Rothera

 

ROTA 66007S001

ROTB 66007S002

ROUB 66007S003

 

IDS ROTA break on 20-FEB-1997

 

ITRF ROTA break on 20-FEB-1997

 

DM#375 ROTB new station since 01-MAR-2005

 

PW ROTB is in ITRF2005 but uses very few DORIS data. The coordinates mostly come from the local tie

 

Preliminary computations:

 

ROTB in ITRF2005 is

 

ROTB 2000.0 909182.595 -2264787.387 -5873052.235 19.86 -4.44 0.83

 

DORIS derived (ign07d02) using fixed velocity is

 

2000.0 ROTB 909182.5742 -2264787.3901 -5873052.2370 19.86 -4.44 0.83

statistics ROTB XYZ 0.0010 0.0012 0.0012 119

 

This is compatible with the ITRF2005 published coordinates

 

In ITRF2005, ROTA is (before break)

 

ROTA 2000.0 909378.238 -2264934.554 -5872956.862 19.86 -4.43 0.83

 

In ITRF2005, ROTA is (after the break)

 

ROT1 2000.0 909378.237 -2264934.546 -5872956.863 19.86 -4.43 0.83

 

So the break does not seem to be significant after all.

 

Geodetic local tie is

 

ROTB 66007S002 ROTA 66007S001 195.643 -147.167 95.373 0.001

 

Using recent DORIS weekly solutions (ign07d02) and fixing velocity to the ITRF2005 value, we obtain

 

2000.0 ROUB 909182.5913 -2264787.4401 -5873052.3846 19.86 -4.44 0.83

statistics ROUB XYZ 0.0019 0.0015 0.0015 44

 

Final computation:

 

Geodetic local (from SIMB) is

 

ROUB --> ROTB :     -0.021              0.053               0.139   sig = 0.001

ROUB --> ROTA :     195.622                       -147.114          95.513             sig = 0.002

 

As ROTB, in ITRF2005  is :

 

2000.0 ROTB 909182.5947 -2264787.3867 -5873052.2349 19.86 -4.44 0.83

 

we obtain:

 

2000.0 ROUB 909182.616 -2264787.440 -5873052.374  19.86 -4.44 0.83

 

Using DORIS weekly solutions (ign07d02) and fixing the velocity to the above ITRF2005 values, we obtain :

 

2000.0 ROUB 909182.5938 -2264787.4420 -5873052.3875 19.86 -4.44 0.83

statistics ROUB XYZ 0.0034 0.0027 0.0024 11

 

which provides a good confirmation

 

Recommendation:

 

ROTA break on 20-FEB-1997

 

ROTB use original ITRF2005 coordinates

 

ROUB derive coordinates from ROTB + geodetic local tie

2000.0 ROUB 909182.616 -2264787.440 -5873052.374  19.86 -4.44 0.83