%??This?program?is?the?implementation?of?the?recursive?stochastic?subspace
%??identification?technique?based?on?Balanced?Realization?that?is?designed
%??to?identify?the?modal?properties?of?mechanical?systems?and?structures
%??from?output-only?vibration?data.
%??-----------------------------------------------------------------
%??function?[wdratpolesmodes]?=?rssi（YTorderH）
%??RETURNED?ARGUMENTS
%??w?:?Undamped?natural?frequencies
%??drat?:?Damping?ratios
%??poles?:?System?poles
%??modes?:?Mode?shapes

%??INPUT?ARGUMENTS
%??Y?:?Stochastic?data?file
%??T?:?Sampling?period?（sec）
%??order?:?Desired?model?order
%??H?:?Block?Hankel?dimensions
%??-----------------------------------------------------------------
%??This?work?is?the?culmination?of?an?undergraduate?thesis?project?by
%??Anthony?Reid?with?the?CMTE?at?the?Department?of?Mechanical?Engineering
%??The?University?of?Queensland?（2001）.
%??“Recursive?output?only?subspace?identification?for?in-flight?flutter?monitoring.“
%??Goethals?I.?et?al?（2004）

%??Chiu?Jen?Ku?20100920

%%?function?[wdratpolesmodes]?=?acva（YTorderH）

%??Global?variables?defined?for?use?by?thesis.m?（the?GUI?controlling?CVA.m）
%??to?optimise?the?application?of?CVA?over?a?range?of?modal?orders
%global?U?S?p?data?L_plus

%??Cross?correlations?for?the?Hankel?&?Toeplitz?matrices?（as?a?3D?array）
%??Block?dimensions
[MN]?=?size（Y）;
p?=?H（1）;
q?=?H（2）;
MAXLAGS?=?p+q-1;

%??Find?the?correlation?matrices
%[Cdata]?=?Correlate（YMAXLAGS）;

%??Fast?implementation?of?the?correlation?formula
H?=?[];%zeros（datadata（MAXLAGS+1））;
f