Instrumental Variable Estimator for 3D Bearings-Only Emitter Localization

This paper develops a closed-form three-dimensional passive bearings-only localization algorithm based on the method of instrumental variables. The proposed localization algorithm is shown to attain a significant reduction in bias and root-mean-square error vis-à-vis orthogonal vector and pseudolinear estimators. It also has less computational requirements than a maximum likelihood estimator thanks to involving no iterative computations that are prone to instability problems. Further complexity reduction is shown to be achievable by averaging bearing measurements over finite-length non-overlapping windows. Simulation studies are provided to illustrate the effectiveness of the proposed instrumental variable estimation algorithm in a radar localization application.