Reseach Of High-dynamic P Code Rapid Acquisition

GNSS systems (Global Navigation Satellite System) includeAmerican GPS, Russian GLONAS, the European Union’s Galileo systemand China’s Compass (Beidou) system,so GNSS has an important rolewhich can not be ignored in the military, aviation and aerospace. But mostspacecraft work in high dynamic environment that the running speed of thecarrier or its acceleration has a great range. So how to improve the signalreception performance in high dynamic environment has become moreimportant.High dynamic environment, caused by the high-speed movement ofthe GNSS receiver carrier frequency with a lot of the Doppler frequencyshift,brings a lot of difficulties.to the acquisition of the signal.Since theP-code is a long code, long cycle code, so need long time to finishacquisition.But Long acquisition time not only result in the increase of thecomputational complexity of the system, but also will reduce the capacityof the acquisition system for high dynamic endure. So this paper focuseson the research of P code signal acquisition algorithm in the high dynamicenvironment, specific work as follows:1. Introduced GNSS navigation system signal structure and itsacquisition principle,also the principle of the P-code signal generator andsimulate the P-code signal.Than analyzes the influencing factors affect theperformance of the signal acquisition..2. Analysis effect caused by the signal of the Doppler frequency shiftand its Doppler frequency shift to the P-code coherent output in the highdynamic environment.3. Analysis the design which the P code frequency domain FFTparameters fast acquisition in high dynamic environment detailedly,and it’s parameters. In order to better improve the anti-interference ability ofthe system a new improved program that based on the combination ofmultichannel parallel matched filter and FFT P code fast acquisitionscheme has been given. Than do lots of research and analysis the problemssolved by the improve program, and at the same time to do some detailedanalysis of the settings and select all parameters of the program.4. To the question of weak signal in high dynamic environment, the Pcode fast acquisition scheme need dynamic detection. So the acquisitionprogram need to improved.Duffing chaotic oscillator with mathematicalalgorithms acquisition scheme was been given to detect the P code signalfrequency. Duffing chaotic oscillator dynamic fast acquisition system canquickly finish the P code acquisition, and also through the layered arrayDoppler shift compensation to narrow the range of frequency deviation.