GPSSHD

                                                                                
----+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
GPSSHD                                                                          
----+----0----+----0----+----0----+----0----+----0----+----0----+----0----+----0
                                                                                
                                                                                
COLUMNS FORMAT         DESCRIPTION                         DEFAULT VALUE & UNITS
                                                                                
1-6     A6     GPSSHD -  This option will instruct                          
               GEODYN to produce yaw polynomial input for                      
               GPS runs if this is not available. The                
               computation are being done in GEODYN             
               according to the Journal of Geodesy Paper                     
               by Bar-Sever.
               
               The GPSSHD option will turn any GPS data
               reduction run into an ORBGEN run automa-
               tically, regardless of what other cards
               are present.

               Yaw polynomials will be computed and output
               on unit 48 of GEODYN IIE, in the form of
               YAWPOL group cards. These YAWPOL group cards
               may be then included in the global part of
               the setup for data reduction with the
               appropriate yaw modeling. NOTE [1]
                                                                                
25-44   D20.5  12 hrs + endarc time                               YYMMDDHHMMSS

45-59   D15.3  Cutoff angle that helps save some computation      deg 20
               NOTE [2]
                                                                                
NOTE [1]: The end of the GPSSHD group is denoted by the presence        
          of the SHDEND card. In between the GPSSHD and the SHDEND 
          option cards we enter the required YAWRAT cards with yaw     
          rate and yaw rate rate information.                        
                                                                                
NOTE [2]: GPS satellites are not completely shadowed, unless the beta 
          angle of the orbit plane is about 15o (in absolute value)
          or less. In a GPSSHD run, GEODYN will compute the beta angle
          for each GPS satellite at EPOCH. If the absolute of the 
          beta angle is greater than the cutoff (20o or the input
          on columns 45-59), for a particular GPS satellite at epoch,
          then that satellite will be excluded from all further
          consideration in the GPSSHD run.


IF CARD OMITTED:
DEC 1998

9812.0

GLOBAL SET



Patrick Dahiroc
1998-09-10