| Global Positioning System(GPS)has been widely used in various trades and industries.Highly dynamic GPS receivers can be applied in fields of satellites,aircrafts and bullet trains.But in highly dynamic environment,due to the relative fast motion between GPS receivers and satellites,it is difficult to apply the traditional GPS capture techniques to GPS receivers.This paper analyzes the characteristics of GPS signals and proposes specific capture algorithms which are to provide theoretical support for the capture technology of GPS receivers in highly dynamic environment.Firstly,this paper briefly describes the development of GPS navigation technology,the characteristics of the GPS signals and their mathematical models under such conditions,and then realizes the simulation of GPS signals in highly dynamic environment.Secondly,after analyzing traditional GPS acquisition algorithms,the paper proposes two joint acquisition algorithms of codes and Doppler frequency and one acquisition algorithm of discrete cosine transform domain filtering.Based on the analysis of these algorithms,the paper realizes the algorithm simulation and compares their performances.Finally,the paper makes a comparison of these algorithms in different application scenes with different signal parameters.The simulation results show that:in highly dynamic environment,compared with traditional capture algorithms,these two kinds of joint acquisition algorithms of codes and Doppler frequency and the code acquisition algorithm of discrete cosine transform domain filtering can get better performance in capture accuracy as well as capture probability,they can also meet the requirement of highly dynamic GPS receivers. |
