Research Of Quick Positioning Method In BDS Receiver

With the rapid development of global satellite communication technology,satellite navigation and positioning have become key technologies that affect people's daily lives and even national security strategies.The Beidou satellite navigation system independently developed by China has entered the third stage and has been widely used due to its excellent performance and service quality.With the rapid advancement of information technology and living standards,users are increasingly demanding performance requirements for navigation products to be launched quickly.The first positioning time(TTFF)after start-up is a very important performance indicator for satellite navigation receivers,and it also directly affects the user's experience with positioning products.Therefore,based on the Beidou satellite navigation system,this article studies the rapid start technology of the navigation receiver.Aiming at the characteristics of BeiDou satellite navigation system,this paper proposes a quick start method for BeiDou navigation receiver.The reconstructed signal transmission time method is one of the most commonly used methods for the receiver in the hot start mode,but the disadvantages of the method in terms of prior information requirements and errors are also obvious.In this paper,Beidou navigation receiver compares the reconstruction signal transmission time method with the traditional hot start,and points out the limitation of this method,especially the influence of the local clock,whether it is the traditional hot start or reconstructed launch time method.All have a dependency on the local clock.In order to solve this problem,this paper presents a fast start method based on the BeiDou navigation system receiver.This method mainly uses the characteristics of the satellite satellite signal sub-frame synchronization time in BeiDou satellite navigation system to acquire the signal transmission time quickly.In order to judge whether the ephemeris is valid,when the receiver enters the hot start mode,and then use the relative transmission time relationship to construct an equation to solve the receiver position.When the ephemeris is valid and the positioning environment is good,the Beidou navigation receiver can still perform a hot start using this method without the local clock providing the current time,complete the positioning function,reduce the amount of computation,and get rid of the hot start for the local The dependence of the clock has expanded the application environment and application scope of the hot start mode.Finally,the method was verified on the Beidou navigation receiver system platform in the laboratory.After testing,the Beidou navigation receiver achieved rapid start positioning without local clock RTC and network assisted time,and the signal was better.In this case,the first positioning time is similar to the traditional hot start,which verifies the feasibility of the proposed method.