We first studied the characteristics of alignment performances of two computer-aided alignment algorithms i.e. merit
function regression (MFR) and differential wavefront sampling (DWS). The initial study shows i) that, utilizing damped
least square algorithm, MFR offers accurate alignment estimation to the optical systems with non-linear wavefront
sensitivity to changes in alignment parameters, but at the expense of neglecting the coupling effects among multiple
optical components, and ii) that DWS can estimate the alignment state while taking the inter-element coupling effects
into consideration, but at the expense of increased sensitivity to measurement error associated with experiment apparatus.
Following the aforementioned study, we report a new improved alignment computation technique benefitted from
modified MFR computation incorporating the concept of standard DWS method. The optical system used in this study is
a three-mirror anastignmat (TMA) based optical design for the next generation geostationary ocean color instrument
(GOCI-II). Using an aspheric primary mirror of 210 mm in diameter, the F/7.3 TMA design offers good imaging
performance such as 80% in 4 um in GEE, MTF of 0.65 at 65.02 in Nyquist frequency. The optical system is designed to
be packaged into a compact dimension of 0.25m × 0.55m × 1.050m. The trial simulation runs demonstrate that this
integrated alignment method show much better alignment estimation accuracies than those of standard MFR and DWS
methods, especially when in presence of measurement errors. The underlying concept, computational details and trial
simulation results are presented together with implications to potential applications.