content(symbol): 一阶导数记号统一为分子布局 Jacobian
点号 \dot 仅表对时间求速率;参数/角度导数改用分子布局 Jacobian ∂f/∂x^T。D 单阵、E 多星静态导数小节据此重排,附录 A 增第 14 条记号规则。
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@@ -156,28 +156,17 @@ $\zeta_\ell\in\mathbb C$ 为第 $\ell$ 条链路的未知复干扰系数,$\sig
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\end{bmatrix},
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\end{equation}
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%
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其关于全局角度参数的一阶导数为
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本小节采用分子布局的 Jacobian 记号:对向量值函数 $\mathbf f$ 与参数向量 $\mathbf x$,$\partial\mathbf f/\partial\mathbf x^\Tran$ 的行随 $\mathbf f$ 分量、列随 $\mathbf x$ 分量,链式法则即对应 Jacobian 的矩阵相乘;角度部分记 $\boldsymbol\xi=[\alpha,\beta]^\Tran$。其关于全局角度的 Jacobian 为
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%
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\begin{equation}
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\mathbf u_{\alpha}
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\triangleq
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\frac{\partial \mathbf u}{\partial \alpha}
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\frac{\partial \mathbf u}{\partial \boldsymbol\xi^\Tran}
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=
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\begin{bmatrix}
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-\cos\beta\sin\alpha \\
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\cos\beta\cos\alpha \\
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0
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\end{bmatrix},
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\qquad
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\mathbf u_{\beta}
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\triangleq
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\frac{\partial \mathbf u}{\partial \beta}
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=
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\begin{bmatrix}
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-\sin\beta\cos\alpha \\
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-\sin\beta\sin\alpha \\
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\cos\beta
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\end{bmatrix}.
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-\cos\beta\sin\alpha & -\sin\beta\cos\alpha \\
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\cos\beta\cos\alpha & -\sin\beta\sin\alpha \\
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0 & \cos\beta
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\end{bmatrix}
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\in\mathbb R^{3\times2}.
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\end{equation}
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根据第~\ref{subsec:refSatParameterization} 小节的参考星参数化,静态模型中第 $\ell$ 颗卫星对应的归一化 Doppler 统一写成
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@@ -198,27 +187,20 @@ $\zeta_\ell\in\mathbb C$ 为第 $\ell$ 条链路的未知复干扰系数,$\sig
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\nu_{\mathrm{ref}}.
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\end{equation}
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%
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因此其一阶导数统一写为
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因此其关于主参数 $\boldsymbol\eta=[\boldsymbol\xi^\Tran,\nu_{\mathrm{ref}}]^\Tran$ 的 Jacobian(行向量)为
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%
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\begin{equation}
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\frac{\partial \nu_\ell}{\partial \alpha}
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\frac{\partial \nu_\ell}{\partial \boldsymbol\eta^\Tran}
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=
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\frac{\partial \Delta\nu_\ell(\boldsymbol\xi)}{\partial \alpha},
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\qquad
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\frac{\partial \nu_\ell}{\partial \beta}
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=
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\frac{\partial \Delta\nu_\ell(\boldsymbol\xi)}{\partial \beta},
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\qquad
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\frac{\partial \nu_\ell}{\partial \nu_{\mathrm{ref}}}=1.
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\begin{bmatrix}
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\dfrac{\partial \Delta\nu_\ell(\boldsymbol\xi)}{\partial \boldsymbol\xi^\Tran}
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& 1
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\end{bmatrix}
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\in\mathbb R^{1\times3},
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\label{eq:A6_domega}
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\end{equation}
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%
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上式利用了正文中采用的
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$\nu_\ell=\nu_{\mathrm{ref}}+\Delta\nu_\ell(\boldsymbol\xi)$
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这一参考星链路参数化形式。特别地,对参考星有
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$\Delta\nu_{\ell_{\mathrm{ref}}}(\boldsymbol\xi)=0$,因而
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$\partial\nu_{\ell_{\mathrm{ref}}}/\partial\alpha=0$、
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$\partial\nu_{\ell_{\mathrm{ref}}}/\partial\beta=0$。若改用别的等价参数化,只需将上述三个 Doppler 链式导数替换为对应结果即可。
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其中末元 $\partial\nu_\ell/\partial\nu_{\mathrm{ref}}=1$ 来自参考星链路参数化 $\nu_\ell=\nu_{\mathrm{ref}}+\Delta\nu_\ell(\boldsymbol\xi)$。特别地,对参考星 $\Delta\nu_{\ell_{\mathrm{ref}}}(\boldsymbol\xi)=0$,故其角度部分 $\partial\Delta\nu_{\ell_{\mathrm{ref}}}/\partial\boldsymbol\xi^\Tran=\mathbf 0$。若改用别的等价参数化,只需替换该 Doppler Jacobian 即可。
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再定义第 $\ell$ 颗卫星本地坐标系下的来向向量
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%
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@@ -244,55 +226,61 @@ $\partial\nu_{\ell_{\mathrm{ref}}}/\partial\beta=0$。若改用别的等价参
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\arcsin\big(u_{\ell,3}^{\mathrm{loc}}\big).
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\end{equation}
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对任意 $x\in\{\alpha,\beta\}$,有
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记本地角向量 $\boldsymbol\xi_\ell^{\mathrm{loc}}=[\alpha_\ell^{\mathrm{loc}},\beta_\ell^{\mathrm{loc}}]^\Tran$。本地来向对全局角的 Jacobian 为
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%
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\begin{equation}
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\frac{\partial \mathbf u_\ell^{\mathrm{loc}}}{\partial x}
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\frac{\partial \mathbf u_\ell^{\mathrm{loc}}}{\partial \boldsymbol\xi^\Tran}
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=
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\boldsymbol{\Omega}_\ell^{\Tran}\mathbf u_x.
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\boldsymbol{\Omega}_\ell^{\Tran}\frac{\partial \mathbf u}{\partial \boldsymbol\xi^\Tran}
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\in\mathbb R^{3\times2}.
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\label{eq:A6_uloc_jac}
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\end{equation}
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%
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进一步可得
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对其第 $i$ 行 $\partial u_{\ell,i}^{\mathrm{loc}}/\partial \boldsymbol\xi^\Tran$ 应用 atan2/arcsin 链式法则,得本地角对全局角的 Jacobian
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%
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\begin{equation}
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\frac{\partial \alpha_\ell^{\mathrm{loc}}}{\partial x}
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\frac{\partial \boldsymbol\xi_\ell^{\mathrm{loc}}}{\partial \boldsymbol\xi^\Tran}
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=
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\frac{
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u_{\ell,1}^{\mathrm{loc}}\,\dfrac{\partial u_{\ell,2}^{\mathrm{loc}}}{\partial x}
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-
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u_{\ell,2}^{\mathrm{loc}}\,\dfrac{\partial u_{\ell,1}^{\mathrm{loc}}}{\partial x}
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}{
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\big(u_{\ell,1}^{\mathrm{loc}}\big)^2 + \big(u_{\ell,2}^{\mathrm{loc}}\big)^2
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},
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\qquad
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\frac{\partial \beta_\ell^{\mathrm{loc}}}{\partial x}
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=
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\frac{\dfrac{\partial u_{\ell,3}^{\mathrm{loc}}}{\partial x}}{\sqrt{1-\big(u_{\ell,3}^{\mathrm{loc}}\big)^2}}.
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\begin{bmatrix}
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\dfrac{
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u_{\ell,1}^{\mathrm{loc}}\,\dfrac{\partial u_{\ell,2}^{\mathrm{loc}}}{\partial \boldsymbol\xi^\Tran}
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-
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u_{\ell,2}^{\mathrm{loc}}\,\dfrac{\partial u_{\ell,1}^{\mathrm{loc}}}{\partial \boldsymbol\xi^\Tran}
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}{
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\big(u_{\ell,1}^{\mathrm{loc}}\big)^2 + \big(u_{\ell,2}^{\mathrm{loc}}\big)^2
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}
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\\[1.2em]
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\dfrac{\partial u_{\ell,3}^{\mathrm{loc}}/\partial \boldsymbol\xi^\Tran}{\sqrt{1-\big(u_{\ell,3}^{\mathrm{loc}}\big)^2}}
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\end{bmatrix}
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\in\mathbb R^{2\times2},
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\label{eq:A6_local_angle_chain}
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\end{equation}
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%
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其中 $\partial u_{\ell,i}^{\mathrm{loc}}/\partial\boldsymbol\xi^\Tran$ 为 \eqref{eq:A6_uloc_jac} 的第 $i$ 行。
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记局部阵列导向矢量关于局部方位角和局部俯仰角的一阶导数分别为
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阵列导向矢量 $\mathbf a_\ell$ 仅通过本地角 $\boldsymbol\xi_\ell^{\mathrm{loc}}$ 进入,其关于本地角的 Jacobian(阵列流形 Jacobian)为
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%
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\begin{equation}
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\dot{\mathbf a}_{\ell,\alpha}
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\triangleq
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\frac{\partial \mathbf a_\ell}{\partial \alpha_\ell^{\mathrm{loc}}},
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\qquad
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\dot{\mathbf a}_{\ell,\beta}
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\triangleq
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\frac{\partial \mathbf a_\ell}{\partial \beta_\ell^{\mathrm{loc}}}.
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\frac{\partial \mathbf a_\ell}{\partial (\boldsymbol\xi_\ell^{\mathrm{loc}})^\Tran}
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=
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\begin{bmatrix}
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\dfrac{\partial \mathbf a_\ell}{\partial \alpha_\ell^{\mathrm{loc}}}
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&
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\dfrac{\partial \mathbf a_\ell}{\partial \beta_\ell^{\mathrm{loc}}}
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\end{bmatrix}
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\in\mathbb C^{M_\ell\times2}.
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\label{eq:A6_a_local_jac}
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\end{equation}
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%
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则对任意 $x\in\{\alpha,\beta\}$,根据链式法则有
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由链式法则,$\mathbf a_\ell$ 关于全局角的 Jacobian 为
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%
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\begin{equation}
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\mathbf a_{\ell,x}
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\triangleq
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\frac{\partial \mathbf a_\ell(\boldsymbol\xi)}{\partial x}
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\frac{\partial \mathbf a_\ell}{\partial \boldsymbol\xi^\Tran}
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=
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\dot{\mathbf a}_{\ell,\alpha}\frac{\partial \alpha_\ell^{\mathrm{loc}}}{\partial x}
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+
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\dot{\mathbf a}_{\ell,\beta}\frac{\partial \beta_\ell^{\mathrm{loc}}}{\partial x}.
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\frac{\partial \mathbf a_\ell}{\partial (\boldsymbol\xi_\ell^{\mathrm{loc}})^\Tran}
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\,
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\frac{\partial \boldsymbol\xi_\ell^{\mathrm{loc}}}{\partial \boldsymbol\xi^\Tran}
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\in\mathbb C^{M_\ell\times2}.
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\label{eq:A6_da_chain}
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\end{equation}
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@@ -305,82 +293,49 @@ $\partial\nu_{\ell_{\mathrm{ref}}}/\partial\beta=0$。若改用别的等价参
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\qquad t=0,1,\ldots,T-1.
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\end{equation}
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%
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因此其关于 $\nu_\ell$ 的导数为
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因此其关于链路 Doppler $\nu_\ell$ 的导数为
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%
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\begin{equation}
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\dot{\mathbf q}_\ell
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\triangleq
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\frac{\partial \mathbf q_\ell}{\partial \nu_\ell}
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=
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j\,\operatorname{diag}(0,1,\ldots,T-1)\,\mathbf q_\ell.
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j\,\operatorname{diag}(0,1,\ldots,T-1)\,\mathbf q_\ell
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\in\mathbb C^{T\times1}.
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\label{eq:A6_qdot}
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\end{equation}
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%
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从而对任意 $x\in\{\alpha,\beta\}$,有
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由 Doppler 链 $\nu_\ell=\nu_{\mathrm{ref}}+\Delta\nu_\ell(\boldsymbol\xi)$,$\mathbf q_\ell$ 关于主参数的 Jacobian 为
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%
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\begin{equation}
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\mathbf q_{\ell,x}
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\triangleq
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\frac{\partial \mathbf q_\ell}{\partial x}
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\frac{\partial \mathbf q_\ell}{\partial \boldsymbol\eta^\Tran}
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=
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\dot{\mathbf q}_\ell\frac{\partial \nu_\ell}{\partial x},
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\qquad
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\mathbf q_{\ell,\nu}
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\triangleq
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\frac{\partial \mathbf q_\ell}{\partial \nu_{\mathrm{ref}}}
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=
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\dot{\mathbf q}_\ell\frac{\partial \nu_\ell}{\partial \nu_{\mathrm{ref}}}
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=
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\dot{\mathbf q}_\ell.
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\frac{\partial \mathbf q_\ell}{\partial \nu_\ell}
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\,
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\frac{\partial \nu_\ell}{\partial \boldsymbol\eta^\Tran}
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\in\mathbb C^{T\times3},
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\label{eq:A6_dq}
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\end{equation}
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%
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其中最后一步同样利用了
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$\partial \nu_\ell/\partial \nu_{\mathrm{ref}}=1$。
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其中 $\partial\nu_\ell/\partial\boldsymbol\eta^\Tran$ 取 \eqref{eq:A6_domega};其角度部分记 $\partial\mathbf q_\ell/\partial\boldsymbol\xi^\Tran=(\partial\mathbf q_\ell/\partial\nu_\ell)\,(\partial\nu_\ell/\partial\boldsymbol\xi^\Tran)\in\mathbb C^{T\times2}$,$\nu_{\mathrm{ref}}$ 列因 $\partial\nu_\ell/\partial\nu_{\mathrm{ref}}=1$ 即 $\partial\mathbf q_\ell/\partial\nu_\ell$。
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对空时导向向量
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$\mathbf g_\ell=\mathbf q_\ell\otimes \mathbf a_\ell$
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应用 Kronecker 积求导法则,可得
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%
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\begin{equation}
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\mathbf d_{\ell,\alpha}
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\triangleq
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\frac{\partial \mathbf g_\ell}{\partial \alpha}
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=
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\mathbf q_\ell \otimes \mathbf a_{\ell,\alpha}
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+
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\mathbf q_{\ell,\alpha} \otimes \mathbf a_\ell,
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\end{equation}
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\begin{equation}
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\mathbf d_{\ell,\beta}
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\triangleq
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\frac{\partial \mathbf g_\ell}{\partial \beta}
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=
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\mathbf q_\ell \otimes \mathbf a_{\ell,\beta}
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+
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\mathbf q_{\ell,\beta} \otimes \mathbf a_\ell,
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\end{equation}
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\begin{equation}
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\mathbf d_{\ell,\nu}
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\triangleq
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\frac{\partial \mathbf g_\ell}{\partial \nu_{\mathrm{ref}}}
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=
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\mathbf q_{\ell,\nu} \otimes \mathbf a_\ell
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=
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\dot{\mathbf q}_\ell \otimes \mathbf a_\ell.
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\end{equation}
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%
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进一步定义
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对空时导向向量 $\mathbf g_\ell=\mathbf q_\ell\otimes \mathbf a_\ell$ 应用 Kronecker 积求导法则。注意 $\mathbf a_\ell$ 不依赖 $\nu_{\mathrm{ref}}$、$\mathbf q_\ell$ 不依赖角度,其关于主参数 $\boldsymbol\eta$ 的 Jacobian 按角度块与 $\nu_{\mathrm{ref}}$ 列分块为
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%
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\begin{equation}
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\mathbf D_\ell
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\triangleq
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\frac{\partial \mathbf g_\ell}{\partial \boldsymbol\eta^\Tran}
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=
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\begin{bmatrix}
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\mathbf d_{\ell,\alpha} & \mathbf d_{\ell,\beta} & \mathbf d_{\ell,\nu}
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\mathbf q_\ell\otimes\dfrac{\partial \mathbf a_\ell}{\partial \boldsymbol\xi^\Tran}
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+
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\dfrac{\partial \mathbf q_\ell}{\partial \boldsymbol\xi^\Tran}\otimes\mathbf a_\ell
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&
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\dfrac{\partial \mathbf q_\ell}{\partial \nu_\ell}\otimes\mathbf a_\ell
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\end{bmatrix}
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\in \mathbb C^{M_\ell T \times 3}.
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\in \mathbb C^{M_\ell T \times 3},
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\label{eq:A6_Dl}
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\end{equation}
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%
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其中角度块(前两列)由 \eqref{eq:A6_da_chain} 与 \eqref{eq:A6_dq} 的角度部分给出,$\nu_{\mathrm{ref}}$ 列(第三列)因 $\partial\mathbf a_\ell/\partial\nu_{\mathrm{ref}}=\mathbf 0$ 简化为 $(\partial\mathbf q_\ell/\partial\nu_\ell)\otimes\mathbf a_\ell$。此处用到 Kronecker 混合积:$\mathbf q_\ell\otimes(\partial\mathbf a_\ell/\partial\boldsymbol\xi^\Tran)$ 的第 $k$ 列为 $\mathbf q_\ell\otimes[\partial\mathbf a_\ell/\partial\boldsymbol\xi^\Tran]_{:,k}$,$(\partial\mathbf q_\ell/\partial\boldsymbol\xi^\Tran)\otimes\mathbf a_\ell$ 同理。
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\subsubsection{Fisher 信息矩阵的分块构造}
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@@ -751,9 +706,10 @@ $\mathbf J_{\psi,\ell}$ 的实参数化二维实子空间与复矩阵 $\mathbf G
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\mathcal P_{\mathbf G_\ell}^\perp
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\mathbf D_{\ell,k'}
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\Big\}.
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\label{eq:E2_Ieff_block}
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\end{equation}
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%
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复系数 $\zeta_{\ell,k}^*\zeta_{\ell,k'}$ 必须保留在 $\Re\{\cdot\}$ 内,因为它和右侧厄米积都是一般复值,不能逐因子取实部。$K=1$ 时 $\zeta_\ell^*\zeta_\ell=|\zeta_\ell|^2$ 退化为实数,可提到 $\Re\{\cdot\}$ 外,此时上式即回到 \eqref{eq:A6_Ieff_final} 的单用户基线。
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复系数 $\zeta_{\ell,k}^*\zeta_{\ell,k'}$ 必须保留在 $\Re\{\cdot\}$ 内,因为它和右侧厄米积都是一般复值,不能逐因子取实部。$K=1$ 时 $\zeta_\ell^*\zeta_\ell=|\zeta_\ell|^2$ 退化为实数,可提到 $\Re\{\cdot\}$ 外,此时 \eqref{eq:E2_Ieff_block} 即回到 \eqref{eq:A6_Ieff_final} 的单用户基线。
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\subsubsection{用户分离的可辨识性条件}
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@@ -767,7 +723,7 @@ $\mathbf J_{\psi,\ell}$ 的实参数化二维实子空间与复矩阵 $\mathbf G
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%
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\gls{efim} 非奇异 $\Leftrightarrow$ 联合矩阵 $[\bar{\mathbf J}_{\eta,0}^\Tran,\ldots,\bar{\mathbf J}_{\eta,L-1}^\Tran]^\Tran$ 列满秩,即 ``$3K\le \sum_\ell M_\ell T$ 且不同用户的白化 score 之间不存在跨星全局共线性''。
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正文第~\ref{subsec:userSeparability} 小节给出的几何陈述——``两个用户在所有 $L$ 颗星上相干度 $\rho_{\ell,kk'}\to 1$ 时分离失效''——可由此式严格化:当某对 $(k,k')$ 满足
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正文第~\ref{subsec:userSeparability} 小节给出的几何陈述——``两个用户在所有 $L$ 颗星上相干度 $\rho_{\ell,kk'}\to 1$ 时分离失效''——可严格化为:当某对 $(k,k')$ 满足
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%
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\begin{equation}
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\mathcal P_{\mathbf G_\ell}^\perp\mathbf g_{\ell,k}
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@@ -788,9 +744,10 @@ $\mathbf J_{\psi,\ell}$ 的实参数化二维实子空间与复矩阵 $\mathbf G
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=
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\mathcal I_{\mathrm e}^{-1}(\boldsymbol\eta_{\mathrm{mu}})
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\in\mathbb R^{3K\times 3K}.
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\label{eq:E2_crb_mu}
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\end{equation}
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%
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若只关心第 $k$ 个用户的 \gls{doa} $\boldsymbol\xi_k$,先把上式按 $(\boldsymbol\xi_k,\text{其余})$ 分块再取 Schur 补
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若只关心第 $k$ 个用户的 \gls{doa} $\boldsymbol\xi_k$,先把 \eqref{eq:E2_crb_mu} 按 $(\boldsymbol\xi_k,\text{其余})$ 分块再取 Schur 补
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%
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\begin{equation}
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\operatorname{CRB}(\boldsymbol\xi_k)
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