although she is a member of the French Transport Ministry. She began her presentation by briefly explaining that a great deal of work is currently underway in preparation for the December Council of Ministers decision point. The current organizational structure for the Galileo definition phase was also described, including:
- the Galileo steering committee - consisting of representatives of all EU member states, ESA, and two countries outside the EU (Switzerland and Norway);
- a program management board as overseeing the staff that manages current Galileo definition phase contracts (this staff will become the Galileo program office);
- working groups focused on specific issues such as liability and user requirements.
Under the current Galileo definition phase, a number of important activities are underway as described by Ms. Mamlouk. These include international negotiations, the establishment of user and security requirements, the investigation and selection of an appropriate public-private-partnership group, and the continued study of the Galileo satellite design. 9 separate studies have been funded to date, with a corresponding total expenditure of 100 M Euros.
After showing a timeline for the completion of the various stages of the program, including the definition phase (2000), the design and development phase (2003), in-orbit validation (2006), and system deployment (2008), Ms. Mamlouk described some of the system's proposed services. As previously reported, three basic levels of service will be provided, a mass market open access service (OAS), controlled access service 1 (CAS1) for commercial applications, and controlled access service 2 (CAS2) consisting of a safety-of-life service (SAS) and a governmental access service (GAS). She stated that the performance of the OAS will be high, while CAS1 will add additional services and guarantees. CAS2-SAS has been conceived to provide the required reliability/continuity of service to a small group of users such as aviation, while GAS will be aimed at providing a highly reliable service for certain classes of users such as law enforcement. This service would probably remain available even in a time of crisis.
Regarding the current status of the overall Galileo system architectures under investigation, Ms. Mamlouk explained that the goal is to reduce the overall cost of providing satellite navigation services and perhaps even additional communications capabilities. She also specifically mentioned that integrity broadcasts from the MEP constellation is being seriously considered because of improved visibility of this broadcast in high latitude regions compared to a GEO-based integrity broadcast. Two main options for the space segment of Galileo seem to be primary architecture candidates at this time. One would be a MEO-only 30 satellite constellation in three orbital planes, while the second option would be a 24 satellite, 3 plane MEO constellation with 8 equally spaced GEO satellites.
Turning to potential GPS and Galileo interoperability, Ms. Mamlouk stated that the two systems must be interoperable. However, she believes that GPS timing and coordinate references could be improved, and should be improved together with Galileo. Although she favors total seamless interoperability from a receivers perspective with at least 8 GPS/Galileo satellites in view at all times, she stressed that independence must still be maintained to provide the best protection against failures for the user.
The next topic addressed by Ms. Mamlouk was the concept of public-private partnerships (PPPs) for the eventual operation of Galileo. Two adequate PPP proposals have been received by the EC to date. In implementing the PPP concept, she stated that there is a need balance public needs with private sector desires, which she believes can be combined in the service architecture. She also stated that the EC is committed to WTO (world trade organization) rules and all other international rules, and any cost recovery mechanisms implemented by the Galileo PPP eventually selected will fully comply with these rules.
Discussing liability, Ms. Mamlouk shared her opinion that the widespread acceptance of satellite navigation will be hindered if the liability issue is not adequately addressed. According to her, the Galileo program is attempting to do this by guaranteeing signal, continuity and integrity, proposing regional management of integrity, and actively participating in legal study groups. She also mentioned that liability issues are on the EC's agenda for talks with the US and with Russia.
Frequency spectrum for Galileo was the last subject covered by Ms. Mamlouk. She stated that frequencies are being considered with the knowledge that users will benefit from the combined use of GPS and Galileo. She then showed an illustration of the RNSS bands that included 7 distinct Galileo frequency bands ranging from 1 to 40 MHz in width. Six of the proposed frequencies were in L-band, while one was in C-band. A final decision on the overall signal baseline, according to her, will be made in July 2000.
1120 IGEX-98 CAMPAIGN Jim Slater
Before beginning the prepared portion of his presentation, Mr. Jim Slater of the US National Imagery and Mapping Agency (NIMA), corrected an earlier statement by George Weber, regarding the accuracy of WGS 84. According to Mr. Slater, WGS 84 has been accurate to 5 centimeters, not 1 meter, for a number of years.
Turning to a discussion of the International Glonass Experiment (IGEX), Mr. Slater explained that the campaign was conceived by the IGS, after combined GPS/Glonass receivers of geodetic quality became available in 1998. IGEX was chaired by Mr. Pascal Willis and was conducted under the auspices of the International Association of Geodesy. The campaign was a tremendous success and participation from around the world was much higher than anticipated.
The set-up of the experiment was modeled on the IGS network designed to collect GPS data, and IGEX data was collected and handled in the same manner. It is the belief of the IGEX team that the campaign and its results could act as a model to be followed for the eventual scientific use of data from multiple GNSS systems.
Mr. Slater concluded his briefing by stating that 31 IGEX stations are still sending data to 3 global analysis centers even though the experiment is officially over. However, the future collection of useful data is uncertain due to the lack of operational (only 8 at the time of the presentation) Glonass satellites.
1145 FRENCH GEODETIC NETWORK Pascal Willis
Mr. Pascal Willis, Institut Geographique National, discussed the status of the French Geodetic Network. The network currently consists of 12 stations that record dual frequency GPS data but do not transmit real-time differential corrections. However, some stations do download every hour and provide hourly data for geodetic applications. Discussions regarding the value of using these stations to provide corrections for DGPS broadcast capability are currently under way within the French government. Issues including the existence of a free service versus a private company broadcast of corrections are being addressed as part of the discussions.
1150 GPS ACTIVITIES IN JAPAN Hiroshi Nishiguchi
To begin his discussion of GPS activities in Japan, Mr. Nishiguichi focused on spectrum issue and summarized the official positions of the Asia-Pacific block on WRC 2000 issues related to GPS:
- Agenda item 1.9 - MSS sharing of 1559 to 1567 MHz sharing is not feasible and Resolution 220 should be suppressed;
- Agenda Item 1.15.2 - New Space-to-Space RNSS Allocation fully support the 1559-1610 allocation and support the 1215-1260 with condition (not specified);
- Agenda item 1.15.1 - New RNSS Spectrum supports the language for an L5 allocation that comprises the modification of the CPM (conference preparatory meeting) report.
The second subject covered by Mr. Nishiguchi was the current utilization trend for GPS in Japan. He showed data that was heavily focused on the automobile navigation market, which is by far the largest GPS market in Japan. He then discussed existing GPS augmentation systems in Japan, including: MSAS (awaiting MTSAT launch); Beacon DGPS; FM-DGPS; DCMA-RTK and dedicated wireless Link RTK-DGPS; and finally, the GEONET GPS reference station network. New trials and experiments using GPS that are soon to be conducted in Japan include RTK applications utilizing a cellular telephone -based communications link, and PHS or cellular (IMT2000)-based GPS telematics.
Mr. Nishiguchi concluded by stating that he expects a large market expansion will result from the eventual elimination of selective availability (SA) and the GPS industry in Japan looks forward to its discontinuance.
1158 GPS AND GNSS ACTIVITIES IN HONG KONG Simon C. W. Kwok
Speaking at a CGSIC IISC meeting for the first timer, Mr. Kwok thanked Mr. Canny and Mr. Nishiguchi for getting him involved in the IISC and also thanked Dr. Dennis Milbert and Dr. Charlie Challstrom of the US Department of Commerce's National Geodetic Survey (NGS). He then provided a summary of his presentation which covered current GPS activities in Hong Kong, differential services provided within the borders of Hong Kong, and planned future activities under development.
Under current activities, Mr. Kwok first discussed time and frequency applications of GPS and mentioned GPS use by the Hong Kong Observatory, the standards and Calibration Laboratory of the Hong Kong Industry Department, the Mass Transit Railway (positive train control), and private sector mobile phone and paging companies. He then began a more detailed discussion of geodetic applications and first mentioned Hong Kong's2000 GPS Reference Network that consists of 46 stations tied to the ITRF reference frame providing 5mm +0.2ppm accuracy at the 95% confidence level for geodetic/geophysical applications. An Active GPS Control Station Network is also under development that should enable the use of low-cost single frequency receivers and short observation times (5 -10 minutes) for post processing applications or will enable centimeter-level accuracy using fast (single epoch) integer ambiguity resolution with no initialization for RTK surveying applications.
Under the category of differential services, Mr. Kwok discussed the use of DGPS in marine navigation activities. The Maritime DGPS Radionavigation Service is based on a station operated by the Marine Department that transmits RTCM corrections at 289 KHz over a 500 kilometer radius. His discussion of developmental activities covered projects under consideration for land use, maritime use, and aviation use of GPS. He also provided a great deal of additional details regarding future improvements to the Active Control Station Network.
Mr. Kwok concluded his informative presentation by stating that Hong Kong has chosen to invest heavily in GPS infrastructure because it brings social and economic benefits to society.
1225 UPDATE ON THE SWEDISH NETWORK OF PERMANENT REFERENCE STATIONS (SWEPOS) Andreas Engfeldt
Andreas Engfeldt of the Swedish National Land Survey provided an update of national GPS activities taking place in Sweden. He discussed Time/frequency activities, survey/geodesy/GIS activities, and navigation activities.
Mr. Engfeldt then provided an update on the Swedish Network of Permanent Reference Stations (SWEPOS). SWEPOS provides both private and public sector differential services based on a subset of the network. A new project, known as NeW-RTK, allows for the broadcast of SWEPOS network data for RTK (real-time-kinematic) applications using the Swedish National Broadcasting Service.
Other development activities, industrial aspects of GPS, national policies and decisions, and a summary of national responsible authorities for GPS within Sweden can be found in a written summary report prepared by Bo Jonsson of the Geodetic Research Division, National Land Survey of Sweden.
1235 CANADA UPDATE Dennis Hains
Discussed the Canadian active Control System and the Canada-wide DGPS propose Program to deliver GPS-C (differential corrections) to all Canadians using satellite communications
1240 CLOSING REMARKS Mike Saville and Tom Rice
Mr. Saville recognized the efforts of the presenters in making it to the meeting and then gave the floor to Captain Rice, who promptly closed the session