The problem of passive ranging is complex, yet important. This paper f
ormulates it as a nonlinear least squares problem which is solved via
the Newton-Raphson technique. We use the FEED method for rapid prototy
ping and the automatic evaluation of partial derivatives. The paper pr
esents two significant results. (1) The approach leads to rapidly conv
ergent and accurate estimates of position for a variety of different n
oise models. (2) The use of FEED has led to a new and exact solution t
o the question of evaluating the effect of noise on parameter estimate
s without the need to perform Monte Carlo computational experiments. N
onlinear methods such as this require preliminary parameter estimates,
for which we suggest associative memory neural networks.