Research Of High Performance GPS Signal Acquisition Technology

With the global satellite navigation technology widely applied to various areas, highperformance GPS receiver has become a hot spot of the current study, whereas, highperformance GPS signal acquisition technology is the key aspect. Therefore, this paper studyshigh performance GPS signal acquisition technology. The main research work of the paper aresummarized as follows:GPS signal search strategy research. This paper analyzes detection performance anddwell times of a single detector, M/N search detector and Tang search detector. Theexperimental results show on the condition that M/N detector get the best detectionperformance which take M=5, N=8, Tang search detector has better detection performancethan the single detector and5/8search detector, and dwell times is moderate.C/A code fast acquisition algorithm research. GPS signal acquisition is three dimensionalsearch of satellite numbers, code phase and doppler frequency. From reducing acquisitionalgorithm search dimension, this paper designs fast C/A code acquisition algorithm, whichcan cancel search doppler frequency and realize parallel search satellite numbers and codephase. The theoretical analysis and simulation results show that compare with FFT acquisitionalgorithm, signal compression method and delay-and-multiply method, the computation ofdesigned algorithm is reduced to95%、90%and22%, acquisition time is reduced to98%、96%and70%, greatly shorten the acquisition time and improve the acquisition speed.Weak signal acquisition technology research. This paper studies coherent acquisitionalgorithm, non-coherent acquisition algorithm and differential coherent acquisition algorithm,and analyzed computation and sensitivity of these three algorithms. The experimental resultsshow on the condition that integration time is20ms, the sensitivity of differential coherentacquisition algorithm is only less than coherent acquisition algorithm1dB, while thecomputation is only3%of the coherent acquisition algorithm. Therefore, differential coherentacquisition algorithm is the most suitable for acquiring weak GPS signal.Generalized differential acquisition algorithm based on frequency error correctionresearch. Considering carrier frequency offset error of the existed weak signal acquisitionalgorithm affects the correlation function peak, this paper designs the generalized differentialmethod based on frequency error correction, frequency error is introduced into local carrieroscillator in order to reduce frequency offset. Theoretical derivation and simulation resultsshow that compare with differential coherent acquisition algorithm and generalizeddifferential acquisition algorithm, the designed algorithm improve acquisition sensitivity4dBand3dB respectively, and get higher acquisition frequency offset accuracy, has strong noise suppression and has best detection performance.