Research And Implementation Of Tracking Loop In Multi-Mode GNSS Receiver

With the popularity of GNSS, the receiver has become a hotspot. As known, the premise on which the GNSS receiver works normally is that it can track the satellite signal stably, demodulate the required navigation data information which is used for navigating and positioning. Tracking algorithm is very important in GNSS receiver. This thesis mainly studies the design of tracking loop and algorithm in high dynamic condition.Firstly, the thesis briefly introduces the background of navigation and positioning. Then it describes the function modules of GNSS receiver in detail. The whole process from transmitting the satellite signal to decoding the data in GPS receiver is deduced. The thesis mainly analyzes the design of tracking loop. Several algorithms of the discriminator of FLL, PLL, DLL are compared and then the appropriate algorithm of them is determined for GPS receiver. Loopfilter of FLL, PLL, DLL is researched. In high dynamic condition, the satellite signals will show some new features, which bring about higher requirement of tracking loop better. According to the above, several techniques including 2-nd FLL assisted 3-nd PLL, carried tracking loop assisted code tracking loop, avoiding the dead locking phenomenon of the carrier frequency and INS(Inertial Navigation System) are put forward for high dynamic condition. Finally, tracking loop is realized and simulated. Then the simulation results are provided. Satellite signal is tracked stably when acceleration and quadric acceleration are existed between satellite and receiver. The tracking loop which run stably are all realized in this thesis and meet the requirement of system design.