Research And Application Of Tracking Loop In High-Dynamic Gnss Receiver

With the development and application of global navigation satellite system (GNSS), Researches of receivers for GNSS signals in high-dynamic circumentance have become the hot spots.How to keep the stability of the continuous tracking, how to get the navigation messages successfully and how to get the positions, velocities, and times of receivers especially in the automotive and high dynamic circumstances have become the priority among priorities.Just taking the GPS signal of GNSS signals as an example, the paper first introduces the satellite signal’s composition and generation principle, then introduces three big modules of the high-dynamic GNSS receiver.Meanwhile, It analyzes the whole processing procedure of the signal from the satellite to the receiver.This paper introduces the design of the tracking loop of the receiver. It analyzes the loop discriminators and loop filters, including the derivations of the formulas and the corresponding simulations,and gets the discriminator algorithms’performances,then it finally obtains the suitable discriminator algorithms and filter orders.At the same time, the formulas are derived for the thresholds and the error values of the loops.In the view of the high dynamic circumentance, the strategies of frequency-locked loop auxiliary phase-locked loop, carrier loop auxiliary code loop and inertial navigation system (INS) are presented. Also, in order to ensure the stability and accuracy of tracking, the paper puts forward the strategy of the carrier-smooth-pseudorange. At the same time in the view of the multipath effects, the paper analyzes the effects on tracking loop by the simulations, and puts forward the corresponding methods to weaken multipath effects.In order to save hardware resources,some modules are designated for fixed-point processing especially.Finally, this paper introduces the implementation of the whole tracking process.It sets parameters and simulates the tracking algorithms in software platform. Meanwhile, the paper also gives a comparative testing result under various testing scenarioes using a source system in the hardware platform.Finally it is proved that the design of the tracking loop is the normal and stable.