通过新提出的余切关系定理，解决了单站纯方位观测的非线性问题。
A new cotangent theorem is deduced to solve the nonlinearity for bearing-only measurement .
根据所提出的余切关系定理，实现了纯方位观测的直线运动目标跟踪。
According to the author 's Cotangent relations theorem , bearings-only target tracking with linear motion is achieved .
余切定理