Kalman filtering Kalman smoothing 時点 観測値 観測方程式の誤差項の分散 状態方程式の誤差項の分散 カルマンゲイン フィルター化推定値 フィルター化推定値の分散 1期先の予測値 1期先の予測値の分散 平滑化推定値 time observation variance of observation error variance of process noise Kalman gain filtered estimates variance of filtered estimates 1-step-ahead forecasts variance of 1-steo -ahead forecasts t=T-1,T-2,T-3,....3,.2.,1 とTから過去に遡る逐次計算(backward recursion) smoothed estimates KFAS $y $att $Ptt $a $P $alphahat t y[t] Ht Qt Kt a{t|t] p[t|t] a[t+1|t] p[t+1|t] a[t+1|T]-a[t|t] p[t|t]/p[t+1|t] a[t|T] 0 200 10000 1 1120 12000 1300 =J7/(J7+D7) =I7+(C7-I7)*F7 =J7-J7*F7 =I6 =J6+E7 =M8-G7 =H7/J8 =G7+K7*L7 2 1160 12000 1300 =J8/(J8+D8) =I8+(C8-I8)*F8 =J8-J8*F8 =G7 =H7+E8 =M9-G8 =H8/J9 =G8+K8*L8 3 963 12000 1300 =J9/(J9+D9) =I9+(C9-I9)*F9 =J9-J9*F9 =G8 =H8+E9 =M10-G9 =H9/J10 =G9+K9*L9 4 1210 12000 1300 =J10/(J10+D10) =I10+(C10-I10)*F10 =J10-J10*F10 =G9 =H9+E10 =M11-G10 =H10/J11 =G10+K10*L10 5 1160 12000 1300 =J11/(J11+D11) =I11+(C11-I11)*F11 =J11-J11*F11 =G10 =H10+E11 =M12-G11 =H11/J12 =G11+K11*L11 6 1160 12000 1300 =J12/(J12+D12) =I12+(C12-I12)*F12 =J12-J12*F12 =G11 =H11+E12 =M13-G12 =H12/J13 =G12+K12*L12 7 813 12000 1300 =J13/(J13+D13) =I13+(C13-I13)*F13 =J13-J13*F13 =G12 =H12+E13 =M14-G13 =H13/J14 =G13+K13*L13 8 1230 12000 1300 =J14/(J14+D14) =I14+(C14-I14)*F14 =J14-J14*F14 =G13 =H13+E14 =M15-G14 =H14/J15 =G14+K14*L14 9 1370 12000 1300 =J15/(J15+D15) =I15+(C15-I15)*F15 =J15-J15*F15 =G14 =H14+E15 =M16-G15 =H15/J16 =G15+K15*L15 10 1140 12000 1300 =J16/(J16+D16) =I16+(C16-I16)*F16 =J16-J16*F16 =G15 =H15+E16 =G16 11 ? t=11 の時の予測値 =G16