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Bernese GPS Software Version 5.0 - Bernese GNSS Software

Bernese GPS Software Version 5.0 - Bernese GNSS Software

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22. Data Structure<br />

22.4.5 Satellite Information File<br />

Type: ASCII<br />

Directory: ${X}/GEN (UNIX) or %X%\GEN (Windows)<br />

Extension: Variable.<br />

Content: Satellite information (block, sensor offsets, masses, etc.) for <strong>GPS</strong> (PRN <<br />

100), GLONASS (100 < PRN < 200), geostationary (300 < PRN < 400),<br />

and LEOs (PRN > 900). For Galileo 200 < PRN < 300 is reserved.<br />

Created by: User-defined. Available from BSW aftp server.<br />

Used by: Most orbit and processing programs.<br />

Example: Figure 22.7. An update version of the file SATELLIT.I05 is available at the<br />

anonymous BSW ftp area (see Section 4.12)<br />

Remark:<br />

• The file contains all satellite information necessary for <strong>GNSS</strong> data processing. All<br />

information is annotated with a time window which allows it to include the entire<br />

history of the satellite constellation in the same file. The information is contained in<br />

two data sections (PART 1 and PART 2). A third section (PART 3) gives information<br />

on the different flags and parameters, provides internet addresses of related sites, and<br />

contains a change log.<br />

• In PART 1: PHYSICAL SATELLITE PARAMETERS the satellites are listed with block<br />

numbers, COSPAR numbers, attitude flag, time window, (launch and decommissioning)<br />

masses, area-to-mass ratio (not used), a priori radiation pressure model number,<br />

a priori coefficients (corrections to the a priori model) for the direct radiation pressure<br />

(DP0), for the y-bias (P2), and for the direction perpendicular to the two (P3) in m/s 2 .<br />

Not used are the air drag model specification, and the air drag coefficient. The last<br />

column (IFRQ) gives the frequency number for GLONASS.<br />

• PART 2: ON-BOARD SENSORS contains for each satellite the sensor name(s), time window<br />

(which needs to be the same as in the first section!) sensor offsets (for microwave<br />

antenna or SLR reflector), and sensor boresight and azimuth unit vectors w.r.t. a<br />

satellite-fixed coordinate system. The sensor name has to be defined in the antenna<br />

phase center file.<br />

• The satellite information file contains the information concerning the radiation pressure<br />

model to be used. We recommend to use the Rock T model as a priori model<br />

for <strong>GPS</strong>, even if the differences to the other models is negligible for the creation of<br />

the standard orbits from tabular / precise orbits. No a priori model is available for<br />

GLONASS.<br />

• If a new satellite is launched the information for this new satellite has to be included<br />

into the file. A new line has to be added in both parts and time window, block<br />

number, antenna offsets, etc. has to be introduced correctly. You may copy the lines<br />

from another satellite and adapt it accordingly. Pay attention in particular to the<br />

block and the antenna offsets. Check that no time window of an inactive satellite<br />

with the same PRN number is overlapping with that of the new satellite. An up-todate<br />

SATELLIT.xxx file may be downloaded from the anonymous BSWUSER ftp area<br />

(http://www.aiub.unibe.ch/download/BSWUSER50/, see Section 4.12).<br />

• Observations without satellite information for the specific epochs are removed by<br />

programs RXOBV3 and RNXSMT. A corresponding warning message is issued.<br />

Page 486 AIUB

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