IGS Analysis Center Coordinator (ACC) at GFZ Potsdam
General Information About the IGS Products
These WWW-pages are meant to give information about the quality of the
IGS Products. The page you are currently reading should be of interest for
the general IGS "customer". The other pages contain figures and tables
summarizing the results from the IGS orbit combinations.
Those pages are mainly of interest for the IGS Analysis Centers but of course
everybody is free to visit them and look at their content.
The tables and figures of the Final page are updated every Saturday.
The other pages are updated shortly after corresponding combination. The figures show the
results of the last 60 weeks except for the "Final (ALL)" page which
shows the results of the IGS orbit combinations since its beginning at
the end of 1993.
The IGS Analysis Center Coordinator (ACC) is, among others, responsible
for generating the official IGS combined products. Currently, there are
three official IGS product lines, namely the IGS Final-, the IGS Rapid-,
and the IGS Ultra-Rapid products.
The availabe IGS products are:
- IGS Final products (IGS)
The IGS Final products have the highest quality of all IGS products.
They are made available on a weekly basis,
every Friday, with a delay of 13 (last day
of the week) to 20 (first day of the week) days. The IGS Final products
are the basis for the IGS reference frame.
- IGS Rapid products (IGR)
The IGS Rapid products have a quality comparable to that of the Final
products. They are made available on a daily basis with a delay of merely
17 hours after the end of the observation day, i.e., the IGS Rapid products
become available on a daily basis at 17:00 UTC. For most applications
the user of IGS products will not be able to notice any significant
differences between results obtained using the IGS Final and
the IGS Rapid products.
- IGS Ultra rapid products (IGU)
To reduce the age of the Predicted orbits, the IGS has started with the
generation of so-called "Ultra rapid" products. Like the IGS Predicted
products the Ultra rapid products are available for real time use.
However, the Ultra rapid products are provided twice per day, at 03:00 and
15:00 UTC. In this way the average age of the predictions is reduced to
9 hours (compared to the 36 hours for the IGS predicted products).
This should lead to significantly improved orbit predictions.
Contrary to all other IGS orbit products the IGS Ultra rapid orbits files
contain 48 hours of orbit. All other orbit products contain 24 hours.
The first 24 hours of the IGS Ultra rapid orbit are a "real" orbit, i.e.,
an orbit based on real GPS data coming from the IGS hourly network.
The next 24 hours are a predicted orbit. The orbits are, however,
continuous at the boundary between the real and predicted orbit part.
It is possible that the IGS Ultra rapid products will replace
the IGS Rapid products in the near future. This will depend on the quality of the two products.
For
statistical information on the ultra-rapid products, see these pages
at the TU Vienna (new broswer window opens).
Where to get more information about the IGS ?
For more information about the IGS (International GPS Service) please visit
the IGS Central Bureau which is located at the Jet Propulsion Laboratory, in
Pasadena, California, U.S.A.
- Especially helpful are the two following IGSCB pages:
Where to get the IGS products ?
Please use the link below to get information on the location of
the different IGS products.
How to use the IGS products?
Below we try to address some of the frequently asked questions regarding the
use of IGS products. Currently only two topics are handled, but more are to
follow.
Jun 19, 2003, originator G. Gendt
