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Study on joint passive localization using time difference of arrival and frequency difference of arrival to improve the accuracy of four-satellite localization

In order to reduce the influence of time-difference-of-arrival measurement error on localization accuracy of time-difference-of-arrival-based four-satellite localization, we first introduce the frequency-difference-of-arrival information to the existing four-satellite time-difference-of-arrival localization algorithm and propose a time-difference-of-arrival/frequency-difference-of-arrival joint four-satellite localization method. The time-difference-of-arrival/frequency-difference-of-arrival localization method can improve the localization accuracy significantly as compared with time-difference-of-arrival localization method. We also derive the geometric dilution of precision of four-satellite localization for precision factor analysis. The simulation results show that, as compared with time-difference-of-arrival localization, absolute position measurement accuracy has little influence on time-difference-of-arrival/frequency-difference-of-arrival localization accuracy. Under the same conditions, the localization accuracy of four-satellite time-difference-of-arrival/frequency-difference-of-arrival is better than that of four-satellite time-difference-of-arrival. And time-difference-of-arrival/frequency-difference-of-arrival localization improves the distribution uniformly of geometric dilution of precision regarding the diamond configuration.