Geolocation of a known-altitude moving source using TDOA and FDOA in the presence of altitude error

Abstract

Using precise source altitude prior information can significantly improve the source geolocation accuracy. However, in practice, the available source altitude may contain certain errors due to the movement of the source, which can affect the geolocation accuracy. This paper considers geolocating a moving source using time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements in the presence of altitude error. The geolocation performance when the known altitude is assumed accurate but in fact has errors is investigated analytically. An efficient closed-form estimator is then developed for localization. The analysis results validate that the proposed closed-form estimator can attain the constrained Cramér-Rao lower bound (CCRLB) over small noise regions. Simulations show good agreement with the theoretical developments and demonstrate the good performance of the proposed geolocation method.