Réunion du Projet GEOIDE ENV#14
tenue le 2 novembre 2001 à
Meeting of the GEOIDE Project
held on November 2nd,
2001 at Montreal (Viasat)
9:00 Mots de bienvenue / Welcome addresses
People present at the meeting :
CRG-UL : Rock Santerre, Brian Morse,
Stéphanie Michaud, Nicolas Balard
UNB : Richard Langley, Sunil Bisnath
McGill: Xiao-Wen Chang
Viasat: Denis Parrot, Claude St-Pierre, Luc
GSD : Pierre Tétreault
9:05 Résumé des activités de recherche depuis
juin 2001/ Summary of research activities since June 2001
Dr. Kim has continued his work on an optimised
least-squares ambiguity search technique, cycle-slip corrections and quality control for
real-time applications. The research has also dealt with physical and mathematical
correlations. Dr. Langley summarized Dr. Kims most recent work, because Dr. Kim is
working right now on a research contract in South Korea. He will be back at UNB by the end
of November. Full papers on this work, published in the proceedings of ION-GPS 2001 and
KIS-2001, can be found on the UNB Web site <http://gauss.gge.unb.ca/papers.pdf/>.
Dr. Kim also submitted a refereed paper to the U.S. Journal of Navigation.
S. Bisnath, a Ph.D. student at UNB, who joined the
Project ENV#14 team last summer has worked on reliable cycle slip detection and repair and
precise point positioning (PPP) software. Full papers describing his work, published in
the proceedings of ION-GPS 2001 and KIS-2001, can be found on the UNB Web site. He
presented results from PPP which were obtained from both static and kinematic data
(including Low Earth Orbit satellite CHAMP). Initital rms values for 3-D positioning of 20
cm have been attained.
L. Lamoureux presented some PPP results obtained
from the software originally developed by GSD (P. Héroux). This modified software is
going to be added to the Viasat GPS software suite. Close cooperation between Viasat and
UNB is planned to compare results from the two PPP software packages independently
developed and to possibly unify the two approaches.
C. St-Pierre showed results obtained from Dr.
Zhus algorithm (CRG-U.Laval) to calculate a smoothed float ambiguity solution which
takes also into account the occurrence of several cycle slips. Drastic improvement, in
comparison to the original float solution actually coded in the Viasats EzSurv
software, is clearly demonstrated. IP agreement has to be signed between Viasat and the
CRG about this new algorithm.
Dr. Zhu also worked on the use of a priori
height, obtained from the tide gauges, as a quasi observation in GPS-OTF data processing.
A paper has been submitted to Geomatica, last August. Dr. Zhu returned to South Central
University, China, in July. He is planning to come back to the CRG, next February.
Brian Morse, a professor of Civil Engineering,
worked with Stéphanie Michaud (a research assistant at the CRG) and Jimmy Siles (a civil
engineer with an M.Sc. in hydrodynamics, now a research assistant working on Project
ENV#14, since September 2001) on the determination of ship under keel clearance for secure
maritime navigation. Data from field tests collected during the Fall 2000, for the St.
Lawrence Seaway, are now available to the Project ENV#14 research team. In relation to
these works, Dr. Morse got a mandate (a contract) with the Centre de développement des
Transports (CDT), to further process and analyse squat and under-keel clearance
algorithms. An abstract, summarizing the results obtained thus far has been submitted to
the Canadian Civil Engineering Conference to be held next June.
12:15 13:00 Lunch time
13:00 Planification des futures activités de
recherche / Planning of future research activities
Dr. Chang, from the Department of Computer Science
at McGill University, officially joined the Project ENV#14 Team. He is a specialist in
computer algorithm optimisation and GPS integrity solutions. Two of his graduate students
will be working to topics related to the project (see the Appendix for a short description
of their future works).
Many pieces of software, new algorithms and results
have been developed, tested and analysed. It is now time for technology transfer to our
industrial partner. In this perspective, several agreements should be signed to protect
Intellectual Property, namely:
- The development of the algorithm for smoothed float GPS phase
- The fusion of PPP software (UNB-Viasat).
- The software modules related to cycle slip detection and stochastic
- The squat model equation (U.Laval-CDT).
Two new refereed papers have been submitted, one by
Dr. Kim (Navigation) and another one by Zhu and Santerre (Geomatica). Planning of other
papers to be submitted to refereed journals has been made. Here are some proposals:
- A paper on PPP combining Viasat and UNB algorithms and software
(Action: S. Bisnath and L. Lamoureux).
- A paper on squat and UKC based on the presentation to the Canadian
Civil Engineering Conference (Action: B. Morse and S. Michaud).
- A paper on the efficiency and robustness of precise GPS navigation
(Action: X.-W. Chang)
- A collective paper on the current status and future trends into the
field of precise GPS marine navigation (Action: B. Morse).
CoI in GNSS
A Centre of Innovation in GNSS has been proposed by
UofC. Presentations have been given to representatives from UNB, Viasat and GSD. The
GEOIDE Network is aware of this proposal. Coordination will have to be addressed between
GEOIDE and this new CoI in GNSS, if this project really goes ahead
GEOIDE Phase II
The full proposal of the Galileo Project (LOI#19),
involving the 3 universities active in GPS (Laval, UNB and Calgary) and McGill University,
has been submitted to the GEOIDE Business Office, by October 15th, 2001. The
other participants are: GSD, Viasat, NovAtel and Thales. The acceptance will be known at
the beginning of February and if the answer is positive the project will start April 1st,
2002, for a 3-year period.
15:00 Visite des nouveaux locaux de Viasat / Visit
of Viasats new facilities
15:30 Fin de la réunion / End of the meeting
The next project meeting is scheduled for the second
week of March 2002. Again, the meeting will probably be held at Viasats office, in
Montréal. The date will be announced later.
Appendix: Description of the projects of the two
McGill M.Sc. students
Ms. Lan Yin:
Chris Paige and Xiao-Wen Chang have recently
developed an efficient and numerically reliable recursive least squares algorithm for
carrier phase based positioning. In the algorithm, ambiguities are not fixed as integers,
because for many applications like those VIASAT Geo-Technologies Inc. has, float ambiguity
solutions are enough for the desired accuracy of position estimates. In order to apply our
algorithm to real data, we need to incorporate an algorithm for cycle slip detection
and/or correction. Ms. Yin is doing comparisons of some typical available methods for
cycle slip detection and/or correction. She will incorporate one of the best methods in
our positioning algorithm. She is also expected to extend our current positioning
algorithm to handle both carrier phase measurements and code pseudorange measurements.
Ms. Ying Guo:
Recently a few people in the GPS community have
applied adaptive robust estimation techniques to GPS based positioning. Some test results
suggest the techniques are promising. However there are two main problems with the
literature. One is that no any paper we have seen deals with the implementation issue.
When we implement a method, we have to consider a few key issues like efficiency,
numerical reliability, and memory. The other is that the methods in the literature are for
general estimation problems. But the estimation problems arising from GPS have
special structures, which should be used to make the methods more efficient. Ms. Guo is
developing efficient and numerically reliable algorithms for Kalman filtering based
adaptive robust estimation for general purposes. After that, she will develop specific
algorithms for GPS based positioning by taking advantages of the special structures of the
position estimation problems.
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