The structure of Section I in the period 1999-2003, was established
during the IUGG General Assembly in Birmingham, and was similar to that for the
previous four-year period, in that it consisted of one Commission, one Special
Commission and four Special Study Groups. These were:
The Commissions and SSGs have all been productive during the period
1999-2003, and full details of their activities are reported below. I will
therefore only highlight a few of the more significant aspects of the progress
that has been made.
There has been some progress towards realizing the AFREF project, aimed
at establishing a continental geodetic reference frame for Africa. Although
steady progress has been made, with the support of IAG, there is still a
considerable way to go before such a frame is fully implemented. I hope that
developments will continue, and the project will repeat the success of the
SIRGAS project in South America.
There has been substantial activity in the topic of GPS as an
Atmospheric Remote Sensing Tool, as GPS is proving to be of significant
importance in a number of atmospheric research and operational applications. In
terms of meteorology, there is now considerable development of GPS networks for
near real-time forecasting, and growing interest in long time-series data sets
for climate studies. The activity in ionospheric studies has been considerable,
not least due to the recent period of maximum solar activity.
Signal multipath is still a considerable problem in many environments,
but significant progress has been made over the last four years through
improved hardware solutions, novel data analysis techniques and sophisticated
approaches to system modeling. Interestingly, as with propagation delay,
multipath is turning out to be of interest in its own right, not just as a
nuisance factor. It is also of growing importance as indoor GPS positioning
becomes more available.
Improvements in stochastic and functional modelling have led to
substantial improvement in both the accuracy and reliability of precise
kinematic positioning solutions. The multiple reference station approach to
providing corrections for RTK positioning has led to much improved performance.
However, there is still a way to go before long-range sub-centimetre accuracy
is achieved.
A growing area of research in the application of geodesy to engineering,
has been the use of pseudolites to augment GPS signals, as well as for sole
use, and integrated with other sensors. This promises to be an area of
continuing interest, particularly in terms of aiding indoor GPS measurement, or
providing a “seamless” positioning solution..
Section I has also played a major part in numerous scientific meetings
during the last four years, including for example the Mobile Mapping Technology
workshop in Cairo, Egypt in January 2001, the symposium on Vertical Reference
Systems in Cartagena, Colombia in February 2001, and the workshop on GPS
Meteorology in Tsukuba, Japan in January 2003. In addition the Section played a
full role in the very successful IAG Scientific Assembly in Budapest, Hungary,
in 2001 and will be contributing to many of the symposia, in addition to the
specific Section 1 meeting, at the forthcoming IUGG General Assembly in
Sapporo, Japan.
It is increasingly apparent that there has been growing interaction and
overlap between the Sections of the IAG (Section I and Section II in
particular) as well as between the Sections and the IAG services. This is no
more apparent than in Section I with for example the subject of global and
regional networks being of primary importance to both Commission X and the IGS.
For these reasons, the IAG review of its structure, presented and approved at
the Scientific Assembly in Budapest, addressed the growing importance of the
IAG Services, whilst also redefining the Section/Commission structure in an
attempt to recognise the changing geodetic scene.
In the new structure the present five sections and their associated
commissions and special commissions will be abolished, to be replaced by four
topic-related Commissions (each with a sub-structure of sub-commissions and
SSGs). Under this structure a new Commission 4 on “Positioning and
Applications” will be established, following the Sapporo General Assembly. This
new Commission will encompass much of the role of the current Section I, whilst
also recognising the growing involvement of geodesists in the application of
geodesy. The exact sub-structure is still to be confirmed but I hope it will
enable a much better recognition for the substantial activities of geodesists
in the ever growing applications market. This includes not only engineering but
also navigation and a wide range of scientific fields, where geodesy is often
implicitly involved, but often not explicitly visible. Furthermore the IAG
Services, such as the IGS, will have a more explicit role in IAG activities in
the future as they will be better integrated with the new Commissions.
Finally, I
would like to express my sincere thanks to everyone who has contributed to the
Section’s activities over the last four years, notably the Section officers,
and in particular my Section Secretary, Prof Chris Rizos, for his tremendous
efforts. I wish him every success in his role as President of the new
Commission 4.