The purpose of this paper is to describe an approach
which performs data fusion on the output of
multiple, spatially separate, sensors engaged in the
real time tracking of obstacles in a helicopter's
environment. The generated information can be used
either as a flight director aid or as feedback
required by an automatic collision avoidance system.
Obstacle track estimation has been commonly carried
out using the Kalman filter (KF) for linear
estimation, or the extended Kalman filter (EKF) for
use on nonlinear problems. However, certain
assumptions made in the derivation of the EKF
algorithms render it sub-optimal for aerial obstacle
track estimation. Additionally, the EKF has problems
with initialisation and divergence (stability) for
many non-linear processes.
Research at the University of Southampton has
highlighted a link between fuzzy networks and
associative memory neural networks. This link is
important as it allows new learning rules to be
developed for training fuzzy rules, and learning
convergence to be proved. This paper explores
methods of fusion of estimates using neuro-fuzzy
models, and addresses some of the weakness of the
Kalman filter approximation introduced by the
assumptions made in its derivation.