BRUS00BEL Site Information Form (site log v2.0)
     International GNSS Service
     See Instructions at:
       https://files.igs.org/pub/station/general/sitelog_instr_v2.0.txt


0.   Form

     Prepared by (full name)  : GNSSatROB ([email protected])
     Date Prepared            : 2023-03-10
     Report Type              : UPDATE
     If Update:
      Previous Site Log       : brus00bel_20200604.log
      Modified/Added Sections : 11


1.   Site Identification of the GNSS Monument

     Site Name                : Brussels
     Nine Character ID        : BRUS00BEL
     Monument Inscription     : 
     IERS DOMES Number        : 13101M004
     CDP Number               : (A4)
     Monument Description     : STEEL MAST
       Height of the Monument : 5 m
       Monument Foundation    : CONCRETE BLOCK
       Foundation Depth       : 3 m
     Marker Description       : BRASS NAIL
     Date Installed           : 1993-10-20
     Geologic Characteristic  : SAND
       Bedrock Type           : SEDIMENTARY
       Bedrock Condition      : FRESH
       Fracture Spacing       : 0 cm
       Fault zones nearby     : NO
         Distance/activity    : (multiple lines)
     Additional Information   : Station located at old astrolab observ. dome.
                              : On 2012-02-14, BRUS has been decommissioned
                              : because the antenna monument was destroyed due
                              : the need to remove asbestos in the building
                              : around the antenna. The station BRUX, located
                              : about 100 m from BRUS, is included in the EPN
                              : and IGS network, as replacement.


2.   Site Location Information

     City or Town             : Brussels
     State or Province        : Brabant
     Country or Region        : BEL
     Tectonic Plate           : EURASIAN
     Approximate Position (ITRF)
       X coordinate (m)       : 4027893.860
       Y coordinate (m)       : 307045.710
       Z coordinate (m)       : 4919475.030
       Latitude (N is +)      : +504752.14
       Longitude (E is +)     : +0042133.18
       Elevation (m,ellips.)  : 149.7
     Additional Information   : (multiple lines)


3.   GNSS Receiver Information

3.1  Receiver Type            : ROGUE SNR-8000
     Satellite System         : GPS
     Serial Number            : T-174
     Firmware Version         : 2.8
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 1993-10-20
     Date Removed             : 1994-04-24
     Temperature Stabiliz.    : (deg C) +/- (deg C)
     Additional Information   : (multiple lines)

3.2  Receiver Type            : ROGUE SNR-8000
     Satellite System         : GPS
     Serial Number            : T-171
     Firmware Version         : 2.8
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 1994-04-24
     Date Removed             : 1995-09-30
     Temperature Stabiliz.    : (deg C) +/- (deg C)
     Additional Information   : (multiple lines)

3.3  Receiver Type            : ROGUE SNR-8000
     Satellite System         : GPS
     Serial Number            : T-321
     Firmware Version         : 2.8
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 1995-09-30
     Date Removed             : 1997-01-14
     Temperature Stabiliz.    : (deg C) +/- (deg C)
     Additional Information   : (multiple lines)

3.4  Receiver Type            : ROGUE SNR-12 RM
     Satellite System         : GPS
     Serial Number            : 251
     Firmware Version         : 3.2.32.4
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 1997-01-14
     Date Removed             : 1999-03-29T06:30Z
     Temperature Stabiliz.    : (deg C) +/- (deg C)
     Additional Information   : (multiple lines)

3.5  Receiver Type            : ROGUE SNR-8000
     Satellite System         : GPS
     Serial Number            : T-321
     Firmware Version         : 3.2.32.1
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 1999-03-29T06:30Z
     Date Removed             : 1999-05-25
     Temperature Stabiliz.    : (deg C) +/- (deg C)
     Additional Information   : (multiple lines)

3.6  Receiver Type            : ROGUE SNR-8000
     Satellite System         : GPS
     Serial Number            : T-321
     Firmware Version         : 3.2.32.9
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 1999-05-25
     Date Removed             : 1999-09-20T06:30Z
     Temperature Stabiliz.    : (deg C) +/- (deg C)
     Additional Information   : (multiple lines)

3.7  Receiver Type            : AOA SNR-12 ACT
     Satellite System         : GPS
     Serial Number            : 251-U
     Firmware Version         : 3.3.32.2
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 1999-09-20T06:30Z
     Date Removed             : 2000-01-27T06:00Z
     Temperature Stabiliz.    : 18.0 +/- 0.5
     Additional Information   : Simultaneously with the receiver change the
                              : RG-223 antenna cable was replaced by a 85 m
                              : heliax LDF2-50A cable from Andrew Cooperation.
                              : This new cable has a loss of 1.05DB per 30 m.

3.8  Receiver Type            : ROGUE SNR-8000
     Satellite System         : GPS
     Serial Number            : T-413
     Firmware Version         : 3.2.32.9
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 2000-01-27T06:01Z
     Date Removed             : 2000-03-27T11:15Z
     Temperature Stabiliz.    : 18.0 +/- 0.5
     Additional Information   : (multiple lines)

3.9  Receiver Type            : ASHTECH UZ-12
     Satellite System         : GPS
     Serial Number            : UX219994206
     Firmware Version         : UF00
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 2000-03-27T12:00Z
     Date Removed             : 2001-03-20T12:30Z
     Temperature Stabiliz.    : 18.0 +/- 0.5
     Additional Information   : (multiple lines)

3.10 Receiver Type            : ASHTECH Z-XII3T
     Satellite System         : GPS
     Serial Number            : RT919994505
     Firmware Version         : 1L01-1D04
     Elevation Cutoff Setting : 0 deg
     Date Installed           : 2001-03-20T13:00Z
     Date Removed             : 2012-02-14T07:35Z
     Temperature Stabiliz.    : 18.0 +/- 0.5
     Additional Information   : - Up to 27/01/2003 the filled in Firmware
                              : Version was not correct (UF00)
                              : - 2003-03-18T08:09Z Deactivation of smoothing
                              : in conversion from raw data to RINEX
                              : (XYZAshRx program) on request of IGS CB
                              : - 2012-02-14T07:35Z Site dismantled due to the
                              : removal of asbestos in the building around the
                              : antenna pillar.

3.x  Receiver Type            : (A20, from rcvr_ant.tab; see instructions)
     Satellite System         : (GPS+GLO+GAL+BDS+QZSS+IRNSS+SBAS)
     Serial Number            : (A20, but note the first A5 is used in SINEX)
     Firmware Version         : (A11)
     Elevation Cutoff Setting : (deg)
     Date Installed           : (CCYY-MM-DDThh:mmZ)
     Date Removed             : (CCYY-MM-DDThh:mmZ)
     Temperature Stabiliz.    : (none or tolerance in degrees C)
     Additional Information   : (multiple lines)


4.   GNSS Antenna Information

4.1  Antenna Type             : AOAD/M_T        NONE
     Serial Number            : 182
     Antenna Reference Point  : BPA
     Marker->ARP Up Ecc. (m)  :   3.9702
     Marker->ARP North Ecc(m) :   0.0000
     Marker->ARP East Ecc(m)  :   0.0000
     Alignment from True N    : 0 deg
     Antenna Radome Type      : NONE
     Radome Serial Number     : 
     Antenna Cable Type       : RG-223
     Antenna Cable Length     : 30 m
     Date Installed           : 1993-10-20
     Date Removed             : 2000-04-27T12:10Z
     Additional Information   : (multiple lines)

4.2  Antenna Type             : ASH701945B_M    NONE
     Serial Number            : CR519994604
     Antenna Reference Point  : BPA
     Marker->ARP Up Ecc. (m)  :   3.9702
     Marker->ARP North Ecc(m) :   0.0000
     Marker->ARP East Ecc(m)  :   0.0000
     Alignment from True N    : 0 deg
     Antenna Radome Type      : NONE
     Radome Serial Number     : 
     Antenna Cable Type       : ANDREW heliax LDF2-50A
     Antenna Cable Length     : 85 m
     Date Installed           : 2000-04-27T12:15Z
     Date Removed             : 2012-02-14T07:35Z
     Additional Information   : Site dismantled due to the removal of asbestos
                              : in
                              : the building around the antenna pillar.

4.x  Antenna Type             : (A20, from rcvr_ant.tab; see instructions)
     Serial Number            : (A*, but note the first A5 is used in SINEX)
     Antenna Reference Point  : (BPA/BCR/XXX from "antenna.gra"; see instr.)
     Marker->ARP Up Ecc. (m)  : (F8.4)
     Marker->ARP North Ecc(m) : (F8.4)
     Marker->ARP East Ecc(m)  : (F8.4)
     Alignment from True N    : (deg; + is clockwise/east)
     Antenna Radome Type      : (A4 from rcvr_ant.tab; see instructions)
     Radome Serial Number     : 
     Antenna Cable Type       : (vendor & type number)
     Antenna Cable Length     : (m)
     Date Installed           : (CCYY-MM-DDThh:mmZ)
     Date Removed             : (CCYY-MM-DDThh:mmZ)
     Additional Information   : (multiple lines)


5.   Surveyed Local Ties

5.1  Tied Marker Name         : GPS Chimney
     Tied Marker Usage        : EUREF89
     Tied Marker CDP Number   : (A4)
     Tied Marker DOMES Number : 13101M003
     Differential Components from GNSS Marker to the tied monument (ITRS)
       dx (m)                 : 65.256 m
       dy (m)                 : 31.520 m
       dz (m)                 : -65.110 m
     Accuracy (mm)            : 1 mm
     Survey method            : GPS CAMPAIGN
     Date Measured            : 1995-03-15
     Additional Information   : this point is the EUREF 0045 marker

5.x  Tied Marker Name         : 
     Tied Marker Usage        : (SLR/VLBI/LOCAL CONTROL/FOOTPRINT/etc)
     Tied Marker CDP Number   : (A4)
     Tied Marker DOMES Number : (A9)
     Differential Components from GNSS Marker to the tied monument (ITRS)
       dx (m)                 : (m)
       dy (m)                 : (m)
       dz (m)                 : (m)
     Accuracy (mm)            : (mm)
     Survey method            : (GPS CAMPAIGN/TRILATERATION/TRIANGULATION/etc)
     Date Measured            : (CCYY-MM-DDThh:mmZ)
     Additional Information   : (multiple lines)


6.   Frequency Standard

6.1  Standard Type            : EXTERNAL CESIUM
       Input Frequency        : 5 MHz
       Effective Dates        : 1994-04-27/1994-08-23
       Notes                  : (multiple lines)

6.2  Standard Type            : EXTERNAL H-MASER
       Input Frequency        : 5 MHz
       Effective Dates        : 1994-08-23/2001-03-19
       Notes                  : (multiple lines)

6.3  Standard Type            : EXTERNAL H-MASER
       Input Frequency        : 20 MHz
       Effective Dates        : 2001-03-20/2003-07-03
       Notes                  : (multiple lines)

6.4  Standard Type            : EXTERNAL CESIUM
       Input Frequency        : 20 MHz
       Effective Dates        : 2003-07-03/2003-08-01
       Notes                  : step of 6.15 ns in the antenna cable
                              : between 2003-07-03 and 2003-07-10

6.5  Standard Type            : EXTERNAL H-MASER CH1-75
       Input Frequency        : 20 MHz
       Effective Dates        : 2003-08-01/2010-03-31
       Notes                  : CH1-75 active H-maser.
                              : It is the source of UTC(ORB).
                              : UTC(ORB)-BRUS_1PPS (cable delay +
                              : delay from 1PPS_in to internal reference)
                              : = 48.6 ns
                              : 10MHz from  distr. amp. HP5087A,
                              : then frequency doubler up to 20MHz.

6.6  Standard Type            : EXTERNAL H-MASER CH1-75A
       Input Frequency        : 20 MHz
       Effective Dates        : 2010-03-31/2010-11-05
       Notes                  : CH1-75A active H-maser.
                              : It is the source of UTC(ORB).
                              : UTC(ORB)-BRUS_1PPS (cable delay + delay from
                              : 1PPS_in to internal reference)
                              : = 47.6 ns
                              : 10MHz from  distr. amp. HP5087A,
                              : then frequency doubler up to 20MHz.

6.7  Standard Type            : EXTERNAL CESIUM
       Input Frequency        : 20 MHz
       Effective Dates        : 2010-11-05/2011-12-19
       Notes                  : (multiple lines)

6.8  Standard Type            : EXTERNAL CH1-75A MASER
       Input Frequency        : 20 MHz
       Effective Dates        : 2011-12-19/CCYY-MM-DD
       Notes                  : The 5MHz output of the CH1-75A (maser3) passes a
                              : Minicircuits FD-2+ frequency doubler and then is
                              : used as input to a SpectraTime femtoStepper. The
                              : output of this phase stepper (equal to UTC(ORB))
                              : is used as an input to the receiver.

6.x  Standard Type            : (INTERNAL or EXTERNAL H-MASER/CESIUM/etc)
       Input Frequency        : (if external)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Notes                  : (multiple lines)


7.   Collocation Information

7.1  Instrumentation Type     : CRYOGENIC GRAVIMETER
       Status                 : PERMANENT
       Effective Dates        : 1993-10-20/2000-08-21
       Notes                  : (multiple lines)

7.2  Instrumentation Type     : SEISMOMETER
       Status                 : PERMANENT
       Effective Dates        : 1993-10-20/CCYY-MM-DD
       Notes                  : (multiple lines)

7.x  Instrumentation Type     : (GPS/GLONASS/DORIS/PRARE/SLR/VLBI/TIME/etc)
       Status                 : (PERMANENT/MOBILE)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Notes                  : (multiple lines)


8.   Meteorological Instrumentation

8.1.1  Humidity Sensor Model  : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 69855
       Data Sampling Interval :    60 sec
       Accuracy (% rel h)     : 2 % rel h
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : -4 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 1998-11-15/2000-07-19
       Notes                  : Meteo sonde delivered unreliable data
                              : at the end.
                              : Height diff 2 ant with respect to marker

8.1.2  Humidity Sensor Model  : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 70804
       Data Sampling Interval :    60 sec
       Accuracy (% rel h)     : 2 % rel h
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : -4 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 2000-07-20/2001-02-19
       Notes                  : Height diff 2 ant with respect to marker

8.1.3  Humidity Sensor Model  : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 70804
       Data Sampling Interval :    60 sec
       Accuracy (% rel h)     : 2 % rel h
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : -3.84 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 2001-02-19/2003-09-08
       Notes                  : Height diff 2 ant with respect to marker

8.1.x  Humidity Sensor Model  : 
       Manufacturer           : 
       Serial Number          : 
       Data Sampling Interval : (sec)
       Accuracy (% rel h)     : (% rel h)
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : (m)
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Notes                  : (multiple lines)

8.2.1  Pressure Sensor Model  : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 69855
       Data Sampling Interval :  60 sec
       Accuracy               : 0.5 hPa
       Height Diff to Ant     : -4 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 1998-11-15/2000-07-19
       Notes                  : Meteo sonde delivered unreliable data
                              : at the end.
                              : Height diff 2 ant with respect to marker

8.2.2  Pressure Sensor Model  : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 70804
       Data Sampling Interval :  60 sec
       Accuracy               : 0.5 hPa
       Height Diff to Ant     : -4 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 2000-07-20/2001-02-19
       Notes                  : Height diff 2 ant with respect to marker

8.2.3  Pressure Sensor Model  : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 70804
       Data Sampling Interval :  60 sec
       Accuracy               : 0.5 hPa
       Height Diff to Ant     : -3.83 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 2001-02-19/2003-09-08
       Notes                  : Height diff 2 ant with respect to marker

8.2.x  Pressure Sensor Model  : 
       Manufacturer           : 
       Serial Number          : 
       Data Sampling Interval : (sec)
       Accuracy               : (hPa)
       Height Diff to Ant     : (m)
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Notes                  : (multiple lines)

8.3.1  Temp. Sensor Model     : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 69855
       Data Sampling Interval : 60 sec
       Accuracy               : 0.5 deg C
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : -4 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 1998-11-15/2000-07-19
       Notes                  : Meteo sonde delivered unreliable data
                              : at the end.
                              : Height diff 2 ant with respect to marker

8.3.2  Temp. Sensor Model     : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 70804
       Data Sampling Interval : 60 sec
       Accuracy               : 0.5 deg C
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : -4 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 2000-07-20/2001-02-19
       Notes                  : Meteo sonde delivered unreliable data
                              : at the end.
                              : Height diff 2 ant with respect to marker

8.3.3  Temp. Sensor Model     : PAROSCIENTIFIC MET3
       Manufacturer           : PAROSCIENTIFIC
       Serial Number          : 70804
       Data Sampling Interval : 60 sec
       Accuracy               : 0.5 deg C
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : -3.83 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 2001-02-19/2003-09-08
       Notes                  : Height diff 2 ant with respect to marker

8.3.x  Temp. Sensor Model     : 
       Manufacturer           : 
       Serial Number          : 
       Data Sampling Interval : (sec)
       Accuracy               : (deg C)
       Aspiration             : (UNASPIRATED/NATURAL/FAN/etc)
       Height Diff to Ant     : (m)
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Notes                  : (multiple lines)

8.4.1  Water Vapor Radiometer : Generation 3 ETH ZURICH and CAPTEC
       Manufacturer           : ETH ZURICH and CAPTEC
       Serial Number          : WVR-III-BR-A-112000-FE
       Distance to Antenna    : 97 m
       Height Diff to Ant     : 7 m
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : 2001-01-24/CCYY-MM-DD
       Notes                  : (multiple lines)

8.4.x  Water Vapor Radiometer : 
       Manufacturer           : 
       Serial Number          : 
       Distance to Antenna    : (m)
       Height Diff to Ant     : (m)
       Calibration date       : (CCYY-MM-DD)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Notes                  : (multiple lines)

8.5.1  Other Instrumentation  : Meteorological radiosonde station

8.5.x  Other Instrumentation  : (multiple lines)


9.   Local Ongoing Conditions Possibly Affecting Computed Position

9.1.x  Radio Interferences    : (TV/CELL PHONE ANTENNA/RADAR/etc)
       Observed Degradations  : (SN RATIO/DATA GAPS/etc)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Additional Information : (multiple lines)

9.2.x  Multipath Sources      : (METAL ROOF/DOME/VLBI ANTENNA/etc)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Additional Information : (multiple lines)

9.3.1  Signal Obstructions    : TREES
       Effective Dates        : 1993-10-20/2004-12-05
       Additional Information : (multiple lines)

9.3.x  Signal Obstructions    : (TREES/BUILDINGS/etc)
       Effective Dates        : (CCYY-MM-DD/CCYY-MM-DD)
       Additional Information : (multiple lines)


10.  Local Episodic Effects Possibly Affecting Data Quality

10.1  Date                    : 2004-11-28/2004-12-05
      Event                   : TREE CLEARING

10.x  Date                    : (CCYY-MM-DD/CCYY-MM-DD)
      Event                   : (TREE CLEARING/CONSTRUCTION/etc)


11.  On-Site, Point of Contact Agency Information

     Agency                   : Royal Observatory of Belgium
     Preferred Abbreviation   : ROB
     Mailing Address          : Av. Circulaire 3
                              : 1180 Brussels
                              : Belgium
     Primary Contact
       Contact Name           : GNSSatROB
       Telephone (primary)    : 
       Telephone (secondary)  : 
       Fax                    : 
       E-mail                 : [email protected]
     Secondary Contact
       Contact Name           : Pascale Defraigne
       Telephone (primary)    : 
       Telephone (secondary)  : 
       Fax                    : 
       E-mail                 : [email protected]
     Additional Information   : (multiple lines)




12.  Responsible Agency (if different from 11.)

     Agency                   : (multiple lines)
     Preferred Abbreviation   : (A10)
     Mailing Address          : (multiple lines)
     Primary Contact
       Contact Name           : 
       Telephone (primary)    : 
       Telephone (secondary)  : 
       Fax                    : 
       E-mail                 : 
     Secondary Contact
       Contact Name           : 
       Telephone (primary)    : 
       Telephone (secondary)  : 
       Fax                    : 
       E-mail                 : 
     Additional Information   : (multiple lines)


13.  More Information

     Primary Data Center      : ROB
     Secondary Data Center    : BKG
     URL for More Information : 
     Hardcopy on File
       Site Map               : (Y or URL)
       Site Diagram           : (Y or URL)
       Horizon Mask           : (Y or URL)
       Monument Description   : (Y or URL)
       Site Pictures          : (Y or URL)
     Additional Information   : (multiple lines)
     Antenna Graphics with Dimensions

ASH701945B_M
Dorne Margolin with chokerings, Model 701945-01 REV B
milled chokerings, watertight design

                       +-------+
                     /     +                             <-- 0.1280 L2
                    |      +      |                       <-- 0.1100 L1
  +-----------------+-------------+------------------+    <-- 0.1006 TCR
  |                                                  |
  |                                                  |
  |                                                  |
  |                                                  |
+-+--------------------------------------------------+-+  <-- 0.0376
+-------------------+-------------+--------------------+  <-- 0.0346 BCR
                    |             |
                    |             |
                    +------x------+                       <-- 0.0 BPA=ARP

<--                      0.3794                      -->

ARP: Antenna Reference Point
L1 : L1 Phase Center                   L2 : L2 Phase Center