Date: Wed, 21 Mar 2001 09:18:13 +0000 From: Werner Gurtner Subject: [IGSLEO-5] Format Issues for the LEO Pilot Project To: igsleo@igscb.jpl.nasa.gov Message-id: <3AB871D5.54464C40@aiub.unibe.ch> Organization: University of Berne Sender: owner-igsleo Precedence: bulk ****************************************************************************** IGS LEO Mail 21 Mar 10:09:24 PST 2001 Message Number 5 ****************************************************************************** Author: Angelyn Moore, John Dow, Werner Gurtner Format Issues for the LEO Pilot Project *************************************** Angelyn Moore, John Dow, Werner Gurtner Dear colleagues, unfortunately it took longer than estimated to collect the reactions to the mail sent on Tue, 13 Feb 2001 regarding the format discussions we had at the Potsdam LEO meeting. They can be summarized as follows: All answers except the one from GFZ explicitly agreed to at least one of the following proposals: - RINEX format version 2.20 (i.e., including the proposed LEO extensions) for all file-oriented GPS data, both for spaceborne and ground station receiver data - SP3 format for precise orbit exchange, at least for the duration of the Pilot Project - GFZ Champ Data Format for auxiliary data, at least for the duration of the Pilot Project It was stated by different colleagues that the Pilot Project should be used to gather experience with - the simple, well-known SP3 format for orbits, being aware of possibly missing data fields - the existing GFZ Champ Data Format and to postpone the decision to go to a more general RINEX-type of format The GFZ colleagues proposed the following: - RINEX format version 2.20 for all low-rate GPS data for both spaceborne (10 sec) and ground station (30 sec) data - GFZ BINEX format for all high-rate GPS data, i.e., - 50 Hz occultation data - 1 Hz ground station data They feared that relevant information could be lost in the conversion to RINEX (precision, channel numbers). (Comment by WG: The RINEX 2.20 proposal covered both the channel number as well as an increase of the precision by any number of digits). - CHAMP precise orbits in GFZ CHAMP Orbit Format (30 s, 1 d arcs) Their proposal to use the GFZ CHAMP Data Format for accelerometer, star sensor and thruster data corresponds to the preferences of the other Pilot Project members. - File naming: GFZ proposes to stick to their convention for primary data access to avoid renaming or parallel archiving on their side. They would like to leave the renaming into the proposed IGS conventions to the users within the pilot project. - They propose that the same procedure could be applied for the data formats, too. In a subsequent discussion Ch. Reigber agreed to convert three months of BINEX data to RINEX 2.20 and to make available the data on a separate server accessible by standard ftp procedures. Orbits could be converted to SP3, too. To summarize: - The LEO PP members who answered the call prefer RINEX for all GPS data, the IGS filenaming scheme was not questioned, they prefer to generate and exchange LEO precise orbits in SP3 and they agree to the GFZ Champ Data format for the auxiliary data. - GFZ will prepare a limited data set in the requested formats on a server separate from their web-based system. CDDIS agreed to collect and make available all data and products generated within the frame of the IGS LEO Pilot Project. Details will be worked out later. Angelyn Moore John Dow Werner Gurtner