Design And Simulation Of GPS Receiver Baseband Signal Processing Algorithm

Global Positioning System (GPS) is currently playing a significantly important role in the field of navigation and positioning. With the rapid development of telecommunication and microelectronics industries, GPS receiver, an equipment which receives and processes GPS satellite signals, is undergoing a high-speed evolution. GPS software receiver is getting more and more attentions due to its flexibility, upgradeability, modularity.In-depth researches on GPS receiver signal processing algorithms are conducted in this thesis. A new concept is presented to optimally design a sine look-up table for the first time. In order to solve the question that how to design an optimal sine look-up table of numerically controlled oscillator in a receiver, Fourier series expansion and optimum theory are used. The theory of optimal design of sine look-up table under a given condition is established, the relationship between performance and number of quantization levels is derived too. Both theoretical derivation and simulation results show that for the cases when the numbers of quantization levels are 2 and 4, the losses of energy of coherent integration for optimally-designed sine look-up table are 0.91dB and 0.19dB respectively. Theoretical derivation points out that the loss is not more than 0.014dB for 8-level quantization.For the research on GPS receiver baseband signal processing algorithms, Matlab is used as development platform to create a model of standalone single frequency GPS receiver to implement these functions: signal preanalysis, signal acquisition, fine estimation of Doppler shift, satellite signal tracking, bit synchronization, estimation of CN0, navigation message demodulation and navigation solution. Through dealing with several sets of real signals, it shows that the basic functions of a GPS receiver could be realized by this model.