Research of weak GPS signal acquisition algorithm

GPS has been broadly applied in every fields of our social life, since the environment around us has been becoming more and more complicated, satellite navigation positioning technology with low SNR gains more and more attention. However, the current GPS signal structure and signal power levels are barely sufficient for indoor applications. Errors due to multi-path and noise associated with weak indoor signals limit the accuracy and availability of GPS in difficult indoor environments. This paper present an overview of GPS positioning technologies based on indoor environments. An adapted acquisition algorithm based on differential correlation is introduced. Analyzes two common methods for improving the SNR of the test statistic: coherent integration (COH) and non-coherent integration (NCH), then points out their disadvantage when used in low-SNR circumstance. By means of math model, the adapted acquisition algorithm based on differential correlation (DF) is introduced in detail. With the help of simulation, the simulation results indicate that this algorithm can acquire GPS signal with low SNR using the shorter time.