Design Of High Sensitivity GPS Signal Acquisition Algorithm Optimized For Calculation Amount

With the increasing popularity of Location Based Service(LBS),people need Global Positioning System(GPS)receivers to provide comprehensive positioning and navigation services in both indoor and urban complex environments.Conventional GPS acquisition algorithm has a large amount of calculation in the weak signal scenario,and the design of high sensitivity GPS acquisition algorithm optimized for calculation amount is of great significance.First of all,this thesis studies the effects of signal detection algorithm and parameter search strategy on the acquisition calculation amount and the acquisition sensitivity.Then,this thesis presents a dynamic dwell GPS acquisition strategy(DDAS).The simulation results show that DDAS reduces the number of hypothetical parameters that the GPS acquisiion algorithm needs to search and reduces the amount of acquisition calculation.Secondly,this thesis proposes a convolutional neural network based GPS signal detection algorithm(CEI-NN)that uses convolutional neural networks(CNN)to identify the enveloping characteristics of the acquisition detection.The simulation results show that the CEI-NN reduces the signal integration time required for GPS signal detection and reduces the amount of acquisition caculation.Finally,a software prototype of the CNN based dynamic dwell GPS acquisition algorithm(DD/NN)is implemented based on DDAS and CEI-NN.The acquisition architecture of the prototype is based on folded matched filter and frequency mixer,whose dynamic dwell acquisition is implemented by switching the CEI-NN signal detection algorithm and the MAX-TC signal detection algorithm.In this thesis,Monte Carlo simulations are performed on the DD/NN,Maximum(MAX)and Double Dwell/Maximum(DD/MAX)based on GPS constellation simulator signals.The simulation results show that the acquisition probability of DD/NN is 61% when the received signal power is-146 dBm,which is 20% higher than the MAX and DD/MAX.And the signal acquisition false alarm probability of DD/NN is less than 1%.At the same time,the acquisition calculaton amount of DD/NN is approximately 17.6% of the MAX and 16.6% of the DD/MAX.