Ascension

 

ASDB 30602S004

 

JoG: ASDB data should be deleted from 21-JAN-2002 to 13-APR-2002

Unknown data problem

 

DM#492 ASDB Corrosion of the antenna base plate

Measured displacement N = +1 mm, E = -21 mm, U < 1 mm

 

= (in XYZ) -5.07 -20.04 0.99

 

IDS ASDB data should be deleted from 21-JAN-2002 to 13-APR-2002

 

PW: ASDB Looking at the DORIS time series, I suggest to put a break at 21-JAN-2002, just in case the antenna is not exactly back at the same place after the corrosion. Only 1 position was computed in ITRF2005.

 

Position in ITRF2005 was :

 

2000.0 ASDB 6121161.5600 -1563943.1888  -872613.0551  -4.38  -13.24  10.89 

 

When looking at DORIS results before 20-JAN-2002 and fixing the velocity I get :

 

2000.0 ASDB 6121161.5577 -1563943.1891 -872613.0598 -4.38 -13.24 10.89

statistics ASDB XYZ 0.0028 0.0036 0.0023 140

 

so there is an excellent agreement

 

When looking at DORIS results after 20-JAN-2002 and fixing the velocity, I get

 

2000.0 ASD1 6121161.5746 -1563943.1813 -872613.0557 -4.38 -13.24 10.89

statistics ASD1 XYZ 0.0012 0.0012 0.0009 280

 

so there seems to be no need to estmate a different position after the break; We can use the ITRF2005 position and velocity before and after the break.

 

Recommendation:

 

ASDB delete data from 21-JAN-2002 to 13-APR-2002

ASDB discontinuity on 21-JAN-2002

Verify if the break is significant or not