“…Then the error quaternion is E = (e0, e) =Λ p •Λ, Euler parameters' vector is E = {e0, e}, the error's matrix is C e ≡ C(E E E) = I3 − 2[e×]Q t e with matrix Qe = I3e0 +[e×], the error's vector is δφ = {δφi} = 2e0e, and error δω={δωi} is defined as δω = ω − C e ω p . Angular mismatch vector l = −δφ l , l ∈ N0, is filtered with period Tp and then the vector values f k are applied in the developed digital control law for the GD cluster (Somov et al, 2005)…”