Abstract: Aiming at the problem of time difference of arrival (TDOA) ambiguity when triple satellites were tracking moving radiation emitter with high pulse repetition frequency (HPRF), this paper proposed a tracking algorithm to resolve TDOA ambiguity based on multiple observation filtering. Firstly, this paper gave the mathematical model of the TDOA ambiguity, including the causes of TDOA ambiguity, the calculation method of the TDOA window and the number of ambiguous TDOAs. Then, ambiguous TDOAs were approximated by the Gaussian Mixed Model (GMM). After that, all ambiguous initial values of filtering were roughly obtained by the localization algorithm based on TDOA of triple satellites, and the cubature Kalman filter (CKF) was combined with the Gaussian sum (GS) filter algorithm to track the radiation emitter under the ambiguous TDOA observation. Finally, the Gaussian components with smaller weights were deleted to reduce the amount of calculation, and the weighted average of last filtering results was taken as the final output. Simulations prove that the proposed algorithm can resolve TDOA ambiguity more effectively than other methods.