Beidou No. 2 Civil Software Receiver Algorithms And Simulation

In recent years, satellite navigation enjoys a great popularity in social life and military applications because of considerable economic profits. As a result, it becomes one of the three fastest developing information industries. China planned to construct its own satellite navigation system in1983, hoping to establish the system in three steps. In the moment, the second phase is deploying, expecting to complete in2012.The major purpose of the thesis is to study existing baseband algorithms, in order to build the BeiDou-2(BD2) software receiver. Firstly, the composition of the Compass navigation system is briefly introduced. Then, existing acquisition algorithms are listed and compared. A new half-chip based averaging correlation acquisition algorithm is proposed for MEO signals. Simulation shows that the modified algorithm reduce the computation load; however, the code acquisition precision is bounded in half chip. Secondly, delay locked loop (DLL) and phase locked loop (PLL) is analyzed with respect to linear locked loop model, respectively. Some typical discriminators and low pass filters is provided so that it will be more convenient to build the loop. The tracking progress of software tracking loop is verified by simulation. In addition, signal synchronization and positioning theories is also discussed roughly in the paper. Finally, a unified signal processing channel model based on the chosen base-band algorithms is constructed. This model can be configured to deal with any kind of BD2satellite signals. Therefore, the BD2software receiver is able to construct with at least4channels, which is namely multi-channel Compass software-defined receiver. The simulation results show that the receiver can get a satisfying positioning accuracy.