Acquisition of beidou-2 signal in the presence of thermal noise, Doppler shift and interference

Abstract

Global navigation satellite systems are enduring for a fast change. GLONASS and GPS which are the oldest satellite navigation system are being revolutionized to meet the current application in the presence of interference, Doppler and thermal noise. Major developments are in the form of increasing the navigation signal frequencies and changing the number of components. In the pursuit for Global navigation operation, Chinese satellite navigation system BeiDou-2 and Europeans satellite navigation system Galileo are under development. China has become the latest entrant into global navigation satellite systems (GNSS) and the research for developing GNSS receivers for BeiDou-2 is experiencing a new upsurge. With the current functionality of the Beiodu-2 constellation and the promise of the complete Global constellation by 2020, efforts have been focused on the 1561.098 MHz B1I signals for the software receiver implementation. In this thesis the acquisition of Beiodu-2 software receiver is implemented by evaluation of Cross Ambiguity Function CAF by FFT based Coherent Parallel Code Search scheme in the presence of Interference, Doppler and Thermal Noise.. The DVB-T device along with active antenna is configured as a front end which provides the digital samples of BeiDou to the host computer for software receiver implementation in terms of the acquisition of Beiodu-2 satellites. The results have been verified by analyzing the sky plots of Beiodu-2 B1I signal of particular sites where Beiodu data was collected. In addition, a Beiodu-2 B1I GNSS signal generator is designed and implemented in Matlab which is to be used for algorithm development and testing. The BeiDou-2 software acquisition part of the receiver is implemented in Matlab and is capable of performing BeiDou satellite acquisition on both actual and simulated data with extreme properties. Interference, Doppler and Thermal noise are the major concerns facing the BeiDou GNSS applications and are important parameters which describes the BeiDou receiver performance. In this thesis the post-correlation carrier to noise ration CNR and carrier to interference ratio CIR for the BeiDou-2 B1I signal is analytically derived. Monte Carlo simulations have been employed to develop the simulation model for the Beiodu-2 receiver acquisition performance. The agreement between theoretical and simulation results supports the validity of the Algorithm.