一个标量系统的状态方程和观测方程分别为????[????+1]=????????[????]+????[????] ????[????]=????[????]+????[????]。卡尔曼滤波误差方差和预测误差方差分别为????????[????????]=(1−????[????])????????[????????−1]=????????2????????[????????−1????????[????????−1]+????????2、????????[????????−1]=????2????????[????−1????−1]+????????2P_x ̃[k∕k]=(1-K[k]) P_x ̃[k∕k-1]=(σ_w^2) P_x ̃[k∕k-1]/(P_x ̃[k∕k-1]+(σ_w^2) ) P_x ̃[k∕k-1]=(a^2) P_x ̃[k-1∕k-1]+(σ_n^2)，则下列说法中不正确的是： A: 第k时刻的滤波误差方差P_x ̃[k∕k] £ 第k时刻的预测误差方差P_x ̃[k∕k-1] B: 第k时刻的滤波误差方差????????[????????]P_x ̃[k∕k] ³ 第k时刻的预测误差方差????????[????????−1]P_x ̃[k∕k-1] C: 滤波误差方差????????[????????]P_x ̃[k∕k] £观测噪声方差????????2σ_w^2 D: 预测误差方差P_x ̃[k∕k-1] ³扰动噪声方差σ_n^2