只测视线角速度的目标可观性判据

Target observability criteria from bearing-rate-only measurements

在二维平面内,把已有的只测视线角的目标可观判据扩展到只测视线角速度的情况.针对N阶机动目标,在直角坐标系中,通过分析导弹与目标相对运动方程,给出了只有视线角速度量测值情况下目标不可观的充分必要条件(目标不可观判据).目标不可观判据分为两种简单的表达形式:一种是对弹目相对距离的约束;另一种是对视线角的约束.在修正极坐标系中,通过分析系统的Fisher信息阵,得到了在只有视线角速度量测值情况下常加速度目标可观的充分必要条件.结果表明:目标不可观判据与在修正极坐标系中得到的充分必要条件是一致的,与只测视线角的目标可观判据不冲突;推理简单,不要求分析可观性矩阵和非线性微分方程,因此简单易用.

Target observability criteria previously established for bearing-only tracking in two dimensions was extended to that for bearing-rate-only tracking.For unobservability of Nth-order dynamics target from bearing-rate-only measurements,by an analysis of the relative movement equation of missile and target,the necessary and sufficient conditions（target unobservability criteria） were presented in Cartesian coordinates.The unobservability criteria has two simple forms,one is the restriction of relative distance of missile and target,and the other is the restriction of line-of-sight angle.For observability of constant acceleration target from bearing-rate-only measurements,by an analysis of the system fisher information matrix,the necessary and sufficient conditions were obtained in modified polar coordinates.Result shows that the target unobservability criteria is identical with the necessary and sufficient conditions established in modified polar coordinates,and is consistent with the target observability criteria for bearing-only tracking,besides which,is derived easily without examination of an observability matrix and nonlinear differential equations,which fits it for appliance.