[IGSMAIL-3105]: OSLO IGS Network-COST 716 Workshop Summary
Ruth E. Neilan
rneilan at mail1.jpl.nasa.gov
Fri Nov 17 16:59:53 PST 2000
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IGS Electronic Mail 17 Nov 16:57:13 PST 2000 Message Number 3105
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Author: Ruth Neilan
Dear colleagues,
This message contains a brief summary of the Oslo Workshop, jointly
conducted between the IGS and the COST 716 that was held in July.
For reference, the agenda of the IGS Workshop portion is also
appended at the end of the summary and numerous web site links are
included as a resource. The recommendations stemming from this
important workshop are contained in a separate subsequent message.
Workshop participants can be viewed in the Extended Abstracts book
referred to below.
Many thanks to those of you who made this workshop such a success -
with sincere regards,
Ruth
Summary
IGS Network Workshop
Oslo, Norway
10-15 July 2000
The second major IGS Network Workshop was held in Oslo, Norway, July
10-14, 2000. The purpose of this workshop was to focus on aspects of
the network targeted at improving the infrastructure and network
operations in support of the quality and timeliness of IGS products.
Dr. Angelyn Moore, IGS Network Coordinator and Deputy Director of the
IGS Central Bureau in JPL Pasadena did an exceptional job convening
this workshop, which was considered a great success by all who
attended. The local host and logistics were managed excellently by
Dr. Hans-Peter Plag of Statens Kartverk, the Norwegian Mapping
Authority (NMA). Much appreciation is expressed to Bjorn Engen,
Director of Geodesy Division at NMA, and his staff, to note a few:
Oddgeir Kristiansen, Rune Hanssen, and Svein Rekkedal among others.
Bjorn Engen is one of two IGS Network Representatives to the
Governing Board, thus it was a good opportunity to organize this
meeting with his support. The venue for the workshop was at the
beautiful Soria Moria Hotel on a hill overlooking Oslo. The
atmosphere enjoyed by old and new colleagues will not be forgotten.
This was the first occasion that the IGS Network workshop was
convened as a multi-disciplinary meeting. On Monday and Tuesday, July
10 and 11, the workshop was devoted to 'COST Action 716'. COST
stands for 'European Cooperation in the Field of Scientific and
Technical Research'. Action 716 is 'Exploitation of Ground Based GPS
For Climate And Numerical Weather Prediction Applications'. COST is a
framework for scientific and technical cooperation, allowing the
co-ordination of national research on a European level. COST Actions
consist of basic pre-competitive research as well as activities that
serve public utility. The main objective of 716 is assessment on an
international scale of the operational potential for exploiting
ground based GPS networks to provide near real time observations for
numerical weather prediction and climate applications. In parallel,
the IGS has a dedicated troposphere working group estimating total
zenith path delays (ZPD) and precipitable water vapor (PWV) at a
number of the IGS stations. Also, a number of the IGS agencies and
their networks have either implemented or are moving towards
real-time processing activities, many pursuing similar applications
in terms of groundbased meteorology. The synergy for having a joint
workshop was quite evident.
A joint COST/IGS session was planned for Wednesday, July 12, followed
by the IGS Network Workshop focusing on detailed IGS infrastructure
issues July 13 & 14. The detailed agendas can still be found at
http://www.gdiv.statkart.no/igsworkshop/
An excellent book of extended abstracts prepared by the Norwegian
Mapping Authority is available:
http://www.gdiv.statkart.no/igsworkshop/book/
This is the first IGS workshop where a commercial publisher will
actually handle the proceedings. This will be a joint, peer reviewed
proceedings published by Elsevier and it will be available sometime
early in 2001. A number of copies have been secured by the IGS for
distribution and archival. However, copies will be available for
sale directly from Elsevier, more information will be provided in the
future.
Executive Summary
The IGS Network Workshop focused on a number of key issues facing the
IGS in terms of moving products closer to real-time delivery. The
IGS has been generating an unofficial product called the Ultra Rapid,
which is delivered twice daily from the analysis centers to
prospective users. This requires hourly retrieval of data files and
twice daily processing of the products. In order to make these Ultra
Rapid products and predictions available in a more reliable fashion,
a number of issues must be addressed by the IGS network community.
The three key issues seem to be:
- hourly data operations and reliability,
- the availability of hourly data from the data centers, and in
particular the global data centers,
- as the IGS network moves closer to supporting real-time
applications, development of an exchange format for data from the
different sites around the world is needed as a standard
It's very clear that many of the participating agencies within the
IGS already run regional or national networks in real-time, some at
high rate (1second sampling), and with essentially no latency in data
streaming (less than a few seconds). If the IGS is to support these
kind of applications from a global level, there must be an
international standard which the IGS can develop, adopt, and promote
to realize a subset of the global infrastructure which supports
real-time, high reliability applications.
COST Workshop Summary
The COST Workshop opened Monday morning with a description of the
COST Action. These COSTS are based on inter-governmental agreements
between 32 countries to initiate research activities within Europe.
This is open to industry, natural research centers, universities, and
other agencies to create scientific networks and applications.
Currently, there are more than 70 initiatives within COST and over
200 COST Actions at the moment. COST 716, the focus of this
workshop, was under the meteorology initiative, of which there are
currently seven with three new ones being planned. There are four
working groups in this COST Action 716, which will be meeting over
the next few days of the workshop. This COST 716 was initiated in
September of 1999 and there are four working groups,
1) To produce the state-of-the-art product requirements,
2) A demonstration of these,
3) Working group on applications and developing applications, and
4) What the plans are for those applications.
The COST home page is here:
http://www.belspo.be/cost/
Action 716:
http://www.oso.chalmers.se/Geo/cost716.html
Gunnar Elgered from Sweden chairs COST 716. He stated that the
primary purpose of 716 was to study the combined affect of the GPS
errors and atmospheric errors and see how they de-correlate with
distance and to assess how the GPS observations can be utilized for
operational meteorology.
Mark Higgins, Representative of the UK Meteorology office, discussed
the applications of GPS from studies that they have been conducting
throughout Britain. The primary message from his talk was
meteorological offices use many sensors worldwide, but the potential
for tracking the very rapid changes with GPS is what could prove most
useful. Key questions such as "When will it start to rain over
Wimbledon?" and also how can GPS improve timing for forecast
predictions are of most interest. He also stated that they'd like to
have, within an hour and one-half after the observations are made,
information that a local forecast office could use for the next 36
hours. This information would be most useful for the first 12 hours.
He showed some interesting cases where GPS had seemed to work quite
well and other cases where it clearly did not. Most of their models
are using the total path delay and some of the questions that he
summarized, representative of subsequent discussions as well, were:
where, how and when to use surface pressure observations? what are
the height correction schemes for GPS? how do the horizontal
observation errors correlate with ground based GPS, what is the
height variation of g, etc. They also noted that they'd really like
to get the climate users on board and engaged with this activity.
Network Workshop Summary
The overview for the workshop began with an introduction by Gunnar
Elgered, who went over the details of COST 716 as stated above. Jim
Zumberge, from JPL, followed with a presentation on the effect of the
removal of selective availability SA and the way in which satellite
clocks can be handled within the IGS. With the removal of SA,
intentional frequency dithering of GPS satellite clocks, it now
seemed possible to do a combined predicted clock as well as
presenting the possibility for predicting a real-time clock to a much
greater accuracy than previously available. With SA on, the
transmitter clocks would indicate excursions of roughly 20
centimeters per second (rms slope of the transmitter clocks), with
tens of centimeter variations over a few hours. With the removal of
SA, studies indicate an improvement to ~a millimeter per second
variation. He indicated that clocks based on the 30second GPS data
could be good to ~4mm, and for 10second data to the ~2mm levels.
The next aspect within the IGS workshop was a focus on the IGS
Rapid-Ultra Rapid products. Gerd Gendt from GFZ in Potsdam, talked
about the improvement of the Ultra Rapid (sub-daily) over the Rapid
(daily) and how much improvement could be made for the Ultra vs. the
Rapid with better network configuration and performance. He was
recommending to shorten the time from the current 12 hour data sets,
which the analysis centers are using, to six hours, submitting orbit
estimates every 4 hours instead of every 12. The greatest difficulty
that most analysis centers are having in terms of achieving these
objectives is the availability of data and also the reliability of
the data centers. He suggested that some kind of real-time integrity
or quality monitoring would be preferred.
Hans van der Marel from Delft presented recommendations on operations
for GPS ground based meteorology and also discussed the NRT or Near
Real Time networks within Europe, planned to support upcoming
demonstrations within COST 716. An NRT demonstration is planned for
February 2001, which will be the first time that the output from the
GPS ground network will be input into the analysis for numerical
weather prediction (NWP). The NRT networks within Europe
participating in this are the Magic Network, the Gasp and the Alpine
Network. He stated that the NRT reference network will depend
heavily on IGS and EUREF networks and that they will be using IGS
Ultra products and predictions.
Throughout the remainder of the day there were presentations from
Stick Ware of UCAR describing SUOMI Net, a project to install over
100 receivers at different universities, primarily located in the U.S
for the purpose of atmospheric studies. Jens Wickert described the
CHAMP GPS ground network and applications from CHAMP for space-based,
air ground based meteorology. Ron Muellerschoen from JPL presented
an interesting result on real-time network being operated out of JPL
for real-time, continuous orbits and positioning which resulted in
~30-40 centimeter orbits. Tim Springer, the IGS Analysis Center
Coordinator, went on to describe the current status of products
within the IGS.
The remainder of the day and the following two days focused more on
detail in terms of routines for data validation, quality checking,
what the directory structure should be for hourly data, how to have
similar directory structures implemented at the regional,
operational, and global data centers. The discussion on various
communications schemes, VSAT, internet, wireless also raised
discussions of LDM, a system developed by UniData Corp. in
association with UCAR for the distribution of primarily atmospheric
data.
There was an extended discussion on data formats for real-time data
as it became evident that there are currently as many as eight
different formats being used by participants within the IGS. A
working group was formed to discuss the formats and to make a
recommendation for an internationally accepted standard or format to
be used by the IGS. Some of the binary formats include: the native
format coming out of the receivers; UNAVCO's proposal of BINEX;
Norwegian Mapping Authority's SATREF network format called RIBEX;
Delft is using a type of binary RINEX, NCBI; GFZ reported on a type
of binary format which is based Turbo-binary compressed (used by GFZ
and JPL for CHAMP network operations, as well as a GFZ-BINEX format)
and JPL is using a format known as 'SOC'. There was a recommendation
that the IGS investigate the RTCM format utilized by most of the real
time corrections, navigation and RTK applications within the broader
GPS user community. There were descriptions from various regional
operators describing activities, e.g., Bob Twilley from Australia,
Ludwig Combrinck from South Africa, and from applications e.g., Susan
Skone from Calgary using the IGS network to conduct ionospheric
research. Bruce Schupler from Honeywell gave a very interesting
presentation on frequency phase center responses to radomes and
calibration of antennas. He also considered the impact of the new GPS
civil frequency at 1175 MhZ, which may require a new band pass filter
on the antennas. Professor Gu Guohua gave an interesting description
of the CMONOC network within China - the 'Crustal Motion Observation
Network of China' which includes 25 permanent continuous fiducial
stations, 56 basic stations and 1000 regional stations, the latter
operated just occasionally in a campaign style mode. He described
that they have satellite communications at most of the 25 stations
and that their data center has the possibility to store 81 GB on line
with 16 workstations and a number of IBM servers. CMONOC has
proposed to the IGS to become a data center, a mirror site for the
Central Bureau information system, and, as soon as practical, become
an analysis center for regional analysis within the IGS. For the
data centers, Carey Noll showed that currently 50% of the hourly
files are delivered within 15 minutes. This was met with the
recommendation that hourly files should be more reliable, more
accessible, and their latency should be no more than 10-15 minutes
after the hour. There was also the recommendation that the broadcast
ephemeris be added to the hourly data. Tom Herring and Tim Springer
presented results that used the time series of the GPS stations to
assess current performance and quality, noting some particular
difficulties and problems with stations that would not be detected by
the currently available programs, such as the TEQC of UNAVCO. Tom
showed an approach developed at MIT of using SNRs and the stability
of Lc phase rms as an indicator of station performance over time.
See his website for examples and tools:
http://www-gpsg.mit.edu/
A contest was held for the best poster presentation with the award
being a donated receiver from Ashtech. A committee comprised of 3
members from COST and 3 from IGS was established to review each
poster and met to agree on the best deserving poster. The winner was
Jan Dousa, and co-author Leos Mervart from the Research Institute of
Geodesy, Topography and Cartography in the Czech Republic, for their
poster 'On Hourly Orbit Determination'. Many thanks to Ashtech for
their generous contribution and engaged support of the IGS.
The general workshop concluded on Friday, July 14 at noon. A summary
session was held in the afternoon present per IGS tradition attended
by the Conveners, Central Bureau, and Governing Board members. The
key recommendations stemming from the summary session are in a
separate message. This concludes the brief summary of the highlights
from the IGS Network Workshop 2000. We encourage interested people
to obtain a copy of the proceedings that will go into much more depth
on all of the issues discussed above.
Regards,
Ruth Neilan
IGS Central Bureau
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Wednesday, 12 July 2000
Opening Remarks
Welcome from Statens Kartverk: Bjorn Engen
9:00-9:25 Welcome from the IGS: (Ruth Neilan for)Christoph Reigber
Opening Remarks: Angelyn Moore
Practical Details: Hans-Peter Plag
Real-time Analysis Center Issues, Now and Future: G. Gendt, J. Zumberge
9:25-9:45 An Overview of COST Action 716 G. Elgered
(Extended abstract)
9:45-10:05 Position Paper G. Gendt and J. Zumberge
10:05-10:25 COST and the IGS (Extended H. VanderMarel
abstract)
10:25-10:45 SuomiNet: A GPS Network for R. Ware
Real-time Atmospheric Sensing
10:45-11:00 break
11:00-11:20 Occultation requirements (Extended J. Wickert
abstract)
11:20-11:40 JPL real-time analysis software R. Muellerschoen
11:40-12:00 Ultrarapid products -- quality T. Springer
dependence on network performance
12:00-12:20 IGS Hourly Data and Products for P. Fang
Near Realtime GPS/Met Applications
12:20-12:40 Panel discussion Session conveners &
authors
12:45-1400 Lunch
Network Requirements: Caissy, Gurtner
14:10-14:30 Position paper M. Caissy and W. Gurtner
The Western Canada Deformation
14:30-14:50 Array: Continuous GPS Network M. Schmidt
Operations at PGC
14:50-15:10 JPL and UNAVCO Network operations D. Stowers
in light of LEO ops
15:10-15:30 Multipurpose GNSS network R. Hanssen
operations
15:30-16:00 break (+ finalize poster setup?)
16:00-16:20 Real-time Data Streaming from GPS M. Jackson, C. Meertens,
Networks and C. Rocken
16:20-16:40 Data Formats (Extended abstract) A. Moore, summarizing
input from several groups
16:40-17:00 Panel discussion Session conveners &
authors
17:00-18:00 Poster viewing + icebreaker
Thursday, 13 July 2000
-------------------------
Regional operations & equipment issues: M. Chin, L Combrinck
9:20-9:40 Position paper M. Chin, L. Combrinck
The Response of GPS Antennas -- How
9:40-10:00 design, environment, and frequency B. Schupler
affect what you see
GPS Receiver Tracking Performance
10:00-10:20 under Ionospheric Scintillation S. Skone
Conditions (Extended abstract)
10:20-10:40 GPS Site Continuity A. Niell
10:40-11:00 break
EUREF, The Regional Densification
11:00-11:20 of the IGS in Europe (Extended C. Bruyninx
abstract)
11:20-11:40 The Australian Regional GPS Network B. Twilley
11:40-12:00 Progress in the Crustal Movement G. Gu et. al.
Observation Network of China
12:00-12:30 Panel discussion Session conveners &
authors
12:45-14:00 Lunch
14:00-14:30 Poster + exhibit viewing
Data systems: C. Noll
14:30-14:50 Data flow/Backup (Extended C. Noll
abstract)
14:50-15:10 Hourly data flow H. Habrich and D. Stowers
15:10-15:30 IGLOS-PP (GLONASS Pilot Project) W. Gurtner
(Extended abstract)
15:30-16:00 break
16:00-16:20 IGS Support to LEO Missions -- data T. Yunck
systems
16:20-16:40 CHAMP-ISDC - The IT Project for B. Ritschel
Satellite Missions
16:40-17:00 UNAVCO Community GPS Seamless C. Meertens, F. Boler, L.
Archive (GSAC) Project Estey, and M. Scharber
17:00-17:30 Panel discussion Session conveners &
authors
20:00 Banquet
Friday, 14 July 2000
-------------------------
Quality of the IGS Network: T. Herring, T. Springer
Current status of IGS station
9:20-9:40 quality feedback (Extended A. Moore
abstract)
9:40-10:00 Current State of IGS Analysis: T. Herring, T. Springer
Quality Assessment
10:00-10:20 Radome lessons learned J. Johansson and G.
Hedling
Fundamentalstations - an important
10:20-10:40 key for the combination of space W. Schluter
techniques
10:40-11:00 Panel discussion Session conveners &
authors
11:00-11:20 Break
11:20-12:00 Break out into working group discussions
12:00-12:25 Plenary: brief working group reports
12:25-12:40 Closing session Workshop organizers
12:45-14:00 Lunch
14:30-17:00 Wrap-up and plans Program Committee (Closed
session)
Poster presentations
-------------------------
The IGS Global Data Center at the
Carey Noll and Maurice Dube CDDIS -- an Update (Extended
abstract)
Roman Galas, Christoph Reigber, and H/R GPS Ground Tracking Network for
Jens Wickert CHAMP
Roman Galas and Wolfgang Koehler A Binary Exchange Format for GPS Data
M. Schmidt, H. Dragert, W. Hill, N. New GPS Monument Design for Permanent
Courtier GPS Installations in the Western
Canada Deformation Array
PyGPS: a GPS data processing
Alexander Voinov automation package (Extended
abstract)
Preliminary results of processing of
Zinovy Malkin, Alexander Voinov EUREF observations using non-fiducial
strategy (Extended abstract)
Iskander Gayazov, Maxim Keshin, GRAPE software for GPS data
Alexander Fominov processing: first results of ERP
determination (Extended abstract)
L. Estey, C. Meertens, and D. Hunt Application of BINEX and TEQC for
Real-Time Data Management
O. Ruud, D. Stowers, M. Jackson, B.
Perin, K. Feaux, and D. Maggert UNAVCO GPS Network Operations
J. Neumeyer Th. Nischan and M. Technical solutions of GFZ global GPS
Ramatschi network
Matthijs van Domselaar, Yehuda Bock,
Peng Fang, Paul Jamason and Michael Activities at the Scripps Orbit and
Scharber Permanent Array Center (SOPAC)
IGS Stations as Tectonic Tracers and
G. Steblov and M. Kogan Importance of Local Densification
(Extended abstract)
Jan Dousa, Leos Mervart On Hourly Orbit Determination
(Extended abstract)
Proposal for a Binary Receiver
Kees de Jong and Hans van der Marel Independent Exchange Format (Extended
abstract)
Real-time GPS and Glonass Integrity
Kees de Jong and Hans van der Marel Monitoring and Reference Station
Software (Extended abstract)
J. Dow, R. Zandbergen, J. Feltens, ESA/ESOC GPS receivers. Current
C. Garcia, I. Romero. status and future plans.
Ensuring timely and consistent data
Plag, H.-P., Kristiansen, O. delivery by automated control
procedures
Plag, H.-P., Kierulf, H. P.;
Kristiansen, O.; Opseth, P. E.; Extended GPS site documentation
Rekkedal, S.
Geirsson, H., Arnadottir, T., and The Icelandic Continuous GPS Network
Bergsonn, H. - ISGPS (Extended abstract)
Hanssen, R. I., and Opseth, P. E. The SATREF Receiver Independent
Binary Exchange Format (RIBEX)
Hanssen, R. I., Halvorsen, T., and GNSS Data Integrity Monitor System
Vang, P. (GDIMS)
A Simple GPS Precise Point
Heroux, P. and Kouba, J Positioning Interface Using IGS Orbit
Products
Italian GPS Network: Operational
Faccia, R. activity of Centro di Geodesia
Spaziale di Matera (Extended
abstract)
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