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First results of X/S and X/Ka-band catalog combinations with full covariance information

Andreas Iddink, Christopher Jacobs, Thomas Artz, Axel Nothnagel 22.09.2014

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


Motivation
Features of the ICRF2




ICRF2 (Defining-Sources)



3414 sources 2197 single session sources 295 defining sources NNR to ICRF1 consistency with VTRF2008 only S/X band observations only one single monolitic solution

1

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


Motivation
Features of the ICRF2




ICRF2 (Defining-Sources)



3414 sources 2197 single session sources 295 defining sources NNR to ICRF1 consistency with VTRF2008 only X/S band observations only one single monolithic solution

1

Goals for the ICRF3


Improved frequency coverage Combined product of multiple VLBI solutions

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


Motivation
X/Ka catalog (8.4 / 32 GHz) X/S catalog analysis center 1
2

X/S catalog analysis center 2

Goals for the ICRF3


Improved frequency coverage Combined product of multiple VLBI solutions

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


Motivation
X/Ka catalog (8.4 / 32 GHz) X/S catalog analysis center 1
2

X/S catalog analysis center 2

Combination of datum-free normal equation systems (X/S) with solutions including full covariance information (X/Ka)

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


Generating a X/S Catalog
1. Step: Generating a X/S catalog based on daily datum-free GSFC SINEX files (Combination of datum-free normal equation systems) X/S datum-free single session NEQs ST VE ST VE ST VE ST VE ST VE ST VE VE VE E X/S datum-free monolithic NEQ
ST SO

X/S GSFC CRF
3

EOPs

SO
about 4000 SINEX files

3

- session selection

- datum definition - parameter reduction - parameter estimation

- arc / global parameters
- parameterization

Station positions (ST) , EOPs (E) , Source positions (SO)
First results of S/X and X/Ka-band catalog combinations with full covariance information Andreas Iddink ­ 22.09.2014


GSFC X/S Catalog
1. Step: Generating the X/S catalog based on daily datum-free GSFC SINEX files

4

3

Deviation in declination



1682 estimated global source positions (at least 3 good observations in each session necessary) including all 295 defining sources
First results of S/X and X/Ka-band catalog combinations with full covariance information Andreas Iddink ­ 22.09.2014


X/Ka Catalog
2. Step: Import of the X/Ka catalog with full covariance information (Data provided by Christopher Jacobs et al. (JPL)) X/Ka solution information X/Ka JPL CRF

solution vector

5

and

full covariance matrix

3

Features of the provided X/Ka catalog solution vector with 631 X/Ka sources (1262 parameters) including 208 of 295 defining sources NNR constraint uses these 208 defining sources no station positions or EOPs available
First results of S/X and X/Ka-band catalog combinations with full covariance information Andreas Iddink ­ 22.09.2014


X/Ka Catalog
2. Step: Import of the X/Ka catalog with full covariance information

6

3

Deviation in declination

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


First Catalog Comparisons

7

GREEN: X/Ka and X/S catalog (443 sources including 208 defining sources ) RED: only X/Ka catalog (188 sources) BLUE: only X/S (1227 sources)

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


Southern Celestial Hemisphere

8

GREEN: X/Ka and X/S catalog RED: only X/Ka catalog BLUE: only X/S

123 of 188 only X/Ka sources are in the southern celestial hemisphere
First results of S/X and X/Ka-band catalog combinations with full covariance information Andreas Iddink ­ 22.09.2014


X/S and X/Ka Catalog Residuals (Defining Sources)
Residuals between X/S and X/KA catalog after transformation (3 rotations)

1 mas

9

Estimation of 3 rotation angles between the X/S and X/Ka catalog (Transformation based on the 208 defining sources)

Catalog Pair X/S vs. X/Ka

Rotation angles (x,y,z) [mas] (-0.03 , 0.02, 0.002)
Andreas Iddink ­ 22.09.2014

First results of S/X and X/Ka-band catalog combinations with full covariance information


Reconstruction of datum-free X/Ka NEQ
Information about used constraints
- NNR constraint - 208 of 295 defining sources - three rotations constrainted to 20 as

Generating constraints matrix

=



10

X/Ka catalog
solution vector

X/Ka datum-free NEQ

and

full covariance matrix





-1 = -

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


X/S and X/Ka Combination Approach
X/S datum-free monolithic NEQ
ST

X/S & X/Ka combined datum-free NEQ
ST

Combination on the level of datum-free normal equations
EOPs EOPs
11

X/Ka datum-free monolithic NEQ

- datum definition - parameter reduction - parameter estimation

X/S & X/Ka combined CRF

First results of S/X and X/Ka-band catalog combinations with full covariance information

Andreas Iddink ­ 22.09.2014


Residuals Combined Catalog minus Original X/Ka Catalog

1 mas

12

To be investigated


Non ITRF telescope positions Frequency dependence Core shift ,,Source Tie"
Andreas Iddink ­ 22.09.2014

First results of S/X and X/Ka-band catalog combinations with full covariance information