      SUBROUTINE IHG(MSUN,M5,MPE)
C
C COMPUTE THE PAYLOAD TO IHG TRANSFORMATION MATRIX (MSUN).
C
      REAL*4 MSUN(3,3),M5(3,3),MPE(3,3)
C
      MSUN(1,1) = M5(1,1)*MPE(1,1) + M5(1,2)*MPE(2,1) + M5(1,3)*MPE(3,1)
      MSUN(1,2) = M5(1,1)*MPE(1,2) + M5(1,2)*MPE(2,2) + M5(1,3)*MPE(3,2)
      MSUN(1,3) = M5(1,1)*MPE(1,3) + M5(1,2)*MPE(2,3) + M5(1,3)*MPE(3,3)
C
      MSUN(2,1) = M5(2,1)*MPE(1,1) + M5(2,2)*MPE(2,1) + M5(2,3)*MPE(3,1)
      MSUN(2,2) = M5(2,1)*MPE(1,2) + M5(2,2)*MPE(2,2) + M5(2,3)*MPE(3,2)
      MSUN(2,3) = M5(2,1)*MPE(1,3) + M5(2,2)*MPE(2,3) + M5(2,3)*MPE(3,3)
C
      MSUN(3,1) = M5(3,1)*MPE(1,1) + M5(3,2)*MPE(2,1) + M5(3,3)*MPE(3,1)
      MSUN(3,2) = M5(3,1)*MPE(1,2) + M5(3,2)*MPE(2,2) + M5(3,3)*MPE(3,2)
      MSUN(3,3) = M5(3,1)*MPE(1,3) + M5(3,2)*MPE(2,3) + M5(3,3)*MPE(3,3)
C
      RETURN
      END 
