In target tracking with a passive sensor such as infrared seekers, angle-only information is determined. In this case no information about the range of the target is provided and unobservable system is resulted. This paper studies the observability of discrete time three-dimensional bearing-only target tracking. The target is assumed to be moving in a straight line while a single moving observer (own-ship) measures its relative (elevation and azimuth) bearing angles. By transforming the inherently nonlinear bearing measurements into a pseudo-linear form, a linear Least Squares (LS) estimator is formulated. Observability is then analyzed by studying the solvability of the associated LS problem. This approach has the advantage of providing simple unobservability conditions as opposed to other approaches in the continuous time setup. In this paper, most of motivation and problem formulation is taken from [9]. It is shown that for no maneuvering target, at least three independent measured bearings for system observability is required.

Meeting Name

2006 IEEE Conference on Computer Aided Control System Design, 2006 IEEE International Conference on Control Applications, 2006 IEEE International Symposium on Intelligent Control


Electrical and Computer Engineering

Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2006 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 2006