Interactive multiple Kalman filters based 3-D target tracking for two airborne platforms with bearings-only measurements

Target tracking by two airborne platforms with bearings-only measurements has obtained distinct interest recently. It is a nonlinear problem that Kalman filter (KF) can not be applied directly. Using extended Kalman filter (EKF) to solve this problem will get high computational burden involved because the Jacoby and Hessian matrices for the measuring equation should be calculated online. In this paper, the triangular ranging formula is derived for two bearings-only platforms first. Then the location error is proved to be zero mean Gaussian noises. This enables the traditional Kalman filter applicable. To further improve the tracking accuracy, interactive multiple model (IMM) is adopted to estimate the target state from the converted measurements. Simulation for both non-maneuvering and maneuvering target is also included to illustrate the proposed approach has high accuracy with much lower computational burden.