Abstract: A navigation and localization method for a middle- and low-altitude aircraft is proposed which integrates passive localization using pilot signals from a code division multiple access(CDMA) cellular network with an inertial navigation system(INS). The method calculates weighted least squares twice according to the time difference of arrival (TDOA) of pilot signals from a CDMA cellular network, and then utilizes the original information of INS to resolve ambiguity, thus finally accomplishing the three-dimensional real-time localization of the middle- and low-altitude aircraft. In the Gaussian white noise condition, Monte Carlo simulation shows that the algorithm is of high computing speed and high precision, and that the mean square error approaches Cramer-Rao lower bound (CRLB). Hence it provides a theoretical reference for real-time requirements of integrated navigation.

Key words: inertial navigation systems, passive location, CDMA cellular network, time difference of arrival(TDOA), ambiguity resolution, Monte Carlo methods