I need to fill NA's using a panel regression of this specific form (AR(1):

β should be estimated recursively over the sample period. The formula can also be found in Genre et al. (2013), "Combining expert forecasts: Can anything beat the simple Average?" , p.112f.
This is my Data:
Dez 1999 Mrz 2000 Jun 2000 Sep 2000 Dez 2000 Mrz 2001 Jun 2001 Sep 2001
[1,] 1.2 1.4 1.5 1.8 1.9 1.9 2.0 1.9
[2,] 1.2 1.2 NA 1.6 NA 2.0 NA 2.5
[3,] 1.3 1.7 NA 1.7 1.8 1.5 1.8 1.5
[4,] 1.1 1.4 1.4 1.5 1.6 1.6 1.7 1.9
[5,] 1.6 1.9 1.5 1.4 1.3 0.9 NA 1.7
[6,] 0.9 1.8 1.6 NA NA 1.8 1.8 1.8
[7,] 1.4 1.8 NA 1.6 1.8 1.7 NA 1.8
[8,] 1.4 1.3 1.7 1.5 1.6 1.5 1.9 1.6
[9,] 1.8 2.0 1.9 1.9 1.8 1.8 2.2 2.0
[10,] 1.3 1.7 1.6 1.6 1.6 1.8 2.1 1.7
[11,] 1.0 NA 1.7 1.7 NA NA NA 1.7
I found the imputeTS package in R , but I dont know if it can help me.
