Memo:      Calc Solve Interface
===============================
1999.11.10                                              1999.11.19-18:39:56

Leonid Petrov
pet@leo.gsfc.nasa.gov

  Calc computes theoretrical delay and delay rate, partial derivatives and 
a lot of calibratiuons and contributions which can be applied to theoretical
delays. some of them are applied to the total theoretricals by Calc, some of
them are applied to theoreticals by Solve during processiion the session.
Interface of applying calibrations is implemented via CORFxx file. CORFxx file
contains a list of calibration and the list of items (lcodes) from the database
associated with the names of the calibrations. CORFxx file has a description of
its format at the beginning of its bory. It is assumed that a SOLVE copies
CORFIL.template which is a part of a distributive of MK4 software system to
CORFIL. This file is copied by the program solve_reset to the scratch directory
WORK_DIR and renamed to CORFxx, where xx are user SOLVE initials.

	I. Meaning of calibrations in CALC 9.1
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	
	I.1  Solid Earth tides


a) + "ETD CONT"  -- Contribution due to Earth solid tide in according with IERS 
   1996 conventions: IERS TN21. p. 56-66. The anelastic Earth model is used. 
   Tides of the second and the third order are taken into account.
   Love numbers h=0.6078, l=0.0847, h(2) = -0.0006, l(2)=0.0002 are used for
   the zero-frequency tide.

b) + "ETD CONT" + "ELASTCON"  --  Contribution due to Earth solid tide 
   in according with IERS 1996 conventions: IERS TN21. p. 56-66. The elastic 
   Earth model is used. Tides of the second and the third order are taken into 
   account. Love numbers h=0.6026, l=0.0831, h(2) = -0.0006, l(2)=0.0002 are 
   used for the zero-frequency tide.

c) - "PERMDEF " -- Contribution due to the Earth solid tides with 
     zero-frequency. Love numbers h=0.6078, l=0.0847, h(2) = -0.0006, 
    l(2)=0.0002 are used. 

d) + "ETD CONT" + "PERMDEF" -- Contribution due to Earth solid tide in 
   according with IERS 1996 conventions: IERS TN21. p. 56-66. The anelastic 
   Earth model is used. Tides of the second and the third order are taken into 
   account. Love numbers h=0.0, l=0.0, h(2) = 0.0, l(2)=0.0 are used for the 
   zero-frequency tide.

e) + "C82ETCON" -- Contribution due to Eath solid tides with the second
   and third tides in the mode of compatibility with Calc 8.2. Not recommended
   for routine use.


	I.2  Nutation


a) + "WAHR NUT"  -- Contribution due to IAU 1980 nutation model is used 
                    instead of IERS 1996 model.

b) + "GDNUTCON"  -- Contribution of geodesic nutation is applied.


	I.3  Pole tide


a) + "PTD CONT"  -- Contribution due to revised pole tide contribution.
                    Pole tide is computed with respect to a modeled pole
                    coordinates: X_actual - X_model; Y_actual - Y_model.
	            where
                    X-model(arc-sec) = +0.0039 + 0.00062*T  
                    Y-model(arc-sec) = +0.1485 + 0.00333*T  
                    where T = number of years since 1945.85. The value of 
                    Y-model used below will be the negative of the above, 
                    since the sign of Y-pole is flipped in the wobble module. 

b) + "PTD CONT" + "PTOLDCON" -- Contribution due to full pole tide contribution.
                    Pole tide is computed with respect to a total pole
                    coordinates.


        II.4  Others


a) + "OLD EQE "  absolete contribution for emulation of the coding error in 
     Calc 8.2 in computation of equation of equanox. Should not be used anymore!


b) + "fEED ROT" -- Contribution for delay rate due to feed horn rotation.
     It is zero for group and phase delay. Feed horn rotation for phase delay
     is saved under lcode PARANGLE and is alvays applied by SOLVE for phase
     delay observables regardless the status of "FEED ROT" contribution.


	II. Computation of a nutation offset wrt IAU1980 model.
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


a) The averaged difference in a priori nutatiuon model (IERS 1996) minus the 
   reference nutation model (IAU 1980) is computed. Lcodes "NUT 1996" and
   "NUT WAHR" supply nutation angles used for computations. The avereging is 
   done with equal weights over all scans of the session, reagardless whether 
   that scan is used in the estimation or not. "Nutation offset wrt IAU1980 
   model" is formed as "estimate of nutation angle" minus "mean difference 
   of the a priori nutation model minus the reference mutation model".

b) If calibration "GDNUTCON" (geodesic nutation) is applied, it is subtracted 
   from "Nutation offset wrt IAU 1980 model (psi)".