Abstract: According to the author’s Cotangent relations theorem, bearings-only target tracking with linear motion is achieved. For the single/multiple senor measurements including elevations based target tracking problem, theorems for both target trajectory parameters estimation and tracking are proposed. With the supports from the single sensor bearings, and the elevation constants, target elevations are predicted by estimations of target heading angles and the deduced invariable-information of ratios. Then, target parameters estimation by two sensors measurements is analyzed, and the tracking principium by three-sensor synchronous measurements is discussed. Simulation results show the reliability and the practicability of the peoposed algorithms.

Key words: geometry theorem, single sensor target tracking, angle measurement, trajectory invariable-information