Research On Baseband Algorithms Of Dual-frequency GPS Receiver

The pipeline is the main transport channel for oil and gas, it takes great responsibility of the energytransportation. The pipeline spreads across the country and its safety is the focus of the whole society.While the pipeline may happen to sink or rise, to be moved or even broken because of geological disastersor human destruction. So it is very necessary to monitor the abnormal displacement of the pipeline.In recent years, GPS is widely used because it’s not subject to the climate change, all-weatherautomatic monitoring and high accuracy. Monitoring field has huge demand for dual-band GPS receiver.But dual-band GPS receiver technique is monopolized by United States and Europe’ company. In China,the rcceiver has relied on the import for a long time. The cost severely curtailed the application inMonitoring field.The major difficulty of dual-band GPS receiver lies in tracking GPS L2signal, affected by AS policyof United States Department of Defense, there is only encrypted P(Y) Code modulated in L2band, it’s hardto track L2P(Y) signal. From1999, GPS modernization program has been carried out, civilian code—L2Ccode was added to L2band. The emergence of the L2C signal makes the L2signal easy to use.The paper introduces the structure and its propertiesal of L1C/A signal and L2C signal. Analyse theacquisition algorithm. Acquire GPS L1C/A signal according to its characteristics. Illustrates the traditionalacquisition algorithms are not suitable for L2C signal. Depend on proving traditional algorithm, presenteL1C/A signal aid CM code acquisition algorithm, CM Code aid CL Code acquisition algorithm, CM Codesection superposition acquisition algorithm and CL Code section superposition acquisition algorithm. Thenverify the algorithms by using simulating signals. Analyse PLL and DLL, design tracing loop withsecond-order PLL and second-order DLL, track L1C/A signal and L2C signal successfully. Implement thedual-band GPS basebond algorithm.