The Implementation Of Global Position System Weak Signal Real Time Processing Based On Field Programmable Gate Arrays

Traditional GPS receiver could not acquire GPS signal resulting into damaging positioning because of weak signal whose Carrier Noise Ratio always under 34 dB-Hz in the bad invironment such as in the urban canyon and especial in the tunnel or indoor environment. Quick positioning technology has a booming future especial in the traffic accident, fire or earthquake, many developed country government have establish the corresponding policy to deal with this issue. The key of this problem is GPS weak signal processing.The emphasis of this thesis was placed on GPS weak signal processing. This paper presented a new acquisition method which uses the batch processing based method instead of traditional series search method to enhance the ability of receiving weak signal and improve the speed of computation. Another algorithm named Double Block Zero Padding was used to accelerate the signal acquisition speed. To improve sensitivity and decrease the probability of losing lock in the traditional Delay Lock Loop signal tracking method the Kalman Filter algorithm was presented. Signals with different Carrier Noise Ratios were designed according to the received raw data. The simulation results confirmed the good performance of the new methods. The paper utilized FPGA technology to implement the primary construction of signal processing aimed to the characteristic of algorithm and carried out the testing with development board. The experiment also showed the feasibility. It was conclude that batch processing based method and DBZP based method performed the strong bility and short time of acquiring GPS weak signal, Kalman Filter algorithm show the high sensitivity and precision.