PSINS不可交换（圆锥/划桨）误差补偿

不可交换（圆锥/划桨）误差补偿

多子样不可交换误差补偿

使用 cnscl（coning-sculling）函数，进行多子样（2-6、单子样+前一周期）误差补偿补偿，调用子方法有：
优化不可交换误差补偿（适用圆锥运动条件）；
一般方法不可交换误差补偿（适用多项式运动条件，调用conepolyn）；
扩展形式不可交换误差补偿（调用coneuncomp）；
高阶误差补偿（调用conehighorder）。
其中 cnscl（coning-sculling）函数内容如下：

function [phim, dvbm, dphim, rotm, scullm] = cnscl(imu, coneoptimal)
% Coning & sculling compensation.
%
% Prototype: [phim, dvbm, dphim, rotm, scullm] = cnscl(imu, coneoptimal)
% Inputs:  imu(:,1:3) - gyro angular increments
%          imu(:,4:6) - acc velocity increments (may not exist)
%          coneoptimal - 0 for optimal coning compensation method,
%                        1 for polinomial compensation method.
%                        2 single sample+previous sample
%                        3 high order coning compensation
% Outputs: phim - rotation vector after coning compensation
%          dvbm - velocity increment after rotation & sculling compensation
%          dphim - attitude coning error
%          rotm - velocity rotation error
%          scullm - velocity sculling error
%
% See also  cnscl0, conepolyn, scullpolyn, conetwospeed, conecoef,
%           insupdate, DR, imuadderr.

% Copyright(c) 2009-2014, by Gongmin Yan, All rights reserved.
% Northwestern Polytechnical University, Xi An, P.R.China
% 07/12/2012, 04/12/2016
global glv
    if nargin<2,  coneoptimal=0;  end
    [n, m] = size(imu);
    if n>glv.csmax  % the maximun subsample number is glv.csmax, if n exceeds, then reshape imu
        [imu, n] = imureshape(imu, n, m);
    end
    %% coning compensation
    wm = imu(:,1:3);
	if n==1
        wmm = wm;
        if coneoptimal==2
            dphim = 1/12*cros(glv.wm_1,wm);  if m<6, glv.wm_1 = wm; end
        else
            dphim = [0, 0, 0];
        end
    else
        wmm = sum(wm,1);
        if coneoptimal==0
            cm = glv.cs(n-1,1:n-1)*wm(1:n-1,:);
            dphim = cros(cm,wm(n,:));
        elseif coneoptimal==1 % else: using polynomial fitting coning compensation method
            dphim = conepolyn(wm)