*-- Author : S.Burke / J.V. Morris
      SUBROUTINE FKINV(MES,CMES,GMES,IERR)
**********************************************************************                                        
*                                                                    *                                        
* Invert the measurement covariance matrix                           *                                        
*                                                                    *                                        
* ERROR CONDITIONS;                                                  *                                        
*       IERR =   0 ; normal termination                              *                                        
*   ->  IERR = 107 ; measurement covariance not positive definite    *                                        
*                                                                    *                                        
*   ->  Fatal error                                                  *                                        
*                                                                    *                                        
**********************************************************************                                        
*KEEP,FKECODE.                                                                                                
*KEND.                                                                                                        
**********************************************************************                                        
            CALL FKERR(IUTIL,IROUT,IFATAL,IMCV,IERR)
            CALL FKERR(IUTIL,IROUT,IFATAL,IMCV,IERR)
*