Analysis of the Earth Orientation Parameters  

updated October, 2010

comparison of EOP series

Time scale : Modified Julian Date Besselian Year     Graphic dimension x
Begin     End   Remove tidal variations from UT1/LOD1

series IAU 2000 model2 read starting
date
x y x-iy UT1-
UTC
UT1-
TAI

sinε0
UAI 1980

UAI 1980

sinε0
+i dε
dX
UAI 2000
dY
UAI 2000
dX
+i dY
UAI
2000
dx/dt dy/dt LOD
        mas mas mas ms ms mas mas mas mas mas mas mas/d mas/d ms
Select EOP      
  COMBINED EOP series of our service
C04 read 1962- 1 1 1 1 1 1 1 1 1 1 1 - - 1
C01 read 1846- 1 1 1 1962- 1962- 1900- 1900- 1900- 1984- 1984- 1984- - - -
  OTHER COMBINED EOP series
  read 1993- 1 1 1 1 1 - - - - - - 1 1 1
  GPS EOP series
    1993- 1 1 1 1 1 - - - - - - 1 1 1
    1996- 1 1 1 1 1 - - - - - - 1 1 1
    1996- 1 1 1 1 1 - - - - - - 1 1 1
    1996- 1 1 1 1 1 - - - - - - 1 1 1
    1996- 1 1 1 1 1 - - - - - - 1 1 1
    1996- 1 1 1 1 1 - - - - - - 1 1 1
    1996- 1 1 1 1 1 - - - - - - 1 1 1
NOAA     1996- 1 1 1 1 1 - - - - - - 1 1 1
SIO     1996- 1 1 1 1 1 - - - - - - 1 1 1
series IAU 2000 model2 read starting
date
x y x-iy UT1-
UTC
UT1-
TAI

sinε0
UAI 1980

UAI 1980

sinε0
+i dε
dX
UAI 2000
dY
UAI 2000
dX
+i dY
UAI
2000
dx/dt dy/dt LOD
Select EOP      
  VLBI EOP series    Upper script * means non operational series
CGS read 1980- 1 1 1 1 1 1 1 1 - - - - - 1
AUS read 1983- 1 1 1 1 1 1 1 1 1 1 1 - - -
BKG read 1984- 1 1 1 1 1 1 1 1 1 1 1 - - 1
  read 1999- - - - 1 1 - - - - - - - - -
GSFC read 1979- 1 1 1 1 1 1 1 1 1 1 1 - - 1
  read 1997- - - - 1 1 - - - - - - - - -
IAA read 1979 1 1 1 1 1 1 1 1 1 1 1 - - -
IAA int.   read 1980- - - - 1 1 - - - - - - - - -
IVS read 1979- 1 1 1 1 1 1 1 1 1 1 1 - - 1
MAO read 2000 - 1 1 1 1 1 1 1 1 1 1 1 - - -
OPA read 1989- 1 1 1 1 1 1 1 1 1 1 1 1 1 1
SPBU read 1989- 1 1 1 1 1 1 1 1 1 1 1 - - -
  read 1997- - - - 1 1 - - - - - - - - -
USNO read 1979- 1 1 1 1 1 1 1 1 1 1 1 - - 1
  read 1993- 1 1 1 1 1 - - - - - - - - -
series IAU 2000 model2 read starting
date
x y x-iy UT1-
UTC
UT1-
TAI

sinε0
UAI 1980

UAI 1980

sinε0
+i dε
dX
UAI 2000
dY
UAI 2000
dX
+i dY
UAI
2000
dx/dt dy/dt LOD
Select EOP      
  SLR EOP series    Upper script * means non operational series
    2003- 1 1 1 1 1 - - - - - - - - 1
    1983- 1 1 1 1 1 - - - - - - - - -
  read 1983-2001 1 1 1 1 1 - - - - - - 1 1 1
    1993- 1 1 1 1 1 - - - - - - - - -
    1992- 1 1 1 1 1 - - - - - - - - 1
    2002- 1 1 1 - - - - - - - - - - 1
  MAO 1983-2001 1 1 1 1 1 - - - - - - - - 1
    1996- 1 1 1 - - - - - - - - - - 1
    1993- 1 1 1 1 1 - - - - - - - - -
series IAU 2000 model2 read starting
date
x y x-iy UT1-
UTC
UT1-
TAI

sinε0
UAI 1980

UAI 1980


sinε0
+i dε

dX
UAI 2000
dY
UAI 2000
dX
+i dY
UAI
2000
dx/dt dy/dt LOD
Select EOP      
  DORIS EOP series    Upper script * means non operational series
    1999- 1 1 1 - - - - - - - - - - -
    1993- 1 1 1 1 - - - - - - - - - 1
  EOP series from optical observation    Upper script * means non operational series
  read 1900-1992 1 1 1 1 1 1 1 1 - - - - - -
  read 1900-1992 1 1 1 1 1 - - - - - - - - -
  read 1832-1997 - - - - - - - - - - - - - 1

Lagrange Interpolation with time interval of day(s)       First date (optional)

Produce file of the selected parameters       Draw data

Spectral analysis (FFT, complex for 2D signal) Amplitude (Ampl.)2 Log10(Ampl.)2)
min. frequency       max. frequency (in cycle per unit of time)

     
Periodogram < periods < in the time unit - 1D signal only.
The sampling is determined by Period max / Period min
Weighted least square fit of periodic components (periods in unit of time)
Positive periods         Polynomial of degree
Negative periods  
(take negative periods only for 2 dimensional signal)
        Draw residuals and input data     Draw fit and input data     Print residuals

In-phase and out-of-phase terms (a, b) are estimated, as well as amplitude A and phase φ :

1-D : X = A cos[2π/T (t-t0) + φ] = a cos[2π/T (t-t0)] + b sin[2π/T (t-t0) ]
2-D : X +i Y = A exp[i 2π/T (t-t0) + i φ]
with the reference epoch t0 = 1/1/2000 0hUT that is :

X = a cos[2π/T (t-t0)] _ b sin[2π/T (t-t0) ]     Y = b cos[2π/T (t-t0)] + a sin[2π/T (t-t0) ] with a = A cos φ     b = A sin φ


     
Vondrak filter Remove parabolic trend Produce data file Draw   with input data
(P0) time unit     Transfer coefficient for P0 :T0= %
  • The Vondrak filter transfer function at another period P is given by :
    T=1/(1+(P0/P)6 (1-T0)/T0)
  • For the case "Select band around" the periods in [P0 - 0.1*P0, P0 + 0.1*P0] are transmitted with the rate > T0%.
  • For the case "Remove band around" the periods outside [P0 - 0.1*P0, P0 + 0.1*P0] are transmitted with the rate > T0 %.

Singular Spectral Analysis (SSA) -  Zoom between and   
The extracted components are decorellated over time windows of (in the time unit) with the interpolation lag (in the time unit). Firt step consists in the determination of the eigenvalues and eigenvectors printed by decreasing weight. Then 5 singular components are reconstructed according to the following combinations of eigenvectors, to be stated from the analysis of the eigenvalues .

RC1 (Reconstructed Comp. based upon eigenvectors N° 1 and N°2 )
RC2
RC3
RC4
RC5

   produce time series (date, signal, RC1,RC2,RC3,RC4,RC5,residuals) draw

     
Partial Interface with the C-Library MIMOSA developped by S. Lambert.
Thank you for bringing to our knowledge any possible mistake, mail to : christian.bizouard at obspm.fr

1- Variations produced by the solid Earth zonal tides (IERS 2000 model)
2- The reference model for the celestial pole offsets is the precession-nutation model IAU 2000