Abstract: The direct position estimation (DPE) technology is robust to weak signals and multipath interference, which can overcome the shortcomings of traditional two-step methods that can not work normally in complex environments such as cities with tall buildings and indoors. This paper summarizes and analyzes the research status of the direct position estimation technology from three aspects: theory, implementation and application. According to previous researches, the problems of huge amount of computation, low positioning accuracy, and the need for initialization are summed up in the realization of direct position estimation. A receiver design framework in complex environments is presented in the application layer. The receiver judges whether to use DPE for navigation and positioning according to the signal availability, which can improve the positioning performance of the receiver in complex environments with minimal computational resources.