1. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S Proposals for Extended Parameterization in SINEX Markus Rothacher GeoForschungsZentrum Potsdam (GFZ) Unified Analysis Workshop December 5-7, 2007 Beach Resort Monterey, CA

2. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S General: For the future more flexibility is needed in the SINEX format to allow for other parameters to be combined and other representations Combination of Troposphere Parameters: Troposphere zenith delay parameters are heavily correlated with station heights (0.98 at 15deg), gradients with horizontal position Troposphere parameters can serve as a local tie between techniques (VLBI, GPS and DORIS values have to be identical) Most analysis centers are representing troposphere by piece-wise linear functions (simple and physical) Motivation (1)

3. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S Combination of Clock Parameters (IVS): Clock pararmeters are also heavily correlated with station height Combination of clock parameters in the future will strengthen quality of station heights Most IVS analysis centers are representing clocks by piece- wise linear functions (simple and physical) Very distant goal: combination with clocks from GPS, etc. Motivation (2)

4. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S Subdaily resolution of ERPs and other parameters: The representation of ERPs as an offset and drift per day might be critical with the increasing precision (VLBI2020, Galileo, Compass, …) Higher resolution is already done by some VLBI and GPS analysis centers (tidal, non-tidal, episodic signals) 2-hour resolution: estimation of offsets and drifts for each subinterval does not make sense any more: Offset/drift: 12*2=24 parameters with jumps at boundaries Piece-wise linear: 13 parameters with continuity Similar arguments for subdaily coordinates (interesting tidal and non-tidal subdaily signals) Motivation (3)

5. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S Homogeneous GGOS-D SINEX Time Series: Reprocessed global solutions for GPS, VLBI, SLR with two software pakages each Daily resolution for GPS Troposphere parameters, nutation, radio source coordinates and low-degree harmonics included 1-hour ERP resolution Very interesting data sets for combination studies But: No official SINEX format supporting the distribution of these series to the space geodetic community Motivation (4)

6. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S Proposal 1: A simple, but not elegant extension of the parameter space to allow new parameters and for a piece-wise linear representation Additional names of parameters defined (quite confusing) Not future-oriented Proposal 2: Generic and flexible naming of parameters concerning different representations, easy to interpret Flexibility to go for other parameterizations in the future (e.g. cubic splines, polynomials of higher degree, …) Generic use in software packages (e.g. offsets/drifts) Two Possibilities

7. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S Examples: STAX_0 (station coord. x-comp. as constant offset) TRO0DN (troposphere north gradient as piece-wise linear) Character 1-3: Parameter group (station coordinates, pole, UT/LOD, nutation, troposphere, satellite orbits, radio sources, geocenter coordinates, potential coefficients, biases, antennas, …) Character 4: Distinction of the component (e.g. x/y/z, north/east/up, right ascension/declination, cosine/sine,...) Character 5: Distinction between different parameter representations _ = Constant offset D = Offsets of a piece-wise linear, contin. repres. P= Nodes of a polygon S= Spline representation Character 6: Distinction between offsets and rates (could be extended, if necessary) 0 = Offset 1 = Rate Proposal 2: Parameter Naming

8. Unified Analysis Workshop, December 5-7, 2007, Beach Resort Monterey, CA GG S New SINEX, but just the usual parameters: 1.Combination Centers: modify their software to translated the new names to their internal parameter naming convention 2.Analysis Centers: modify their software to write the new names and the new SINEX version number New SINEX, new parameters (only based on an agreement of the Services): 1.Analysis Centers: modify their software to write the new parameters 2.Combination Centers: modify their software to process and combine the new parameters Consequences of Proposal 2