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Global Velocity
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EGM96 Correction Calculator Jules map server Earth ILP GSRM EarthScope 		Science Product Support - GPSVEL Site Offsets and Data Exclusions

Site offsets and data exclusions are given a code to represent a known or suspected origin. In the case of multiple configuration changes on the same date more than one code (up to 4) can be used, the offset may be explained by any of the codes.

IGS format site logs contain records that indicate either a change in receiver configuration or a change in antenna configuration. A new record in the log might indicate a change to a new receiver/antenna of the same type or a different type, either could cause an offset.

Since there is no seperate record in IGS format site logs for radome or antenna height changes they are recorded using a new antenna record. In the case of a new antenna record, if the antenna or radome name is not changed from the previous record (i.e. same make of equipment but new and hence a change) there is no way to know if a new antenna record relates to changes in antenna or radome configuration. Because of this ambiguity D and A often appear together.

Receiver, Antenna and Radome character codes follow the IGS conventions. Uncertainty in the origin of the offset may be expressed by appending a question mark to the string.

Current codes are:

    A = Antenna change

    C = Co-seismic - Nearby earthquake

    D = Dome - Change of Radome

    E = Error - Recording error in site log or email

    F = Flange - Flange, Radio Frequency screening, Radio Frequency filtering or other Antenna modifications

    H = Height change - Recorded change in Antenna height

    M = Monument move - Offset used to connect adjacent sites

    O = Oscillator - Change in external/internal receiver clock configuration

    M = Monument move - Offset used to connect adjacent sites

    P = Physical damage - Physical damage to site equipment, eg. lightning, vandalism etc.

    R = Receiver change

    S = Splitter - Antenna splitter used to connect more than one receiver to an antenna

    U = Unknown

    ? = Uncertainty in assigned codes

Fields in the offset file

Field Chars Format Related Codes Explanation
0 1 * or space All Commenting out field
1 2-5 4-char site name All Name of site
2 7-10 4-char site name M Name of additional site connected by estimating offset
3 12-20 Decimal year All Date of offset
4 22-32 yy:dayofyear:sec All Date of offset
5 35-38 4 char GPS week All GPS week of offset
6 40-43 Up to 4-char code string - Explanatory offset code string
7 45-47 3 char U or N or E All Visible appearance of offset in time series
8 49-68 20 char Receiver code R Receiver operating before offset
9 70-89 20 char Antenna code A Antenna in use before offset
10 91-94 4 char Radome code D Radome in use before offset
11 96-115 20 char Receiver code R Receiver operating after offset
12 117-136 20 char Antenna code A Antenna in use after offset
13 138-141 4 char Radome code D Radome in use after offset
14 143-149 7 char height change H Difference in before and after antenna hgts
15 151-153 Char center code ADEFHMOPRS Center used for related site information, analysis
emails and site logs, e.g. igs
16 155-158 4 char integer email number ADEFHMOPRS Analysis email number
17 160-163 4 char log number yymm ADEFHMOPRS Analysis site log name extension, e.g. igs0109.log.
NOTE aus logs are mmyy
18 165-167 3 char integer distance C Horizontal surface distance to earthquake epicenter in km
19 169-171 3 char magnitude C Earthquake magnitude
20 173- Multi-char comment string Any Comments and additional info

Fields in the exclusion file

Field Chars Format Related Codes Explanation
0 1 * or space All Commenting out field
1 2-5 4-char site name All Name of site
2 7-15 Decimal year All Start date of exclusion
3 17-28 yy:dayofyear:sec All Start date of exclusion
4 30-33 4 char GPS week All Start GPS week of exclusion
5 35-43 Decimal year All End date of exclusion
6 45-56 yy:dayofyear:sec All End date of exclusion
7 58-61 4 char GPS week All End GPS week of exclusion
8 63-66 Up to 4 char code string - Explanatory code string
9 68-71 3 char U or N or E All Visible appearance in time series
10 73-91 20 char Receiver code R Receiver operating during exclusiong period
11 93-112 20 char Antenna code A Antenna in use during exclusion period
12 114-117 4 char Radome code D Radome in use during exclusion period
13 119-121 3 char center code ADEFHMOPRS Center for related site information, analysis emails
14 123-126 4 char integer email number ADEFHMOPRS Analysis email number
15 128-131 4 char log number yymm ADEFHMOPRS Analysis site log name extension, e.g. igs0109.log.
NOTE aus logs are mmyy.
16 133 Multi-char string Any Comments and additional info

Web information

Site logs and site information can be accessed via the Internet. <stat> is the 4-char lowercase site id and <email#> is the 4 char integer email number.

IGS:

AUS:

  • AUS homepage
  • AUS site logs (log names are <stat>MMYY.log, MMYY = date)
  • AUS site info: http://www.auslig.gov.au/geodesy/argn/<stat>.htm
  • AUS emails: http://www.auslig.gov.au/geodesy/hypermail/argn-l/<email#>.html

EUR:

  • Euref homepage
  • Euref site logs (log names are <stat>YYMM.log, YYMM = date)
  • Euref site info: http://www.epncb.oma.be/info/<stat>.html
  • Euref emails: ftp://ftp.epncb.oma.be/pub/mail/eurefmail.<email#>

SIR:



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Last modified Saturday, 22-Jul-2006 00:27:59 UTC
 

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