Subject: [SIR-Mail] No.468: igs08_1707.atx: Update including JPSREGANT subtype calibrations & R743 From: Laura Sanchez ******************************************************************************** SIR Electronic Mail 2012-09-25 07:56:33 UTC Message No. 468 ******************************************************************************** Dear IGS colleagues! The absolute IGS antenna correction file (igs08_wwww.atx) has been updated. The new release is called ´igs08_1707.atx´. It contains the following changes: 1) Subtype calibrations provided by Geo++ GmbH for two Javad antennas (JPSREGANT_DD_E, JPSREGANT_SD_E): JPSREGANT_DD_E1 NONE JPSREGANT_DD_E2 NONE JPSREGANT_SD_E1 NONE JPSREGANT_SD_E2 NONE Those calibrations will be needed for the switch from the reference frame realization IGS08 to IGb08 that should take place on 7 October 2012, the start of GPS week 1709 (to be announced in a further IGSMail). As the switch to the subtype calibrations will cause coordinate changes for all affected stations, the subtype antenna names should not be considered before IGb08 is adopted. More details can be found below. 2) The last out of three GLONASS-M satellites launched on 4 November 2011 was added with a preliminary z-offset value of 245 cm: R743 (R08) Compare [IGSMAIL-6660], [IGSMAIL-6661] as well as the following message provided by the Information-Analytical Centre: > According to GLONASS System Control Centre, the Glonass-M #743 SV residing near orbital slot 2 will be set healthy on 20 September 2012 at 18:30 (MT). In the almanac Glonass-M #743 will be designated under system number 8 http://www.glonass-ianc.rsa.ru/en/content/news/?ELEMENT_ID=324 3) One additional robot calibration provided by Geo++ GmbH: ASH701023.A NONE This single-frequency antenna type was installed at the M-GEX station GRAC (Grasse) between 1998 and 2000: http://igs.org/igscb/station/pendinglogs/grac/grac_20111019.log 4) One robot calibration provided by Leica Geosystems AG and performed by Geo++ GmbH: LEIGS08PLUS NONE The updated antenna correction model is available at ftp://igs.org/pub/station/general/igs08_1707.atx or ftp://igs.org/pub/station/general/igs08.atx With best regards, Ralf Schmid and Robert Khachikyan on behalf of the IGS Antenna Working Group Why subtype calibrations for the JPSREGANT antennas? ---------------------------------------------------- Sometime in 2000, Javad changed the setup of two of its JPSREGANT antenna types (JPSREGANT_DD_E, JPSREGANT_SD_E) that introduced a 3-4 cm position bias (mainly in the vertical component). Unfortunately, these new subtypes did not produce a new name definition and proper recognition within the IGS. At first, this was only a problem for those IGS stations that were equipped with the new subtypes. With the switch from igs_01.pcv to igs05.atx in November 2006, mean PCV values over the two subtypes were adopted for both antenna types. Since that time, all stations equipped with one of the JPSREGANT antenna types are affected by a vertical bias of up to 2 cm that shows up in coordinate time series, if the antenna is exchanged. Extremely disadvantageous are such biases furthermore, if so-called local ties with respect to nearby located instruments are considered. As the IGS aims at estimating station coordinates with an accuracy of a few mm, coordinate biases of 2 cm cannot be ignored. However, as not only the antenna types, but also the station coordinates have to be corrected, the problem can only be solved in conjunction with an update of the IGS reference frame. As the switch from IGS05 to IGS08 was missed, the transition to IGb08 represents another opportunity. Which stations are affected? ---------------------------- According to Geo++, the subtypes are defined as follows (as Geo++ didn´t get each single antenna for calibration, the classification can only be vague; especially with respect to JPSREGANT_SD_E, the exact borderline is unknown): > | JPSREGANT_DD_E1 | Dual -depth chokering antenna, external | > | | different PCV due to systematics within series; | > | | no unique criteria, but guess is serial number RA | > | JPSREGANT_DD_E2 | Dual -depth chokering antenna, external | > | | different PCV due to systematics within series; | > | | no unique criteria, but guess is serial number RRA | > | JPSREGANT_SD_E1 | Single-depth chokering antenna, external | > | | different PCV due to systematics within series; | > | | no unique criteria, but guess is serial number | > | | below RA0131 | > | JPSREGANT_SD_E2 | Single-depth chokering antenna, external | > | | different PCV due to systematics within series; | > | | no unique criteria, but guess is serial number | > | | above RA0132 | ftp://igs.org/igscb/station/general/rcvr_ant.tab With the help of the classification given above, the Antenna Working Group tried to identify all subtypes ever installed within the IGS network. If possible, the subtype was also verified by the purchase/installation date, by the analysis of coordinate time series as well as of coordinate or troposphere ties. With one exception (IRKJ), the additional evidence was always consistent with the subtype assumed from the serial number of the antenna alone. Active IGS stations: | Site | Antenna subtype | Installed | Removed | S/N | |------|----------------------|------------|------------|--------| | CAGZ | JPSREGANT_DD_E2 NONE | 2001-10-01 | !!ACTIVE!! | RRA052 | | CONZ | JPSREGANT_DD_E1 NONE | 2002-05-16 | 2005-05-17 | RA0178 | | DLFT | JPSREGANT_SD_E1 NONE | 1999-02-17 | 1999-03-29 | RA0043 | | DLFT | JPSREGANT_DD_E1 NONE | 1999-03-29 | 2004-03-08 | RA0077 | | DLFT | JPSREGANT_DD_E1 NONE | 2004-03-08 | dormant? | RA0077 | | FFMJ | JPSREGANT_SD_E2 NONE | 2002-02-18 | 2005-05-19 | RA0294 | | HUEG | JPSREGANT_SD_E2 NONE | 2002-02-21 | 2005-12-05 | RA0310 | | HUEG | JPSREGANT_SD_E2 NONE | 2005-12-05 | 2008-03-13 | RA0291 | | KHAJ | JPSREGANT_SD_E1 NONE | 2001-07-18 | dormant? | RA0032 | | MDVJ | JPSREGANT_DD_E1 NONE | 2001-07-18 | !!ACTIVE!! | RA0195 | | MOBJ | JPSREGANT_SD_E1 NONE | 2007-05-24 | !!ACTIVE!! | RA0033 | | MOBK | JPSREGANT_SD_E1 NONE | 2007-05-24 | !!ACTIVE!! | RA0033 | | MTBG | JPSREGANT_DD_E1 NONE | 1999-07-01 | 2008-11-09 | RA0085 | | NOVM | JPSREGANT_SD_E1 NONE | 2006-11-07 | !!ACTIVE!! | RA0038 | | STR2 | JPSREGANT_DD_E1 NONE | 2000-02-18 | 2003-01-18 | ???005 | | TITZ | JPSREGANT_SD_E2 NONE | 2001-09-27 | 2003-01-14 | RA0291 | | TITZ | JPSREGANT_SD_E2 NONE | 2003-01-14 | 2008-02-20 | RA0311 | | UNBJ | JPSREGANT_DD_E1 NONE | 2001-05-23 | 2012-06-01 | RA0193 | | ZIMJ | JPSREGANT_SD_E1 NONE | 1999-02-03 | dormant | RA0059 | |------|----------------------|------------|------------|--------| Former IGS stations: | Site | Antenna subtype | Installed | Removed | S/N | |------|----------------------|------------|------------|--------| | DREJ | JPSREGANT_SD_E2 NONE | 2001-09-05 | 2002-02-01 | RA0290 | | DREJ | JPSREGANT_SD_E2 NONE | 2002-04-04 | 2003-11-17 | RA0292 | | DREJ | JPSREGANT_SD_E2 NONE | 2003-11-17 | 2007-03-06 | RA0293 | | DWH1 | JPSREGANT_DD_E1 NONE | 2000-10-05 | ????-??-?? | RA0083 | | KOU1 | JPSREGANT_DD_E2 NONE | 2002-01-20 | ????-??-?? | RRA31 | | NOVJ | JPSREGANT_SD_E1 NONE | 2001-07-24 | ????-??-?? | RA0038 | | SUNM | JPSREGANT_SD_E1 NONE | 2001-06-12 | 2010-10-12 | RA0024 | | UNB1 | JPSREGANT_DD_E1 NONE | 2001-05-23 | ????-??-?? | RA0193 | | WTZJ | JPSREGANT_SD_E2 NONE | 2002-04-11 | 2005-08-02 | RA0295 | |------|----------------------|------------|------------|--------| Not corrected: IRKJ (JPSREGANT_SD_E NONE) In this special case, only a verification of the serial number or an individual calibration of the antenna after the decommissioning will bring clarity. Expected station position changes --------------------------------- For the affected IGS08/IGb08 stations, differential PPP tests were carried out individually to estimate the impact of the phase center calibration change on the position. The position changes of non-IGS08/IGb08 stations are based on latitude-dependent models (compare [IGSMAIL-6356]) that are available upon request. The estimated station position changes [mm] are (provided by Paul Rebischung without any warranty): | Site | Antenna subtype | dE dN dH | IGb08 | |------|----------------------|-------------------|-------| | CAGZ | JPSREGANT_DD_E2 NONE | +0.4 +0.1 +9.5 | X | | CONZ | JPSREGANT_DD_E1 NONE | -1.3 -1.7 -22.0 | X | | DLFT | JPSREGANT_SD_E1 NONE | -0.7 +0.2 -16.2 | - | | DLFT | JPSREGANT_DD_E1 NONE | -0.9 -2.2 -17.9 | - | | DREJ | JPSREGANT_SD_E2 NONE | +0.5 -0.1 +14.8 | - | | DWH1 | JPSREGANT_DD_E1 NONE | -0.9 -2.0 -18.3 | - | | FFMJ | JPSREGANT_SD_E2 NONE | +0.5 -0.1 +14.9 | - | | HUEG | JPSREGANT_SD_E2 NONE | +0.4 -0.2 +15.1 | - | | KHAJ | JPSREGANT_SD_E1 NONE | -0.6 +0.4 -17.6 | X | | KOU1 | JPSREGANT_DD_E2 NONE | +0.4 -0.2 +10.2 | - | | MDVJ | JPSREGANT_DD_E1 NONE | -0.6 -2.3 -19.3 | X | | MOBJ | JPSREGANT_SD_E1 NONE | -0.7 +0.2 -15.7 | - | | MOBK | JPSREGANT_SD_E1 NONE | -0.7 +0.2 -15.7 | - | | MTBG | JPSREGANT_DD_E1 NONE | -0.9 -2.0 -18.3 | - | | NOVJ | JPSREGANT_SD_E1 NONE | -0.7 +0.2 -15.7 | - | | NOVM | JPSREGANT_SD_E1 NONE | -0.7 +0.2 -15.7 | - | | STR2 | JPSREGANT_DD_E1 NONE | -1.4 -1.8 -20.6 | - | | SUNM | JPSREGANT_SD_E1 NONE | -0.3 +0.2 -15.2 | - | | TITZ | JPSREGANT_SD_E2 NONE | +0.5 -0.1 +14.8 | - | | UNB1 | JPSREGANT_DD_E1 NONE | -0.9 -2.0 -18.5 | - | | UNBJ | JPSREGANT_DD_E1 NONE | -0.9 -2.0 -18.5 | - | | WTZJ | JPSREGANT_SD_E2 NONE | +0.5 -0.2 +15.0 | - | | ZIMJ | JPSREGANT_SD_E1 NONE | -0.6 +0.5 -17.4 | X | |------|----------------------|-------------------|-------| Steps to consider the antenna subtypes -------------------------------------- With ”igs08_1707.atx”, the necessary subtype calibrations are made available. However, they should not be used before IGb08 is adopted. At the same day when IGb08 is adopted (probably 7 October 2012), the IGS will provide updated site logs including the subtype antenna names for all stations given above. The files ”igs.snx” as well as ”igs_with_former.snx” are derived automatically from those site logs and will, thus, contain the correct subtype antenna names shortly thereafter. The file ”IGb08.snx” that will be made available together with the announcement of IGb08 will already contain the correct JPSREGANT subtypes. With a view to the second IGS reprocessing campaign repro2, also the subtypes of decommissioned and former antennas will be corrected. However, for the general IGS user mainly those stations are interesting, where JPSREGANT antennas are still active. If dormant stations (DLFT, KHAJ, ZIMJ) are ignored, special attention should be paid to the following five stations: CAGZ MDVJ MOBJ MOBK NOVM Station operators of those five stations are urged to consider the correct subtype name in their RINEX headers starting with the adoption of IGb08. In preparation for repro2, it is the intention that also the headers of historical RINEX files should be corrected. Users are asked to update their station metadata files in time, if necessary. Those users who want to transform old results to be consistent with the new frame are referred to [IGSMAIL-6356]. _______________________________________________ IGSMail mailing list IGSMail@igscb.jpl.nasa.gov http://igscb.jpl.nasa.gov/mailman/listinfo/igsmail ********************************************************************************