function?rotvec?=?CTMat2RotVec（CTMat）;
%
%?Converts?coordinate?transformation?matrix?to?rotation?vector
%?
%?M.?S.?Grewal?L.?R.?Weill?and?A.?P.?Andrews
%?Global?Positioning?Systems?Inertial?Navigation?and?Integration
%?2nd?Edition?Wiley?2006
%
%?1.?Compute?antisymmetric?part?of?CTMat?to?get?sine?of?theta
%
A??????????=?（1/2）*（CTMat?-?CTMat‘）;
sine_theta?=?sqrt（A（32）^2+A（13）^2+A（21）^2）;
%
%?2.?Solve?for?theta?using?Eq.?C.125
%
theta?=?atan2（sine_theta（CTMat（11）+CTMat（22）+CTMat（33）-1）/2）;
%
%?3.?Use?truncated?Taylor?series?approximation
%????near?theta?=?0?for?theta/sin（theta）
%????and?symmetric?part?of?CTMat?near?theta?=?pi
%????in?alternative?formula?to?avoid?computing?theta/sin（theta）?
%
if?sine_theta?????if?theta?????????thetaoversintheta?=?1+1/6*theta^2+7/360*theta^4;
????????rotvec?=?thetaoversintheta*[CTMat（32）;CTMat（13）;CTMat（21）];
????else
????????%
????????%?Compute?symmetric?part?of?CTMat
????????%
????????S?=?（1/2）*（CTMat+CTMat‘）;
????????%
????????%?Use?Eq.?C.133ff?for?solution
????????%
????????%?This?can?still?give?different?sign?on?rhovec?if?theta?=?pi
????????%?but?rhovec?and?-rhovec?represent?the?same?rotation?under
????????%?those?conditions.??This?is?a?problem?with?rotation?vector
????????%?representation?not?with?this?function.
??