Improvement of baseline length repeatabililty due to replacing Mark-3 VLBI system with Mark-4

One of the measrures of the overall accuracy of the space geodesy technique is the statistics of the baseline length repeatability. The smaller value of the repeatability, the better.

It is instrutive to see how this statisticds was improved or degraded over last decade.

Mark-3 system.

Lower limit of number of sessions:   8
Baseline lengths range: [    0.1, 12346.6 ]  km
Date range:             [1996.01, 1999.00 ] 
Root Repeatability:    1.30 mm +   1.28D-09*L
( rep = sqrt ( A**2 + (B*L)**2 )

Distance  1000 km :    1.83 mm
Distance  2000 km :    2.88 mm
Distance  5000 km :    6.55 mm
Distance 10000 km :   12.91 mm
Distance 12756 km :   16.44 mm

Mark-4 system.

Lower limit of number of sessions:   8
Baseline lengths range: [   53.8, 12400.6 ]  km
Date range:             [2003.01, 2006.00 ] 
Root Repeatability:    1.92 mm +   1.42D-09*L
( rep = sqrt ( A**2 + (B*L)**2 )

Distance  1000 km :    2.39 mm
Distance  2000 km :    3.42 mm
Distance  5000 km :    7.33 mm
Distance 10000 km :   14.28 mm
Distance 12756 km :   18.16 mm

Mark-3 baseline length repeatability

Mark-4 baseline length repeatability

Details: Baseline lenghts were computed from the 2007b_bas solution. All baselines with more than 8 observing sessions were used in the solution.

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Last update: 07-FEB-2007 08:53:19