[IGSMAIL-6662] igs08_1707.atx: Update including JPSREGANT subtype calibrations & R743

Ralf Schmid schmid at dgfi.badw.de
Mon Sep 24 09:00:36 PDT 2012


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].


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