Hallo Mahmood,

I think precision of calculation of position of sun need not to be extremely high.
If deviation from correct angle is 'a' then Efficiency would be (according to projection law):

Efficiency = cos (a) x 100%

So, even with a devation of a=10°, which corresponds to a tracking time delay of about 40min (!), Efficiency is about 98.5%. So, power loss is only 1.5%.
Seems, that rather rough approximation formula can be good enough, when only Efficiency of solar system is important.
And it seems, that tracking actualisation interval can be in the range of 10...15min. Or am I wrong?

Good luck,
Kai